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UNITED STATES DEPARTMENT OF AGRICULTURE
Contribution from the Bureau of Plant Industry WM. A. TAYLOR, Chief
Washington, D. C.
PROFESSIONAL PAPER
June 26, 1919
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
By J. H. Kempton, Assistant in Crop Acclimatization.
CONTENTS. Page. Page.
Endosperm texture in maize..............-- 1 | Summary of the inheritance of aleurone Crosses between the Algeria and a Chinese color’... 2.233 Sees DE wR SY a He 61
TG ASE SB Se Se er oes ee oe Ee 3 | Correlation between endosperm texture and Third generation of the hybrid Dh 234...... 10 aleurone Colones seen aces ee eee 65 Summary of the progeny of Dh 234.......... 17 | Method of measuring correlations............ 67 Third generation of the hybrid Dh 237...... 17 | Gametic correlations in the two hybrids Dh Crosses between the two hybrids Dh 234 and QZARATAC MD NAS Gps cee ee Nonbs O eae ae eat he 68
2373-6). eo. sodabbodacocoupeedsonooe. 21 | Correlation in the second generation of the Differences in reciprocals. ..:..:-..-2..s.02-: 27 Lays oy a el Day AR YS ee I eal a IE RSIS 69 Summary of the inheritance of waxy endo- Correlation in the second generation of the
JANUS Joe chodes Sudpenctioshsudgosbogpaoeedn 29 hybrid ADE Qs. ese EEE A ER ye 70 Inheritance of aleurone color................. 30 | Correlation in crosses between the two hy- Gametic composition of the two hybrids Dh brids Dhi234 and Dh 2375 25 tees eee 73
SAAT GODIN 237 Shier adel sce - Soc heh eee eS 32 | Correlation in the third generation of the Composition in the second generation of the iy bridh hy 2349 7b 2 ec alas Nas Wins as 75
MUI GD 234 < oS. fo nicisla sw wwices «30 tee te 34 | Correlation in the third generation of the Composition in the second generation of the hy bridhD hy 237k). a, | Ee ee 78
PPM EN 2G, os Be ojos asia aio pci sicyaeisicio aie cic 36 | Second generation of the crosses between the Composition in the third generation of the two hybrids Dh 234 and Dh 237........... 88
Te Wh 2347-67 7). ded. Cae. 39 | Summary of the correlation between endo- Composition in the third generation of the sperm texture and aleurone color.......... 95
|v arc 1D gad oie a Pe i ae AS iil) OCHO es Aaa sc oodrodigcdddscca sod 97 Summary of the hybrid Dh 237............. 50 |) Literature cited; 2 .stiepe- $2 -)[- tien. 99 Progeny of the crosses between the two hy-
DRASHO he2347an duh 23 iieesnee cece eels < - 50
ENDOSPERM TEXTURE IN MAIZE.
In 1908 Mr. G. N. Collins found in a variety of maize imported from China a new type of endosperm which was entirely unlike the endosperms of any other varieties previously known, being neither horny, starchy, nor sweet. This new texture of the endosperm was designated cereous or waxy, which well describes its appearance, the cut surface of the seed resembling a hard wax (3).1
1 Serial numbers in parentheses refer to ‘“ Literature cited,” page 99.
89356°—19—_—_1
2 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
In subsequent breeding work this waxy endosperm was found to. be alternative to horny endosperm, behaving as a recessive character when crossed with American flint and dent varieties. The new endosperm character has proved to be adapted for investigation of some of the problems of heredity in maize. The inheritance is defi- nitely alternative, no blending or intermediate stages having been found. This absence of intergradations between the new waxy endosperm and the other endosperm textures simplifies the classifi- cation of material and renders the numerical relations of this char- acter more definite and hence of more significance than those ob- served with other Mendelian characters of maize thus far studied where intermediates are comparatively common.
In the first crosses that were made the behavior of the waxy endosperm was very similar to that of a Mendelian unit character, the approximation being so close that the deviations were at first con- sidered accidental. But with the progress of the investigation and the accumulation of larger numbers of individuals it became apparent that the deviations from the theoretical Mendelian ratios, though never large, were too definite to be ascribed to chance. It further developed that a correlation existed between the waxy texture of the endosperm and the red and blue colors in the aleurone cells of the Chinese maize in crosses with other varieties. |
This bulletin reports the results of a series of crosses between the Chinese variety and an African pop corn made for the further study of the correlation between the endosperm texture and the color of the aleurone. In these experiments large numbers of seeds were classified with respect to the endosperm and aleurone characters. While the results are in the main similar to those previously reported, the experiments now comprise such large numbers of individuals as to place the deviations from the expected ratios beyond question and also to establish more definitely the existence of the correlation be- tween endosperm texture and aleurone color.
The subject became somewhat involved when it was found that the aleurone color had to be resolved into two factors, and it became necessary to analyze the behavior of correlated characters where the correlations are between factors. In attempting to understand the correlations of the characters, both the theory of reduplication (1) and the linkage theory (11) have been kept in mind.
The experiments have yielded a body of evidence that should be of value in testing the general applicability of current theories of the. segregation or alternative inheritance of characters and also in test- ing explanations that may be advanced in the future. To be of value in this connection, it is necessary that the data should be placed
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 3
on record in the most complete and available form. An effort has been made to tabulate the results in such a way that pedigrees can be traced readily, and it is hoped that the data may have a value apart from the explanations that are suggested or considered in the body of the bulletin.
CROSSES BETWEEN THE ALGERIA AND A CHINESE VARIETY.
FIRST GENERATION.
In 1911, pollen of a plant of the white Chinese variety with waxy endosperm, was used on a plant of a colored variety of pop corn that has been grown under the name Algeria.t| The resulting ear was indistinguishable from pure seed ears of the Algeria, both the aleurone color and the horny texture of the endosperm of the latter showing complete dominance. This hybrid ear received the num- ber Dh 227. :
The same year a cross was made, using the white waxy Chinese variety as the female parent and the Aigeria as ‘the male parent. This hybrid ear received the designation Dh 234,
SECOND GENERATION.
Seeds from Dh 234 and Dh 287 were grown in 1912 and in 1918, and 96 hand-pollinated ears were produced. These 96 ears bore four classes of seeds: Colored waxy, white waxy, colored horny, and white horny. The color of the aleurone is discussed later and may therefore be disregarded in analyzing the inheritance of the endosperm texture. The numerical results are presented in Table I. —
1The original seed of this variety was obtained from Dr. Trabut in Algeria by Mr. W. T. Swingle. Dr. Trabut has recently informed Mr. Swingle that the variety is not an Algerian yariety, having been introduced into Algeria from Morocco. /
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4 BULLETIN 754, U. 8. DEPARTMENT OF AGRICULTURE.
TABLE I.—Inheritance of endosperm texture in 96 ears of maize, the progeny of the twe hybrids Dh 234 and Dh 237.
{Lines bracketed together in pairs indicate ears borne on the same plant; ears selected for planting are designated by an asterisk (*).]
HYBRID DH 234, CHINESE VARIETY X ALGERIA.
Pedigree No. of— Number of seeds. Percent- Self-pol Eoveted! Deca te eee \ = = e - Progeny ear. linated ¢.| Total. | Waxy. ee nce iret 1 2 3 4 5 6 7 8
LOQG Ease mens me Noes see oad 11062 see at 657 160 164 — 4 0.5 24.3 MOOSE ee es eh eS a MOSS see 599 167 149 18 2.5 28.2 TH i mead SEE eae 110StC Tee 533 146 133 13 1.9 27.3 TiO VIS Soe ee ee Aa Se a Self....... 517 129 rsh Meats aes Ieee 24.9 TUUPR3: We GBS £7 Meee pa ed G2 glee PPE dowtis: 272 80 68 12 1.4 29.4 STG) Oy eS 20, aa ee ANSE 573 136 143 eT 1.0 23.7 HUQ ReRE Segoe cas coe cet: Selfassst-5 609 161 152 9 1159) 26.4 THOGHEI SEALE PRL Ue doi. 2t 690 182 172 10 1.3 26.3 fH OS SPER ee oe eee es does 691 183 172 11 1.4 26.4 AHOG ee Mer NORE SE tre LTE. ee 402 86 100 —14 2.3 21.3 AO TRP RE BOS Fe Pee H1Z9H tT) ow 745 204 186 18 2.2 97.5 TUITE DS oS ak a eee Rly nea lea Seite 747 165 186 — 21 2.6 22.2 itt eee en te eee CRS doz. 733 201 183 18 23 27.4 THUS) 2 Ee eae Siac ISa se _s 643 181 160 21 2.8 28.1 TUT SS i I ap 182 428 120 107 13 ei 28.0 TELUS tO i ie eae THE ae 508 137 127 10 1.5 27.9 AUT Geen emt hd ASS Pee 322 83 80 3 5 26.0 TIUE/ 2, Se, ee eee OTS Salis Seeks 564 137 141 — 4 5 24.2 TUS 2k eae 2 ee oe area ay 1 2 dow 623 137 155 — 18 2.4 21.9 TUTTE AD) A SR RR THO goes 414 107 103 4 6 25.8 MDD ee ee a ne TW Geb eee: 655 145 163 — 18 2.4 22.1 LC EOTEE 2 Re eae ees ay Salits wap 687 152 172 — 20 2.6 22.5 TIBI i Oe Iie doen 555 139 130 E 1 gente. See al eaten ee 25.0 IHIGS Cpe Ae ree. yee py 17262 23 510 110 127 — 17 2.6 21.5 TBD Sse Ce eee le ne ey laine Self 605 143 151 — 8 1.1 23.8 Des ae ae et eke oT 132s ee 275 63 69 — 6 12 22.9 TEED aire TE an Selene. 571 119 143 — 24 3.4 20.8 SPA; G5 a ae eae L7QAE ee 773 166 193 — 27 3:3 21.5 TRG 2h BE eS rr Self:-<2c2. 212 45 53 — 8 1.9 21.3 UG RBS peels oi wpe de er 314 W744 2 | ene 522 140 130 10 151i BE VES TSS fey Sie, AC a Self ee 614 143 153 — 10 1.4 23.3 TG OQ Ne eet Tce (iRote 4 Uae bees dO. ccc 334 71 83 — 12 253 21.2 ESO MRC re Seay 1733: 676 133 169 — 36 4.7 19.7 TES la 6 eae 8 a rae Selisee nas 659 149 165 — 16 2.1 22.6 5S DEBI oat MRAM kt bare xe) ', 1720 See 707 151 177 — 26 3.4 21.4 GROSS a aa ae Selinn enn 679 154 170 — 16 Bot 22.7 TESS Seen ete glk Date la Rae DR do:seee 492 107 123 — 16 2.5 e7 15SD Ne 1 74D aN eee 440 100 110 — 10 1.6 22.7 PEGG errs Screed! (h 13 eet ae 725 172 181 — 9 1.1 23.7 TES Ge EUG Pyee ege eae Soli aaaiee 592 136 148 —= 12 TA7, 22.9 ESSE Se ae RS ea ISS cee 609 150 152 — 2 23 24.6 THO eee ate Gee ay ee SF tara | Selfao shee 626 146 156 — 10 1.4 23.3 AQ sess oh oe il An WW86a ae 679 152 170 — 18 2.4 22.4 ALR ee toed dew yar ilies Thy BY eae 631 159 158 1 7 25.2 TUE PA aS ig SEL yale ty ype ae ae 515 120 129 == 9 1.4 23.3 ARR i oS PRE ce a ioe Selina 570 119 142 — 33 4,7 20.9 NAA ems tien hare a Be ore tea. ey 491 111 123 — 12 1.9 22.6 ASAE RE SRY Nee inane Selene cs: 417 101i 104 — 3 5 24.2 fae NY NID ape a fk iy epee 800 205 200 5 U7, 25.0 PAT Ne ok ee ee Ty (eae 633 140 158 — 18 2.5 22.2 AES, See SARA eet TAQ HL 607 146 152 — 6 8 24.0 1549 Ssaqcoconhoe neh osostsecqsgases Self S52 60505906 479 118 120 yay 2 ne 24.6 GSO Wi Ae AO ob ELE 1740 cane 383 79 96 —17 3.0 20.6 GAGS Lk SINS TRS Se Dt Selim co. 578 123 144 — 21 3.0 21.2
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INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 5
TABLE I.—Inheritance of endosperm texture in 96 ears of maize, the progeny of the two hybrids Dh 234 and Dh 287—Continued.
HyYsBrRiIp DH 237, ALGERIA X CHINESE VARIETY.
Pedigree No. of— Number of seeds. Percent- E Ae D+E. age of Progeny ear. eaeee _| Total. | Waxy. Has feat ee ve 1 2 3 4 5 6 q 8 LD PAL Se 18 GSE BR Et OAC ED DOI pe 2 Oe ae 648 139 162 — 23 ByiYl 21.4 LOTTO ip usa a i eae LD Be on A 1 a 672 157 168 — 11 1.5 OB. 8} LO eps Sere 2k ERAN a ore Selfiscco-2- 837 201 209 — aS 9 24.0 IN 7/ SSSR SS Ae Ls Met mA ee 15 eEE ey 723 177 181 ese) ais 24. 4 INGOs e BE Res See oes Selfseeaces 319 80 SOs eae aa ay 25.0 DOR pe care ieee ah ee ma ee LN LO eae 747 180 187 = 8 24.1 ESO SPs i OE EEE APES ARAN | NB po bbe 741 155 185 — 30 Bai) 21.0 TG Ee rapa Be ea ay ee We se Oh iene & eee 58 4 134 146 =I?) 1.7 22.9 DS 2 rere iar tema ny tae astete em aele Soltteees 575 134 144 — 10 1.4 2353 LGR at ie a Ne ee a ge Peale dozsece 758 187 189 =, a4 24.6 RY Se eee ae ae Re eae eg PUTS ee 446 73 111 = 38 6.1 16. 4 LES HRS Sie eS i 8 SS SD a a TR Self......- 627 135 157 — 22 3.0 21.5 TUTTO) Se Wee Aa oe tN es Be ID Bye Ree 615 176 154 29 3.0 28. 6 11) By (eet uae Seca oat 2S ah aval Self aa. 740 193 185 g 1.0 26. 0 LNB Yo) aot epee RT ee Peo al nee LISS Sse a s4 548 140 137 3 4 25.1 Wi20 sys se ae on secre eek SERS Br 459 141 115 % 4,2 30. 7 LPH edt ee Sie alee resect Stetina. Self....... 712 165 178 5/718) 1.7 23. 2 17/77 petal cies Barapa al pani ee Mer 543 eae 677 162 169 ao 9 23.9 OS shape eyes Oe oe oa Olfsss-.2- 664 136 166 — 30 4.0 21.0 1G BIAS” Renee ent EOL Rea eee © 15232 2 ee 374 119 93 26 4.5 31.8 VPS et SA = een COWRA L51Q Swe 472 114 118 A 6 24, 2 720 EASE eee el Self......- 560 122 140 ake 2.6 21.6 PA A SEA fi A Mente act x WO2G Fee 503 110 126 — 16 2.4 21.9 117 (043) rane SOc Ons Sak, MEE Hee Dec OS 533 es 613 169 153 16 2.2 27.1 IPRS Se aaa se Gee eee ee, aa MESO eos cone 401 92 100 = 8 1.4 22.9 LGR 3 PS RE SPR DM” UM eee 1586R2 28 532 126 133 4 1.0 DRY Tl OLE ee tt. See ARTA Lhe NEE ES EP e SB ee 419 95 105 — 10 Weg Qo Paki 8 Ott S SHOT Peer pide 634 161 158 3 4 25.4 U7 bye ees Shee Bane ee eee Re bos 516 119 129 — 10 1.5 23.1 LB Gunes Ae a ee ss, een em 15402. 2 2282 458 102 114 ly 1.9 2253 BOs Ae ee oo A Selfers ee 595 138 149 = 11 1.5 23. 2 7 (EPA ees 9S SR 2 ile dose 472 119 118 1 57) 25, 2 (AON SINE Sal tet EN 5505s ee 630 161 157 4 6 25.6 LCS SO RR ae eae Nag emer Self#seaics2 485 110 121 — il a7, 220 noe ieee) SE Ue 153 eas 559 119 140 5 Ol 3.0 21.3 UE SCR Sa eet Renae area Selly Self....... 575 118 144 — 26 3.7 20. 5 {i745 Soe GOO AEE a ae WEY oscbose 512 133 128 5 8 26. 0 7k SERRE Eb eee eee re ee wr Selftzee: 625 149 156 a 7/ 1.0 23. 8 iar LM AW NSLS Goat We. | eee OO 154755 4..23 621 162 155 7 1.0 26.1 ESS COGS OnE Geese aie ae Selfsseece 658 147 164 Sy Que PPA tes Seo: Ra ee ThASm eto 538 139 134 5 8g) 25.8 WADA SES SER ER costo. Geert Self....... 342 90 85 5 9 26.3 otal AAC oS, Bose dacecoes|\ 2 Z4186 5,779 6, 047 —268 5.9 23.9 ke S—————————S.)| OOS ees S OOS OOOO OOO Total for both hybrids.|............ 54,759 | 13,088 | 13,690 —602 8.8 23.9 ce Sg re on a op are ey
6 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE. EXPLANATION OF TABLE I.
In column 1 of Table I is found the pedigree number of the individual ears. When it so happened that two ears borne on the same plant were pollinated in such a way that they both appear in the same table, they are bracketed together, thus facilitating a com- parison of the behavior of two crosses having the same female parent and different male parents.
Column 2 gives the pedigree number of the ear that resulted from self-pollinating the plant that served as the male parent of the ear in column 1.
Thus, for example, the first two ears were borne on the same plant but were fertilized with pollen secured from different plants. The male parent of ear No. 1099 bore the self-pollinated ear No. 1106, while the male parent of ear No. 1100 bore the self-pollinated ear No. 1103. The seed classes of these self-pollinated ears can be found by referring to Nos. 1106 and 1103, where they occur in their numeri- cal places in column 1.
In column 2 the word “ Self” indicates that the ear represented in column 1 is the result of self-pollination.
As a further example, Nos. 1104 and 1105 may be taken. It is here possible to compare the result of crossing with a sister plant, the behavior of which, when self-pollinated, is shown under No. 1108, with the result of self-fertilizing the same plant.
Columns 3, 4, and 5 are self-explanatory. Column 6 gives the deviation of the observed from the expected number of seeds, on the assumption that horny and waxy were approximating a 3 to 1 ratio.
Column 7 (headed DE) gives the number of times the observed deviation (D) exceeds the probable error (E), and affords a basis for judging whether the difference between the observed and expected is a real or chance deviation. To facilitate the translating of D~E into probabilities, reference may be made to Table II, which shows the values copied without recalculation from Pearl and Miner (12). It was not thought necessary in Table I to include the probable errors, which were calculated by the formula
0.6745./0.25 x 0.75 x ytotal seeds,
since their only present use is in comparison with the deviations.
The 96 ears shown in Table I were the results of self-pollinations, crosses between sister plants, or crosses between the two hybrids. In all cases the expected percentage of waxy seeds was 25. The progeny of the two hybrids have been examined and tabulated separately, but as no significant differences were found between them, it will save space to consider them as a single group.
The 96 ears produced a total of 54,759 seeds, of which 23.9 per cent were waxy. This deviation of 1.1 per cent from the expected
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 7
25 per cent, though seemingly small, is nevertheless 8.8 times the probable error and could be expected to occur as the result of chance only once in over a billion times. The percentage of the individual ears ranged from 16 to 82..
TABLE II.—Probability of occurrence of statistical deviations of different mag- nitudes relative to the probable error.’
Odds against Odds against Odds against we oeeurrente ie occurence ihe cocurtence Deviation of a deviation Demation of a deviation Deviation of a deviation (probable error). pa Bret than || (probable error). or great than || (Probable error). pee ian the designated the designated the designated one. one. one. Obese ses ceseee 1.00 to 1. DeSy eevhert teeter vira 9.89 tol Gi () petermiien sep ee start mtn 142.26 to 1. UN Ua 2 Ae Ua ees Sie 1.18 to 1. VNC GARD eee rete Aiea A 11.58 to 1 7 ERIE eA Rl ats ated 174.75 to 1. lft 2, See an hee Ce 1.39 tol QUST A Sag Sy AN 13.58 to 1 rT Mecee ee ay ANY ai 215.92 to 1. I Seb SSR SrENeS eee 1.63 to 1 DIAS TS) Gg RAMS ae ASE 15.95 tol PAN Se sea ra es ey au BO 267.10 to 1. U6 hse aan See 1.90 tol PAS Vina) Te anny Wy A) 18.80 to 1 AAR CAN inet eS Sa Mage 332,33 to 1. 5 ARES ees eae 2.21 tol BY (Oa ee ee a 22.26 to 1 AB re & Shl hd Babe. 415.67 to 1. 118 Ria ee rae A 2.57 to 1 SHU UI eae aiid 26.40 to 1 Pe oye sieges, aa Al is HE 519.83 to 1. 1-7/5 § RR Oa SOR 2.98 to 1 em, lease a au uit 31.36 to 1. aN Ap Ae fo ON 656.89 to 1. LADS aoe ee ae ae 3.45 to 1 Bee eslscésobousenl pee @ imoyal, ALR Sa sagen SNe 825.45 to 1. HISD A6 Sera eee eS 4.00 to 1 Ca SSC A eae 44.87 tol. Au see) Oi eine caida laps 1051.63 to 1. 2.0/4 SO edie | ates 4,64 to 1 Bs ili ee 53.95 tol BQ it ase vare mat led en 1350.35 to 1. PAILS ae eae A RS 5.38 to 1 Sh es ey eS et eat ed 64.79 tol CoH OR A ous cy de 19,230 to 1. PP ess 5 ean wean mee Bea 6.26 to 1 587 ee CR eta Loa ne 78.37 tol Oeste aes ote 434,782 to 1. AAS. Spee Ek Rea ae 7.28 to 1. SPSS RS EE 95.15 to 1. SO a Rue ae Over a billion. AEN SR Ar, Sa Hes 8.48 to 1. BIO Beker aes i) 116.23 to 1.
1 Copied without recalculation from Pearl and Miner (12).
One ear deviated below the expected by 6.1.times the probable error, but with 96 individuals the odds against a deviation of this magnitude would be about 190 to 1.
A similar shortage of waxy seeds has been observed throughout the experiments with this character.
In a previous publication (7) 45 ears were reported, representing many different crosses and having 22,339 seeds with 23.1 per cent waxy, the deviation from the expected 25 per cent being 9.24 times the probable error. Adding this. group to the results obtained from the second generation of the two hybrids Dh 234 and Dh 237, there is a total of 77,098 seeds, 18,267 of which are waxy, while the ex- pected is 19,274 waxy seeds, a shortage of 1,007+81 seeds, a devia- tion of 12.4 times the probable error. A deviation of this magnitude would be expected to occur as the result of chance only once in well over a billion times.
The approximation of the observed percentage of waxy seeds to the theoretical 25 per cent is very close for the individual ears of the hybrids Dh 234 and Dh 237, only two of the ears deviating by larger amounts than could be reasonably ascribed to chance, and of these one was below and the other above the expected percentage. The large number of individuals involved has made it possible to accurately measure small differences which ordinarily would escape
Sit BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
unchallenged as very good approximations of actual observation to © theory.
The percentages of waxy seeds shown by the individual ears for the first-generation hybrids and those previously reported (7) have been plotted in figure 1, which shows that the deviation from 25 per cent is not the result of a few aberrant ears. It readily can be seen that while the mode and mean are considerably below the expected 25 per cent, the curve very closely approximates the normal prob- ability curve.
Although the graph (fig. 1) bears a striking resemblance to the normal probability curve, there is reason for believing that the indi-
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iG 16) (75 AB AI 20... 2EO C22 23; 24¢- 25.26 27, 28 29 4SOUS i Aa 2asS
Fic. 1.—Diagram showing the percentage of waxy seeds on 141 ears obtained from the second generation of the hybrids Dh 234 and Dh 237 and the ears previously reported. The dotted line shows the probability curve for this ponulawien of 141 ears, the mean and standard deviations being the same.
viduals do not form a homogenous group deviating from a common mean.
Asa means of determining whether the varying percentages of the individual ears are chance deviation from the mean of the entire group, a method has been proposed by ‘Yule (16) by which a theo- retical standard deviation is calculated, based on the harmonic mean of the observed individual ears.
The “ goodness of fit” of the observed standard deviation to the calculated standard deviation is measured by the probable error of the former.
INHERITANCE OF WAXY ENDOSPERM IN MATZE. 9
For the ears in the accompanying graph the calculated standard © deviation is 1.95, and the observed standard deviation is 3.11. The difference is 8.5 times the probable error.
Since 45 of the individual ears represent crosses between the Chinese variety and horny varieties other than the Algeria, it may be well to examine the curve without these ears. Omitting these 45 ears, the standard deviation is reduced to 2.5, the mean remain- ing unchanged at 23.9. The theoretical standard deviation is also slightly reduced. The difference is now 5.2 times the probable error, a difference still too large to be ascribed to chance.
Thus while the mean percentage of waxy seeds reappearing in the second generation of waxy X horny hybrids is 23.9, which is too large a deviation from 25 per cent to be ascribed to chance, the indi- vidual ear approximations are not sufficiently close to the observed mean to be considered as chance departures from it. The explana- tion that at once presents itself is that through mistakes in classifica- tion a varying number of waxy seeds were being included in the horny group.
Endosperm texture is not subject to the minute spotting encoun- tered in the aleurone color, and in the series of crosses here reported the classes were unusually good, owing to the fact that the Algeria parent was a pop corn and had a minimum of soft starch. Two instances where the endosperm was part horny and part waxy have been reported (5) and four additional seeds have since been found. When these mosaic seeds were planted and self-pollinated, they be- haved as normal seeds heterozygous for horny endosperm.
Since mosaic endosperms are known to occur, it is of course con- ceivable that the horny or waxy portion of the seeds may be so reduced as to escape detection, but since such seeds are heterozygous, the only result could be to erroneously class heterozygous seeds as waxy, but this would increase rather than diminish the number of seeds classed as waxy.
A deficiency in the number of individuals with the recessive character does not readily admit of the explanation that the devia- tion is due to mistakes in classification. Such an explanation would require that some of the individuals exhibiting the dominant char- acter were in reality homozygous recessives. Where a deficiency in the number of individuals with the dominant character occurs, such deviation could be the result of mistakes in classification, since it is conceivable that a failure or a partial failure of dominance results in some individuals exhibiting the dominant character to such a slight degree as to pass for homozygous recessives. If waxy seeds were being included in the horny group, some all-waxy ears would be se- cured in self-pollinating plants grown from the horny séeds.
10 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
Since the deviation observed was approximately 1 per cent, only one ear of every hundred would be expected to be all waxy. Several hundred ears, the result of self-pollinating plants grown from the horny seeds of waxy X horny hybrids, have been secured, but no all-waxy ears have been found.
The shortage of waxy seeds not only occurs where the expected ratio of horny to waxy is 3 to 1, but was also observed in crosses between waxy endosperm and aie: endosperm where the Mendelian dihybrid ratio was expected (8). Here the deviation was 1 per cent below the expected 18.75, and it should not occur as the result of chance oftener than once in 15,000 times.
THIRD GENERATION OF THE HYBRID DH 234.
Three ears were selected for planting from the hybrid Dh 284. These three ears are Nos. 1099, 1110, and 1111 in Table I. The last two ears were borne on the same plant. Ear No. 1110 repre- sents a cross between the two hybrids and is discussed later, with the results from a similar ear taken from the hybrid Dh 2387,
One of the two ears remaining, No. 1111, was self-pollinated, while No. 1099 was the result of pollen from another plant of the same hybrid. Both of these ears were close approximations of the expected 25 per cent waxy, as was also a self-pollinated ear secured from the male parent of No. 1099.
There were four classes of seeds on Nos. 1099 and 1111, colored and white horny and colored and white waxy. These classes were planted separately, and reciprocal crosses were made between white waxy and colored horny and colored waxy and white horny plants. Wher- ever possible, self-pollinated ears were secured from all the classes, but since the self-pollinated plants grown from waxy seeds resulted in ears all the seeds of which were waxy, these ears do not appear in the tables, |
To avoid unnecessary complications, the inheritance of aleurone color is discussed separately from the behavior of the texture of the endosperm. The color of the aleurone appeared not to affect the behavior of the waxy endosperm as far as the percentage of waxy seeds was concerned. The progenies were examined with this point in mind, but since no differences were found it was not thought nec- essary to discuss the behavior of the colored seeds separately from the behavior of the white seeds.
The results obtained from the progeny of ears Nos. 1099 and 1111 were also examined separately, but presented no significant difference in their behavior, and to avoid unnecessary repetition the progeny of these two ears will be considered together. The progenies of the four classes of seeds from the two ears are separately indicated in Tables III and IV.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 11
WAXY X HORNY.
The ears resulting from pollinating the plants grown from the waxy seeds of pedigree Nos. 1099 and 1111 with plants grown from the horny seeds of these same ears are shown in Table III. Column 1 of Table III gives the pedigree number of the progeny ear of * Dh 234 from which the plants that produced the ears in that section of the table were grown. In this same column will be found symbol letters which indicate the character of the seeds from which the plants that produced the ears in the table were grown. The letters W and @ indicate white or colored aleurone. The symbol used for waxy endosperm is X and for horny endosperm /Z.
The symbols given first indicate the charactér of the seeds from which the female parent of the ears in the table were grown. For
Ped S592 /62/
Fic. 2.—Diagram showing the relations of ears Nos, 1592, 1621, and 1622.
example, the first group of five ears which are separated from the following ears by a total are the result of crossing plants grown from the white waxy (WY) seeds with plants grown from the col- ored horny (CZ) seeds of ear No. 1099. In this group the white waxy plants were used as the female parents. Column 3 in Table III gives the pedigree numbers of the ears representing the recip- rocal cross. The classes of seeds produced by the reciprocals are found in Table IV.
There were 11,724 seeds on the 27 ears shown in Table IIJ. The expectation of waxy seeds was 50 per cent, and the observed percent- age was 49.5. The deviation of 60 seeds is 1.65 times the probable error and can, of course, be ascribed to chance. Three ears deviated from the expected percentage by more than 8 times the probable error, and one ear, No. 1592, showed a deviation above the expectation of 5.7 times the probable error.
j2 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The reciprocal of ear No. 1592 is No. 1621 (Table IV). There was also a self-pollinated ear from the male parent of No. 1592, No. 1622 (Table IV). The relations of these two ears are shown in figure 2.
The difference between the two reciprocal ears is 5.9+2.62 per cent. The self-pollinated ear obtained from the horny parent does not show a significant deviation from 25 per cent. The plant which bore ears Nos. 1621 and 1622 is shown by the cross with waxy to have 60.8 per cent of the male gametes bearing the waxy charac- ter and 54.9 per cent of the female gametes with this character.
The expected result of self-pollinating a plant with such a gametic series would be an ear with 33.4 per cent waxy, from which ear No. 1622 with 28.5 per cent deviates 4.9242.1, a deviation which is not significant. The plant, then, which bore ears Nos. 1621 and 1622 produced an excess of gametes bearing the waxy character, this ex- cess being greater in the male gametes. An excess of male gametes bearing the waxy character is contrary to the results obtained with most of the ears where it was found that the waxy gametes were below instead of above the expected percentage.
The observed excess of waxy seeds on ear No, 1592 might be ex- plained by the assumption that a failure of the dominance of the horny endosperm resulted in some of the heterozygous horny seeds being classified as waxy. Another generation grown from the waxy seeds would throw light on this matter, since if the observed devia- tion was due to a failure of dominance 10 of every 100 plants grown from the waxy seeds, when self-pollinated, would be expected to result in ears with some horny seeds,
HORNY X WAXY.
As the result of pollinating plants grown from the horny seeds with plants grown from the waxy seeds of ears Nos. 1099 and 1111, 39 ears were obtained (Table IV). In this same table are also shown the ears resulting from self-pollinating the heterozygous horny plants. These ears will be discussed later, but it was thought advisable to include them in Table IV, since it makes possible the comparison of the behavior of the horny plants when self-pollinated with their behavior when pollinated with homozygous waxy. AI- though only 2 of the 29 ears deviated from the expected percentage in excess of three times the probable error, the deviation for the total number of seeds is 3.9 times the probable error.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 1
TasBiE I1Il.—IJnheritance of endosperm texture in 27 ears of maize, the waxy X horny progeny of the two ears Nos. 1099 and 1111, the progeny of hybrid Dh 234.
Pedigree No. of— Number of seeds. ; a Man 0 Seog ice PS fy | MN Nee a RAB US EY Ae Ora Per- Parent ear and pedigree No. of Ez DE Conte progeny. Self-polli-| Recipro- x4 | Devia- | B80 nated g..|cal cross. | TOt@l. | Waxy. pected tion Wey y. 1 2 8 4 5 6 v| 8 9 Ear No. 1099, WX x CH: 110) Sk RE eo Re eee 1644..... 1643. ..2 506 227 253 —26 3.4 44,8 UG Ts I) RE ies gente a Seen ane eee eaten Oa ees ee None 230 120 115 5 98 52.2 TGS) DEF ed ee es ee Sie a None do..... 257 109 128 —19 3.51 42.4 TESTS fe el Be aR as ine rei et erie SIEVE do doa 438 220 219 1 14 5u. 2 SG eee ee eA ik rate, LOSSe etree 1632....- 114 56 57 — i 27 49.1 TOG alleges eh eth atta te eiarett steal ictrerte aiais s 1,545 732 772 —40 3.02 47.4 Ear No. 1111, WX X CH: GARR tee et WEE eek FAS 1696..... None... 712 381 356 25 rll 53.5 UGH selene el Ee el Sao are 1644.....]..- Os 96% 286 139 143 — 4 62 48.6 FG Dee te cn RE | IE ELA UO sacelttos Gower 611 302 305 — 8 36 49.4 IPR a sa ean es pee a re ar al ls eeeMl aS UU Sasadllbas doreree 387 202 193 9 1.3 52.2 TG GO a eta athe epee eee None....]...d0....- 600 283 300 —17 2.06 47.2 CUNO) lea eles eget ee a MIG eee Ne ges Pee Phe ae ie 2,596 | 1,307 | 1,298 9 52 50. 4 Ear No. 1099, CX XWH: SG ee ape mee A RAE ee Tole 1596..... 537 283 268 15 1.92 52.7 LISTS) 5 bate cs Seek Le bates aa ee Seracaig None None.. 404 204 202 2 29 50.1 TGP ees Misi ea pete Starter Ep vat 1605..... 1604... 127 53 63 —10 2. 63 41.7 TS ES Ages SORE re Seager tN Me 4 aba None....| None.... 645 327 322 5 258 50.6 TGV (OS eee tye te I Mes Beas SP Bia 1618-35. IIe aae 519 253 259 — 6 .78 48.8 TUGA7(O) Ake oie ee ged eee, Som ce eSB Tah 1610..... 468 221 234 —13 1.78 47.2 TERE y Cates Pee 8 OR op poe Nate 1612..... None 503 246 251 — 5 66 49.0 TIGA AO, doe ED, Std ete, AinY Uday SoC elt elie a ih 6235 eee 406 195 203 — 8 1.17 47.8 TSC sep SR Sabet pete a Me ee Sa i 1620..... 1619..... 580 291 290 1 12 50. 2 115) UNE ag Te SOE Sea eae 16220 1621..... 307 187 153 34 5.7 60. 8 TUS C mredaet puny asian Aarne poe tGI2E See: LGM ene 764 377 382 — 5 53 49.4 Team SS PB SNORE SONU A) PRN RRM DD A ean I 5,260 | 2,637 | 2,630 7 28 50.1 Ear No. 1111, CHXWH: ; 1569) ae ES SE San: Peni None GSA eee 658 329 BOO UIE Ca Ben ae et 50.0 TIGA) acd oe, Sieve ea Reetemeed WO 1687..... 1686..... 403 205 201 4 59 50. 9 GG Tee ose hs te None None 87 45 43 2 . 63 51.7 LGA See eaten Siena Baan Seer (OE. 2 ..d0... 352 170 176 — 6 1.0 48.3 GY (eg ook BAe EAS) penne bho ae G2 eee dose 342 153 171 —18 2.89 44.7 GLOWS 2a DRT Ae en None....} 1690..... 481 224 240 —16 2.16 46.6 TOVREA: WER Ayla! acai ce wine Oe Nantel OMe MOO Na D203 ale26n |) Wel 35h 2e5 48.5 Total of the above four SOUPS Eye se ae Seale | eee ren aac | eae g Bel 11,724 | 5,802 | 5,862 —60 1. 65 49.6
From an examination of the crosses shown in Tables III and IV it is possible to determine whether the male and female gametes bearing waxy endosperm are produced in equal numbers. All the female gametes in Table III were bearing waxy endosperm, so that the results obtained are the ratios prevailing in the male gametes. In Table IV all the male gametes were bearing waxy endosperm, so that the ratios here represent the proportion pre- vailing in the female gametes.
14 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE LV.—IJnheritance of endosperm terture in 39 ears of the horny X wary and 28 ears of the horny X self progeny of the tivo maize ears Nos. 1099 and 1111, the progeny of hybrid Dh 234.
[Lines bracketed together indicate ears borne on the same plant.]
| Pedigree No. oi— Horny X waxy. Horny X self.
| j | | f x A Parent ear and Number ofseeds. : Number of seeds. | ‘: Se Sp eee Sal progeny. pean ios aes ars Ss | bt | = | = nat ite eros ae (ee == . ie] = % se eee | a | BI BEIS| 3 [EE at eE)e|5 | 22 SiIL@ |RElo|F 18 Se 1S |REIB| F]8 E Ela lalalea |e |E ls ljalale i ic. a Blea alan’ 2 Last, Slitie blac 1 2 2 ia | 5 | ia) A oa he | | | Ear No, 1099 i CH xX WX ae BGP Cox | epee ts MES ae ae evens Gaee eM Spon (ears et hey ee is: ee AN waxy t|)*--- Foe | al 227, 214 13 E85) Gag ff ee ed Ree eae (See 2 | 566] 307) 283) 24 2.99 54.2)... | 1625 ee! Se ae eee | fee FS Ce irs ee Ee ! GIG = 3045 _° | Alfiwaxy._[o26._..2 | 497) 273) 248 25) 3.35 ae PS Fa I aa | eras Cae th eel 5 RGD | Sie) ell Of oe Ut ae rea] ee 2s ae (ER Ded FT oat oe | | 213 = 15) 2.25 53.6 aa ts Allwaxy--| 1565.....] 298} 149 qi ea ee iS Dane ee | PSS ae ees ies RSs eS | eee SS eee | es es es nes eee = SeeN's ees Lae: | x03 356 = i Bsa gt Say a : | | ene es | ae Bre Set Se e fs. | ea Soe eal $6371 25.3 All waxy..|22....-.5 | 4241 208 212'— 49.0 Ci eee | Selé..-=. ==: [sence eeeee noose Se ee Gee | | ana OF | Aiteexe ee Be i 65 61 po fe Ae eee eee Meee ie Rat: [eee | 396] 196| 198 — Pres ee eis feed Deed LBac So 1642--—. i Self. <-: ee ae eee Eee ee eee Ee ee | | 1G43<- == 32S! 15522... 511) 263) 256) Cie | eis Repee: EO pies hares fe SS iota eae ee eee: in Cob Se | eal fd ig ad had ph Cea! eee aoe 15. All _.| 1560... 510} 255, 255)... _]..-.- Pi) Gates baer Soe 1646_____-. Safe. 6 - i )Be 2 0 BY Re dete ee ee cre Y ees ee | ay aed s53 PSES | 387} 193 193 wate 7 5) Poetiee Sees peewee areas Fay, Le Does RS (RL) ee | ee ae 5, 239/2, 705 2, 620, 85) 3.48). 51. 6| 4,477 Ear “No. 1099, | pal, | | HX CX: PhO Allwaxy. | 4567.....) 292 =| 146) al 97] SOSA ech See ae [RTT ise eee Ea eee | ee oe ee | gai} 486! 21024! 3.46) 44.2f.... |. i Se pean a Peerin! paaecga te pee SWS | | | 4GO2 see = | Aliwaxy.. None ZI 522 1s 161 — 3 49}; 49. Of. 2-2 |oez = 2 fs e8| eas see eS iis ees RaSoin Ss poset SceeaPe eee as oad eae | 1604-2. | Allwaxy..| 1572...-. Aiea O71 ita sos Rc a ae 6s! i PD) MEM, ies) oe) fee 1605.....-- ee Soares ae © one Heche core ees Se 5 1606 sess | ise None....| 3911 204 195! dl 73 oe page | ee owe Greer | aes 1607. ge eee es See ee = aes ereg Bf 2 AD ger: Hees S 257, 7 64 227-5 | Hel" | etn oe ie ee ae 1610....... None...--- | 1579....- 303 = a 3 “5 aa ee | Peres fea} Be ° Bees ¥ ica Altwasy. 1594 Set | 689 362) a4) is| 2.04] 52.6)... Hiro Sees ee jOcte 1612. | Selfenvece |e frescos bese | ogee ime ek. | “a a 4 112 25 440 3L.1 [5 eee fet oe | sete cae as plete eRe ee oe pee a = a4 .73, 23.9 i a be ee cy eee 416 219' 208 11 1.60 52.6....... eis frets Fe Pk a [i eee Rr ee en ET (eae CP ae OR AM Be Ee ea sl 4 2 14 3.41 32.0 i | i pigeee | All waxy Gs eae: WRC RES: ER <- aes ee 50. O..... |: 22s =
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
15
TABLE 1V.—I/nheritance of endosperm texture in 39 ears of the horny X waxy and 28 ears of the horny X self progeny of the two maize ears Nos. 1099 and 1111, the progeny of hybrid Dh 234—Continued.
Pedigree No. of— Horny X waxy. Horny self. iaaronteacend Number of seeds. 7 Number of seeds. 7 pedigree No. of ; Bs - a progeny. Self-polli- | Recipro- ins Bp, reo BO > nated 3. | cal cross. ~ |e se aie - | Srl ss ia a hm lok] SS] [oe] a bm 1a] 3 oe 3 i S| "S ) 8 a eas ‘¢ © S S is © + | 8 S E| & B B/E le |A]A la e | EF |e |A py 1 2 3 4 5 6 |7| 8 9 10 | 11 | 12 | 18] 14] 15 Ear No. 1099, | WHx CxX— Continued. ICP SaaS All waxy..} 1592. -...- SAS OT Ra A Adela oae lsc aes |etellere seiele Braye ete ete ees M622 racy Glbisaboded dene decoda Meee aoseal shes Man See woeee| 207] > 59} 52) 7] 1.44) 28.5 16 23eee eter All waxy..| 1584....- ADT |e ZO3| 245) LOM L190 | Oo SHO leery ctees a ey iacalcbelesal lage en ee 1 oa eee dosee-ce | None == SYA eXO iB Bil! GPU OO Gee Be saslisnooollaboolsaeaslencode Motalees ec ey | Mba aber a wee! 4,384/2, 2292, 192| 37] 1.66, 50.8| 3,041/ 824) 760| 64] 3.9 | 27.1 Ear No. 1111, ee eo WH X CX 1682524255 All waxy.-.| None AUK BN OPE A Gays (leob aes Manuclosoen soodlseoualbadas. 1O83ee eee Cl Eee ara cate aia, crate aie lfarateieretal| iarererave Vajare ell erevasel| arma alaylate 383}, 83; 96)/—13) 2,27| 21.7 LAG) o1 eae Nees All waxy..| 1663..... CUE OA Wan X: OA eal NE ETO: Se 7 INU ea 9 aa PAR eR MGSO ae el'slre eres ora None... CAPA WP Phe PB i esi ad bee Re Ne el ea aligonod qodis sasellsaeaod 168Gseeecee All waxy. .-| 1665..... SAO OSL So ly S| P2500 | bd 5es- iealee eae cece [ese ars [ere | Neen ses IG6S7E Noo. Selle esata) re ae cis oc meine tet aise ese cin meolena fie eee oles < 565] 145; 141) 4 25.6 1690 Seer All waxy..| 1676..... COO P2987 SOO 2h 25a Gerd es Sle lice ee (ie aan | vere tae aga Ie eet G92 eects CE) De RS es eee ope rm | ea eee a etc aedPteg ray dels le Me 533) 128) 133/— 5} .74) 24.0 PROG ANS e || raretets ejetere as |lerelooia aeyetele 2, 365)1, 196)1,182} 14) .85) 50.6) 1,481} 356) 370)—14! 1, 24.0 Ear No. 111i, j CH XWX 1694.52 3: OMG. secre lier ctarroce re sialfcvereeiael| eter forall a vere I ares ten etree Hite 578) 142) 144)/— 2 24.6 ee Sea All waxy..| None a PAPA I) MG OHSUGSD Bee egal dalisoSsleae 4 lbue ae 1696S ae et SSIS) Wis a Se ae egg i | ak A Heel fae ee Me a | 373]50) O9|kt 793/816 26.5 16982 Fees aS OOLa ated olleincictele alate) trislere seltetlalcu| sletsicia|isia'spelincctotel ioe siete 540} 129) 135)/— 6 23.9 11700 syste All waxy..| None SLU 8 240|F 255 —LO PTS | ASZO Ee SEs | eee ee ea is ee ee ZOO re) 5.<)- Ce Dies pees Sars ease | ete eel Pyle Ks RBG THC 451| 110) 113)/— 3 24.4 TOS: - : 2 .'0.2 All waxy. .; None.. USP A AMO TOT ale eect GPa ee eee clsooleceallyeauaibace. {ih08 Byapniae ye padOues ee COvaes: PAK VAN PLAS Ri Oi eat hoes ee MAAso lsaoae aceleecuolageoee 7{ 0 Sie TiS i A SI Se Sea al ese Ps cen a A 569} 156] 142) 14) 2,05} 27.4 hes, Sa utan All waxy. .| None ADS 240 F229 PV 52| Sable ele ee Ee ladies ei (Pee ee 7h ae Del ey reas eyetio ce seers Acie Sraicll sense sec Teecal is ater alice aie 415 103} 104;— 1 24.8 ae Bese 3 All waxy..| None.. LSU OS OO lich Airey So hed oi O|ieiatavere ell ature, carer are tlt ean [Pei ictal ee a ICIS 12 Be ee es Gove 2 2 ||Bidoris.- TG y G4 SOS SOW SQe Sie see ak eC le he bed a ee US ee do. dork - SOL SC ZEO Vie Bar OLQieee es ae coe. tol ee een CUS ey NDS peel bee dOreee ee Oneea= CRON 6 MeO a Ud a SY aera reas ee A Oe Beecellacoalseaen odes oc ee Sane ee doze: ed Oven 200 ie LSS Wi JAS pe Slels Sol 02,8). 6 52 ct ele ce elas ow. calcite 17) Re stepee Rd Dg ie Gel TIC epee [SHA ol MEAS ml wea Ae | lac aed i FU a 549) 128) 137;/— 9} 1.31] 23.3 BGAN Re betccy eras oh a otek Be mapas 3, 317/1, 687/1,658| 29] 1.5 | 50.9] 3,475| 867) 869|— 2 24.95 Total of the above four groups. .|15, 305 7, 817|7, 653] 164| 3.9 | 51. 0\12, 474|3, 114/3,118|— 4|.....| 25.0
The horny X waxy crosses (Table IV) have a higher percentage of waxy seeds than the waxy X horny crosses (Table III). difference is 14+0.41 per cent, a difference 3.9 times the probable
This
16 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
error. While this difference could be expected as the result of chance once in 116 times, a more detailed examination of the mate- rial indicates that the difference observed for the totals is not thus to be explained. The four groups on Table IV are the reciprocals of the four groups on Table III. Thus the uppermost group on Table IIT is the reciprocal of the uppermost group on Table IV, etc.
A comparison of the four groups on Table III with the corre- sponding four groups on Table IV reveals the fact that in every case the groups on Table III have a lower percentage of waxy seeds. The percentages and probable errors for the four reciprocal groups are shown in Table VY.
TaBLE V.—Inheritance of endosperm texture in the progeny of the two maize ears Nos. 1099 and 1111, by groups as shown in Table III and their recipro- cals as shown in Table IV.
Percentage of waxy seeds.
Progeny of— Nature of cross. ee D +E, : able Reciprocal + oe group. Cross. Difference. ATEN OS O99 ee Aas eee WIE SCH 5 ieee 47.4+0. 89 51.640. 47 42+ 1 4.2 DE ATEN CO SSL pe Se ae ee ORS see 50.4+ .67 50.94 .59 .5 +£0.89 oO) HW ateNO 099) 2 oo See ese CXE XW Sak 50. 1+ .47 50.8+ .51 69+ .69 1.0 ATEN OS Hd see eet ies cues taalan cer GOs Geet ee 48.54 .7 50.6+ .69 2.1 + .98 2.1
PDOUALN ce Pokina hac eae DG SO ola oye 49.64 .31 50.64 .27 Lia 4 3.9
Taking each group by itself, the only significant difference is that observed between the WX X CH and the CH K WX group from ear No. 1099. In this case the difference is 4.2 times the probable error and should occur as the result of chance but, once in 217 times.
As above observed, however, the differences are uniform in that whenever the male parent is heterozygous for horny endosperm and
. the female parent homozygous for waxy endosperm the percentage of
waxy seeds on the ears is lower than in the reciprocal group. This difference in reciprocals indicates a deficiency of effective male gametes bearing the waxy endosperm. This result could be brought about by a higher death rate for the gametes with the waxy char- acter, or a less vigorous growth of the pollen tubes of such gametes, or a failure of the plants to form the gametes in equal numbers.
HORNY X SELF.
As the result of self-pollinating plants grown from the horny seeds of ears Nos. 1099 and 1111, 28 ears were obtained. (Table IV, col- umns 10 to 15.)
The ears resulting from self-pollinating the plants grown from horny seeds show a remarkably close approximation to the expected 25 per cent of waxy inheritance, the two individual ears that devi-
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. Li
ated in excess of three times the probable error being no more than could be expected in a group of 28 ears.
With 12,400 seeds the probable error for a 25 per cent ratio is 0.082 per cent. We may, therefore, feel reasonably certain that if the real ratio deviated from the pepe by as much as three-tenths of 1 per cent the deviation could have been detected. Furthermore, the distribution of the percentages is as uniform as could be expected. Measured by the method proposed by Yule (16), the range is really smaller than the expected. In other and even larger groups it has been shown that there is a deviation of approximately 1 per cent; and since in these groups the deviation from the observed means was greater than the expected, it becomes almost certain that the devia- tions are due to the abnormal behavior of some of the individuals rather than to a small and consistent deviation. It would thus appear that the present group differed from the preceding by includ- ing none or very few of the aberrant individuals.
SUMMARY OF THE PROGENY OF DH 234.
The total number of ears representing the progeny of the hybrid Dh 234 and expected to have 50 per cent of the seeds waxy is 66. These 66 ears had 27,029 seeds with 50.4 per cent waxy, the deviation in this case being about 1.9 times the probable error.
While the observed percentage of waxy seeds for the 66 ears is a very close approximation to the expected percentage, we have seen that the two major groups, waxy X horny and horny X waxy, that make up this total, differ from each other by an amount that would be expected to occur as the result of chance but once in 116 times.
Had the crosses all been made in one direction—i. e., waxy by horny—there would have been a significant deviation below the ex- pected number of waxy seeds. Had the crosses been confined to horny by waxy, the number of waxy seeds would have been in excess. Since the reciprocal crosses were made in approximately the same numbers, the fit of the observed percentage of waxy seeds for the total to the expected percentage appears good.
THIRD GENERATION OF THE HYBRID DH 237.
Four ears were selected for planting from the hybrid Dh 237. These four ears are Nos. 1129, 1130, 1131, and 1134 (Table I).
The last two ears represent crosses between Dh 287 and Dh 234, and their progenies are considered separately following the analysis of the progeny of ears Nos. 1129 and 1130. These last-mentioned ears were borne on the same plant. Ear No. 1129 was the result of self-pollinating a plant of Dh 237, while ear No. 1130 was the result of pollinating this same plant by another plant of the same hybrid.
89356 °—19——2
18 BULLETIN 7}, U. S. DEPARTMENT OF AGRICULTURE.
Ear No. 1129 had 24.1 per cent of waxy seeds, a close approxima- tion to the expected 25 per cent, the deviation being less than the probable error. The deviation of ear No. 1130 was 3.7 times the probable error below 25 per cent. The plant that served as the male parent of ear No. 1130 bore ear No. 1135, the result of self-pollina- tion. The deviation of this ear was also below the expected 25 per cent by three times the probable error. This fact would indi- cate that the low percentage of waxy seeds observed on ear No. 1130 was due to the male parent, since there was also a deficiency of waxy seeds when the male parent was self-pollinated.
TastE V1.—Inheritance of endosperm texture in 20 ears of maize, the wary X horny progeny of the tivo ears Nos. 1129 and 1130, the progeny of hybrid Dh 237.
|
| Pedigree No. of— | Number of seeds.
{
Parent ear and pedigree No. of
- __ @ | centage oety- ‘Se £ poll! Recipro- Total. y Se of beng é-| eal eross. | ~"* wss¥- | 1 hea 9
Ear No. 11%, WX x CH: : SER ee ee ee | 1794.2... 5L2 Yi ee te ee ea gt ee = [}:) | oe Ee 47.0 Re Soe ee eee | 1800... 48.6 7 | 7 SRP eee ne ie Ree SEE ee Bi 7. eee Pee do. 5 +7 LCs pe Se Se el oe eae pie i}. ) | Se Af 2 ile 50.2 cf 7a ed be ee ae er } 1800... | None. 47_2 1 os Ee Se RD ae pee ee (OER MEE REWER 47.9
Ear No. 1130, WX x CH | EE oe ee SS None_..- 45.7 Me et ER eet +. .-do 54.5 oye ie coites 20 Rie le at ee ae __.do 49.5 (il) See SS ae ee ..-d0 54.0 DiS eee ie ies Se Se ya bales ead 1851____- J.) Se 53.0 20) Se ak i ee ae | Nome... -} 5.0 eiigee Ser ee eae 1855 54.3 aged ite AS Ps ER, p32. oe foils wee 52.0
Ear No. 1129, CX x WH | (7 OS ee SE ee a ee Wi74_ 5L4 fie. es ES 77, eee 52.0 177) Le ee ee ee None... 5L4 1 yr) Cee er Een, neuen Bev ca 5L5
Ear No. 1130, CX x WH
1 11S a a ee = le CP eee 1828. _ 2. 48.6 eee Oe ee eee | ina7 2 2.0 127, 7 PUI aN oc ee ater So ee 1}s 7 ease « ‘53.8 ey 2 es oR ee Gee None.... | 835 | = z Bet 2 45.0 Weal 2 ea ee ee O87 | 03s! 2 | y 43.5 Total of the above four groups. ._-_.-._.-.---- eee Sa
If any difference in the behavior of the progenies of Nos. 1129 and 1130 occurred, a lower percentage of waxy seeds on the progeny of ear No. 1130 would be expected. A careful analysis of the progeny with this point in mind failed to reveal any significant differences, sO that the differences observed in the percentage of waxy seeds of the two ears, Nos. 1129 and 1130, must, for the present, be ascribed to
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 19
chance; at least it does not appear to be hereditary. There were four classes of seeds on ears Nos. 1129 and 1130—colored and white waxy and colored and white horny. The four classes from each of these ears were planted separately and are separated in the tabulation, but since no differences appeared in the percentage of seeds with waxy endosperm from the colored and white seeds, they are discussed to- gether. To avoid repetition, the progeny of the two ears are consid- ered together, since the differences found between them were slight. The ears secured from the progeny of ears Nos. 1129 and 1130 are shown in Tables VI and VII. There were no ears with aberrant ratios larger than might be due to chance.
Tarte Vil.—Inheritance of endosperm texture in 26 ears of the horny X wary and 17 ears of the horny X self progeny of the two maize ears Nos. 1129 and 1130, the progeny of hybrid Dh 2387.
[Lines bracketed together in pairs indicate ears borne on the same plant.]
Horny X waxy. Horny X self. Pedigree No. of—
Smal 4 ° < ° Pa rent A a on a Number of seeds. ° Number of seeds. 2 pedigree No. o - - progeny. 3 | ae ro g & ee : Oe a Nocy Aa RG FAS) As Self-polli- | Recipro-} _; | 5 |eR| % SSH lage | Rae 8 Leth os oR nated. | cal cross. 8 a as S t |e g a ag - b |e BS ie ja! ea a ee Ete e py 1 2 3 4 5 6 7 8 9 10 | 11 | 12 | 18 | 14 | 15 Ear No. 1129, WH xX CX: 117/( Pe Bee None..... None AA4SK 209) +224)— V5 2599) 46.6)o 2 <li oe ek Oe ee Cisse, Bat ls On aE ae do 613} 309) 306 STOO IO A Pe sey eet te aees Pa T ye Ica] (ies Micra Ne ECAC: Secs rene SLT | ee aM ar NT cele eS 2 Sa UHL 254 63 64) — 1) 0.01) 24.7 see see None..... 1768....-. HOS ee el SOL iy ah Ol rrdee 2 Is (5. ls ete ea | tia) re | |e aT ee IWS Aes ees Sele hs Aas 2 catia Ses | name aie A eka Ada AT IN 272 80 68 12} 2.50) 29.4 ioe Oe None....- None... ADS) 2209 yi QU Almere he Ser ZeNN aR are te UT UR Ue oat a Be Soe eae SS Ler Some | Bresette Se ate es tera ord ica eee Wet naira a an Ub 319 64 80} —16| 3.07} 20.0 TTL bee None..... None ATO 2O4 those ——se At he 41 AOL |e ee aL alate RET ONT oe 2 SOE ee Seley ah Bet taeain Si cremate | pays ota Elta ate 20 Piaget Sa 4741 114] 118] — 4 63] 23.6 17423 (Se See None ee None ANTM FAB Paty RS a EGA ee oe eo llosceallaersalocane WiS2ass 8 2 FOYE O atesy Se end ESES OE es Aa Fay | rs TC Bp 475; 118] 119} — 1 15} 24.9 117423 eee as Allwaxy..| 1770..... BoP) Alle PASI SIO TO ae ee ee ae SAR ese None..... None 591) 307) 295 SPAN TUS ZeM GHGS C0 fee ee SS Fe Wall bass || gn li7fcla eee ee PSI) ORAS ESR at Lie SPDR La i sae bee |p A | ee 412 90} 103} —13} 2.20) 21.8 1S6on ee None..... None AVG OR DPB TPT TG ee ee ee ol ee ele. iY poetics Nino seanal esa seocer| obs BBO tects ees errs sate rel ener 450; 106} 112) — 6 97, 23.6 17 fc} 2 ee None..... None... SSG |e SO ley] OS males My SiN 4 ee | ego ees [ ee Noes | en eo MotaleK 2/5 oe oe eee 4, 960|2, 434 250 ae 46] 1.89) 49.1|2,656] 635] 664) —29} 1.90) 23.9 Ear No. 1130, ea WAH Xe C2xe- 37 (ee att waxy..}| 1818..... GUN SHO) BAS PAP IAT A Dee ee les Noe ESPACE ie, CicnSel | LSA} LIS Hears iS Fa ere aE OES] CACORE iT Ui Si LS] [Sen ol] et [a 404; 109] 101 8] 1.36] 27.0
‘20 BULLETIN 754, U. 8. DEPARTMENT OF AGRICULTURE.
TasBLeE VII.—Jnheritance of endosperm texture in 26 ears of the horny X wary and 17 ears of the horny X self progeny of the two maize ears Nos. 1129 and 1130, the progeny of hybrid Dh 237—Continued.
Horny X waxy. Horny X self. Pedigree No. of— = Pascnt eiband Number of seeds. S Number of seeds. = pedigree No. of =O “= Fa progeny. — g Sh a r= Ssh FS) AS ces 2. S - jag Self-polli- | Recipro-| _- bm |ee| 3 | A los > S|2e!/ 3 |S /os8 natedg. |calcross.| 3 gl eH) ys ee ate 8S [KR eS e (Pe ae i Ko) Ss 2s >) ro) ° S x= 9) ro) e/EF je jajaja |e] ie 1A] e@ Ie 1 2 3 415) 6 ac) 8 14g, | 10) ett 3S | 0S cies Ear No. 1130, | WH X Cx— Continued Sesto 3 All waxy..|... do.s-.) 4340-216)" 2t7[— tes 4) 4g° elec ce ee ee eee eee ey ae a Cepek ae (a 2 O.. 511) 250) °255|— 5]. 26] 4gro]s ooo. [a a Sea ea pe gee ae dei 1825... _. 503). 254) 25, Sh. S05 Sb fe ee cape see a) Seka Ue daaee IRE Be 297|.127|.°148|— 291-3. 61} 49.9) |. Ob ee ce) aera SFT aera s MEM Deeg (RRS SSS eal Vale eA | EP is FS 541| 126] 135] — 9! 1.32] 93.3 Patil fb. cea eee: 2, 900|1, 433/1,450/— 17} .94| 49.5] 945] 235| 236] — 1] .14] 24.9 Ear No. 1129, CH x W Leer Sige eemtad Lmeece series | A BAONE Secon | coors) Some been omer 634} 172} 158} 14! 1.90 reas ae None....- None.. 553) S680 2276 ——~Sn.1. 01) 48. 5|. alo se | ea Se el ee 1796-7. Caio Bed MIR | BIR E BO S e Se Se 296] 66, 74| — 8| 1.59 Oy fe ek Me None:|..=.|'Nene:-..}, 230] 137) 215p 2) .39| 50.9]-.-..| 21 Se ee 1798... -- CAAT ae Bie | ian See Ree bea) Oe ae es eee ae 752| 194} 188] 6] .75 < mOges 5 None..... 1764..... S10; 262) 255) 7 292) 54). 8. oe ee 1800......- 7 Rg ne eee B Rvae ee ten Bee ae | eS 755} 191) 189} 2) .25 otal aaah Nees Te 1,293| 647| 647)... 2.6 | 50.0|2,437} 623} 609] 14] .97 Ear No. 1130, y CHX WX: : ee ae oe All waxy..| 1804..... 545) 260) 272|— 26 1.520478). fe... -|- =e. epee a Saar a Ab 3 do. 28 None. 2). , 415}: 208|..207|.-- al. .44b 50a). le: =. LSS en eee fetes SF | pee my | SRPMS Sore Wal Shee) Nea Te Sea Sd 308] 75, 77| — 2| .39 it i ARE 5 All waxy:.|\Nene....|- 537] 282) 268|¢ 24) 4.79) 52.6): ..--}2---s)2e ‘ BRAG 2 se do she ee doe 23) | 621)! 205) S10) = 517259) 49s0 eee he eee 2 oes i S47. 2: Sele... 00. WOUa! We ap RARE ees ey pear inne ts (ae 721| 155) 180| —25} 3.19 ; ASAE ee a All waxy..| 1815...-- 581} 299) 290 9} 1.15) 51.4)..... | i230. 20 i ee eee ' 1a gaa: 1813... 561] < 273) 230|— 7}. 87) 48.7]. ese. |e ee ! 77) eee Salt. ot... |). oll eee pe Oe ee ei eae 547) 126] 137| ii] 1.61 i oi eet All waxy..| 1816..... 614) 306) 307;— 1b 12) 4938 | eee il i ed eee Selene. 2.22 tLe Oe eee ae ee ee 563} 132) 141) — 9} 1.30] 23.5 fh = Es pe ee eee eee ae Ss eS i Get Mieke fii ta Seed ee: 3, 874|1, 933|1,937|\— 4] .19| 49.9|2,139} 488] 535| —47| 3.48} 22.8 ? ? | | i Total of the above four ed 6, 7 6,513|— 1.71| 49.518, ee 2,044) —63| 2.40) 24.3 The four groups in Table VII are the reciprocals of the four f . . : i groups in Table VI. The first group in Table Vlis WX X CH from , ear No. 1129 and the first group in Table VII is WH X CX from the
same ear.
Since one parent was homozygous for waxy endosperm, it be- comes possible to test whether the same ratio of waxy to horny genes is found in the male gametes as in the female gametes of the heterozygous parent.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 21
The percentage of waxy seeds in Table VI is the percentage of male gametes bearing this character, while the percentage of waxy seeds in Table VII is the percentage of female gametes bearing the waxy character.
The difference between these reciprocal groups is very small, indi- cating that for the progeny of the hybrid Dh 2387 there is little or no difference in the percentage of male and female gametes bearing waxy endosperm.
The fact is further demonstrated when the individual groups are examined. Table VIII gives the percentage of waxy seeds for the four pairs of reciprocals, with the differences between them.
Taste VIII.—IJnheritance of endosperm texture in the progeny of the two
maize ears Nos. 1129 and 1130, by groups as shown in Table VI and their reciprocals as shown in Table VII.
Percentage of waxy seeds.
Progeny of— Nature of cross. ade = ; D = &E, Table eciproca é group. cross. Difference. ALIN O Wl 29 ane scnitciswicie viele e\ PV Nd Oc eee 47.9+0. 64 50. 0-0. 94 2.141. 14 1.85 HAT NOMS OS Shee oe wistcarcate|iaateras Gost Ree fees 52.0+ .63 49.9+ .54 2.14 .83 2.53 ATYNOWI29 = ecco sciewrctctecccice COX XW Fh eee 51.5+1.00 49.14 .68 2.141. 21 116783 HariNo alls ewes cesussemecel cue Oke cee 49.54 .74 AQ U5 Fs OSs] ae tc ae nena |e epee ree Notaltes el [eee dente BED CG E [Bes eae 49.94 .36 49.54 .3 At .47 285
In the first instance the percentage of waxy seeds is lower when heterozygous plants were used as male parents, but in the next two pairs of reciprocals this condition was reversed, the percentage of waxy seeds being higher when heterozygous plants were used as the male parents.
In none of the pairs of reciprocals was a significant difference found, so that the percentage of male and female gametes bearing waxy endosperm may be said to be alike for the progeny of the hybrid Dh 287.
In this regard the progeny of the two hybrids differ. The progeny of the hybrid Dh 234 showed that a significant deficiency of male gametes bearing the waxy character occurred, while no such de- ficiency is found on the progeny of the hybrid Dh 237,
CROSSES BETWEEN THE TWO HYBRIDS DH 234 AND DH 237.
Three of the ears that were selected for planting were the result of crossing the two hybrids Dh 234 and Dh 237. These ears are Nos. 1110, 1131, and 1134 (Table I).
As only self-pollinated ears were secured from ear No. 1131, the progeny of this ear is discussed separately from the progenies of ears Nos. 1110 and 1134.
a
Se ae
Sareea Sa
we
ee a Se ee
= -> =
992 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
Ear No. 1131 had 22.9 per cent waxy seeds, while self-pollinated ears secured from the male and female parents had 24.2 and 23.3 per cent waxy, respectively, as shown by the following diagram:
Pedigree No. 1132 (Table I), 23.34+1.2 per cent waxy
Hybrid Dh 237 wen ay ae ee TET ie)
*—\ Pedigree No. 1131 (Table I), 22.941.2 per cent waxy. Hepad Dh 334/004 Self. Pedigree No. 1117 (Table I), 24.241.2 per cent waxy.
As can be seen from the diagram, neither of the parents of ear No. 1131 deviated from the expected 25 per cent by a larger per- centage than could be ascribed to chance, although both parents, as well as ear No. 1131, were below the expected percentage.
As ear No. 1131 was all colored, there were only two classes’ of seeds, horny and waxy. These were planted separately and self- fertilized by tubing (6). The waxy seeds when self-pollinated resulted in all waxy ears. Such ears, therefore, were not tabulated.
HORNY.
Four ears that were the result of self-pollinating horny plants were secured from the horny group. These ears are shown in Table IX.
Two ears were above and two below the expected 25 per cent of waxy seeds. The deviation on all of these ears could be ascribed to chance. The four ears had a total of 1,055 seeds, with 24.3 per cent waxy, the deviation of 0.7 per cent being 0.74 times the probable error. TABLE I1X.—Jnheritance of endosperm texture in ears Nos. 1893, 1894, 1895, and
1897, the progeny of maize ear No. 1131, self-pollinated, the progeny of @ cross between the hybrids Dh 234 and Dh 237.
Number of seeds. |
| D+E Percentage
Pedigree. Geers
‘ Expected ae Z
Total. | Waxy. waxy. Deviation. |
94 84 | 10 | 1.61 27.9
No, 1893...--------------- 337 4 6 7 Ear N QO, 1894 FE) Ih 261 rss) 65 —10 Ap 83 21. 1 Ear No, 1895. .---------------- 33 11 8 3 i. 55 30.0 Ear No, 1897..---------------- 424 97 106 — 9| 1.51 22.6 Total.....-------------- 1, 055 257 | 264 7 ¥/ 74 | 24.3 Cee ea ee ee ee SS SS
There are two remaining ears that represent crosses between the two hybrids Dh 234 and Dh 237. These ears are Nos. 1110 and 1134 (Table I), as shown by the following diagram:
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 93
Pedigree No. 1111 (Table I), 22.2+1.0 per cent waxy. Hybrid Dh 234 ole. | ~ Fay Pedigree No. 1110 (Table I), 27.5+1.1 per cent waxy.
Hybrid Dh Hiya io
Self, Pedigree No. 1132 (Table I), 23.3+1.2 per cent waxy.
Pedigree No. 1133 (Table I), 24.6+1.0 per cent waxy.
Hybrid Dh 237 Gi Te asa een Te
— No. 1134 (Table I), 16.8+1.2 per cent waxy.
Hybrid Dh 234/7° - »~ Self, Pedigree No. 1118 (Table I), 21.9+1.1 per cent waxy.
Kar No. 1110 and the two self-pollinated ears secured from the parents are all approximations of the expected 25 per cent. This is not true of ear No. 1134. The diagram shows that the female parent of the self-pollinated ear No. 1134 was a close approximation to the expected 25 per cent, while the self-pollinated ear from the male parent was below the expected by 3.1 per cent, which is almost three times the probable error. Although both parents could reasonably be said to approximate the expected 25 per cent, ear No. 1134 is below the expected by 8.7 per cent, which is 6.1 times the probable error.
There seems to be no very good explanation of this departure, either the female gametes selected male gametes bearing the horny endosperm or a differential death rate prevailed for the zygotes with waxy endosperm.
There was no difference in the behavior of the progeny of ears Nos. 1110 and 1134. The ears secured from self-pollinating plants grown from the horny seeds of No. 1134 bore 2,277 seeds, of which 25.5 per cent were waxy, the deviation being less than the probable error. Only one ear of the five secured deviated in excess of three times the probable error, and that ear, No. 1923 (Table XI), was in excess of the expected.
The 10 ears representing the progeny of ear No. 1134 that were ex- pected to have an equal number of waxy and horny seeds had 4,943 seeds, with 49 per cent waxy. The deviation of 1 per cent is but 2.1 times the probable error. The progeny of ear No. 1134 failed to throw any light on the observed deficiency of waxy seeds in the parent ear. |
The two ears, Nos..1110 and 1134, that represent crosses between the two hybrids had but two classes of seeds, colored horny and colored waxy. These classes were planted separately. As no signifi- cant differences were found in the behavior of the progeny of the two
RNR RINE SM fA Pe BRR RES CE STREP
roa i
a oT
or eee
= 5
24 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
ears, they will be considered together. The ears secured from the progeny of Nos. 1110 and 1134 are shown in tables X and XI. The ears resulting from pollinating homozygous waxy plants with heter- ozygous horny plants are extremely variable. Five of the eleven ears deviated from the expected percentage in excess of three times the probable error. With the exception of the ears shown in Table X the remaining ears show no significant deviation.
Taste X.—IJnheritance of endosperm texture in 11 ears of maize, the wary X horny progeny of ears Nos. 1110 and 1134, the progeny of crosses between hy- brids Dh 234 and Dh 237.
Pedigree No. of— | Number of seed8.
Parent ear and pedigree No. of ae ie progeny. eli- ecip- 3 ; polli- rocal | Total, | Waxy. et tees
nated¢g.]} cross, y- =
1 2 | 3 | 4 5 6 7 Ear No. 1110: | Ree a a Se SE Se 1878.55. (A877 2. 3 525 239 262 (= 3 1.) eee ee gts 2 CORSE ES! 1875 ----| 1872.06 22 649 289 324} — 35 Pelee 5s See ee None-...-| 387iee 450 204 225}; — 21 a Big eee do....| None....| 679 306 339 | — 33 Boece ee ee ey 1875-4 |---do.--.| 739 380 369 11 Dota Seer 52S) 5 Saal oe bereie 8,042] 1,418]. 1,521 | —103 Ear No. 1134 | f HSOS asd ee Se ke None....| None 516 | 237 258 | — 21 SUG es acm ge OFF (7. ne | - 572 261 286 | — 25 (oes 22S SIRT 1918} £0 $917 25! 765 415 382 33 Oa eS ee ek Te None None.. 443 219 221; — 2 MUNG Sissi Fur 1923....- 1922.....| 315 158 157 1 iD ea SEE aaa See ee 19253 55% 1924... ..| 485 217 242.) — 25 Zin ey eee Nie ce eee 3,096 | 1,507| 1,548) — 41 Total ofabove two groups |..----.-..-- | a ee 6,138 | 2,925 | 3, 069 ayaa] :
The two groups in Table XI are the reciprocals of the two groups in Table X and since one parent is homozygous for waxy endosperm it is again possible to determine whether a difference exists in the percentage of male and female gametes bearing the waxy endosperm.
The ears in Table X show the proportion of waxy to horny endo- sperm in the male gametes, while the ears in Table XI show the proportion of waxy to horny endosperm in the female gametes. Table XII shows the differences observed in the reciprocal groups.
Table XII shows that a difference exists between the male and female gametes in the proportion of gametes bearing waxy endo- sperm, the male gametes bearing the waxy character being deficient.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. DAG)
Taste XI.—IJnheritance of endosperm texture in eight ears of the horny X wary and eight ears of the horny X self progeny of the two maize ears Nos. 1110 and 1134, the progeny of crosses between hybrids Dh 234 and Dh 237,
[Lines bracketed together indicate ears borne on the same plant. ]
Horny X waxy. Horny X self. Pedigree No, of— 5 =F ° 3 Barontoanand Number of seeds. x Number of seeds. pedigree No, : BO. : me a Bas eeer es Pi ire og 3..| & Sk So]. 2 kosise as ae se eiaile Cie E ues | psc limi lies a raun) Sie se | oo | 2 (Slee el + le |21 2 lel E| +E as eS py ee pS SP Yee Mey amy Tey Nites SEI vey Velo Wy 1 2 3 4 5 6 rh 8 9 | 10} 11 | 12 | 13 | 14 | 15 Ear No. 1110 US (ee se All waxy..] 1861..... SL 83 40h Toes al) ONG Bees aes larcere liemstorers | tetera lereeets IRoVE te ees ee None...... 1860.2... 137 71 68 3 Aa Paci Lesce FPS pyres [sR A (eS IS Ai Seeese USD aes PSY SU TB eager Me ry hc has iP ool | Mcrae Le 8 Aa Se a ee a 716} 151) 179) —28) 3.1} 21.1 1S 7 Genie clerete None:..... None 377} 201) 188 S| OekS| POSTE |e oe cal as eiomitialeremcalliecierehletarclete ICY (SS Aaa All waxy..} 1856..... 424) 226] 212 DIU PAO Ho 8 ress eI Seoeed EesrclSeaaniloaeoae S87 Sse seeee RES ie yA We i Te el a i | 496} 122) 124) — 2) .26) 24.6 1S AAS hes sel ee GOs Race eee cya saa lateeatelleinicecalinoaural ae enolate 136) +28 34] — 6] 1.52] 20.6 OCA asl eee ace celbes See weemete 1,019 1} 509 22) 2.04} 52.2/1,348) 301) 337| —36) 2.91) 22 3 Fos | es |Scs—— | esses | ooeeoeee= | serena | oeccaaoe | oa | | ess | | es Ear No. 1134 OMA Aree All waxy..| 1902..... 452) 250] 226 DNs PAN Sel lyGane laceea basco loaecollasuonlaneoc LOS oeacce (eB Bia Ceres El TICE ICSE a SPS ari) Reps ce PT 5 93 86 7| 1.16] 27.0 1920...:.-: All waxy..| 1900..... EISSN SOAS Ouro) aT Ba TA dts ri dhe eee Selle seclicoeac HODTE SS STEM BR et yal ES eee I al Pee siege lee ct ae FSS Me Mk a Pees 519} 133} 130 3] 1.5 | 25.6 1922552505 All waxy..] 1906..... LOAN VOLUN T PHO RS OI NR Ore) ee ih ee ee ee eee Ss clbodoc IPR a ceGaed Seliaae os sere aN ee SoReal ead | See oo TRU ee ne 8 399} 123} 100) 23) 3.41] 30.8 1OQAE Ne ee All waxy..} 1909..... 415} 208} 207 Oe We CES O PSG ee eR a a YES 1925 Baecretete Se Lire eer eters sre are (erate eect SG creel ares sane a a sede Pee 457; 110) 114] — 4) .55) 24.1 1926 es cecieleists (OKO Ses oN RAPS (ORS PERRET [Ee teRes a IB ce A | i 557| 121) 189) —18} 2.25) 21.7 EA RYO a Neste 5) [ARR ea ARE RN eae 1,847} 920) 923) — 3} .27| 49.8)2, 277 580 569 11} .68) 25.5 Total of above two groups.....-- 2, 866|1, 451|1, 433| 18] 1.0 | 50.7/3,625/ 881| 856) 25] 1.42 24.3
TABLE XII.—IJnheritance of endosperm texture in the progeny of the two maize ears Nos. 1110 and 1134, by groups as shown in Table X and their reciprocals as shown in Table XI.
Progeny of—
BAPAN Ose TO)s St ee: Per BATE NO SHUI SAN eee. 8 acca
Percentage of waxy seeds.
Nature of cross, Table X Reciprocal | pisrence, | D+ E
group. cross, DGB GN 5 ha Naar 46.640. 61 52.2+1.0 5.641. 27 4.4 PAce (OKO ear aces 48.74 .61 49.8+ 379 1.1+1.18 9 ndedeanpoadusHeslese 47.74 .43 50.74 .63 3.0+ .76 3.9
Fourteen self-pollinated ears were also obtained from these same horny plants. With these data it is not only possible to determine
whether a difference
exists between the male and female gametes, in
the proportion of gametes bearing the waxy character, but also to compare the relation of the percentage of waxy seeds on the self-
pollinated ear from
the heterozygous parent with the percentage of
male gametes bearing the waxy character, as indicated by the per-
26 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE. >
centage of waxy seeds on ears that result from crossing homozy- gous waxy plants with heterozygous horny plants.
These 14 ears are shown in Table XIII. Column 1 of the table gives the pedigree numbers of the ears borne on the homozygous waxy plants pollinated by heterozygous horny plants. Column 2 gives the percentage of waxy seeds observed on these cars. Column 3 gives the pedigree number of the reciprocal ears of those shown in
column 1. The ears shown in column 3 were borne on heterozygous.
horny plants, the result of pollen from homozygous waxy plants. Column 4 gives the percentages of waxy seeds on the ears shown in column 8. Column 5 gives the difference in percentage of waxy seeds between the reciprocal ears. A minus sign is used in this column to indicate the ears that had a higher percentage of waxy seeds when the male parent was heterozygous horny than when the male parent was heterozygous waxy. Column 6 gives the number of times the difference observed exceeds the probable error. Column 7 gives the pedigree number of the ears which resulted from self- pollinating the heterozygous horny plants which bore the ears shown in column 38. Column 8 gives the percentage of waxy seeds observed on the ears shown in column 7, and column 9 shows the percentage of waxy seeds expected from the gamete classes of the parents in columns 2 and 4. Column 10 gives the number of times the deviation of the percentages in column 8 from the expected 25 per cent exceeds the probable error.
7 TasreE XIII1.—IJnheritance of endosperm texture in 14 ears of maize. the
reciprocal crosses between homozygous wary and heterozygous horny plants.
Waxy X horny. Horny X waxy. Horny X self.
Percentage Per- = Per- : of waxy Pedi- . . Pedi- E = cent- cent- } Difference in ; : Pedigree No. age of tg ace of | reciprocal. D+E. eee D+E., waxy. | ~ a waxy ~*~" | Obser-| Ex- ved. | pected 1 2 3 + 9 10
EGS LSE a aaa em ta eset 44.8 1643 51.4 6.6+42.1 5 23.1 0.42 1 5G5 Wo. SES oo. cS Se 49.1 1632 30.0 943.7 -9 24.5 .19 BY PA ae ee ae 41.7 1604 51.4 9.743.9 =| 21.5 1,97 LUG / eh = Le ae ee eee a 48.8 1617 52.6 3.84:2.2 .0 25.6 3.41 19D ceed head oes 50.2 1619 50.0} — .2+2.1 mil 25.1 - 68 PROZ Reco Soe aoe se el | 60. 8 1621 54.9| —5.942.3 5 33.4 1.44 TRE ee eee ee eee | 49.4 1611 52.6 3.21.8 J 26.0 4.40 UC rl lS ee ak Soe ee 50.9 1686 53.5 2.6+2.4 6 27.2 57 RG se eee ene SS 45.6 1877 53.3 7.7+2.2 .6 24.3 - 60 if Ree es eee 44.6 1874 51.8 7.243, 2 .4 23. 2 3.00 re De 45.6 1920 45.4} — .242.5 6 21.0 50 NO ee ee eh ee 45.6 1917 55. 3 9.7+2.0 -0 25.2 1.16 1O0G A ee ee e 50. 2 1922 49.4 842.5 er 24.8 3.41 BAL | Se Fe Sa ge 44.7 1924 50. 6 5.942.2 S24) 22-6 Bs)
Total........-.--| as gt bitte | Seis aaa a et en
Total 9 excess...| 48.0 |...----- | 52.4 4.44.73 6 25.2 1.38
Total ¢ excess... 50! Gree | 49.4 i SE es] 0 25.0 | 2. 69
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 27 DIFFERENCES IN RECIPROCALS.
It would appear from differences in the behavior of reciprocals in the progeny of Dh 284 and also in the progeny of crosses between the two hybrids that in the descendants of certain ears there is a significant deficiency of male gametes bearing the waxy character. This deficiency may be due to a differential death rate, a lack of vigor resulting in a slower growth of the pollen tube, or an unequal formation of gametes bearing waxy endosperm.
The difference observed is not of sufficient magnitude to account for the deficiency of waxy seeds in the perjugate generation of waxy X horny hybrids. There is evidence to show that the de- ficiency of waxy seeds observed in the perjugate generation of waxy X horny hybrids is not entirely due to this deficiency of effective male gametes bearing the waxy character. There were 14 pairs of reciprocal crosses between identical plants. One parent of these 28 ears was homozygous for waxy, the other parent was homozygous for horny endosperm.
Of the 14 ears shown in Table XIII, 10 indicate a difference be- tween the male and female gametes in the percentage of gametes bearing the waxy character. In 9 of these 10 pairs the proportion of male gametes bearing the waxy character was below the expected percentage and the proportion of female gametes was above the expected, indicating that the difference between the male and female gametes was not only due to a deficiency of male gametes bearing waxy endosperm but also to an excess of female gametes bearing waxy endosperm.
The total for the 14 pairs of reciprocals shows a difference of 2.7 per cent between the male and female gametes in the number of gametes bearing the waxy character. A difference of this magnitude would be expected to occur as the result of chance but once in over 300 times. Ten of the 14 pairs show the percentage of male gametes bearing the waxy character to be lower than the percentage of female gametes bearing this character. |
While the totals show dependable differences, there is but one case where the individual reciprocals differ by a significant amount. Nos. 1902 and 1917 differ by 9.72.0, which is 4.86 times the probable error. The relations of the ears of this last pair are shown in figure 3. The difference in this case is due to both the male and female gametes. There is a deficiency of 4.4 per cent in the proportion of male gametes with waxy endosperm, while there is an excess of 5.53 per cent of female gametes bearing waxy endosperm.
Self-pollinating such an ear would be expected to result in an ear with 25.2 per cent waxy. Ear No. 1918, which is the result of self- pollinating the above heterozygous horny plant, had 27.0 per cent
ee ee SS Se ee eee
PORT a ay ee eee — 2 ae ee
TS a SRS Ce ea ee eg eee Se Se err a ee ae
28 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
waxy, the deviation of 1.8 per cent from 25.2 per cent being no larger than could be ascribed to chance. As long as the deficiency in any class of gametes in one sex 1s made up in the other sex, the discrep- ancy would have to be relatively large before it could be detected in self-pollinated progeny. In an ear of 600 seeds, the deviation above and below 50 per cent would need to be as much as 38 per cent.
Summing up the inheritance of waxy endosperm for the third gen- eration of the hybrids Dh 234 and Dh 287 and the crosses between them, we have 57 ears that are expected to have 25 per cent of the seeds waxy. The observed percentage for the total of 25,329 seeds 1s 24.6 per cent. The deviation from 25 per cent is 2.09 times the prob- able error.
fred (9 0Z, FALE IWIE
Fic. 3.—Diagram showing the relations of ears Nos. 1902, 1917, and 1918.
The second-generation ears of these bybrids, together with 45 ears © previously published (7), determined the percentage of waxy seeds — to be 23.7 per cent. The difference between the second and third generation ears is 0.9+0.21 per cent, which would be expected as the © result of chance once in 142 times.
There were seven groups of ears that made up the total of 25,329 seeds (Table XIII). Of these seven groups, five were below and two above 25 per cent. From this we may conclude that the percentage of waxy seeds for the third generation of the hybrids was signifi- cantly below 25 per cent, but even with the 25,000 seeds involved, it is not possible to determine whether the percentage observed is approxi- mating 23.7 per cent, the mean percentage found for the second- generation ears.
There are 131 ears of the third generation that are expected to | have equal proportions of waxy and horny seeds (Table XIV). The | 131 ears had 57,851 seeds, of which 49.8 per cent were waxy. The
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
deviation of this percentage from 50 per cent is insignificant.
\
29 The
percentage of waxy seeds has been determined as 23.9 per cent for the 198 ears expected to have 25 per cent of the seeds waxy.
The proportion of gametes bearing the waxy character to the gametes bearing the horny character necessary to account for 23.9 per cent of waxy seeds on self-pollinated ears is 48.9 to 51.1.
The 131 ears on this basis are expected to have 48.9 per cent of
waxy seeds.
The deviation of the observed from this percentage
would be expected to oceur as the result of chance once in 25,000
times.
TABLE XIV.—Inheritance of endosperm texture in all the maize ears.
EARS EXPECTED TO HAVE 50 PER CENT OF THE SEEDS WAXY.
Nature of cross.
Progeny of hybrid Dh 234: SING F000) ets PU BT ON Oley wee a Seles ee
B oeeny. 0 of by brid Dh 237:
No. 1129 Baro sls 0 2) 295s J Progeny of crosses between hy- brids Dh 234and Dh 237: AT INIO MEL ER ca 5.5, Serre ATA OF MES ase Se eee
Second penervion ears (Table 1): bride I 234 ee ss oe hae Ep Eidy Dh! 23 (s5-— =n feet
Previously reported...........-..
Progeny of hybrid Dh 234: areNo P1090. 2 Pes 2 ATEN OV UEL Sore ae eee Progeny of cross between hy- brids Dh 234 and Dh 237:
Bar Ne 1130 Yecves tee ys Se
Progeny of cross between hy- brids Dh 237 and Dh 234:
BAIN WL SI cen sp etgece pete
ENO. WS4o 2 oct ost es |
Total for third-generation Ci Ne ae ee SOC ODE ok Ree
Total for both second and
Number of ae Number of seeds.
Per-
DE cent-
Below Ex- age of
Ob D - :
een || LOX Total. | Waxy. | pected Peat waxy
pected waxy. 40 15-| 16,428 | 8,303} 8,215 SSy lanes 03 50.6 26 12 10, 601 5, 316 5,300 16 - 46 50.1 22 12 10, 065 4,942 5,031] — 8&9 2. 60 49.0 24 13] 11,753 | 5,902] 5,876 26 a7 50.2 9 5 AsOGlu|i v1. 949" |" 2.030812) St nr 8°76 48.0 10 6 4,943 2,427 2,471) — 44 1. 85 49.0 131 63 57, 853 28, 839 28,925 | — 86 1.05 49.8 EARS EXPECTED TO HAVE 25 PER CENT OF THE SEEDS WAXY
54 36 30, 571 7, 309 7,643 | — 334 Tex 23.9 42 28 24, 188 5,779 6,047 | — 268 5.90 23.9 45 29 22, 339 5,179 5,58) | — 406 9. 24 250 141 93) )5:77,098) | 2 18)267 |, 19,274.) 1007, |), 1284 23.7 18 8 7,516 1,891 1, 879 12 .47 25.2 10 7 AC OS 6 ummnle 2250 cI 230) |e lg .67 24.6 3 3 1,348 301 337 | — 36 2.91 22.3 11 6 5, 093 1, 258 1,273} — 15 . 62 24.7 6 5 3, 084 725 Wil | — 46 2. 84 2350 4 2 1,055 257 264 |} — U 74 24.3 5 2 2,277 580 569 11 . 68 25.0 57 BR || ol Clee paeN lL ale. ORI We GLSSP lh ee my Alle Moat) 24.6 198 126 102, 427 24, 502 25,607 | — 105 11. 82 23.9
third generation ears...
SUMMARY OF THE INHERITANCE OF WAXY ENDOSPERM.
A large amount of data has been secured that confirms previous observations on the inheritance of the waxy endosperm which had
30 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
been found to reappear in deficient numbers in the perjugate genera- tion of crosses with horny and with sweet varieties of maize.
By adding all of the ears expected to have 25 per cent of the seeds waxy, including the 45 ears previously reported (7), there are 198 ears having 102,427 seeds. The mean percentage of waxy seeds is
~ 23.9 and the deviation of 1.1 per cent would be expected to occur as
the result of chance but once in 10 raised to the fifteenth power.
This deviation though apparently small is certainly too large to be attributed to chance. The apparently slight deviation from 25 per cent and the large number of individuals necessary to establish the significance of such small deviations suggest the possibility that such | departures may not be uncommon for other character pairs which | have not been subjected to such an exhaustive test.
Although the observed deviation could not reasonably be expected to occur as the result of chance, all of the individuals do not approxi- | mate the mean percentage of the whole. An analysis of the “good- — ness of fit” of the individual ears to their observed mean by the use of the method proposed by Yule (16) showed that the individual plants did not form a single homogeneous group with a mean per- centage of waxy seeds below 25 per cent, but that many of the in- dividual ears could not be considered as merely chance deviations.
Thus in hybrids between waxy and horny individuals the mean percentage of waxy seeds reappearing in the perjugate generation is below the expected 25 per cent by an amount too large to be due to chance. The differences between individual plants with respect to this character are also too large to be due to chance.
Reciprocal crosses clearly indicated that in some cases the per- centage of male gametes bearing the waxy character was below that expected. It has not been possible thus far to determine whether this observed deficiency is due to a higher death rate, reduced vigor, or a failure of equal segregation.
The deficiency of waxy seeds can not be due to a fractionation of this character, since such a fractionation could not result in horny seeds but should give seeds that were neither horny nor waxy.
INHERITANCE OF ALEURONE COLOR.
The crosses made between the white waxy Chinese variety and the colored pop variety also produced excellent material for the study of aleurone color. The results in a very striking manner con- form to the Mendelian proportions expected in monohybrid and dihybrid ratios.
In many crosses involving aleurone color the inheritance is blended rather than alternative, and classification is more or less arbitrary. In the Algeria X Chinese hybrids the classes were exceptionally good,
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 31
especially in the second generation, no ears difficult of classification being found.
In the third generation, however, this crisp difference partially disappeared. Several ears were found that were so minutely spotted that an accurate classification was impossible and therefore not under- taken. The deviations in the individual ears were also somewhat wider, a few being found that could not be considered as approxima- tions of any Mendelian ratio founded on reasonable assumptions.
In presenting the results obtained, all possible precautions have been taken to eliminate personal error. There is always room for a slight difference of opinion in the classification of aleurone color, owing to the fact that some persons detect color where others fail.
The chief object of the investigation being to study the correla- tion between aleurone color and endosperm texture, it was desirable to reduce all unnecessary complications. For this reason, only ears that had definitely alternative classes were considered. The conclu- sions, therefore, are based on ears that had very distinct classes, eliminating the chance that aberrant ratios were due to inability to properly classify the seeds. Without doubt much could be learned from a careful study of the inheritance of aleurone color in the ears that did not have definitely alternative classes. This bulletin therefore does not present a complete study of aleurone color, since only a part of the material was analyzed. It is believed that the results do afford an accurate measure of the percentage of white seeds segregating from white < colored crosses on ears with distinct classes.
The number of individuals classified is believed to be larger than in any previous experiment with aleurone color. The numerical equality of the two classes of gametes at segregation has consequently been subjected to a more searching test.
Since faintly colored ears were discarded, it is not surprising that: the inheritance of aleurone color for these hybrids admits of com- paratively simple explanation. That two factors are concerned in the production of aleurone color is clearly indicated by these two hybrids. Most of the ears require an explanation no more compli- cated, but with the partial results of the season of 1914, all the ears of which are not at present completely classified, a third factor be- comes necessary, with a possible fourth.
Jt can easily be seen that many complications are to be expected from the recombination of these factors; hence, this phase of the problem is just touched upon in this bulletin. That these com- plications eventually arise in the study of aleurone color, as with many other characters, certainly limits the general application of Mendelian explanations, but should not conceal the fact that Mende- han segregation does occur with respect to aleurone color and that the numerical relations are wonderfully exact. ;
32 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE. GAMETIC COMPOSITION OF THE TWO HYBRIDS DH 234 AND DH 237.
The percentage of white seeds obtained in the second generation of the hybrid Dh 234 showed that the aleurone color of this hybrid was behaving as a unit character, all the ears approximating 25 per cent white. The second-generation plants of the hybrid Dh 237 fell into two main groups, approximately half of the plants having a monohybrid and the other half a dihybrid ratio of white to colored seeds,
When the two hybrids were crossed, two classes of ears resulted— one group all colored, the other group having the monohybrid ratio | of white to colored seeds. To explain these phenomena, it becomes necessary to assume that aleurone color is the result of two factors. The hybrid Dh 234, all the plants of which, when self-pollinated or crossed with sister plants, resulted in ears with a monohybrid ratio of white to colored seeds, must have been homozygous for one color factor and heterozygous for the other. The plants of Dh 237 which when self-pollinated produced ears with a monohybrid ratio of white seeds were also heterozygous for one color factor and homozygous for the other.
Crosses between plants of this type with plants of the hybrid Dh 234 resulted in ears all the seeds of which were colored, indicating that the factor homozygous in Dh 234 was heterozygous in Dh 237. Since one-half of the plants of the hybrid Dh 237 when self-polli- nated or crossed with sister plants produced ears with a dihybrid ratio of white and colored seeds, these plants must be heterozygous for both color factors. Crosses between plants of this nature and — plants of the hybrid Dh 234 resulted in ears with a monohybrid ratio of white to colored seeds.
It will be recalled that self-pollinating plants of the hybrid Dh 237 resulted in two approximately equal classes of ears, one with a monohybrid ratio of white to colored seeds and one with a dihybrid ratio of white to colored seeds. The hybrid Dh 234 when self- pollinated produced only ears with a monohybrid ratio, but when crossed with plants of the hybrid Dh 237 two classes of ears again resulted, one class having all the seeds colored, while an equal number had a monohybrid ratio of white to colored seeds.
To explain the two classes of ears resulting from self-pollinating first-generation plants of the hybrid Dh 237 and at the same time to explain the results obtained when first-generation plants of the hybrid Dh 237 were crossed with first-generation plants of the hy- brid Dh 234, it is necessary to assume somewhat involved gametic formule.
It is assumed that in the first cross (Dh 237) the Chinese parent had the gametic combination cP cP and the Algeria CR Cr, where
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. ae
G and R are the presence of color factors and er their absence, both C and R being necessary to produce color. Were this true, wherever cR fertilized CR a colored seed would result, and this seed when planted would make the gametes OR and ch, which would give a ratio of 3 colored to 1 white, when self-pollinated.
Wherever c? fertilized Or, a colored seed would result, wnich when planted would make four kinds of gametes as follows: Ch, Cr, ch, and cr. Self-pollinating such a plant would result in an ear with 9 colored to 7 white seeds.
In the second cross (Dh 234) it is assumed that the Chinese parent had the gametic composition of Cr Cr, while the Algeria parent had the gametic combination of CR CR. Wherever Cr fertilized Ch, a colored seed would result, which when planted would make the gametes CR and Cr. Such a plant when self-pollinated would give 8 colored seeds to 1 white. As all the seeds of the hybrid Dh 284 have the combination CC’ Rr, nothing but 3 to 1 ratios could result from self-pollinating any of the plants of this hybrid.
When the combination CR Cr is pollinated with the other hybrid combination of CR cR, an all-colored ear would be the result, but when the combination of Dh 234 CR Cr is pollinated by the other combi- . nation of Dh 237, CR, Cr, cl, or er, an ear having 3 colored seeds to 1 white would be the result. This fulfills the observed conditions. Whenever an Algeria plant with the gametic composition CR Cr is self-pollinated, there should result an ear with 3 colored seeds to 1 white. Nothing but all-colored ears have been obtained as a result of self-pollinating Algeria plants, but there have not been more than 10 or 12 self-pollinated Algeria plants, so that the failure to obtain an ear with 3 colored seeds to 1 white calls for no comment. Two other crosses described below do afford evidence, however, that Chinese plants of the gametic composition c? cP and Algeria plants with the composition CR Cr do occur. On the other hand, whenever a Chinese plant producing Cr gametes was pollinated with Chinese producing cl gametes an all-colored ear should result. We have never obtained any colored seed in crosses between two plants of white Chinese, although a large number of such crosses have been made, a fact which makes necessary the further assumption that plants with the gametic formula ascribed to one of the Chinese par- ent plants must be rare.
An F, plant of the hybrid Dh 234 was fertilized with pollen from a white waxy Chinese plant; the resulting ear was all colored. A second ear on the Chinese plant was Ore pained and was all white, while a second ear on the hybrid Dh 284 was self-pollinated, producing 26 per cent white. These results accord with the idea
89356°—19—_3
>
‘
34 BULLETIN 54, U. S. DEPARTMENT OF AGRICULTURE.
that the Chinese plant was producing gametes cR cR. The cross is shown by the following diagram: all white waxy (observed).
Self Chinese cR :
\-8 ~ all colored (observed).
Hybrid Dh 234 CR, Cr? ~~
Self. 25 per cent white (observed 26 per cent).
An F, plant of the hybrid Dh 237 was pollinated with Chinese, and the resulting ear had 54.1 per cent white, while a second ear of the Dh 287 plant, when self-pollinated, had 25.2 per cent white. As : Dh 237 segregating 3 colored seeds to 1 white, when self-pollinated, has been assumed to have the composition CH cP, a Chinese plant producing only c# gametes would be expected to give 50 per cent
“white when crossed with Dh 287 segregating 3 colored to 1 white, _as In the following diagram:
Chinese cR
NE
Hybrid Dh 237 CR, cR <Q :
50 per cent white (observed 54.17 per cent).
Self. 25 per cent white (observed 25.2 per cent).
COMPOSITION IN THE SECOND GENERATION OF THE HYBRID DH 234.
The hybrid Dh 234 had 46 ears, which were obtained from 31 plants, many plants having two ears. Of these 46 ears, 25 were the result of self-pollination, 12 were the result of fertilization by sister plants of the same hybrid, and 9 were the result of pollinating the hybrid Dh 234 with pollen from the hybrid Dh 237. There ap- peared to be no difference among these three groups as to the per- centage of seeds with colored aleurone, so that they were all tabulated together and arranged numerically by pedigree numbers. Two ears from a single plant are indicated by a bracket inclosing the pedigree numbers of the ears.
The 46 ears are shown in Table XV. The total number of seeds for these ears is 26,383, with 25.8 per cent white, the expected being 25 per cent, a deviation of 0.8 per cent, which is 4.45 times the prob- able error. The individual ears ranged from 21.4 per cent white to 30.9 per cent white, making a continuous series. Five of the ears deviated above the expected in percentage by an excess of three times the probable error, two of these deviating by four times the probable error. Of the 46 ears, 830 had white seeds in excess of the expected number, 13 below the expected percentage, and 3 were exactly 25 per cent white.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
35
TABLE XV.—Inheritance of aleurone color in 46 maize ears, the second-genera-
tion progeny of the hybrid Dh 234, Chinese variety X Algeria.
[Lines bracketed together in pairs indicate ears borne on the same plant; ears selected for planting are
designated by an asterisk (*).]
Pedigree No. of— Number of seeds. i Percent- - i le D+E age of elf- ahs xpecte evia- white Progeny ear. pollinated ¢ Total. | White. |” White. tion. (DEO 2 oy AS A a AAR ie eR RN Iw Soka 657 165 164 1 0.3 25.1 TTA Us ey ae a an edna Ae acta ee OSE tse 599 172 149 23 3.2 28.7 UIC} Loe ag hag dS as te OB oat se 533 165 133 32 4.7 30.9 SN ere ee ea tat Ae ne cae nae Selig ey 517 148 129 19 2.8 28.0 RO SMe eet eo Tere ee A 2 doses 272 68 GS a SEIS Ove | Oe A Reren 25.6 TUNG EN Spy ke nk 10S ese snes 573 151 143 8 1.0 26.3 ATO See ee es PR Re OE: Selina e 609 177 152 25 3.4 29.0 OG a eae a oe ae ee ee ee S Goseeee 690 178 176 2 8 DONT HOSE oe MeN ER SEPT E EL eh eke GO} A SoH 691 196 172 24 3.1 28.3 URL ne ere tee tee 5 eee LZ ror 402 113 100 13 2.2 28.0 TITIES valle 4th et eee Seliess 747 192 186 6 8 25.8 TITUTIO 2 Saye ae ay ee Eee eee | acre doses: 733 215 183 32 4.0 29.3 LITT 8 Ne ee See 9 RN? QE he a STS eas BN 643 168 160 8 ial 26.2 MASSES SIEGES MERE 5 Soe EE Sera a 428 112 107 5 .8 26.1 UNE oy eee eg ee we Maine Se TD Ae 508 . 134 127 7 1.1 26.3 TESLSLIG aes een hey ee Sees LAGE ae 322 87 80 7 1.3 27.0 TUNICS 2 a 5 1 Bet Ve a Ra na Self O97? 564 144 141 3 4 2525 TULA 6 a eT oe Ct eer A do..... 62 174 155 19 2.6 27.9 SUG eee ee epee kines Fe INO se sose 414 117 103 14 eo 28. 2 LIST oa tel WH SE Nea Ce Ieee 655 182 163 19 2.5 Pile th ‘iD Se es Ae Se ss oe eee a Selizeae: 687 191 172 19 225 27.8 SIRS) SS ee a HN Lop A gee Ue ee dows 555 141 139 2 oe 25 4 ie SE Ge Sey eke Swe eee A262 ae 510 130 127 3 4 24.5 TUSSI ea eels te ee Sees Seize 605 156 151 5 si 25. 8 TPR et OS) Aaa Ee eek ae eee dos2es) 571 133 143 — 10 1.4 2353 11S Ries he Ni ly sc et DA aes 773 189 193 =a 4 BO 24.5 ISSUES) SAS eye hE Se ele ya Selieerey 212 53 a bless Spee | ey a 25. 0 USA = Oe See ao aes Og eee ea dos. = 614 148 153 — 5 al 24.1 LSA) = te lees Se OAC aa aire Bei rime es ell dole 334 87 86 1 ae) 26.0 IER) S Aho A AO eS as a WEBoicdsoe 676 182 169 13 U7 26. 95 IGSil pire hetels Meee e Date ee hae Self. 3! 659 176 165 11 1.4 26.7 SZ EIAEIAT he. Seyi bates eeny gy W729. ea eeys 707 158 177 — 19 2.4 22.77 ESBS Sele, sR Sete i a ap eee Selfa. 679 175 169 6 .8 25. 8 TBS ao ae as a NRCS Reith al eal eh Gloecas 492 127 123 4 6 25. 8 WORN fc tek pees Se eee aN Beene ae dorss: 592 148 VAS aac en hare Ee 5 25. 0 LOS ls 2 yieay Eee wee ene eee ars BB Sacese 609 156 152 4 10) 25. 6 USS Ne ee a ae oa a se Seliszan se? 626 138 156 — 18 2.4 22.0 51 5 2 Se a ER i ed UW ABS og 5582 679 161 169 — 8 1.1 23.7 EOL es ee es ee ne IV BX ooae 631 135 158 —) 973) 3.1 21.4 kU Seber, ae Meee ae BAP PBS Es abe 515 114 128 — 14 2.1 22.1 JSS Cis eer gee es ey are aaa Seliteiors 570 131 142 — 11 1.6 23.0 TESS, ale RNB SG a CAO dower 417 109 104 5 -8 26. 1 TSENG) 5 eee 508 ae ene ie aa LATS Seco 800 196 200 —— 4 .5 24.5 1247 (Blea ee et eee eee ee te UGRY/(S SR eA Ae 633 145 158 ilies 1.8 22.8 AO Resins Msg on eA Rey oh esc 7 awk Seligeh sss 479 138 119 19 2.9 28.8 Teese) Wer esse is seen yaaa Oe BML IRS Sig dos eee 578 132 144 Sl iG ¢ 22.8 "TBE ha Day ea Reh anal F le 26, 383 6, 807 6, 596 211 4.5 25.8
36 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The deviation of 4.45 times the probable error above the expected percentage for the total number of seeds, together with the large proportion of ears having an excess of white seeds, indicates a rather definite tendency toward a higher percentage of the recessive class than that called for by the Mendelian theory.
The inclination is to attribute such a small variation to a failure to properly classify the seeds, so that some faintly colored seeds were being included with the white seeds. The number of individuals necessary to detect such a slight error would be very large, so that the number of second-generation ears obtained is not sufficient to shed light on this matter.
COMPOSITION IN THE SECOND GENERATION OF THE HYBRID DH 237.
An examination of the zygotic formule for the hybrid Dh 237 will show that two equal groups of plants are to be expected in this hybrid—one group homozygous for the color factor # and heterozy- gous for the factor C, the other group being heterozygous for both of these factors. Representatives of both groups were obtained, 8 plants exhibiting a dihybrid and 19 plants a monohybrid ratio of white to colored seeds. Although these two ratios were expected in equal numbers, the deviation of 5 plants below the expected for the dihybrid ratio may be looked upon as a chance fluctuation.
In tabulating the plants, only 23 are shown in Tables XVI and XVII, as four plants, owing to the nature of the pollinations, pro- duced all-colored ears only and were not tabulated. It will be re- called that all of the plants of the hybrid Dh 234 were alike in that they were homozygous for the factor C and heterozygous for the factor R.
Two groups of ears are to be expected in crossing these two hy- brids: One group all colored, the result of crossing the plants of Dh 237 constituted eC RR with Dh 234 CC Rr; the other group with a monohybrid ratio of white to colored seeds, the result of crossing plants of Dh 237 constituted Ce Rr with Dh 234 CC Rr. In both eases self-pollinating plants of the hybrid Dh 234 show ears with a monohybrid ratio. In the first instance self-pollinated plants of the hybrid Dh 237 should also result in ears with monohybrid ratios and in the second instance in dihybrid ratios of white to colored seeds.
With this expectation it becomes possible to separate the plants of the hybrid Dh 237 when they were both crossed with the hybrid Dh 234 into two classes, one of which contains plants heterozygous for two color factors and the other with plants homozygous for one and heterozygous for the other factor.
Only four plants of the progeny of the hybrid Dh 237 were ob- served to have a dihybrid ratio of white to colored seeds. These are shown in Table XVII. However, an examination of Table XVI re-
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. ST
veals the fact that eight plants were the result of crossing the hybrids Dh 237 and Dh 234. Since these eight plants resulted in ears with a monohybrid ratio of white to colored seeds, we must conclude from the gametic formula that had they been self-pollinated they would have given dihybrid ratios.
The four ears shown in Table XVII are the result of self-pollinat- ing second ears borne on four of the eight plants just discussed. The plants which as the result of self-pollination produced ears Nos. 1182, 1138, 1721, 1741, 1743, and 1745 in Table XVI also produced second ears, the result of crossing Dh 237 with Dh 234. These latter ears were all colored.
Twenty-nine ears were borne on first-generation plants of the hy- brid Dh 237 that may be compared with the monohybrid ratio of 3 colored to 1 white. As has been said before, some of these ears are seif-pollinated, some are crosses between sister plants, and some are crosses between the hybrids Dh 237 and Dh 234. In this latter cross only plants of the hybrid Dh 237 that were heterozygous for two color factors would give a monohybrid ratio of white to colored seeds when crossed with the hybrid Dh 234.
It may not be immediately apparent that crosses between two groups of plants which when self-pollinated produce ears with 43.75 and 25 per cent, respectively, will give ears with 25 per cent white. A consideration of the gametic formule shows, however, that this is according to expectation. All crosses with this hybrid that resulted in other than all-colored ears approximated 25 per cent white and were therefore included with the self-pollinated and pure-seeded ears in Table XVI.
The 29 ears in Table XVI had a total of 16,947 seeds, with 25.4 per cent white, the deviation of 0.4 per cent in this case being only 1.84 times the probable error. Two of the ears deviated in excess of three times the probable error, both of these being above the ex- pected percentage. The ears ranged from 21.6 per cent white to 28.7 per cent white, forming a well-connected series, and since the range is within four times the probable error, these ears may all be looked upon as deviations from the theoretical 25 per cent. This reg- ularity is an exception to that encountered among most of our pre- vious hybrids and provides an excellent opportunity to study the correlation between endosperm texture and aleurone color in crosses where the percentage of white to colored seeds is behaving in a regu- lar manner.
The four ears resulting from self-pollinating plants of the hybrid Dh 237 that were heterozygous for two factors for color are shown in Table XVII. These four ears had a total of 2,477 seeds, with 43.3 per cent white. The deviation of 0.45 per cent from the expected percentage is less than the probable error. One ear, No. 1726, was
38 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
slightly over 5 per cent in excess of the expected, the deviation in this case exceeding the probable error by 3.5 times. Another ear, No. 1747, was below the expected percentage by 3.3 times the probable error. TABLE XVI.—Inheritance of aleurone color in 29 maize ears, the second-genera- tion progeny of the hybrid Dh 237, Algeria X Chinese variety (monohybrid). [Lines bracketed together in pairs indicate ears borne on the same plant; ears selected for planting are des- ignated by an asterisk (*); ears borne on plants which when self-pollinated proved to be heterezygous
for two color factors are indicated by a dagger (7); ears borne on plants which had they been sel-polli- nated would have proved to be heterozygous for two color factors are indicated by a double dagger (£).]
Pedigree No. of— Number of seeds. : | Percent- Self-polli. E t-| D Fatt SA ; elf-polli- : . xpect- evia- white. Progeny ear. nated ¢. Total. White. ed white ‘tion.
Eee ape Sate 3 Lek eh None...... 647 148 162 —i14 1.9 22.8 1 Oa i SST A SRT UE | BE dO. 265252 672 171 168 3 4 25.4 1 ee Bee ees Os el ee Self aoe 2k 837 241 209 32 3.8 rR RED ge ey ee eS es eee $1052 352. 723 190 181 9 1.1 26.2 TA GS eer 07 See Eels Nae ate Self. 2.5. 319 69 80 —11 ya | 21.6 DPE ees. oe ec re seem GOs. 5. TAT 189 187 2 <3 25.1 ite. eee eRe cs Naee (a) Soe 741 188 185 3 4 25.3 PED see Sas Pt Ee, a Ses Self 33: 575 160 144 16 2.3 27.8 LTRS 2 eee me ee eae a GOss.2.5- 758 175 189 —lt 1.7 23.1 LSS yey SNe Se eee ae ee Pe dQ:=52=- 627 166 157 9 i bap 26. 4 La Be ie eee es eee eee ore UIBy aoe 615 175 154 21 2.9 28.4 IBY pte 2h a5 eee oeeU os Self_...... 74 205 185 20 2.5 Tet 1 B-Series ese ae ji Rop eee 548 128 137 — 9 1.6 23.3 LP ae aR eee lancer: Raper pele ss. 5. 7 160 178 —18 PAS 22.5 E22 ee Fo . Bete Fee 1543225 -5- 77 193 169 24 3.1 28.5 1 17 7-2 5 eae ne cae Sas 8g aaa LAOS eee 37 90 93 —3 1.9 24.1 Tp nate Gime Sone ek oe eee 519i 5 472 125 118 | 7 1.1 26.5 d 172729 Oe eee | U1 eee 421 105 105 [th .2.5 dence) aceeee ce 24.9 i Ip nd ye ai oe laa a 1 SS taeda 613 148 153 —5 ae 24.2 C17 8:1 re i Reet ee Raat Big DAS Bee apie - 401 102 100 2 23 24.9 L763 3 ee Ws oe ete iV 23 Spee 634 164 158 6 -9 25.9 (84 Sais eek eel oe es eee 15S) eee Bae 516 133 129 4 -6 25.8 Gah pe i ees ho 1540-2 2522 458 111 114 —3 = 24.2 LY Gms ele eth Pep a Bical a Salis 2-22 47 119 118 1 rz 25.2 117 Gol eee ee ees ae eae OO. ae 485 120 121 -—1 FA 24.7 Gere eee cee ee i 0 akg ar! 575 vi 144 —17 2.4 77 a LY CS a ES Sa eee Cee ee eee eae ae ee ee 625 139 156 —17 2.4 22.2 Ue GN ike ala le a ace 1 GY Cl na are 621 168 155 is 1.8 27.1 5G es ee aS Sse Sereas sant 342 98 85 13 2.4 28.6 SP OUB e se ee en ee Po ence eee 16, 947 4,307 4,237 70 1.8 25.4
TABLE XVII.—I/nheritance of aleurone color in four maize ears, the second- generation progeny of the hybrid Dh 237, Algeria X Chinese variety (dihybrid).
Pedigree No, of— Number of seeds. Percent- = D+ age of : Self-polli- : Expeci- evia- white. Progeny ear. nated 3. Total. White. peat Se 1 PS eee es earn eM pea eed SM Be 1 | eaters ae 664 284 290 — 6 0.7 42.75 a ee nee ee ee =24d022 2 560 273 245 28 3.5 48.8 1 GTR aa ae eae ees aaa aS2dO.= 222% 595 256 260 —4 -o 43.0 EEE ee ea See eae 4 GQ te 658 259 288 —29 3.3 39.4 Pots) oreo. eS ee a eee 2,477 1, 072 1, 083 —il 66 43.3
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 89 COMPOSITION IN THE THIRD GENERATION OF THE HYBRID DH 234.
Three ears were selected from the progeny of hybrid Dh 234 and planted the following season. Two of these ears are Nos. 1099 and 1111, in Table XVIII. The third ear was a cross between the two hybrids Dh 234 and Dh 287, and since it was all colored it does not appear in Table XVIII. The progeny of this last-mentioned ear are considered later in connection with two similar ears borne on plants of the hybrid Dh 237. The ear numbered 1099 was a cross between two sister plants and had almost exactly the expected per- centage of white seeds. A self-pollinated ear secured from the male parent also was a close approximation to the expected 25 per cent.
The ear numbered 1111 in Table XVIII was the result of self- pollination. This ear also had white seeds, closely approximating 25 per cent. There were four classes of seeds on both the ears Nos. 1099 and 1111. These four classes were planted separately. An ex- amination of the data failed to show any significant differences in the behavior of aleurone color due to the texture of the endosperm, making it possible to disregard the endosperm texture in analyzing the ea one colors.
The progeny from the two ears behaved practically: alike, no sig- nificant differences being found. Hand-pollinated ears to the num- ber of 85 that had both colored and white seeds were obtained, 50 _ears being from the progeny of ear No. 1099 and 35 ears from the progeny of ear No. 1111.
WHITE X COLORED.
Twenty-nine of the 85 ears obtained from the progeny of ears Nos. 1099 and 1111 were the result of crossing plants grown from the white seeds with plants grown from the colored seeds of the same ears (Table XVIII). The table is so arranged that the progeny from each of the four groups of each ear may be examined separately, if desired. In column 1 is found the number of the progeny ear from which the plants that produced the ears whose pedigree num- bers are there given were grown. In this same column are also found the symbol letters for the characters. Thus the first six ears in Table XVIII, which are separated from the remaining three groups by a total, are the result of crossing plants grown from the white waxy (WX) seeds with plants grown from the colored horny (CH) seeds of ear No. 1099. The symbols mentioned first indicate the character of the seeds from which the female parents were grown. The ex- pected proportion of white seeds is 50 per cent. The 29 ears had 11,949 seeds with 47.2 per cent white, the deviation being more than 9.4 times the probable error. A deviation of this magnitude would not be expected to occur as the result of chance more than once in over a billion times.
40
BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
Two of the four groups that make up the total deviated below the
expected by an amount too large to be due to chance.
In one of these
groups the result of crossing white horny by colored waxy seeds from
ear No. 1099, the deviati
ion of 6.9 times the error is due in a large
measure to two ears, both below the expected by an amount more
than eight times the probable error.
One other ear, No. 1653, devi-
ated below the expected by more than seven times the probable error, having only 39.8 per cent white. A reexamination of these ears
failed to reveal errors in
TABLE X VIITI.—/nheritance
Dh 234. [Lines bracketed
Pedigree No. of—
classification.
of aleurone color in 29 ears of maize, the white X
colored progeny of the two ears Nos. 1099 and 1111, the progeny. of hybrid
together indicate ears borne on the same plant.]
Number of seeds.
Per Parent ear and pedigree No. Dk, | cent- of progeny. Self : F E age of -pol- | Recipro- : Expect- | Devia- : linated ¢.] cal cross. Total, | White. | oq white.| tion white 1 2 3 4 5 6 7 8 9 Ear No. 1099, WX X CH: AHO oy ate Paes thay? 1644..... 1643 sto 506 232 253 | — 21 2.8 45.8 ieee Rite cos iuigs Aa 1705....- None... 230 113 This |e) a 49.1 TpASee ik oe aE i RD None....| 1634.....| 562 296 281 15 1.9 52.7 HEN G33 See BUA Cae oe aa ese Spt aes Gdozeere None..- 415 205 207 — 2 38 49.4 PGS a Ae NEETU Cele tei hls dow ea a dow uee 257 128 1ISilgh Paes Lees 50.0 TST a aR at ty DIR hy GO ENG dose 438 212 STO hy 1.0 48.4 f Oba Cee sir Mapa cys. DC Leh So 2,408 | 1,186 1,204 |" — 18 14 49.4 i Far No. 1111, WX X CH: Pee ay rs GARE TEST nN HR OO 1696 ....| None....| 712 345 S560) sal 1.2 48.5 TGs A Re 160422 ea dome 286 149 143 6 weal 52.1 (ap aoa SC ae ORO TEN aa Nee dom 611 282 305, |. = 23 2.7 46.2 TSS ROBES Se oka oe 70S a tba do pees 502 198 251 | — 53 7.0 39.3 Testes en Set TrOpewe ceo don 387 177 193) [2 16 2.4 45.7 i TES ROR E Mentos SADE wero nes THAQye sa hae donee 491 227 DAG | 18 2.4 46.3 ti {1660 Bee ah es Oi eae oes ests None....|..- dowece 600 310 300 10 12 51.6 CRYO) WOE ee reap ay Oh AR he 2 AE ADRAC PENA 3,589 | 1,688 1,794 | —106 5.0 47.0 i War No, 1099, WH X OX: (SS TEU a Uta aang os ce ena a 1582. 05.2 None!-25)) 322 150 161 (ed 1.8 46.6 i ae ATA SUES UG One ne EB oS Se by Pees ae 171 88 85 3 ay 51.5 TCG aeRO NA has (7a None....| 391 196 195 1 12 50.1 EDs See: Cae MEN 1S7Se ye ‘Wane 460 215 930: |) <= 15 2.1 46.8 TA ea ues oy eas None....| 1579....- 303 104 150 = a7 8.4 34.3 TA COC oe Cr ea ne 1589... THA 384 183 192) (eee 1.4 47.6 SATS URN STN te atl None....| None....| 484 178 242 | — 64 8.7 36.8 GION NN iy. Thy le dow 502 259 251 8 mel 51.6 i | TRIOS RAOUL SOUL Ge AEN ae GOUT gle 1590805 a 467 222 Pee) esi 1.5 47.6 A | ACO Me RR ADO Ose 1592. ..-. 348 160 74a) <4 9.2 46.0 4 TGS eC MEME CURT 1585...-. Tas 497 254 248 6 .8 51.5 i TEAST Ces LE Nia 15990405 None.... 67 36 33 3 il 53.8 TO Lae Nee eae NIN GUA Maia 4,396 | 2,045 D198 84-1538 6.9 46.6 Ear No. 1111, WH X CX: ‘ LG 7S AsO TOL eR 1666....- None 297 128 148 | — 20 3.4 43.1 Tl TESTA Are i NN E 1670. Ea RO do...2! 441 199 220ale ok 3.0 45.1 TEQOUS CORT a ee None....|... aos 448 205 994 | — 19 2.7 45.8 i TIGHT She et aed NE ba VES 1666. ae 1665... 370 179 185 lee .9 48.4 4 = —— q Motels dea tO 8 Vamenta 1,556| 711 778 | = 67'|7 5.0 |) aabee “| ‘otal of the above four groups.....---------+- 11,949 | 5,630 5,974 | —344 9.4 47.2
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. Al
The percentages for the three ears are 39.3, 34.3, and 36.8 white. These figures are closer approximations to the Mendelian dihybrid proportion of 43.75 per cent than to the expected 50 per cent white, The nature of the crosses, however, prohibits a dihybrid ratio.
Three ears, Nos. 1610, 1615, and 1653, were all borne on plants erown from white seeds and were pollinated with plants grown from colored seeds of the hybrid Dh 234. The plants grown from the white seeds could be making but one class of gametes, Cr, and the plants grown from the colored seeds were making two classes of gametes, CR and Cr.
_ A self-pollinated ear, No. 1703, was secured from the male parent of ear No. 1653. If the 39.3 per cent of white seeds on ear No. 1653 was due to the male parent being equally deficient in both male and female gametes bearing one of the two color factors the expected per-
FOd. VE /0 I S79
lig. 4.—Diagram showing the relations of ears Nos. 1610 and 1579.
centage of white seeds on a self-pollinated ear would be 15.45 per cent, but since the deficiency was observed only for the male gametes a percentage of 19.65 per cent could be expected. The observed pro- portion on ear No. 1703 was 22.3 per cent, which is not a significant departure from the monohybrid 25 per cent or the 19.65 per cent indi- cated by the deficiency of colored seeds in ear No. 1653.
Further analysis is also possible for ear No. 1610, which had a reciprocal ear in No. 1579. This reciprocal ear gives a close approxi- mation to the expected 50 per cent, while ear No. 1610 was below the expected by 8.4 times the probable error. The difference be- tween these two reciprocals is 18.7+2.4 per cent, a difference of 7.8 times the probable error. No analysis is possible for ear No. 1615, but for the two ears numbered 1610 and 1653 there is indicated either
ne
Te geeeet Saree ae Sa
ide a 4
49 BULLETIN 754, U. 8. DEPARTMENT OF AGRICULTURE.
a failure of dominance in some of the seeds or a deficiency on the part of the male parent of gametes bearing one of the color factors. This deficiency could be due to a differential death rate, a les- sened vigor resulting in a slower growth of the pollen tube, or to a failure of the plant to produce gametes in equal proportions. It will be recalled that the plants heterozygous for colored aleurone are pre- sumed to be making two classes of gametes, CR and C7; a deficiency of white seeds when plants of this nature are used as male parents on plants making oné class of gametes (C7) indicates a deficiency of gametes bearing (7. *The relations of those ears are shown in figures 4 and 5. . The large deviation for the total seeds of the 29 ears is due to a great extent to the three ears that deviated by more than seven times the probable error. These ears must stand as definite excep-
S754 While Fed l6535 VAL
Fic. 5.—Diagram showing the relations of ears Nos. 1653, 1703, and 1702.
tions to the general agreement of the material with theory, but since they stand rather apart from the remaining ears it may be well to exclude them and then examine the totals.
Omitting the data relating to these ears from the total number of seeds for the 29 ears, the percentage of white becomes 48.5. This deviation is 4.6 times the probable error and is still too large to
occur as the result of chance. That there is a tendency toward too ©
few white seeds when heterozygous colored plants are used as male parents is demonstrated for this group, even omitting the ears with obviously aberrant ratios.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 43
TABLE XIX.—IJnheritance of aleurone color in 31 ears of the colored X white and 24 ears of the colored X self progeny of the two maize ears Nos. 1099 and 1111, the progeny of hybrid Dh 234,
[Lines bracketed together indicate ears borne on the same plant.]}
Colored < white. Colored X self.
Pedigree No. of—
Number of seeds. S Number of seeds. S Parent ear and 5 ne eA pedigree No. ] oR an eae of progeny. = 3 iS . +s he : s Ot eee Po 8 Ag Po 8 Ad og £2 ; BOSS ees eG ape SS eelsee la ope 2,2 £2 igh ee OSES LL iKe 4 | 8 |od| 8 2 ees a Se ere ee et a lee elt D ee SS Wein Ney tale fee a }Ee la | aA |A la 1 2 3 4 5 6 q 8 9 10 11 | 12 | 18 | 14) 15 Ear No. 1099, CH X WX. GPs soos SVT SE Bic el GS coast ree estes ol eS lV peg Stel tees cd esl nee 464| 137] 116 21) 3.3} 29.5 6268 eos. All white. . None 427| 219} 214 ESTER ZAM ReaD UO ere neal eior eels ean NU Nee or | Sa TGS YAS Seer oe Onassei 1558 454} 222) 227) — 5 SPAS SO | cee tek iS wee Sha Tega RE its |S ieee GSB essex None.. None 703) 348} 351) — 3 AG HADI |ReySre pete a gece ree aN PI ae pe a 1636.: - ..<.--- SOlie tases cee eeprom ras ay 573} 151] 143 8| 1.1) 26.4 NGSiZpeetios All white... None. 424; 218) 212 6 CB iy MSIE een 1) RRR gal COO a te 638i SL ee ool seete Hae ad) GS-40 0) BERET Once oe Heese) lb aes) Macrae 573} 146] 143 3 4] 25.5 G39 eee aoe All white... None 123 60 61] — 1 03) HC: Sopa eee ea cern PO ORS OTE at a WEL NGAI ee None.. None 396; 199} 198 1 PAGES 0 J Pe Sere te lee ee AL at WN a ET G42) see RS eH i Si a Sa ae | a ate | Fl ears iy ool an (eee PD 551} 134) 138] — 4 6] 24.6 NGI se 6,55 All white... 1552 511} 262) 256 6 Pits Aa Ue) Psat (YC Sn] REA A 1644. 5527.5. SLE Up PS ea al VE SR 2 A TN | on (ae ede 652} 183] 163 20} 2.3} 28.6 1645. 28).25,- All white... None.| 510] 236] 255) —19}. 2.5) 46.3)......|.... Aue oe Maal ese lla Seca 1646.12... : SLSR NRG Gt De he” ae oa PR Wd a 1 A AO a 368/00 7018 92|ies1g|283|soT a5 G4 fi esc ni All white. . None. Bre) loyal his AK By ar OO aa ce came salaoeyallecoclasocc TURN dbl Ss ol PER olin 3, 935|1, 929/1,968| —39| 1.8] 49.0] 3,181| 830] 795] 35] 2.1] 26.1 Ear No. 1111, CH X WX: 16942 52S5- Seige cetera | eer pee tet see eben cee senee|| evap se ke ate 578} 149) 144 5] 7} 25.8 ISR es soue All white... None. 393] 191} 196) — 5 Bye Pcs SHO) Cesc (Cats Met [ce Hepes 16965222. SEE eel SSE SE |e lex ate oy) ae | Het rit | ee 373! 89! 931 — 4] .7) 23.8 1699. .....- All white... None! 511) 252) 255) — 3 AAO ES Pe See ane ean ig emer hereon ey Ct Ae ga gee WOON Sees. SCE USS eG cota lsc HESS Bl fevers El Res lesen lee eset) (ee 451} 128) 113 15} 2.4) 28.4 Ae ee) eee All white... : Bi 0) Peseta (ee Se er aes) MOSS eeciceis SOL EE eee eres eee cterl eeeere ee Naoki eles SI aes eal a 533} 119] 133; —14! 2.1] 22.3 NV OA eevee 02 IM ATTA SP INO) TIAA TIO OR PT Ge ee ee A Slee a eallSesalloasoc WO6ee =e 5 ol": dOssrze ke 3 7) Saal seeaaliee asl loeeesallecelloteca ZO eacereete el) Dir Geres| IS Gonigatae 4 MOO reel tote nae | Scsetel lasers Oneer 582} 140} 145) — 5] .7| 24.0 Fea MES Satz AMMA Aor || INOS ted) OR) OPA > OW ileal Cee Obs sealbescellescocleosealleesellbesec 117 (ti ae PS) ii nes eat Le, Siren) a he RAE 415 92} 104) —12) 2.7) 22.2 De x v2is AN WiniGers| ae N Oneal Sly SOSt men OO Pe aS lie ols |p hae Tc wa yee RA tay cette ili Syl ee DAS So fecersils =< OKO eel MEIN ouaveysh us DUA] ine eyed mrees ety SASF C0 lle WO ON halal 77 ok en A a | ac (ea TIZA Ne ag Sy ee Ea GO> Ge geal ONG mee Chl GEG DIO eles se WMG SSeS elas SAIL sees an i tee ee oe ig Al Us ares ey ele Gog les None iys S04 (meno) eta Di— ase 5 40N0|| nasa ley,. pale ds o| case cl ete fi. Ee ee Mae Gos325e SOIT Ze ak A oS Ae este oe Noeretall teal peepee 117 AK ee Seer SOL Tie arte oes | aan ere crear eels aya 549 IBA ABN Se Salib disc 25.0 Motal sen eee eee ek x. -6| 50.3] 3,481} 854] 870| —16| .9| 24.5
44 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TaBLe XIX.—Inheritance of aleurone color in 31 ears of the colored X white and 24 ears of the colored X self progeny of the two maize ears Nos. 1099 and 1111, the progeny of hybrid Dh 234—Continued.
Colored X white. . Colored X self. | Pedigree No. of— : = i _— Number of seeds. 2 ‘Number of seeds. o- Parent ear and = ° pedigree No. 5 = = = : of progeny. =. 3 © : #8 eS =e] So 0+ ° = 5 eS 21 =e} i So 2 | Ses ee] rs eo] Ss a os Eg ese pees aa aes ee Mee es Se ee bee ane a= a le om ey 12 a | 8 jos| Ss |Aie a se 8 /Seneer eis 1s oS | bee] Sars 1 oH ro) S| x a) ° = * ° ° | B eo B/E JA |AlA le | a2 |] Ee ia | A lA |e 1 2 | = 4 5 |6/7 | 8 | 9 | 10 | 11 | 12 | 18 114] 15 | Pore | | | Bee Ear No. 1099, j } xe Wal | rh? hee SIE eS OE Sees MET pacresaee sles (ie 450] 125) 115) 10 Lg 27.8 ky eee All white. 1604). 127|" G2) - 68] = al 23) 4839) eee Ree: 1573... pines. CaN ha als feces | eG eens (ys Wee 370). 95) asf eel ee 25.0 (lay 7, eee None...... None}! . 645) ~317/°323)-— Gle: a8. 1A ee (ay ise eee elie 520.20]. Be Pe ek Sh) SC ee 539] 149] 135] 14] 2.1) 27.6 rive All white... 1608] 596] 298] 29s8/.....|...-- 5D: 0) .c fed He ibystes Seth (ee 22 hak) Acces ese ee eee ee Bares Sate Gt 557] 140) 139 1] .1) 25.1 170. None.....- 1610} « 468]. 248} 234). a4), 491-5301. = ee ee ee Teer i yee Sete tll hod ee ee. (Bia? Rake 3 aed ter 397| 106] 99! 7] 1.2] 26.7 fe S| aie None.... 1623| 406] 214). 203] 49) (6) 52. 41.5. 2 el eee Debs c ee PT aL Be SLM eters | eeereen |") pene eee) uaa BE 565| 148] 141) 7] 1.0) 26.2 is rhs Be None... 1614) -118)-' Gi) 59]. 2). 656). 2 eee 1589_..-... Saif, oo ee eee | ae | EMG (eames | Uae | 252M 458] 112] 114) — 2] .3) 24.5 fi eee All white.. 1619] 580] :287| 2901 —.a] “.4) 49.4 Sera Sl ee ee eee ECT Re ee ED Self s.. Buf 5 OE NE eee aC = eS Trea 483] 122) 121 1] .2| 25.2 fe een All white 1621) 307) 147) 153) — 6 1.0} 47.9)......].....].....|--.-.]----|-2.-- 1503- fe = SP | eee ie cee menage beer ede Dr aewes ees (eres ee | Gil, Gio 25.0 pias foo wanes ee ap cates 2 3, 247 1,634 1 1,623] -6} 50.3} 4,071/1, 0581, 018| _40| 2.1) 26.0 Ear No. 1111, Rae aad CX X WH: 1665. .....- All white... 1686, 403, 206 201 5 {Was Hee | (eee Pars (eg be 1666942255. Self. eee ree | eae | PE ik [epee (Mealy OTe a8 494) 128} 12 liye ee eae None.....- None S71. -40).-. 43h — 310 150) 46: G2 a le eee 1GSe 2 22s 2 Solis ip ES ae a oe 8 | eo (OSes Ferlieds 23 | 576| 136] 144) — 8] 1.1 166922 >~ = All white.. None 468) 374] 384 —10) 14) 485s ee Se “Tey, ue one ih A pare 78 Ty 9 RS Ppa eins (era ere 743| 205] 186 2) 2: Sa Ye eee 2 58} 620) 620) — 9|.8| 49.3, 1,813) 469] 453 Total of the above four groups. - [2 i106 Da, Ts a 49. 8 12, 5163, »211 3,136 136
COLORED X WHITE.
As the result of poilinating plants grown from the heterozygous colored seeds with pollen from;plants grown from the white seeds of ears Nos. 1099 and 1111, 31 ears were obtained. These ears are shown in Table XIX. The 31 ears had 12,193 seeds with 49.8 per | cent white, the deviation being 0.7 times the probable error. ‘Four- teen ears exceeded the expected, sixteen were below the expected, and one was exactely 50 per cent white. The fit was therefore extremely good. |
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 45
Only one ear, No. 1647, deviated by an excess of four times the probable error, being 8.4 per cent below the expected.
Three éars were borne on the plant that produced ear No. 1647. One ear, No. 1646, was the result of self-pollination and had 21.5 per cent white, the expected being 25 per cent. The other ear was pollinated by a homozygous white plant and had 46.3 per cent white. Although these last two ears did not deviate by a number too large to be ascribed to chance, the fact that they were both below the ex- pected taken in conjunction with the fact that ear No. 1647 was significantly lower than the expected would seem fairly conclusive evidence that there was a deficiency of female gametes bearing white aleurone on the plant that produced these three ears.
The four groups that make up the total in Table XIX are the reciprocals of the four groups that make up the total in Table X VIII. With the exception of the first group, the families resulting from pollinating plants grown from heterozygous colored seeds with plants grown from homozygous white seeds have a higher percentage of ’ white seeds than the reciprocal cross.
The percentages for the families and the difference between the reciprocals are shown in Table XX.
TABLE XX.—IJnheritance of aleurone color in the progeny of the two maize ears Nos. 1099 and 1111, by groups as shown in Table XVIII and their reciprocals as shown in Table XIX.
[The minus sign (—) denotes a difference between reciprocal groups, the opposite of the remaining differ- : ences.
Percentage of white seeds. Progeny of— Nature of cross. yee ; able X Reciproca . :
group. cd Difference. | D +E. War NoyOIG te AIG et WEE CHES tee: 49.4+0. 69 49.0+40.54 | —0.4+0.87 0. 46 PPENO MGs oo Go eee Cae otto Gon see eee 47.04 .56 50.34 .55 3.34 .78 4.25 iat NO.) 1099 fs. 8 ascee eea close WAS ECE eee 46.64 .50 50.34 .59 3.74 .78 4.77 EATEN sl Meee res eS ee see ras GOs 2 se seee 45.64 .85 49.34 .95 3.741. 28 2.90
UR eae eee Sar Se HT ge Yh hl ih 2 at 47.24 .31 49.8+ .31 2.64 .43 6.0
The difference between the reciprocal groups of 2.6 per cent should be expected to occur as the result of chance but once in more than 19,000 times. With the one exception, the groups representing crosses between homozygous white plants and heterozygous colored plants had a lower percentage of white seeds when the heterozygous colored plants were used as the male gametes. This would indicate a de- ficiency of male gametes bearing the colorless aleurone or an excess of the female gametes bearing colored aleurone.
In analyzing the inheritance of waxy endosperm, a deficiency of male gametes bearing the waxy character was observed for the
46 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
progeny of the hybrid Dh 234. The fact that male gametes bearing colorless aleurone are below the expected would seem to indicate that the gametes bearing recessive characters are less vigorous than those bearing the dominant characters. The observed differences could also be explained by assuming the plant to be making an un- equal proportion of male gametes bearing colored and colorless aleurone. /
As the result of ‘self-pollinating plants grown from the hetero- zygous colored seeds of ears Nos. 1099 and 1111, 24 ears were ob- tained. These ears are shown in Table XIX.
The expected percentage of white seeds is 25 and the observed 25.6. The deviation in this case is only 2.3 times the probable error. Only one ear deviated from the expected percentage by more than three times the probable error, all the ears showing a remarkable uni- formity.
Reciprocal crosses between heterozygous colored plants and homo- zygous white plants showed that for the heterozygous colored plants the male gametes bearing colorless aleurone were 3 per cent below - the expected proportion. These same crosses showed the female gametes to be approximately normal. From these facts it would be expected that self-pollinating these heterozygous colored plants would result in ears having approximately 23.5 per cent white. The observed percentage of 25.6 can not be considered as a chance devia- tion from 23.5 per cent, since the deviation of 2.1 per cent is 8.1 times the probable error.
To explain these conflicting results it is necessary to make the as- sumption that the gametes bearing the recessive color find a better medium for growth in the stigmas of the heterozygous plant than in those of the homozygous white plants. An adequate test of this as- sumption would require numbers in excess of 10,000, making it very unlikely that the hypothesis will soon be put to the test.
COMPOSITION IN THE THIRD GENERATION OF THE HYBRID DH 237.
Four ears from the hybrid Dh 237 were selected for planting. Two of the four ears are shown in Table XVII as Nos. 1129 and 1130. The other two ears were the result of crossing Dh 237 by Dh 284, and since all the seeds were colored on both these latter ears, they do not appear in Table XVI. Their progeny are discussed later with the progeny of a similar ear from the hybrid Dh 234.
Ear No. 1129, grown in 1918, was the result of self-pollinating a plant of the hybrid Dh 237. This ear had 747 seeds with 25.1 per cent white, the percentage being almost exactly the expected 25 per cent. Since this ear is demonstrated to be segregating in a normal monohybrid ratio, the progeny plants of the heterozygous seeds are expected to behave in a like manner.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 47
Ear No. 1130 was a second ear on the same plant that bore No. 1129, but instead of being the result of self-pollination as was No. 1129, ear No. 1130 was the result of pollen from a sister plant. The plant. that served as the male parent of ear No. 1130 bore a self- pollinated ear, No. 1135. This ear No. 1135, had 26.4 per cent white, the deviation only slightly exceeding the probable error.
Since we have already seen that the plant which bore ear No. 1130 was segregating in a regular Mendelian monohybrid ratio and since the male parent was also a close approximation to the mono- hybrid ratio, the progeny might also be expected to behave in a regular manner.
There were four classes of seeds on ears Nos. 1129 and 1130— colored and white horny and colored and white waxy. The four classes were planted separately and crosses made between plants erown from the white waxy seeds and plants grown from the col- ored horny seeds and also between plants grown from the white horny seeds and plants grown from the colored waxy seeds. Self- pollinated ears were obtained from all the classes, but since the self- pollinated plants grown from white seed resulted in white ears only these ears were not tabulated.
The results of the different crosses were examined separately, but since no significant differences were found in the behavior of aleurone color between waxy and horny seeds the endosperm textures may be disregarded. Further, there appeared to be no significant differ- ences between the progeny of the two ears, so that they also may be considered together.
WHITE xX COLORED.
As the result of pollinating plants grown from the white seeds with plants grown from the heterozygous colored seeds of ears Nos. 1129 and 1130 thirty ears were obtained (Table X XI). These 30 ears totaled 14,227 seeds, with 50.1 per cent white. This is a re- markably close approximation to the expected 50 per cent. Of the 30 ears, 16 were below, 13 were above, and 1 equaled the expected 50 per cent. Three ears deviated in excess of three times the probable error, all being above the expected 50 per cent. One of these ears, No. 1784, exceeded the expected proportion by 7.3 per cent, and must
stand as'an exception. A deviation of this magnitude would be expected to occur as the result of chance but once in more than
1,500 times. . COLORED x WHITE.
From the progeny of ears Nos. 1129 and 1130 that were the result of pollinating plants grown from the heterozygous colored seeds with plants grown from the homozygous white seeds 20 ears were obtained (Table XXIT).
48 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE XXI1.—Jiheritance of aleurone color in 30 ears of maize, the white X col- ored progeny of the two ears Nos. 1129 and 1130, the progeny of hybrid Dh 237.
[Lines bracketed together indicate ears borne on the same plant.]
Number ofseeds. - -
Pedigree No. of—
Per- Parent ear and pedigree No. of es | cent- e S Ex- - 1D = progeny. Self-polli-/ Recipro- + rhs | Devia- 5 age of nated 9.| cal cross.| otal. ere oeded tion. white. white. 1 it at a ee oe | 2 ee / Ear No. 1129, WX x CH: a EE eee ee SS 1gpgsees ih: Ui ea 536} 255 268} —13 17 52.5 (Fe eS ee aes eee 1800... .- None... 500 237 is iky/ 47.4 DAR the NT oe SITE ee Gert 439 216 2 as 4 49.2 “Ends ee a eee 07982) Shee pe: 537 258 PER fee ert t) 1.3 48.0 Phy] Re ie OU ae 1800..... rept eae 498 251 249 2 3 50.4 Tere ae ee pee i eee None... 528 251 Pek, | eee .9 47.6 (LE Oe Se remem Peer Dees eae ee alee 3,038 | 1,468 1,514] —46 2.5] 484 Ear No. 1130, WX X CH: 5 at 2 ia Sal eel Ge Te RSE ot SS ee ee aL er None....| 1838..... 363 179 iG poo 13 49.3 CLEC CR Se i ce a la GOs: 3. None.. 435 232 217 15 2.1 53.3 Es Uf. Bae oe ee See ee ee sehdoz tes Raacee! 275 127 ae 10 is 46.2 US U0 nA ke apreuleleted eben ag ¥ Pde IO eee 44] 243 220 23 3.3 55.0 (RS eee Sean wee dosdee. 1849..... 465 224 Fee = is 1.1 48.2 CLE Chee ae case aii a 1855-0... 1854... ._ 515 272 257 15 2.0 52.8 ETT EN hae wile Pie eRe cal (Mean arty eae eau | 2,494 | 1,277 1,247 30{/ 1.8 51.2 | Ear No. 1129, WH X CX. es ey Ee ee eee None....| None 448 215 224 — 9 4-7 48. aga AS ay i ets ee ‘dese Laas eee 613 304 306) |) 2 3 49, Faia eee MOE de oy ae 1768-252 533 266 7 erp eee eee 50. (| ae EE ES aes Me Bi (| eae Mages 428 194 214 = | Pay 45. Li eR ENG cc Beit SO ee 476 262 238 24 3.3 55. ETS Op OES ce 8 Pacem cok ae Said: ote Pigott 477 242 238 4 5 50. ages ee Gs ee See eae te edo see 591 339 295 44 5.4 57. AGG St St he) Heyl BEE Poss t Hage 446 214 2 15 1.3 48. 7 Seep See ge ee aN aT eae Be ee 386 189 1031s .3 49. MY FN BRS SOAR EOS Safe | Ra MP I 4,398 | 2,225 | 2,199 E | 50.7 Ear No. 1130, WH X CX. al ee ane I eee ae UE ETE 1819..... ASB: 644 333 322 1.3 51-7 x tat ge ce” ae A Se ym Bap None....| None oll 262 255 .9 51.3 “LES: [ign ae ees ROR ae Poe eet ae wa (eee 642 307 321 1.6 47.8 rs er EX Ss Be RRR ace None....|...do...-- 385 186 192 9 48.3 DD See at a he ane IN ado fee Neos 370 203 185 2.8 54.9 Sigs ee eee ee ee 157A pedo: 435 214 217 4 49.3 (Les leee C6 Be Rie BS oe ihivt Pee A dirce 255 ar 50.5 [ice el saree ae LZ | -None....| 1825... 4. O51 7| 50.9 TES angi aa A Sa Ep oO ese |. doctel igo 148 Es 50.1 Sy ES Oa ence tsbetp ae aed aie tad We anes elons See ei, 2,148 8 50.3 Total of the above four groups.....-.-...-..-- 14,228 | 7,136 | 7,114 | 6| 50.1 i
The expected percentage of white seeds is 50 and the observed 50.1. Only one ear deviated from the expected percentage by three times the probable error, the remaining ears being very close ap- proximations of the 50 per cent. Ten ears were below, eight above, and two equaled the expected. The four groups of ears shown in this table are the reciprocals of the four groups shown in Table X XI.
There are no significant differences between the groups, all showing a remarkable uniformity, the percentage of white seeds for the totals being exactly alike. The reciprocal groups are shown in Table XXIII. This is a striking contrast with the behavior of reciprocal groups in the progeny of Dh 234, in which a deficient number of male gametes bearing colorless aleurone were found.
COWFOWOMDS
a aid
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
49
TABLE XXII.—IJnheritance of aleurone color in 20 ears of the colored X white and 14 ears of the colored X self progeny of the two maize ears Nos. 1129 and 1130, the progeny of hybrid Dh 2387.
[Lines bracketed together indicate ears borne on the same plant. ]
Colored X white.
Pedigree No. of—
Colored x self.
Number of seeds. Pia Number of seeds. gs ~ =“ Parent ear and ; a 2 = pedigree No. 2 a 8 eb of progeny. ‘q oa < rs) Self-polli- | Recipro- i Jj & dj aa nated g. | cal cross. on eeS oy tes Hy fe) Sui Gs SE Loa yee elie k= an lilsal Aliant tie meen Mugen isan eet cl elo eta fas} a=] &, ¢ -|: oO 3 = = is | Oo 6 = i © ah Heiss (rs! be ® ba ye Jes ai (GR vey Aver Naty Mayen gee Nb cara fey fea 0 Tou 1 2 3 4 5 Geena 8 9 10 | 11 | 12 | 18 | 14 | 15 Ear No. 1129, CX X WH: W7oee Sanam All white.{ None BEV OA ORG COAL ORBAN CAN ie ale eS oe eae 7G (Sea aes ESTE Ae res a fe STE eRe LDS PATS le al et ga eat ages een eta 425) 110) 106 4) 0.2} 25.9 IGS ee ase a white.| 1775..... 144 68 TA SY hate WC ce B79 Tl ee RS eee TU AOS aS TIS TEN bi egea S INI OTTO eel eee ote all veers | ee EN ie ae UDA ESM NEES i TAR Ox TOCA sawtigaciomcisidl i aictecektos 576{ 282} 288] —6 1j 49.2) 552) 141 138 3 4| 25.5 Ear No. 1130, Roan a CKX WH: USS Sse se a white.| 1827..... TBM CAOTAY BAA iSO) oats TU RRS Sa ie SU A ee alla cl iO Sa 5hoho|| Wellies sass abe sdSualeesecal loSsaallsseselloaeeel loca lace ae 568} 143) 142 1 Wet 7) TESA ees a aaa ae white.| None.... 207; 109) 108 1 PP) lies ROSH ee A A SRS A Heo Ee il aaa Po {i821 ya Senos SY eH Yi tis elas AP AeA ey clave oo ol beY U H 619} 132) 155) —23) 3.2) 21.4 LU SQDE Merwe: All white-| 1836..... EON PAN) PAU Se alee ae & DDE CD] een S| ah Re |G ss ae ee Hcp aes Sm S235 sere cee INOnNCEEE === None 566] 3807) 283 DAVIN Sis ONAN |e seus | CuNeiraa0s | ice adie hata ga eau | np Rept Rae See ee NS NE Ree ER trees al en Rye eae SGT ae he a 1 pe 520} 133] 1380 3 5| 25.6 RD ew None....-. S30Reeee 584] 287) 292) — 5 CGA 8 ESS NA aE IN aN TN hb ETN Gall eye | ae a a it Ip LE 2, 653/1, 41/1, 326 15] * .9} 50.5)1,707| 408} 427) —19} 1.6] 23.9 Ear No. 1129, MAR G Fa ciel CR hae AO OA Ee ATTITUDE CU UNL PR CHEX Wx: 90%. cele All white .| None BZ) 238|04.256), —18|¢ | 224 AG seemed a See SST VQ eis oe: SLED URES (NS See Ug aT 2 er Pa a 296 76 74 2 4| 25.6 O2ER Soe INNO VAAOAIR SS Seasons RMIT PPA PHM IU) Le OAC VCO SHS NI to cL leew roe Tee 17S ie ae a None...... None 5538]) 28h" 276 5 TOPO OES [eek wea ular AS a ess | ete nea ke | aap 9G se atte: CBee eho evaeernse tape nia | AE Ne lias a MMM ARE GRA ies RRS ad ada 296 65 74| — 9}; 1.8] 21.9 1E7Ao 7 epee ese None...... None 230) 125) 115 MLO HAVE ON eAPAy ee is eeed HeeSIy e | PaR | ES W79Ssess cet SLI DEA eral Sie sete pete Les yrs eae | Sel eat en ane DC VA 752| 178) 188) —10] 1.3] 23.7 H799- 3 Sa None...... M7 G4e2 226 510} 271) 255 TACGY fin AAG a ess Po Fae Vn ie a al a ale T8000 Esse eee FSS i pa hee eae ae Let he a ATG De LA len Ue 755| 215) 189) 26) 3.2) 28.5 {i802 Seite ces All white .| 1752....- 381 USO te AYO) a Na AG 5) |e UAT ACT SPOT LG Io ane Re SO QE eens CED he ata et Di ee et LR VR Fea DAT Go| pe Oo, 3 7| 26.3 A803. S323 50 INione2.22.- None... 2441 130} 120) 10 CO) HSE Mme eel Pek oe af DR PATRI [eh ae eee Tbe fead yee dd ey eagle et) 2, 917/1,463|1,458| 5] .3| 50.2\2,346| 5991 586| —13| .9| 25.4 Ear No. 1130, SBP Bd | HOTT GELi| Re | (Ea LS Aa CH X WX: TSAR es ara All white..| 1804..... 545] 2712 272) — 1 A Ty acs 8 aR Sg PN A) (USACE UR AE as {1840 Lee ee ee doe None 415| 220) 207 114 Ry ad LX) MAP a sO ear a Da SA ed TI RAO: e's jor SLED Dy sess TS ER SE ed enol IS Pye ese Seca | aaa Ege Te Cane ae 308 84 Tes TA MeN Pa) 1 fo% Le a ee aoe white .| None Soy PB PA Fey eT LAO) Z AES Cah | SN I A A re ee ee TE Ee sere [ AS ol 0 Le Set Ie co SERIE es EME oe NCEE IS peace | eee [aa pet De er HE Ea 451} 101) 113) —12| 1.9) 22.4 S46 25.6 Sa fad white -.| None...- ZI OS |e 1 CMe iad ates |e eo | aver ea lit [Peon | ce WDD BAT <e cieisicin 2 Seu re oe eetia sae ee | aetee | tae Sa eC EE MALL ROT ET ROIAI TSO a Ope ee 25.0 S49 Eee cae All white -} 1815....- 581} 301} 290 STA Ped Eze UR a Ue Ma sR ee aera ay | DA a Wa “ TICES RE en GOnaees UOMO se ee COM ASL LOA RSI RSH Po GTA RS 7d bs ua I ae a Ue ae al Ibis eee Soi eee | yee er | ae URRY ieee ter Alm eT nee MICK LM 563i) 132) “L41\— 9) 231-2825 BING Ciena ey ee etna et 2 hk 3, 359]1, 673/1, 679) — 6 3} 49. 9|2,043) 497 vena —14) 1.1) 24.6 Total of the above four groups..| 9, 505/4, 759/4, 752) 7| . 2| 50.116, 648|1, 645(1, 662) —17| .7| 24.6
89356° —19—_4
50 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
COLORED X SELF.
Fourteen self-pollinated ears were obtained that were expected to have 25 per cent white. These ears are also shown in Table XXII, columns 10 to 15. Two ears deviated slightly in excess of three times the probable error, but the remaining ears were very close approxi- mations to the expected 25 per cent. Seven ears were above, six below, and one equaled the expected percentage.
TABLE XXIII.—Jnheritance of aelurone color in the progeny of the two maize ears Nos. 1129 and 1130, by groups as shown in Table XXI and other recipro- cals as shown in Table XXII.
[The minus sign (—) denotes a difference between eae groups, the opposite of the remaining differ- ences.
Percentage of white seeds.
Progeny of— Nature of cross. Table XXI | Reciprocal
group. Cross. Difference. | D+E,
Bare OS 1129 bee es eee os VN CL ees 48. 4+0. 61 49.2+1.4 0.841. 53 0.5
BaryNio M3022. = Pes slat ste Peles dOS ea a 51.2+ .68 50.54 .66| — .7+ .94 215
HareNonbl2 Oss seers soa ono WED XO OZ a 50.74 .51 560.24 .63} — .d+ .81 - 62
WALENOMUIS0 saa osacken aac see cial eects C0 Koa he. i corse ae 50.54 .52 49.94 .58| — .64+ .78 Stitt Oba eee ae ees cae ate WX OC: eset 00.14 .28 50.14 .34 0
SUMMARY OF THE HYBRID DH 237.
From the progeny of the hybrid Dh 237 there were in all 48 plants that produced 64 ears. Of these, 32 ears were below, 28 above, and 4 equaled the expected percentages. There were only 6 ears that must be considered exceptions. While the ratios on these 6 ears can not be brought into accord with the other results, the progeny of hybrid Dh O37 | 1s eee uniform as compared with the sister hybrid Dh 284.
PROGENY OF THE CROSSES BETWEEN THE TWO HYBRIDS DH 234 AND DH 237.
EARS NOS. 1110, 1131, AND 1134.
Three ears representing crosses between the two hybrids Dh 234 and Dh 237 were selected for planting. These three ears were all colored and therefore do not appear in the second-generation tables. The ear numbered 1110 was borne on a plant of the hybrid Dh 234, which, when self-pollinated, produced ear No. 1111, the progeny of which have been considered on pages 39 to 46.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 51
The ears are shown in the following diagram:
Pedigree No. 1111, 25.8 per cent. white.
Hybrid Dh 234 CC Rr oH
Nee -\ Pedigree No. 1110, all colored. Hybrid Dh 287 CeoRRY-¢~
Self \ Pedigree No. 1132, 27.8 per cent. white.
Pedigree No. 1132, 27.8 per cent. white.
Hybrid Dh 237 Ce RR é Pee
i ees No. 1131, all colored. Hybrid Dh 234 CC ae Self \ Pedigree No. 1117, 25.5 per cent. white.
Pedigree No. 1133, 23.1 per cent. white.
HypridiDh 237 CoRR 7-7
\-2-\ Pedigree No. 1134, all colored. Hybrid Dh 234CC Rry- 3 —
Sell, Pedigree No. 1118, 27.9 per cent. white.
The same explanation will apply to all three ears, Nos. 1110, 1181, and 1134. Self-pollinated ears were obtained from the male and female parents of each of the ears, and the results showed all of the plants to be segregating in a regular manner, producing the unit char- acter ratio of 3 colored to 1 white.
It has been assumed that the hybrid Dh 234 was producing gametes CR Cr, and that the hybrid Dh 237 was producing gametes OR cR. Either hybrid, self-pollinated, would result in a monohybrid ratio, while if crossed it would result in ears with all of the seeds colored. If this assumption is correct the expected result of planting the seeds from a cross between two such plants and self-pollinating them would be one ear all colored, two having 3 colored seeds to 1 white, and one having 9 colored seeds to 1 white. °
PROGENY OF EAR NO. 1131.
As only self-pollinated ears were obtained from the progency of ear No. 1131, these ears will be discussed separately.
There were two classes of seeds on ear No. 1131, colored horny and colored waxy. These two classes were planted separately. The ears obtained from both classes are shown in Table XXIV. The upper group of four ears was obtained from self-pollinating plants
Be. BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
grown from the waxy seeds, and the lower group is the result of self- pollinating plants grown from the horny seeds. The 10 ears do not afford a sufficient number to determine whether 1 all-colored ear, 2 ears segregating 3 colored to 1 white, and 1 ear segregating 9 col- ored to 7 white are obtained.
No all-colored ears were obtained. Nine of the 10 ears are approxi- mating 25 per cent white, while the remaining ear, No. 1892, approxi- mates the Mendelian dihybrid ratio. The total number of seeds for the nine monohybrid ears is 2,158, with 24.7 per cent white, the de- viation being less than the probable error. None of the ears deviated in excess of three times the probable error, 5 were below, and 4 above the expected.
TABLE XXIV.—/Inheritance of aleurone color in 10 ears of the colored X self progeny of maize ear No. 1131, the progeny of a cross between hybrids Dh 234 and Dh 237.
Number of seeds.
Cer ACier of cross and pedigree D+E. Fetcentaes o. of progeny. of white. Total. White. ee Deviation. Colored waxy X self: TRS toy fe cena AS es A aN JVs 269 69 67 2 0.4 25.6 Ieee i es eae a A GC IC A 279 rf 69 6 1.2 26.9 ICTS O) se eae AN fe DU 257 58 64 — 6 1.3 22.5 TRSKOTOS AE ay esr see By cee Ut AN 47 10 12 —2 1.0 21.3 ; ARO Gale aapeett Salsa ices 852 212 213 — 1 1 24,9 Colored horny X self: CASS ns Rees eS aad NS aR Upa i 36 18 15 3 1.5 50.0 TofS Sie eu ees ies pel pees EN 337 69 84 —15 2.8 20.5 STS Oe Rena Wen Pe Meee 261 69 65 4 9 26.4 SOD eat ye Se SMU NN pi iene aay 33 5 8 — 3 1.8 15.1 TESTO SU I ae ea aN lacs 251 75 63 12 2.6 29. 8 SSS 7 a yc, US ie ee 424 105 106 — 1 «2 24.8 MT teal eene nial aul cog 1, 306 323 326 | 4 24.7 Total for both groups...| —- 2, 158 535 539 — 4 29 24.7
a Har No, 1892 is assumed to be approximating 43.75 per cent white and is not included in the totals.
PROGENY OF EARS NOS. 1110 AND 1134.
There were also two classes of seeds on ears Nos. 1110 and 1184, colored horny and colored waxy. ‘These two classes were planted separately, and crosses were made between them. Self-pollinated ears were also secured from each class.
The progeny of the two ears were examined separately, but no sig- nificant differences were found, so the progeny are tabulated together.
COLORED X COLORED.
As the result of crossing plants grown from the colored horny seeds with the plants grown from the colored waxy seeds of ears Nos. 1110 and 1134, 24 ears were obtained (Table XXV). The crosses were made using the waxy plants as both male and female parents,
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 53
but as no significant differences were found the endosperm textures may be disregarded. Five all-colored ears were obtained that are not tabulated. The 25 ears tabulated were borne on 28 plants.
The expected proportions for these 28 individual plants is 15.75 plants all colored, 10.5 plants with a monohybrid ratio, and 1.75 plants with a dihybrid ratio. The observed plants fell into two groups only, 5 ears all colored and 23 with a monohybrid ratio. The deviation, though too large to be ascribed to chance, may, neverthe- less, be the result of accident.
The observed deviation would be expected to occur as the result of chance but once in 500 times. Although this deviation would seem significant, it is, in fact, merely accidental. Self-pollinating these plants proved that they were in the expected proportion of 1 homo- zygous for both color factors, 2 heterozygous for one and homozygous for the other, and 1 heterozygous for both factors. The deviations noted from this grouping would be expected to occur as the result of chance eight times in a hundred.
The large deviation from the expected grouping for the crosses between sister plants was probably the result of an unconscious selection of the male parents, since we have seen that the plants were present in the expected proportions. Seven of these 23 ears were borne on plants that were shown by means of self-pollinated ears to be heterozygous for two color factors. But since these seven ears were all the result of pollen from plants that were homozygous for one color factor and heterozygous for the other, they had approximately 25 per cent of the seeds white.
One of the four groups that comprise the total deviated in excess of the expected percentage by 3.7 times the probable error. The deviation in this group is due to an excess of white seeds on ear No. 1876. This ear had 32.4 per cent of the seeds white. The devia- tion of 7.4 per cent above the expected 25 per cent is 4.9 times the probable error. The plant that produced the ear in question bore two other ears, Nos. 1874 and 1875. No. 1874, like 1876, -was the result of pollen secured from a plant grown from the colored waxy seeds of ear No. 1110. The third ear, No. 1875, was the result of self-pollinating the female parent of ears Nos. 1874 and 1876. The self-pollinated ear No. 1875 had 41.6 per cent white, demonstrating the female parent of these three ears to be heterozygous for the two factors for color. Unfortunately, an ear was not secured from the male parent of No. 1876, so the gametic constitution of this plant can not be definitely determined. Ear No. 1876, however, with 32.4 per cent white, is closer to a monohybrid ratio than a dihybrid ratio, but it stands almost midway between the two ratios and can scarcely be referred to either. The relations of these ears are shown in figure 6.
54 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE XXV.—Inheritance of aleurone color in 24 ears of the colored waxy X. colored horny and 28 ears of the colored waxy X self progeny of the two maize ears Nos. 1110 and 1134, the progeny of crosses between hybrids Dh 234 and Dh 237.
{Lines bracketed together indicate ears borne on the same plant; ears that were considered as approxima- tions of 43.75 per cent white are marked with an asterisk (*); ears that were pollinated by sister plants are marked with a dagger (7).]
Colored waxy X colored horny. Colored waxy X self.
Pedigree No. of— Number of seeds. S Number of seeds. eS Parent oar pod pedigree No. o =| Cay lrg o. progeny. © : as o ; a2 : eel] a "4 Pel _ »'d Self-pol- | Recipro- Bp Soasv le ces a's . | oe] s&s . | ae linatedg.) calcross.| 4 | & as 3 | 18 a|s ae fs I | 1, Ss 2S Se IS ts Rel Pe SS ey Ve es ea se Merb er le 1 2 3 4. 5 6 7 8 9 | 10 | 11 | 12] 18 | 14) 15 Ear No. 1110, CXBK CH; eee is Sane 18782 cone 1877es26c $255) 143) SN, AQT 82554) e deen [era ah co eee ae aia Sy Cae Selfsocs lise selseciaclaseescloses loco latent aeons eee 433 91; 108) —17| 2.4) 21.0 DSSS EAE ies SSOe ey. None....) 491) 121) 123) — 2 PII Z ed | Pari es ep sl eh (HE a SSO Ree Selita soe eeeiacatis ss] eseigere (e sisisic | Cicine lereteista eecereelletoine *477| 207; 208) — 1 1| 43.4 S60 eee STO 1874....- 649) 164; 162 2 Bl) ZO |e mate cl cess eee eters Pa Ne Si PPM Se We eso sacse None S| 1 Siler. Ue KO eel O73 Goa soolsoosalsonuclloscoclscaouluesos 186250 bere Selisa goes gaaecelbeeces| meee ete e al haar eater leet *532} 193] 233] —40) 5.2) 36.3 ESOS We aS None....| None....| 679} 174; 170 ANT Ob e250. 6)o ee he shee Slee & cles cee ge lereerens 1 SGA ees o Sie hie Bea ee Ae ele OAS seats bec asosnlbenee *556| 253) 244 9} 1.1] 45.5 NSCS used 1875227 None....| 739) 181) 185) — 4 5) 24RD) os.53] << cash tec ae te peel eee TSGG Sues SORTS Se Rees ee ae rt lee SI Rr Dek ol Wal 676} 158] 169) —11] 1.3] 23.4 ASO TE Ree eee GO es sec gt eee [ecictes ciel ooo meetaleis ce el eters [ere se 69} 22) 17 5] 2.4} 31.9 SES ise y i ele ones Nae NRE et rsa viele: oa RS 95] 21] 24) — 3} 1.1] 22.1 S69 yee ics 3 CK SoGd SGooaDoDdUllooussollacddallncesiieadouilesoec|iscaseo *135 60 57 3] 1.2) 44.4 iy)Ss6esnec sec 6 Cate tll ns ec [AY en IESE Ibi ee i) Alb *51} 18) 22) — 4) 1.7] 35.3 Motalisaed estab ie Ne a 8,533) 892) 883} 91 .5) 25.2] 1,273] 202] 318 —26| 2.5] 23.0 Total pmarked:ieats. 2s cccesee alee cle sea eetene ae see eels cleo *1.751| 731) 765} —34} 2.4] 41.7 Ear No. 1134, CXS XTCHE Ee EE COGOOH| COO COB SO5 | BODOSE BOS bocsce lec Ssslbaccelesetol otoadl aces *695| 284! 304] —20) 2.3] 40.9 NOO2E Since 1918..... TOM e cae F65|> 215] OE 124 259} Dora eee sce ieee eee | eae ee L903 Sasso Self ae ae De |e Se a Eee See i eer a eee 55 9} 144 — 5} 2.3) 16.3 1904 ise Cie None....) None....| 443) 115) 111 A S265 Ose Oe =| AES Shes aos [Bs ess | eee eee IB spusbeHe 1934..... 1935....- OG esntoy ate CEN eS ob HPC Ue en ol egeallssasd|laccodlocoalboade 190G 22 ee 1923.....- Sy SGace 315} 87) 79 to Mee A hP-Zial | Meee Oem EBS n el Cento aollyoasc WOO Tifizta ars eis weiner Sree [ois a terested Rlevevoterailiova.s cici| overeter ella tye cial ns eet mnauay 560} 143) 140 3 4) 25.5 19OG Meee OD eee 1924..... AS52103 S120 18 DS) p21 ease ee ee ere as | eee 1910 See CMEC eI VRID Seo yal a rctctensee | eet elk chs eect | CN ave |G *502} 211! 219) — 8 1.1) 42.0 LOM ea 1934..... 1933..... 484) 129} 121 Si) 153 /26..6) see Se) Se Sleek pa ee ae | eee ere eee IR Se Shoe Belt ee es Sear etic SAC pea UM eg eet ee 562} 134) 140) — 6 .9| 249 1913}... HT a ee BAN es Sots asco ail eesetracnre | ea eeren a rae ee sy Ucn cal Te 619} 144) 155) —11) 1.5} 23.3 OTA ea Re 2) BHR ez eat ego papery a A can gr ale esl ep a *513} 272) 220) 52] 6.5] 53.0 LOO ees alee C5 kc PRP (Sar a PS) wet a LAE SA ies ello 525) 133) 131 2}. 8|) 25.3 A Mor i Lanett alae ste as San 2,858} 731} 712} 19} 1.2) 25.6} 2,321) 563) 580} —17| 1.2) 24.2 Total;smarked earss. Sy sss tes | ee ee Pee oe ie eee aE ey *1,710| 767} 748} 19) 1.3) 44.8 Total, two X XH groups...... 6, 391|1, 623/1,598| 25] 1.1) 25.4] 3,594} 9855] 898] —43] 2.4] 23.8 Tocals Marke Gears oe wis eed is Oe ae |e eee eee | ree *3,461/1, 498]1, 513} —15 7| 43.3
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
55
z | TABLE XX V.—IJnheritance of aleurone color in 24 ears of the colored wary X colored horny and 28 ears of the colored waxy X self progeny of the two maize ears Nos. 1110 and 1134, the progeny of crosses between hybrids Dh 234 i ae and Dh 287—Continued. Colored waxy X colored horny. Colored waxy X self. Pedigree No. of— RE D Number of seeds. ° Number of seeds. ° Parent ear and bs pedigree No. of 2) nA ie Re progeny. © : 8 o ; 35 2 ot a ae m3] a ara Self-pol- | Recipro- a 2 es ES =e seal ities linated 3.) cal cross.) = g as|s | Jo as Sai | A lo = | v e B | B = = y e B |: i BF ia |A]A le SNES esp fey yp Sy ise 1 2 3 4 5 6 vi 8 9 10 11 | 12) 13 | 14] 15 Ear No. 1110, CH X CX: Cy Ale oesoce S62 Roce USGS 81; 21 20) — 1 EDO NON vests parca eaeg elle ly ae | Sanaa | aces at WY Csocscoee Ue Wiegeee None... 538) 144) 134 IO) ipspa LCS) GAR oe I) ea al Fy elie TA USoeeeeeere SY) hese anoon asada Secets) SASH eo Gel Meeae laetad bees 73 19 18 1 -4| 26.0 IRS SS oeeeae None....| 1860..... 137; 41) 34 Tet DOM DO GI eNO pep AN ga esa Le IsVeebeonon ESTED ea Ih Ay ME ED l ACeaeNO a ) MUTE *716} 298) 306} — 8} 1.0] 41.6 PSI O24- ate None....| None.... SUD nO 2S lin SO 3 Ala ee ee | ea ha aes ete Pte US ese nes. UCB ShGoe 1856....- 424; 101} 106) — 5 Hike TAB AGKS Pus I A EE a a NTO a SI Ae IETS Sassi LT see | a aa et rarcteg |e aad Ne aI SS UO 496} 136) 124) 12) 1.8) 27.4 USSO Ree rctertelaele Ore eS arate ca oe cer aS eee ee od ae St ake 371 87 93} — 6} 1.1} 23.4 NSD saves clereie!| eink Os Sateya | srcleiaic eS iecere Ve Store rel eves bec cree aR rea Se *136) 61) 58 3) =. 8| 44.8 Mobalosse rae Ui Suitewis oe ceiek eieleeie 1,557) 429) 387} 42) 3.7] 27.5) 940} 242) 235 7 . 8} 25.8 Total, marked ears ..... BED OE AE eee S| Grice Ss oekel Miser nee eds ate *852} 359] 372) —13} 1.3} 42.2 Ear No. 1134, eae ari ie ulh he a ee oo inva se ek Ole CH X CX: {i918 ies Eaters 1903 Sse 1902....: 452} 120) 1138 Ghee DGS Do eae Soe cs ea ae Ro = pelt eee LON Seer YA RSE EE eS es LES a Aare a Fn aT 345 92 8&6 6} 1.1) 26.6 ‘ope Sh N ie None....}.1906..... 421} 109} 105 CNTR ar ips V6] eign eee) mente fae Uae La | a 1923 eae see OLE PAR eee toiere cra isis lel Catena erera cede die wales woke leet ate 399] 113} 100) 13) 2.2) 28.3 O24 ereraint oes OLO Sees 1OO9 Sa 415) 108) 104 PWIA AT AA OYAS HSU a YO HN RA US BSE pH NO25 20 ceo sic Cligeeea seats tena mecur cl eene demeralecas clamenclec se 457} 111} 114| — 3} .5) 24.3 O28 a eee Stee e CL oisatas | Wey mee ise ie nea lis a Tae Se SL lo i a Do 397) 88! 99] —11) 1.9) 2231 We cmasse None....| None.... 332} 88 83 5 Pal) Wied orto | pe Re LA ge MEA | BC 1 I NOS Ze terete ese sallboe dovces. AFT WA PAy os TI) ie Oe 7A ae Uy toe a ll iee a eoaolaaogalloe ous GRR Ve sau6ee eae Obie ZA LON Gen L Rn 20 jee buco 21 ie day |e were | elias LC espe | at IA a 1OS4e sss Sed igre str eee pte No eae Vee ee Al Ihe ---| *3846] 161) 151 10) 1.6) 46.6 IBD odaaoe OT eee ee OU reer 2221 TMOG Vod|h eae 250 2987) nen oe (ps Ua VA rst FE IR Yaachoree Se ieee as pornicccec tay Al ee cies eset deer ya een bee Ie bh *443) 188] 194) — 6 .9| 42.4 Mo talere Soe Se Noms Wag 2,643) 704; 661} 48) 2.9) 26.6) 1,598} 404} 400 4 3] 25.3 Rotaljmarkedi cars ys yea see lcte Sea ers ep Leek a I eee *789| 349] 345 4 .4| 44.3 Total,two HX X groups...... 4, "4,200 1,113/1,050; 63) 3.3) 26.5) 2,538) 646) 635 11 . 8} 25.4 Total, UOMO BIOs wacky ee |GENSSII, soaaallbase dlooneclloGecallodaoulooace *1,641| 708]. 718} —10} .7) 438.1 Total, foun) Cx Cigroups.- 2-2: 10, 591|2, 736/2,648} 88] 2.9] 25.8) 6,132/1,501/1,533) —32] 1.4) 24.5 Total, LOUL STOUDS WM Ar Kedicars. |p ocean ae eeeme eects enone cices- *5, 102/2, 206/2, 230] —24| 1.0} 43.2
The probable error is so high on ear No. 1874 that the deviation from 25 per cent is insignificant, although the percentage of white seeds on this ear approximates the percentage observed on ear No. 1876 more closely than that observed on the reciprocal ear, No. 1860; the deviation from either is insignificant.
56 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
It becomes of interest to note that there is one other case where a plant heterozygous for two color factors when pollinated with pollen from a plant heterozygous for one color factor and homozygous for the other has a percentage of white seeds intermediate between 25 and 43.75. The ears are Nos. 1933 and 1935, Table XXV. The plant that bore these ears also bore ear No. 1934. The ear numbered 1935 had for a male parent the same plant which served as the male parent of No. 1933. Both of these ears had white seeds in excess of the expected. Ear No. 1934 was the result of self-pollinating the female parent of ears Nos. 1933 and 1935. This self-pollinated ear had 46.6 per cent of its seeds white, demonstrating the plant to be heterozy- gous for two color factors.
The male parent of ears Nos. 1933 and 1935 produced an ear the result of self-pollination, No. 1912. This ear had 24.9 per cent of its
Ped 1860 /874 U B75 876
Fic. 6.—Diagram showing the relations of ears Nos. 1860, 1874, 1875, and 1876.
seeds white, demonstrating the male parent to be approximating the percentage expected if the plant were heterozygous for one color — factor and homozygous for the other.
A reciprocal cross was also made between the plant which pro- duced ears Nos. 1933, 1934, and 1935 and the plant which produced ear No. 1912. The ear representing the reciprocal cross of ears Nos. 1933 and 1935 is No, 1911. This latter ear had 26.6 per cent of its seeds white, the deviation from 25 per cent being only slightly in excess of the probable error. The difference between the reciprocal ears (averaging Nos. 1933 and 1935) is 4.1 per cent, a difference that would be expected as the result of chance once in six times. The relations of these ears are shown in figure 7.
The seeds from three ears, Nos. 1876, 1933, and 1935, were re- examined and the classification: was found to be correct. The dis- tinction between white and colored seeds was very good, no doubtful seeds being encountered. Ears Nos. 1876, 1933, and 1935 indicate
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 57
that the deviation is constitutional, as all the ears are near enough to the same ratio to be placed ina single group. This affords evidence that one of the factors for color is varying, and the rather definite deviation indicates that the change is in the nature of fractionation.
If definite segregation of hereditary units is a fact, then the number of white seeds reappearing in the second generation of white x col- ored crosses will approximate certain percentages. If these per- centages are not approximated, two explanations are possible on the basis of equal segregation :
(1) The predication of additional factors, inhibitors, and assumptions. By this method any percentage is possible, though when more than three factors are required it is seldom possible to test the explanation, since the number of individuals necessary to measure accurately small differences is extremely large. Immediate percentages may be explained by the use of additional fac-
Fed | IS4F PISS) ISS, /W2
Fic. 7.—Diagram showing the relations of ears Nos. 1934, 1938, 1985, 1911, and 1912.
tors, but in most cases it becomes impossible to reconcile the explanation with the behavior of the same individual in other combinations. Not infrequently in- dividual ears of maize are found that seem to fulfill certain comparatively simple explanations, but when the reiated pedigrees are analyzed a frequent result is to find incompatible individuals.
(2) “ Failure of dominance” is the term often used to explain an excess of the recessive character, but this explanation will not serve when the recessive char- acter is deficient. If the fact that hereditary units undergo change during hybridization requires any further evidence than that presented by Castle and Phillips (2) this frequent “ failure of dominance” in generations succeeding the first would seem to furnish this evidence. If in a cross between a colored and a white plant the color proves to be dominant in the first generation, but in sub- sequent generations this complete dominance partially disappears, as it actually does, it seems natural to assume that either the color or the white, or both, have undergone some change, so that they do not stand as unalterably opposed as at first. In other words, a partial blend has taken place. Such a theory without doubt “strikes at the very heart of Mendelism,’”’ but the facts as they are must be acknowledged.
In demonstrating that an excess of white seeds is due to a failure of dominance the seeds bearing this character are planted, and upon
58 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
the appearance of some seeds with the dominant character the “ fail- ure of dominance” is considered demonstrated. This is all very well, but it is also just what would be expected if segregation were not definite or complete. The finding of some seeds bearing the dominant character on plants grown from the suspected seeds does not explain the discrepancies observed in the parent stock unless the proper pro- portion of plants show the dominant character. In most cases the actual number of plants necessary to determine whether this propor- tion is as expected is so large that investigators have been content when some of the plants exhibited the expected dominant character.
COLORED X SELF.
Twenty-eight ears were obtained from self-pollinating plants grown from the heterozygous colored seeds of ears Nos. 1110 and 1134. Of these 28 ears, 17 were considered as approximations of the monohybrid ratio of 3 colored to 1 white. The total number of seeds secured from these 17 ears was 6,182, with 25 per cent white.
‘The individual ears are also shown in Table XXY. The ears
marked with a star are those considered as approximations of some |
percentage other than 25 per cent. Of the 17 ears, none deviated from the 25 per cent in excess of three times the probable error. The remaining 11 ears with two exceptions were close approximations to | the dihybrid percentage of 43.75 per cent white. The total number of seeds obtained from the 11 ears was 5,102, with 48.2 per cent white. The deviation of 0.55 per cent below the expected just equals the probable error. With the exception of ears Nos. 1914 and 1862 none of the 11 ears deviated from the 43.75 per cent white in excess of three times the probable error. The deviations noted on ears Nos. 1914 and 1862 practically balance each other. No. 1862 being 5.2 times the probable error below the expected and No. 1914 being 6.5 times above the expected ratio. Ear No. 1862 has a percentage of white seeds 11.3 per cent above the 25 per cent expected ratio for a monohybrid and 7.45 per cent below the 43.75 per cent expected on a dihybrid ratio. The probable error is --1.4 and the deviation is 5.3 times the probable error from the dihybrid percentage, which the ear more nearly approximates. The same plant which produced ear No. 1862 also produced ear No. 1861, which was the result of pollen from the plant which pro- duced ear No. 1871. These ears, Nos. 1861 and 1871, are reciprocals, and are very close approximations to the monohybrid percentage of 25. If the plant which produced ear No. 1862 was heterozygous for two color factors, pollinating this plant with one homozygous © for one color factor and heterozygous for the other would result in an ear with 25 per cent of its seeds white. This same percentage of © white seeds would of course be the result if both the plants in
Z
INHERITANCE OF WAXY ENDOSPERM IN MAIZ&. 59
question were homozygous for the same color factor and heterozygous for the other. The percentage of white seeds is a fairly close approximation of 31.25 per cent expected on a 11 to 5 ratio, but the assumptions necessary to account for this ratio on ears that result from self-pollination are too absurd to permit such an explanation. The relations of these ears are shown in figure 8.
Here again we have evidence of a change in the effect produced by the factors, but since the same plant behaved normally when crossed with a sister plant in respect to both male and female gametes we must assume that whatever the change it was not suf- ficient to affect the results except where the changed gamete was received from both parents.
If we look upon ear No. 1862 as being a deviation from a dihybrid ratio, there is an excess of colored seeds. If the assumption
UAE AVALN | /86/ /87/
Fie. 8.—Diagram showing the relations of ears Nos. 1862, 1861, and 1871.
is made that this excess is due to a fractionation of one of the factors, this altered factor must be the one for which the plant which bore No. 1871 was homozygous.
Thus the plant which bore ear No. 1862 was forming gametes CR, Cr, ck, and cr. If we assume that a sufficient amount of the factor 2 was included in the gamete C7’ to make the union of the two gametes C7’ result in a colored zygote the ratio of white to colored seeds would be altered and the percentage would be 39.06 white, a percentage closely approximated by ear No. 1862. (See Table X XVI.) This change, however, was not sufficient to produce color when combined with a pure C7 gamete obtained from the sister plant, as is shown by ears Nos. 1861 and 1871.
ee eee ee ee ——— ee
60 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE NXVI—Possible effect of self-fertilizing a plant in which the color factor has become fractionated in such a way as to make the union of the gametes result in a colored zygote.
[The percentage of white seeds is 39.06.]
Gametes. | CR. | CR’. | Cr. | Cr. | cR. | cR’, | ete | cr. Cheats. = 2 Colored. .| Colored - : Colored...) C pioedicl Colored. .| Colored. | Colored - | Colored COR eee ls do fe Palen a ee Hig ees kc art-ria tet et. pees or | Do.
(Co See, See ee ee ee White...|...do Bae AE hem iene | -White Cap eee Be doses al doe sl Wee as eee bere | White...| Do el Pe SS ae ea |_..do | ~2d0:2-- | Ghiored | Colored... White... White. ...|...do-_....- | Do. CR See eae eee: gee ae rele S AGORNeCe Ss does Vexde wee. beagles ees | Do. Chit cee se en ale do doze.a2 White ..|...do. | dose" ee Pat ehe! | Do Chere ae si dOs-2222 White doz: |...do. | dos Seaas do: 2.23 | Do.
The other aberrant ear, No. 1914, which is shown in figure 9, is a very close approximation of the 1 to 1 ratio, the deviation being but slightly in excess of two times the probable error. The deviation is also insignificant from the 56.25 per cent white expected on a 7 to 9 ratio, while the expected ratio was 9 to 7 or 48.75 per cent white. Here again we may be dealing with a fractionation of the factor R ~ in such a way perhaps that enough has been separated from the fac- tor # to occasionally prevent the normal color reaction with the
Colored
Nek! dns cae
Fed. /9/F¢ 19/5 19/2
Fic. 9.—Diagram showing the relations of ears Nos. 1914, 1915, and 1912.
expected percentage of white seeds is 53.1, which is indeed a very close approximation to the observed 53 per cent.
With the assumption that the plant which bore ear No. 1914 was of the type indicated in Table X XVII, such a plant if crossed with ~ one heterozygous for the factor C and homozygous for the normal — R factor would give an ear with the monohybrid ratio of white to colored seeds which fits the observed results, as is shown in figure 9.
factor C. (See Table XXVII.) If this assumption is made, the {
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 61
TABLE XX VII.—Possible effect of self-fertilizing a plant in which the color factor has become fractionated in such a way as to prevent the normal reaction.
The percentage of white seeds is 53.125. [ p g
Gametes. CR. CR’, Cra Cr: eR. cR’. cr’. Crs
Sites ee Colored. -.} Colored. .| Colored. -.| Colored. -.| Colored. .} Colored. .| Colored. -| Colored. RT es CLO were | ae One eee nC One ae VVAELUL Ob tas|ser= CL Omnia) etre One etapa lees Cloacas White. Te ee domes": BK GOS 2 aes WVVILIIG Cael ete CL Ons 15 ees [Ey aG Obese aea er dowae | Winitessss|"u Do! ORS a ai i GOse ee VLG eSaen | eee Ons tee|Me CO seee es eG Omen er Wihi esses | Wed Osea. Do. Ri ee aes ae do......| Colored - -| Colored. -) Colored. -.| White....|...do...... He HE (oKa tags Mah pt Do. EIR AG Ge aes es eae dor se- ped O ee Bs CLO eeee ||P WUE eee l eae CLOssae Decora! ESE OUR) Do. I Sones eee GO meee ead Oss2eeal VWahiteltea||Oee donee: Sowa ie PEG OuSseya sae Obese ae Do. Eh BSS BEES ee dors jaue Vii Gee syn OF eae Oneecoe BOK RH sie erga SE polOua ae 2 Do.
SUMMARY OF THE INHERITANCE OF ALEURONE COLOR.
The total number of ears expected to have 25 per cent of their seeds white was 168. This number includes both the second and the third generation of the two hybrids. The groups are shown in Table XXVIII. The 168 ears had a total of 81,336 seeds, with 25.5 per cent white. This percentage is misleading, for, while it is only
erecta oe} LI CE ee SE > se Bee Cas ele ale CA be SESE a ee | A eS crcl SS a
Bea RedState oh aa ea fea [ee PY J eee
o VRE 7) Weg Po eta ga ee" 25 26) 274 ee 29 so sp go "S37
Fic. 10.—Diagram showing the percentages of white seeds on 163 ears expected to have 25 per cent of the seeds white compared with the normal probability curve.
0.5 per cent above the expected ratio, the deviation for the number of seeds involved is almost five times the probable error.
A deviation of this magnitude should not occur as the result of chance oftener than once in 666 times. The deviation, then, demands an explanation. That this deviation is not the result of a few aberrant ears is shown by the curves in figure 10. Only 11 of the 163 ears deviated in excess of three times the probable error, and only 3 exceeded four times the probable error, although with 163
62 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
ears we would expect 8 to deviate in excess of three times the probable error. There is undoubtedly a tendency to produce an excess of white seeds among most of the groups expected to segregate in a normal Mendelian monohybrid ratio. This tendency to produce an excess of white seeds is more evident in the hybrid Dh 234 and its progeny than in the hybrid Dh 237.
TABLE XN XVIII.—Inheritance of aleurone color in all the maize ears expected to have 25 per cent of the seeds white.
| | | ae ot Number of seeds : Per- Nature of cross. | | D+E. oe Op. | Below | Be hiayaciasl white served.|_ ©X:_ | Total. | White.| pected | “5; ns = pected. | white. | “ | | Progeny of hybrid Dh 234: ‘Ear DGS 10994 22. cae. Basle CE 15 3 7,252 1,888 1,813 75 3.01 26.0 TD gre DSI e eT Hs Li Sh aes a a eg 10 5 5, 294 TESvs: S25") = Sate eae | © eee 25.0 Progeny of hybrid Dh 237: mireNo 1129. eter Wei 7 3| 2,808] 740] 724 16| 1.02] 25.5 BATENOME SO! ses aes Shee ea if 3 3, 750 905 937 — 32 1.79 | 24.1 Progeny of Dh 234 X Dh 237: peaeNon 1M iG ee 18 9] 7,234] 1,833] 1,808 25| 1.00| 25.3 Progeny of Dh 237 X Dh 234: arcNo. (iat. 29. he ae 9 5| 2,158 535 539| — 4 -29| - 24.7 LFA Da NICaSE IS 2 be oe a al oe 8 22 7 9,420 | 2,402 | 2,355 47 1. 66 25.5 Second generation: Eby brid Dir 2342 So eis Bee 46 13 |] 26,383 6,807} 6,596 211 4.45 25.8 laly iol Dina y Ga ae eee eee 29 11 16, 947 | 4,307 | 4,237 70 1.84 25.4 Potalicses ler tec | 163 59 [sabe
81, 336 | 20, 740 | 20, 334
406 | 4.88
One explanation of this deviation would be that through mistakes in classification colored seeds were being included among the white. If this were the case, the white seeds planted and self-pollinated would be expected to result in some ears having colored seeds. The deviation is so small, however, that only one such ear-could be ex- | pected in growing and self-pollinating 200 of the so-called white | seeds. |
If seeds bearing color had been classified as white, crosses between plants grown from the white seeds with plants grown from the colored seeds would be expected to result in some ears with a mono- hybrid ratio of white to colored seeds, instead of equal numbers of white and colored seeds. Several hundred ears representing the above crosses were obtained without finding any ears with a monohybrid ratio.
The possibility, then, that some of the seeds classified as white were in reality colored is remote. In hybrids involving endosperm texture the significant deviations observed have been with the reces- sive class below the expected (5, 7, and 8).
This significant departure above the expected number of recessives is not supported by the remainder of the progeny expected by the
nature of the crosses to have equal numbers of white and colored seeds (Table X XIX).
a
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 63
There were 110 ears of the progeny of both the hybrids that were expected to be segregating in a 1 to 1 ratio. These ears had 47,872 seeds, with 49.2 per cent white. Here again the seemingly close ap- proximation of the observed percentage to that expected by theory is misleading. The deviation of 0.8 per cent is 5.10 times the prob- able error and is evidently too large to be ascribed to chance. Only 4 of the 110 ears deviated from the expected percentage in excess of three times the probable error, and with 110 ears 5 such ears would be expected.
The deviation in this case can not be explained by assuming that colored seeds are being classified as white, as the colored seeds are in excess. It is hardly reasonable to assume that white seeds were being included in the colored class. The second-generation plants from the colored groups failed to produce any all-white ears, which would be the case if the excess of colored seeds resulted from mistakes in classi- fication.
TABLE XXIX.—IJnheritance of aleurone color in all the maize ears expected to have 50 per cent of the seeds white.
Number of Number of seeds. ears. Per- Nature of cross. | l DE, | Centage Ope eo” Ex- || Devia- eat served.| ©*-, | Total. | White.| pected | “j70, IE *|\pected. white. i Progeny of hybrid Dh 234: HaraNiol 099) 42s eee Se 35 20} 13,986 | 6,794 | 6,994 —200 5.01 48.6 Pao ehitia or eet: 25 16 | 10,154 | 4,907] 5,077| —170| 5.00 48.3 Progeny of hybrid Dh 237: are OWMIZOLY boys Aare as 24 14] 10,929] 5,438] 5,463| — 25 il 49.7 Har NOSIS02 6S: o- cee os eee 26 12 12, 803 6,457 | 6,401 56 1.46 50. 4 Ta a epee WIN Gee Sed Rel ee de 110 62) | 47 872/23 590N| 23098741 S41 5910 49.2 |
One parent of each of the ears having equal numbers of white and colored seeds must be homozygous for white aleurone, and is, there- fore, making white gametes only. When these gametes unite with gametes produced by plants heterozygous for colored aleurone, the resulting seeds are expected to be white and colored in equal pro- portions, but this has not proved to be the case. A deficit too large to be due to chance occurs in the number of white seeds. It becomes of interest to note that the largest deviations below the expected per- centage occur in the progeny of the hybrid Dh 234. This is all the more remarkable, since the hybrid in question has been shown to be producing an excess of white seeds on the first-generation ears as well as on the second-generation ears, expected to have but 25 per cent of their seeds white.
Since the variation in the percentage of white seeds, noted for the 47,872 seeds forming the total for the 110 ears which were expected
64 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
to have equal numbers of white and colored seeds, was of necessity confined to one parent, it became of interest to know whether that parent was defaulting equally in the number of male and female gametes carrying white aleurone. The progeny of ear No. 1099 had 6,804 seeds born on homozygous white plants, but pollinated with pollen from heterozygous colored plants. The percentage of these white seeds was 47.5. The heterozygous colored plants grown from seeds of ear No. 1099 bore 7,182 seeds that were the result of pollen from the homozygous white plants. The percentage of these white seeds was 49.6.
The difference between the white plants pollinated with pollen from the colored plants and the colored plants pollinated with pollen from the white plants is 2.140.571 per cent. This difference is 3.67 times the probable error and would seem to indicate that the heterozygous colored plants were making the expected proportions of female gametes with the observed shortage occurring in the male gametes.
A similar analysis of the progeny of ear No. 1111 shows the per- centage of male gametes bearing white aleurone to be below the expected by 5.2 times the probable error.
The homozygous white plants of ear No. 1129 bore 7,434 seeds that were the result of pollen from heterozygous colored plants of this same progeny. The observed percentage of white seeds is 49.7. The heterozygous colored plants bore 3,493 seeds that were the result of pollen from the homozygous white plants. The observed percent- age was 50. The difference between these two groups is but 0.3 per
cent and can not be considered significant, though the variation is.
in the same direction as the cases previously considered.
The progeny of ear No. 1130, progeny of the hybrid Dh 237, varied slightly in the other direction, the male parents proving to have a higher percentage of white than of colored gametes, and while the white female gametes also were in excess, the excess of white male gametes exceeded that of the white female gametes by 0.5 per cent, which is not significant.
Combining the progeny considered above, there were 26,174 seeds which were borne on homozygous white plants, but the eae of pol- len from heterozygous colored plants. The observed proportion of white seeds in these was 48.8 per cent.
The heterozygous colored plants which were the result of pollen from homozygous white plants bore 21,698 seeds. The observed per- centage of white seeds in these is 50. The difference between these two groups is 1.2+0.31 per cent. This difference is 3.87 times the probable error, which is a rather large difference to be ascribed to chance.
SPRL EE
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 05
The hybrid Dh 237 seems to be much more regular in behavior, at least as regards the proportions of white and colored seeds, though this hybrid produced ears segregating in a dihybrid ratio, as well as ears approximating a monohybrid ratio; usually in dealing with two color factors it is found that the inheritance of color is most irregular, the ratios often exhibiting a great range of variation.
Fifteen ears that were assumed to be segregating approximately 9 colored to 7 white are shown in Table XXX. These 15 ears had 6,519 seeds with 43.0 per cent white, the deviation of 0.75 per cent being 1.55 times the probable error and no larger ae can be rea- sonably ascribed to chance.
TABLE XXX.—Inheritance of aleurone color in all the maize ears expected to have 43.75 per cent of the seeds white.
Number of Number of seeds. ears. Per- Nature of cross. D-+E, | centage OB rl eceor Ex: || Devia- white eee X- Total. | White.| pected tiGn , pected. white. i Hybrid Dh 237, Algeria x Chinese variety: Recand fan eas actaciteaanes 4 2 2,477'| 1,072] 1,083 —l1 0. 66 43.3 Hybrid Dh 234 x Dh 237: rroreny ofear Noy tion. 22 )2-7- 6 3 2,020 879 854 25 1.65 43.5 Hybrid Dh 237 X Dh 234: Progeny of ear No. 1131. ......-. MS acciescice 36 18 15 3 1.50 50.0 Progeny of ear No, 1134...-..-..-.. 4 3 1, 986 839 868 —29 1.95 42.2 TaN ET RN Me GR 15 8 6,519 | 2,808 | 2,850 —42 1.55 43.0
CORRELATION BETWEEN ENDOSPERM TEXTURE AND ALEURONE COLOR.
In several hundred crosses between American varieties of maize with horny endosperm and the Chinese variety with waxy endo- sperm a correlation has always been found to exist between the texture of the endosperm and the color of the aleurone. The results of a number of these crosses have been previously reported (7 and 4).
The study of correlation which had been relegated to the back- ground upon the appearance of Mendelism with its theory of inde- pendent units received fresh impetus with the announcement of Bateson and Punnett that the mathematical regularity common in Mendelism was also to be found in the relationships between char- acters. These authors found that correlations were gametic, the parental combinations being found to occur in the gametes more frequently together than separated. To account for this difference in the gametic ratios they have assumed that the cells bearing the parental characters divide or reduplicate more frequently than the cells bearing the characters derived from different parents. For
89356°—19——_5
66 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
some inexplicable reason they assumed that the ratio between the number of gametes in which the parental combinations occurred together to the number in which they were separated would fit a definite series composed of the familiar Mendelian ratios of 8 to 1, 7 to 1, 15 to 1, etc. From this arbitrary series they have evolved an elaborate system of cell division to account for the gametic asso- clations. |
As higher couplings were secured these authors came to the reali- zation that an insufficient number of cell divisions occurred between synapsis and the formation of the gametes to give these higher ratios. As a consequence they have assumed that segregation takes place earlier in the life history of the organism.
Working on the same problem, Morgan came to the conclusion that correlations were due to the fact that the correlated characters were located on the same chromosome (11). At synapsis the chromo- somes derived from one parent pair with those from the other parent and presumably twist around each other. At the maturation divi- sion these pairs of twisted chromosomes split, resulting in the genes that are located close together along the chromosome falling to- gether more often than apart. The degree of correlation depends upon the distance separating the character determiners, or genes. This distance is determined by the percentage of gametes bearing the characters derived from opposite parents which are called “ crossovers.” Thus the adherents of this theory would explain a gametic ratio of 3-1-1-3 as the result of the correlated characters lying 25 units apart on the chromosome.
Morgan and his coworkers, unhampered by an arbitrary gametic series and in fact working with material very unsuited for such an analysis owing to differential death rates, have amassed a wealth of material which has certainly served to a the linkage theory in an exceptionally strong position.
These authors eae no definite gametic series, and in the’ Eas status of the theory such a series would be meaningless, but while the theory makes little provision for such a series, it does not pre- clude it.
Once having established the number of units separating the cor- related characters, deviations too large to be ascribed to chance are looked upon as the mutation of the locus of one or both of the char- acters, the value of the theory resting upon the infrequency of such departures. Whether we look upon a given gametic series as the result of unequal cell division or whether we assume that the gametic ratios are the result of the correlated characters lying a certain dis- tance apart on the same chromosome, the question arises, Is the cor- relation of the same intensity between two characters for the in-
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 67
dividual ears of a given family? Both theories require that this be true and that the correlation between any given pair of characters remain constant.
In this bulletin there is evidence to show that at least in the second generation the correlations observed are for the most part explained by assuming a gametic series of 3-1-1-3.
METHOD OF MEASURING CORRELATIONS.
It has been the common practice to test the “ goodness of fit” of couplings by contrasting the observed series with the calculated series and trusting to the eye to detect the agreement.
The danger of this method has been effectively pointed out by Collins (4), who proposed using Yule’s coefficient of association with its probable error as a quantitative method of making the compari- sons. For the higher degrees of coupling the coefficient of associa- tion with its probable error does not afford a satisfactory method of comparison, since the differences between the higher couplings, when measured by the coefficient of association, are extremely small.
With couplings of this nature and where more than two coupled characters occur, a method proposed by Pearson (13) can be used. By the use of Elderton’s tables (9) the method is very simple. Cau- tion, however, should be observed in applying this method as a measure of correlation where the characters are departing from the Mendelian expected ratios. This method does not distinguish be- tween departures from the Mendelian proportions and differences in the way the characters are combined. Since the behavior of the in- dividual characters from a Mendelian standpoint need not affect their association with each other, we are not concerned with any discrepan- cies between the observed and expected percentages of these charac- ters, desiring only to know whether the characters under discussion are correlated or associated in a given proportion. It is obvious, then, that to measure the “ goodness of fit” of the observed associa- tion to the theoretical association by the use of Pearson’s formula (13) and Elderton’s tables we must first eliminate any differences between the observed proportion of the individual characters and the Mendelian expected ratios, otherwise an injustice will be done to the agreement of the observed with the theoretical association.
Mr. G. Udney Yule has recognized this difficulty in applying Pear- son’s formula to testing the “ goodness of fit” of a coupling ratio where the Mendelian ratios of the characters are skew, and in a letter to Mr. Collins suggested another method (15, pp. 585-590).
This method very satisfactorily corrects the material to the proper Mendelian proportions without altering the degree of association, but it seems to offer little advantage in cases of a low degree of
68 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
coupling over Yule’s coefficient of association, which is not affected by |
the Mendelian proportions of the characters.
As all our observed associations more nearly approximate the lower coupling series of 3-1-1-3 than any of the others proposed, the degree of association has been measured by Yule’s coefficient of asso- ciation (14), which has proved very satisfactory except in cases where one class is unusually low. This method has the advantage of being easily executed and comparatively rapid, which is no small item in figuring the association for hundreds of individuals, though its general application has been challenged by Heron (10).
As we are primarily concerned with comparing observed correla- tion with theoretical expectation rather than accurately measuring the degree of correlation, there can be no real objection to the formula proposed by Yule, which has been used throughout in comparing in- dividuals with a common ancestry.
GAMETIC CORRELATIONS IN THE TWO HYBRID DH 234 AND DH 237.
In all the early crosses between the Chinese variety with waxy endosperm and American horny varieties the second-generation seed showed a correlation between the color of the aleurone and the tex-
ture of the endosperm. The first exception occurred in the hybrid —
Dh 234. The reciprocal hybrid Dh 237 had, however, the usual cor- relation between colored aleurone and horny endosperm. The gametic formulas for the aleurone color have already been
considered on pages 32 and 33, where the hypothesis was adopted that:
in the hybrid Dh 237 the gametic composition of the Chinese parent was cP cR and of the Algeria parent Cr cr. Adding the symbol H for horny endosperm texture and A for the waxy texture, we have for the Chinese c?/A cA and for the Algeria CRH Cri.
In crossing cRA and CPRH a colored horny seed would result which when planted would make gametes CRH, CHh, cRH, and cRh, and when self-pollinated woutd result in ears having 3 colored seeds to 1 white and 8 horny seeds to 1 waxy. Wherever ch and CrH are crossed, a colored horny seed would result, which when planted would make eight classes of gametes, CRH, CRh, Cr, Crh, cRH, cRh, erH, and crh, and when self-pollinated would result in an ear having 9 colored seeds to 7 white and 3 horny seeds to 1 waxy. This has been found to be true with respect to this hybrid, with the additional fact that a correlation exists between endosperm texture and aleurone color.
The Chinese parent of the second hybrid Dh 234 was assumed to have the gametic composition Crh Crh, while the gametic composi- tion of the Algeria parent was assumed to be CRH CRH. All the
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 69
seeds of a cross between the Chinese variety and Algeria would be col- ored horny. These seeds would all produce four classes of gametes, ORH, CRh, CrH, and Crh, resulting in ears with 3 colored seeds to 1 white and 3 horny seeds to 1 waxy when self-pollinated. This was found to be the case for all the ears secured, but no correlation was found between endosperm texture and aleurone color.
Since the aleurone color of the hybrids Dh 234 and Dh 237 is shown to be the result of two independent factors, it becomes appar- ent at once that the correlation previously reported ,as between aleurone color and endosperm texture must be looked upon as a cor- relation between endosperm texture and one of the factors for aleurone color.
CORRELATION IN THE SECOND GENERATION OF THE HYBRID DH 234.
The homozygous color factor in the hybrid Dh 234 was designated C and the heterozygous factor was called &. Second-generation seed from this hybrid produced 37 ears, the result of self-fertilization or of crosses between sister plants in the same hybrid. (Table XX XI.)
If the association were between the endosperm texture and the factor for color R, these ears would show a correlation, but should the association be between the color factor C and the horny endo- sperm texture the 37 ears obtained would exhibit no correlation, since all the gametes are homozygous for this factor. The correlation between aleurone color and horny endosperm texture for the 20,483 seeds borne on the 87 ears was 0.004+-0.013, which is less than the probable error. Two individuals among these 37 ears showed cor- relations more than four times the probable error.
Two correlations, however, exceeding the probable error by 4.6 and 4.1 times would be expected to occur as the result of chance in 37 observations once in about 19 times. As this chance is small, these correlations may be considered as the result of chance. The remaining ears showed no significant correlations; 16 of the 37 ears had negative and the remainder positive correlations between colored aleurone and horny endosperm.
The results from the self-pollinated ears of the hybrid Dh 234 would indicate that there is no correlation between endosperm tex- ture and the color factor which is heterozygous in this maize hybrid. This factor has been designated 2.
er er + ee ee ee
= SSeS) a ee
i Win i Sele, ot ee, aie a Min
—
70 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TaBLeE XXXI—Correlation between the endosperm texture and the aleurone color of self-pollinated and pure-seeded ears of maize in the second genera- tion of the hybrid Dh 234.
[Lines bracketed together in pairs indicate ears borne on the same plant; ears selected for planting are designated by an asterisk (*).]
| | Pedigree No. oi— Number of seeds. Percentage of—
Correla- | Proba- | oa = Total, Boe ble | | Self-polli- .| error, Progeny ear. | Pare a Wx. | WH. 55 Waxy. | White. 1 | 2 4 8 9 | 10 li dl ees Seas 1106_<-.. 38 _ —0.019 | 0.071 24.3 25.1 iL ence Shee ; 1103..... 43 102 | .068 28.2 28.7 0 (0 ee if tis eee 39 139 | .072 27.3 30.9 NUE ee Self... 41 105} .07 24.9 28.6 Si ee oo ieee 19 — .047] .103 29.4 25.0 NOS eee ooo oe jail 2a 30 — .149}| .077 23.7 26.3 ae oa | Self. _... 44 | — .057 | .069 26.4 29.0 Ii eee ee ee es 46 } — .019 | .075 26.3 25.7 {ios ee a |...do. 2 at — .124 . 063 26.4 28.3 HOGS Fees < se | e492 = oS 17 — .277 . 093 21.3 28.0 | feet VEIN I i Self} ° 747 43 — .256 | .065 22.2 25.8 } 733 70 . 201 . 057 27.4 29.3 643 48 014 | .068 28.1 26.2 428 34 .070 | .O081 28.0 | 26.1 508 41 -121 O74 27.9 26.3 322 22 -O17 | .096 26.0 27.0 on4 42 122 | .07 24.2 25.5. 623 40 -076 | .O71 21.9 27.9 414 31 023 | .084 25.8 28.2 655 39 — .064 - 07: 22.1 21d 687 45 -056 | .068 20.5 24.2 5595 37 — .003 . 075 25.0 25.4 605 33 — .095 | .075 23.8 25.8 571 28 -008 | .082 20.8 PAR: 212 12 | .055 | .088 21.3 25.0 614 35 .014| .075 23.3 24.1 334 22 .156| .097 21.2 26.0 659 26 SS igs 22.6 26.7 67 40 .007 | .071 22.7 25.7 492 28 -059 | .083 21.7 25.7 592 32 — .052] .075 22.9 25.0 626 30 — .057 | .07 23.3 22.0 57 27 -008 |} .082 20.9 23.0 417 32 -180} .082 24.2 26.1 633 37 123] .073 22.2 22.8 479 30 — .112} .079 24.6 28.8 | 57 30 054 | 1062 | 21.2] 22.8 | 20,483 | 1, 295 11, 444 | = 008 | 0125| 24.2| 26.3
CORRELATION IN THE SECOND GENERATION OF THE HYBRID DH 237.
If the correlation is between the color factor C and horny endo- sperm, the self-pollinated ears of the hybrid Dh 237 should exhibit a correlation between aleurone color and endosperm texture, since this hybrid has been assumed to be heterozygous for the factor C. From this hybrid 20 ears were obtained that had approximately 25 per cent of the seeds white, indicating that these plants were homo-
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. oh
zygous for the color factor & (Table XXXII). These 20 ears had a total of 12,394 seeds with a correlation of 0.769-0.006 between colored aleurone and horny endosperm. The lowest correlation se- cured in any individual ear was 0.697-+0.385, which is certainly a significant correlation.
The correlation for the combined seeds of these 20 ears was a very close approximation of the 0.766 expected on the assumption that the correlation is the result of a 3-1-1-3 reduplication in the gametes. One ear, No, 1128, has a correlation exceeding the expected 0.766 by 3.8 times the probable error, but the remaining ears are exceptionally close approximations of the 3-1-1-3 coupling, and with 20 ears one such deviation is not surprising. |
TABLE XX XII.—Correlation between the endosperm texture and the aleurone color of self-pollinated and pure-seeded ears of maize having approximately 25 per cent of the seeds white in the second generation of the hybrid Dh 237.
(Lines bracketed together in pairs indicate ears borne on the same plant; ears selected for planting are designated by an asterisk (*).]
Pedigree No. of— Number of seeds. Percentage of—
Progeny ear. eae Motal es (ten | WV Ee nO exGe cH, |W+X.) error. Waxy.| White.
1 2 8 4 5 6 q 8 9 10 11
IPI as a None 647 74 74 65 434 | 0.741 | 0.032 21.4 22.8 ITO a RE do 672 94 77 63 438 789 | .026 23.3 25.4 12ers Secaeta Self. 837 129 112 72 524 786 | .023 24.0] 28.7 hy eee Seeene ors 1125 723 102 88 75 458 751 | .027 24.4} 26.2 Lege eat a tietta Self. .... 319 46 23 34 216 868 | .027 25.0 21.6 iI IBAE) heal ela Al Aloe au Ne 102 87 78 480 .766 | .026 24.1 25.1 eT. Soe een nie Ee 7AL 96 92 59 494 794 | .025 21.0 25.3 HIS 2 0 ore ers, Self. ore. 575 80 80 54 361 739 | .033 23.3 27.8 ii iB 2 esha Meter hp do 758 104 71 83 500 798 | .024 24.6 23.0 [SNe ley he ge do.. 627 83 83 52 409 774| .029 | 21.5 26.4 135) ee a 113765 615 104 71 72 368 764 | .028 28.6 28.4 Si eLearn Solftee. 740 125 80 68 467 829 | .023 2610) |) Nome [Steeped pe Ciel anh Uc 548 70 58 70 350 715 | .037 25.1 23.3 Mes a osc Soleo 712 89 71 76 476 VTA 027 23.2 22.5 [ EGE ee Ba 174 634 85 79 76 394 697 | .035 25.4 25.9 Masters ie Ai Self.2ii¢ 472 60 59 45 308 .749 | .036 | 25.2 25.2 (7 aE Sm | do 485 63 BT 47 318 .759 | .036 23. 6 24.7 HBS PND do B15 59 68 59 389 .702 | 039 20.5 22.1 Tee eee Oy eae le do 625 82 57 67 419 .799 | .030 23.8 22.2 if Sa 0 do 342 58 40 32 212 818 | .031 26.3 28.6
Total 27/11 | OE 12,394} 1,705 | 1,427] 1,247] 8,015 .769 | .0064| 23.8 25.3
Since the hybrid Dh 234 with the gametic composition Crh ChH did not show a correlation between endosperm texture and aleurone color and the hybrid Dh 237 with the gametic composition chh CRH did show a correlation, we can assume that the correlation is between the color factor ( and endosperm texture. Additional evidence that the correlation is between a factor for color and endosperm texture is obtained from the self-pollinated ears of the hybrid Dh 287 that
72 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
had approximately 43.75 per cent white seeds, indicating that the plants in question were heterozygous for both color factors C and R.
If the correlations were independent of the gametic composition, we might expect no consistent differences in the degree of correlation between the monohybrid and dihybrid ears; but if, on the contrary, the correlation is between a factor for color and endosperm texture, the correlation should be reduced in a definite degree on the dihybrid ears. The reason for this reduction in the degree of correlation follows.
A plant which when self-pollinated produces an ear with a di- hybrid ratio of colored to white seeds and a monohybrid ratio of horny to waxy seeds must be heterozygous for both color factors and endosperm texture.
If we assume that the association is between a color factor C and horny endosperm /, and if we further assume that the association results in the combination CH being formed three times as often as the combination CA, we then have the above plant. making the following gametic classes: 3 CRH, 1 CRh, 3 CrH, 1 Crh, 1 cRH, 3 cRh, 1 crH, and 3 crh.
The union of the gametes CrH and cr will result in a white horny zygote; and since C’ and H are the associated factors, these seeds will be produced in relatively large numbers, resulting in a reduc- tion in the degree of correlation between colored aleurone and horny endosperm. 7
A plant which when self-pollinated produces an ear with a mono- hybrid ratio of white to colored seeds, as well as a monohybrid ratio of horny to waxy seeds, must be homozygous for one color factor and heterozygous for the other color factor as well as endosperm texture. If we assume the heterozygous color factor to be the one which is associated with endosperm texture, we have the above plant making the following gametic classes: 3 CRH, 1 CRA, 1 cRH, and 3 ch. The union of gametes CRH with cRH results in a colored horny zygote.
Thus every gamete carrying the color factor C results in a colored zygote, and the correlation is the same as if it were between color and texture rather than a factor for color and texture, and the nor- mal 41-7-7-9 zygotic grouping is expected, and the correlation be- tween colored aleurone and horny endosperm is 0.766.
When the dihybrid ratio of white to colored seeds is obtained, all of the gametes bearing the factor for color C do not result in colored seeds, and the zygotic classes are altered from the above 41—7—7-9 to 123-21-69-48 and the correlation is reduced from 0.766 to 0.570.
From the hybrid Dh 237 four self-pollinated ears were obtained that had the percentage of white seeds closely approximating 43.75,
INHERITANCE OF WAXY ENDOSPERM IN MAIZB. 73
the expected ratio where two independent factors are required to produced a colored seed (Table X.X XII).
TABLE XXXIII.—Correlation between the endosperm texture and the aleurone color of self-pollinated ears of maize having approximately 43.75 per cent of the seeds white in the second generation of the hybrid Dh 237.
Pedigree No. of— Number of seeds. Percentage of—
Self-pol- W+X.!} error.
Progeny ear. linated | Total.| WX.| WH. | CX. CH. Waxy. | White. o. 1 2 3 4 5) 6 7 8 9 10 11
} 1738 ER epee oven See Self..... 664 94 190 42 338 0. 60 0. 045 21.0 42.75 PAUSE Bea ee ea (0) 560 94 179 28 259 653 046 21.6 48.2 NGS 38 Bepeeeecot| Gre do 595 93 163 45 294 577 046 23.2 43.0
1 CY (a aS eee aA (OES do 658 96 163 51 348 601 033 22.3 39.3 Motaless jel. tee ds 2,477 377 695 166 | 1,239 603 023 21.9 43.2
The total number of seeds for the four ears are grouped as follows:
Number of seeds.
Class. CRIA OT el | ILEALER, CNL POMCI UE aan aT oR) Correlation. CH. CX. WH. | WX.
CLES) ay 0 ea 2 Bs aU Sa 1, 239 166 695 377 0. 603+ 0. 0229 Beepectedma.e tactics dees oot: Hee. OF EEE ROE” | Pee: 1,190 203 668 416 . 570
The agreement is very close, the deviation of 0.033 being but slightly larger than the probable error, and none of the four ears comprising the group deviated in excess of twice the probable error.
CORRELATION IN CROSSES BETWEEN THE TWO HYBRIDS DH 234 AND DH 237.
If the above explanation is correct and the association is between the factor for color C’ and horny endosperm Z/, a cross between the two first-generation hybrids should result in two groups of ears, one group all colored, the other group with four classes of seeds, but no correlation. Both these groups were obtained; the all-colored group has been previously discussed under aleurone color, and the progeny of three such ears are considered from the standpoint of correlations on pages 88 to 95.
Nine ears were obtained with the hybrid Dh 234 as the female parent and eight ears were secured with the same hybrid used as the male parent. These 17 ears showed four classes of seeds, indicating that the plants of the hybrid Dh 237 were heterozygous for the color factor C as well as endosperm texture. None of the correla- tions are above 0.1, 9 being plus and 7 minus correlations. The two groups are shown in Table XXXIV. Together they aggregate 10,032 individuals with a correlation of 0.0149+0.0166.
74 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE XXXIV.—Correlation between the endosperm texture and the aleurone color of ears of maize, crosses between the hybrids Dh 234 and Dh 287, using each as the male and as the female parent.
CROSSES BETWEEN HyYpBrips Du 234 * D8 237.
Pedigree No. of— bd Number of seeds. its : Fevpentaes Self-pollinated. Ee q 5 Recipro- a) 2 Progeny ear. calcross.| _; E S ub g Re ret We oy A ts Smale pee | ce Bohl aes He pal GOS ches oat tees 1 2 3 + 5 6 7 8 9 10 11 12 13 WSUS eee se R265 ee ig) ORR Passe 510 28} 102 82} 298 | 0.014 |0.083 | 21.5 | 24.5 24h ae Arey Hee None WOQD eect None....| 773 40 149 126 458 |—.012 | .069 | 21.5] 24.5 POSOM aye Souths We Bacae= PSST aes UiS4 ke 676 36 | 146 97 | 397]. .005} .073| 19.7] 26.9 TSS Pe eae ae ee None SSRs es - 1729.5. 707 35 123 116 433 033 | 073 | 21.4) 2204 POSSEE enn ee ae Ce) W539) 2 None 609 33 | 123] 117] 336 |—.107 | .075 | 24.6] 25.6 540s Oey ee 362 5e: None UR 655+ 679 Sie beset 85 5403 1 2023 S072 oes aaa Ge 5 Se eee ee None (0) None 631 36 99} 123] 373 048 | .074 | 25.2] 21.4 11Ge 8 a ae PR aces 1543 eee NPP se se 515 24 90 96} 305 |—.028 | .087 | 23.3 | 22.1 W546 sess F222. VATE: 15472233 W46sen 32 800 42 154 163 441 |—.151 066 | 25.0} 24.5 NEY fem ee a Ag So Ee aD aes ee 311 {1,110 |1,035 |3, 444 |—.035 | .024 | 22.8 | 24.1 CROSSES BETWEEN HYBRIDS DH 237 * DH 234. TAP esi ee Cie IGF Mey ee L266 SUS erga 472 34 91 80 | 267 -109 | .079 | 24.2; 26.5 NI S4aE See AY ESE Aes MiSdeseee 1osOeseee 516 27 106 92 291 |j—.124 | .082 | 23.1 25.8 IEP AY TS panpiee SNAPS GSR. Sees INoneL- + elos22 ee 613 40 108 129 336 |—.019 | .O71 | 27.1 24.2 ICRI asco cate None 76-5. 5405-2 458 25 86 77 | 270} .010] .088} 22.3} 24.2 5 UP Lie tara a aes 1 Bee PR Sse ee 542 eeee 677 41 | 152] 121 | 363 |—.106 | .068 |} 23.9] 28.5 AGE ea Race et 5A eee Arie 546 see 621 47 121 115} 338 j|—.069 068 | 26.1 27.1 RAG) Sears See None None None 401 27 75 65] 234] .129] .088 | 22.9} 24.9 CPA aes SA ein ately Ce) do do 374 30 60 89} 195 041 | .087 | 31.8] 24.1
4 ° ot sv} — ‘J ‘ ‘ . oe _ Oo bo bo ~J _ a] (fe) co B bX bo ve) i Oo — On i=) bo ~] bo on _ bt om Oo
With an association between one of two factors for color and endo- sperm texture, a variety of zygotic ratios may be obtained, even though the assumption is made that the gametic reduplication is only of the series 3-1-1-8. Table-XX XV gives the degrees of correla- tion expected between endosperm texture and aleurone color where the assumption is made that the reduplication in the gametes between endosperm texture and a factor for color ((’) is of the series 3-1-1-38.
The minus sign is used to indicate a correlation between colored aleu- :
rone and waxy endosperm; the other correlations are between colored aleurone and horny endosperm. Column 4 gives the gametic com- position of the two parents which, when crossed, give the zygotic classes shown in column 5 and the correlations shown in column 1. The letters C and # represent color factors. HW represents the domi- nant character, horny endosperm, and h waxy endosperm.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 75 TABLE XXXV.—Possible degree of correlation between aleurone color and endo- sperm texture, the gametic reduplication being 3-1-1-3.
4 {A correlation between colored aleurone and waxy endosperm is indicated by the minus sign in column 1; the other correlations are between colored aleurone and horny endosperm. ]
Percentage of— : | Gametic composition Zygotic _ Degree of correlation. of aTORES: Becca White. | Waxy. 1 2 3 4 5 TEU Dele 2 eee nie ik Bieed 2a © Satie 9 ae, Area, eet Satete 50 50 | CcRrHh CcRRhh..... 3- 1- 1- 3 Semen) PRS) A ee te os PN Se a) cont ea BS 50 50 | CcRrHh CcRRhh..... 1- 3- 3-1 IAT a ee Seip: NER RS WI Tet ON Ce TF hy een ab 25 25| CcRRHh CcRRAN... 41- 7- 7-9 me ATU VS aE gic he ALU oe 8 ae ee dy a 25 25| CcRRHh CcRRAh... 33-15-15- 1 AT oS ee ees EU ee SRST a a ee et 25 50 | CcRRHAHh CcRrhh..... 7-5-1-3 OI Bsa Fe URES es yf WR ON 25 50 | CceRRHh CcRrhh..... 5- 7- 3-1 (PGE I ESS Pace es May ak ace aS ey 50 25 | CcRRHh ccRRAN.... 7-5-1-3 CSTR aS ee a ame ie 1 ts aie Gk gee Ber ae ome tA 50 25) CcR RHAh ccRRAN... 5- 7-1-3 GAZKO) A I elt CR i Bb PO SERB Fits el AR haa 43. 75 25 | CcRrHh CcRrHh..... 123-21-69-43 Ree eR (peer CPV EN eee cast Pad Oe od i 43.75 25) CcRrHh CcRrHh..... 99—45-—93-19 SEL) SST BOS BR i Rate reed Peres Ee teers Paces 43.75 50 | CcRrHh CcRrhh.....- 21-15-11-17 =a HUD s Sees tes 2s eee extakeeperepeaeim a det eg athe 43.75 50 | CeRrHh CcRrhh...... 15-21-17-11 (Dail AS Ee ie Sa ee RO ce ana Oe cr Pepe Se 50 50 | CcRrhh ccRRHh..... 1-1-1-1 (DBRS ARS EMA ELE NS RL et OAR See ran Bo be 50 25 | CCrrHh cckrHh..... 3- 1- 3-1
1 The first figure in column 5 is the colored horny, followed by the colored waxy, the white horny, and the white waxy zygotes, respectively.
CORRELATION IN THE THIRD GENERATION OF THE HYBRID DH 234.
Two ears from each of the two first-generation hybrids were selected for planting. The four classes of seeds from each ear were planted in separate rows. Crosses were made between plants from the white waxy and colored horny seeds and between plants from the colored waxy and white horny seeds. Self-pollinated ears were also obtained from all the classes, but the ears resulting from self- pollinating the colored horny seeds are the only self-pollinated ears that exhibit four classes of seeds.
The two ears grown from the hybrid Dh 234 are shown in Table XXXII as pedigree Nos. 1099 and 1111. Ear No. 1099 was the result of pollinating a plant of the hybrid Dh 234 with pollen from a plant of the same hybrid which when self-pollinated produced ear No. 1106. Both these ears curiously enough have exactly the same degree of association, or, rather, lack of association, — 0.019 LOT,
The other ear, No. 1111, was the result of self-pollinating a plant of hybrid Dh 234 and had a correlation of —0.256+0.063, heretofore referred to as one of the two ears that might be held to show a significant correlation.
a eee, mead
wy ee ag,
NN aS a eS ee ee Se . ‘\
Rae. Se a ae eee ee re ee a are ee eae a Pee
76 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
TABLE XXXVI.—Correlation between the endosperm texture and the aleurone color of 32 ears of maize, the progeny of ear No. 1099 of the third generation
of the hybrid Dh 234.
WHITE WAXY X COLORED HoRNY.
Pedigree No. of— bd Xr | = ‘ Percent- Number of seeds. S K age of— Self-pollinated. = > jo) Progeny Recipro- ip bess a : ear. cal cross. = : os $s B 2g oe Q $ < = be ee 2 iS) a iS aE Ro Os aS Fie aie 1 2 3 4 5 6 7 8 9 | 10 | 11 12 13 R55 2S eee 16442-- 25 All white | 1643..... 506 | 113] 119 | 114] 160} 0.145 |0.061 | 44.8 | 45.8 waxy 1 es Seed ee 1705 225222) do: 2 None. 230 60 53 60 | * 57 | 0.036 |0.088 | 52.2 | 49.1 5G Sea et None...--- None. 222 )5> Olt 2 257 56 72 53 76 045 | .085 | 43.4 | 51.0 PGA ae je22dos 2-200: dois. 438 92 120 128 |- 98 |—.260 061 | 50.2 | 48.4 To tales. J. ee he RE A BR a: 1,431 321 364 355 391 |—.102 035 | 47.2 | 47.8 COLORED WAXY X WHITE HORNY. | 2 V52Es ea All white .| 1573....... 1604... .. 127 22 40 31 34 |—.247 | .115 | 41.7 | 48.8 GT é Sie Berne None....- Sy Ae ee None 645 166 151 161 167 067 053 | 50.6 } 49.2 TG es ea Of INone!-_ 1610s 468 114 134 107 113 |—. 054 062 | 47.2 | 53.0 Rae a ee 73 (i eeepc Wl 25 eee ays 16255 5e= 406 111 103 84 108 162 065 | 47.8 } 52.4 1599 3. Fe All white .| 1591....... 1619.22 2 580 145 | 142 146 147 014 056 | 50.2 | 49.4 EEE eee Goteeee alet 503m 1621 307 86 61 | 101 59 |—.104 { .078 | 60.8 | 47.9 Wotaleet. MA EL SANE PISS Tae 2,533 | 644] 631} 630] 628] .009 | .027 | 50.7 | 50.7 WHITE HorNy X COLORED WAXY. S&S. GQ2t ae es All waxy..} 1603....... None 322 76 7 82 90 018 | .075 | 49.0 | 46.6 160402 4.2 5. bs dos2:? £25) 316052..52 5.2 1572. 171 46 42 42 41 046 | .103 | 51.4 } 51.5 GOES ees ee lee done 16072 Sao None 391 95 101 109 86 |—.148 | .069 | 52.2 | 50.1 16TO-.32 45 None...- None...... $579N5 5. 303 44 60 104 95 |—.197 | .079 | 48.8] 31.5 HGIQ=2 Se All waxy--| 1620.20.25 1590053 467 110 112 123 122 |—.013 062 | 50.0 | 47.6 1 (GUA & hae aS 2) (oS do.......] 1622. P5OR ET S 348 86 74 105 83 |—.042 072 | 54.9 | 46.0 Lia)! ee el ee donee ss |ENones ena plps4eea 497 134 120 129 114 |—. 044 } .062 | 53.0] 51.5 NO24 ape Boe ee GOLas se alec Oe None.. 67 17 19 13 18 108 | .054 | 44.8 | 53.7 Potal 206.2200: pcgin LR ACES 2, 566 | 60s | 602] 707 | 649 |—.037 | .027 | 51.3 | 47.2 COLORED HORNY X WHITE WAXY. NG62602- shee All waxy..| None...... None....| 427) 412) 107} 5 93 | .068 | .088 | 51.0 | 52.9 1635555524 ONG}. 23) F F UG3GFL SE Leases dots 703 179 169 177 178 -032 | .051 | 49.5 | 50.6 Sy AO Aliiwaxy=3|| 1638222 <2.) 225 does: 424 | 109] 109 99 | 107] .042/] .088 | 51.4 | 49.0 P6392 £320) ok Govse-te ores. 5 he : dort. 123 32 28 33 30 | .019 | .121 |} 48.8 | 52.9 GAT ee ae INGH OMe G42) ee d0-==-< 396 | 106 93 90 | 107] .151 | .066 | 50.2 | 495 1G4S Ss All waxy. .} 1644....... 1G 511 | 1383] 129] 130] 119} .044] .059 | 51.3] 51.4 AGA5 Soe ae do. LOAG T560 Leese 510 | 120} 116] 135] 139 |- .034) .060 | 46.3 | 50.0 Ge Eee ese doz: None... None....| 387 80 85] 113] 109 047 | .070 | 42.6 | 50.0 Totalesecs ia. ith Oe sae ces te 3,481 871 836 892 882 014 | 023 | 50.5 49 0 COLORED HORNY X SELF. GQ wena Selfzae2se- Selfece sel eit eee 464 27s) tO 72} 255 |—.068 | .059 | 29.5 | 21.3 T6565 Soe nse! Ci Co eee eet (eee (a eee el RE 573 49 102 97 325 .239 | .066 | 26.4 | 25.5 WGSSoess sees dole | do S| Se eee 573 34 112 105 322 .030 | .076 | 25.5 | 24.3 LR Dee al ee dOs2 2273)! dO ea eee ee eee 551 31 103 113 304 |—.152 | .076 | 24.6 | 26.2 10% 2 Lee eS eae do: ss dol a a ee 652 45 138 121 348 .009 | .067 | 28.1 | 25.5 1646.25.05). ed0.5.. 355] doe [ys See ae 368| 21] 58] 65] 224] .195| .095 | 21.5 | 23.4 NOY RT [ik Sey Ce oe me Pees. ee Sp wa Tate at OL kee 3,181 | 207 | 623 573 {1,778 0152] .031 | 26.1 | 24.5
a
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
TABLE XXX VII.—Correlation between the endosperm texture and the aleurone color of 23 ears of maize, the progeny of ear No. 1111 of the third generation of the hybrid Dh 234.
WHITE WAxy X COLORED HORNY.
Pedigree No. of— Number of seeds.
Corre- | Prob- ’ lation, | able Progeny ear. Gers eeRTG. Total. | WX. | WH. | cx. | cH, |W+| error. 1 2 3 4 5 6 q 8 9 10 LGAS 5 ORR 2 ere ee GOS aR Se None 712 179 166 202 165 |—0. 062 0. 049 Gp lees eke CEE ree br eas: HEQ42 hy ewe e Gow 286 77 72 62 75 .128 . 078 IGP 2S aL Se Ss WOO Eee creel es do..... 611 142 140 160 169 . 035 . 068 GE GS ree Bes a gee = USS aa55e\laee doles 387 97 80 105 105 . 098 . 068 ROGUE en ee een ne INOTO@S es ee Gdoe-ee 600 155 155 128 162 -119 055 ITO Galles cok Se oy att aetrcrertie ons eee 2,596 650 613 657 676 044 026 COLORED WAXY X WHITE HORNY. GTB 25S Gee een ee eee | NGS TeRb o.o4 | 1686. .... 403 105 101 100 97 | 0.005 0. 067 GO taser ne ee ees ot None ..| None 87 20 20 25 22 |— .064 .144 Ota eereerer er Pee Ne ae yeti 490 125 121 125 119 |— .009 . 061 WHITE HORNY X COLORED WAXY. GSO) ee ds st | All waxy. None.... 448 110 95 126 117 | 0.040 0. 064 NGSG Ae. eS eee oe 8 GOnee=t 1665220" 370 90 89 108 83 |— .125 .071 RO Gale Bere ta ee ee WR i ee ce Re eK, 818 200 184 234 200 |— .036 . 047 COLORED HORNY X WHITE WAXY. GOs Seco ewddas aoe eoeoe All waxy..}| None 393 95 96 117 85 |—0. 164 0. 067 Ll AO eS se ek Se eee NAG Oss Lee doz 511 126 126 119 140 - O81 . 060 17S eee Soe ae BEGORE Bae eal oe dos: 192 51 53 49 39 |— .350 .078 AEDES: (Ore a ec eek BASSE .-do. dora s 458 114 106 126 112 |— .022 . 085 ZARB Baa aOR ee a ene 220: dose 181 56 42 38 45 aa . 096 ZS) Cae eee A eee pad owe. dole 179 57 41 37 44 |— .246 . 096 7/1 Sees eU aA Aa ee .-do. Obese 561 36 150 151 124 .147 . 056 NE: Sa eran SP Rs FEGOLE do..... 304 168 81 73 82 |— .029 .077 AD Hee oA Sa voets cider le we CORgsesee| tee do..... 290 77 73 76 64 |— .060 .079 AMOR LS 5 ah Me OE SAAS Se a LE ea eS 3, 069 780 768 786 735 |— .024 . 024
As no correlation was found on the second-generation ears of this hybrid, none was to be expected on the third-generation ears. Fifty- five ears were obtained, representing many combinations. With the possible exception of two ears, Nos. 1564 (Table XXXVI) and 1704 (Table XX XVII), no correlations were obtained. The individual
ears shown in these tables are so arranged that the ears resulting
== = =
cited EE AE eee
Se a Fe Se
GIRS ECR AR PE le PS Ons
78 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
from the same cross may be readily compared. Ear No. 1564 had a correlation of 0.260+0.06. A correlation of this magnitude would be expected to occur as the result of chance once in 267 times, but since it occurs in a group of four, it would be expected as the result of chance once in 67 times.
Ear No. 1704 had a correlation of 0.850+0.078, which is 4.5 times the probable error, and should occur as the result of chance once in 415 times, but since it is but 1 in a group of 10 individuals, the odds against its chance occurrence are 42 to 1. We may with some propriety conclude that the correlations found on these two ears are accidental. The results, then, as shown by the third-generation ears support the assumption that this hybrid is homozygous for the color factor C.
CORRELATION IN THE THIRD GENERATION OF THE HYBRID DH 237.
Two ears were selected and grown from the hybrid Dh 237. These two ears are shown in Table XXXII, pedigree Nos. 1129 and 1150. Ear No. 1129 was the result of self-pollinating a plant of the hybrid Dh 237, and ear No. 1130 is.a second ear from this same plant. The male parent of this latter ear, when self-pollinated, produced ear No. 1135. Ear No. 1129 had the exact degree of corre- lation which is expected on a 8-1-1-3 coupling, 0.766+0.026, while the second ear of the same plant, No. 1130, had a correlation of 0.794 +0.025. The male parent of ear No. 1130 had a correlation of 0.774 +0.029. These two ears are very close approximations of the 0.766 correlation which is expected on a 3—1-1-3 coupling. There were, of course, four classes of seeds on each of these two ears. The dif- ferent classes were planted separately.
Crosses were made between plants from the white waxy seeds and plants from the colored horny seeds from the same ear. These crosses were made, using white waxy plants as the female parent, and also as the male parent. Self-pollinated ears were also secured from all the plants to make sure that they were of the type expected. The self-pollinated colored horny ears, however, are the only self- pollinated ears that would have all four classes of seeds. The three ears obtained from self-pollinated plants grown from colored horny
seeds of ear No. 1129 are shown in Table X XXVIII.
The correlation for these three ears is 0.770+0.017. This cor- relation is certainly a close approximation of the expected 0.766, but upon examining the three ears that make up the total we find the difference between the extremes to be 0.884+0.06, a difference of more than six times the probable error, which can hardly be ascribed to chance fluctuation. The ear with the lowest correlation (No.
1796, correlation 0.450+-0.063) deviates from the expected 0.766 by
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 719
0.316, which is slightly in excess of five times the probable error. The correlation of 0.45 is rather close to the expected 0.57 where a plant heterozygous for two color factors is self-pollinated, but the percentage of white seeds, 21.9, precludes this explanation.
Fortunately another ear borne on the same plant was pollinated by a plant grown from a homozygous white waxy seed. If ear No. 1796, deviating from the expected correlation of 0.766 by five times the probable error, represents but a chance fluctuation from this correlation, then the first ear of this same plant should, when crossed with white waxy, produce an ear with a correlation approximating 0.8. The ear representing this cross is ear No. 1795. (Table XXXIX.) The correlation found was 0.887+0.05, certainly not an approximation of 0.8. These correlations show that the two ears of the plant were pro- ducing the same ex- cess of gametes bearing colored waxy and white horny genes. The relations of these ears are shown in figure 11.
Since the male parent of ear No.
‘1795 was a homozy- Ped (796 VIG:
gous recessive, the
zygotic ratio ob- Fig. 11.—Diagram showing the relations of ears Nos. 1796 ; and 1795,
served on this ear
is also the gametic ratio of the female gametes within the range of chance fluctuation.
To determine the gametic ratio of this ear as accurately as possi- ble the sum of the two reduplicated groups was divided by the sum of the nonreduplicated groups and the gametic ratio found to be 1.5 to 1, or 3 to 2. The expected correlation on an ear the result of self-pollinating a plant with the gametic ratio of 3-2-2-3 is 0.517. Ear No. 1796 is the result of self-pollinating the plant which bore ear No. 1795 with the above gametic ratio. The observed correlation on ear No. 1796 is 0.45, which deviates from a 0.517 correlation by 0.067+-0.063, the deviation being insignificant. The plant, then, which produced ears Nos. 1795 and 1796 may with propriety be con- sidered as having formed gametes in the proportion of 3-2-2-3, while the majority of ears with a correlation have been shown to approximate the gametic series 3-1-1-3.
The adherents of the linkage theory would look upon this de- parture from the expected as a mutation of the locus of one or both
80 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
of the characters, resulting in the distance separating them being widened from 25 to 40 units. To explain this gametic ratio on the reduplication theory requires but a simple alteration of the pe of cell division, assumed to account for 3-1-1-3 couplings.
The 3-1- 1-3 gametic ratio is assumed to be the result of the type of cell division eens in figure 12, and the 3-2-2-3 coupling merely requires that the cells Ad id aB divide once while the cells AB, ab are undergoing two divisions. (Fig. 13.)
The fact that both of these ears had approximately the expected percentage of both white and waxy seeds demonstrates beyond doubt that the distributions observed are not due to a failure to properly classify the material or to the presence of other factors that would influence the expected proportions. If these correlations are to be
a&B
Fig. 12.—Diagram showing the type of cell lic. 13.—Diagram showing a possible modi- division proposed by Punnett to explain a fication of figure 12 to account for a 3—1-1-3 gametic coupling. 38—2—2-3 coupling.
looked upon as the result of reduplication the only explanation is to admit other series than those proposed. ‘The remaining two ears of the three self-pollinated horny plants are sufficiently close approxima- tions of the expected 0.766.
Five ears were secured from plants grown from the white waxy seeds of pedigree No. 1129 that were the result of pollinating these plants with plants grown from the colored horny seeds of the same ear. Three ears were also obtained where the parentage was re- versed. These eight ears are shown in Table XX-XIX.
The first group had a correlation 0.806+0.017 between colored and horny, the expected being 0.8. Of the individual ears only one de- viated in excess of four times the probable error, that one—No. 1764— deviating by eight times the probable error. The correlation of 0.91, observed on this ear, is intermediate between the 0.8 expected
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 81
on a 8-1 coupling and the 0.96 expected on a 7-1 coupling, though it is a closer approximation of the latter. The deviation of 0.06+-0.013 from the 7-1 coupling is, however, 4.6 times the probable error.
Ear No. 1764 has a reciprocal ear in No. 1799. This ear had a correlation of 0.7, a deviation of 0.10.03 from the expected 0.8, and differing from No. 1764 by 0.210.048, which is almost 4.5 times the probable error. <A self-pollinated ear was obtained from the same plant that bore ear No. 1799. This self-pollinated ear is No. 1800 (Table XXXVIII). The correlation of 0.834 observed on this ear is higher than the expected 0.766. The deviation of 0.068--0.02 from 0.766 is 3.4 times the probable error, which is rather large to be attributed to chance. The relations of these ears are shown in figure 14.
Fic. 14.—Diagram showing the relations of ears Nos. 1764, 1799, and 1800.
Since the female parent of ear No. 1764 was homozygous for waxy endosperm texture, the correlation of 0.91 represents the reduplica- tion in the gametes of the male parent. This reduplication is higher than the expected, the degree of correlation indicating the reduplica- tion to be closer to a 7-1 than a 3-1; in reality the series very closely approximates 4.5-1. The reciprocal ear of No. 1764—No. 1799—has a lower reduplication series than 3-1-1-3, being in reality 2.4-1.
The correlation of 0.834 on ear No. 1800, the self-pollinated ear of the heterozygous colored horny parent, indicates a gametic series in- termediate between the 4.5-1 and 2.4-1.
The expected correlation in self-pollinating a plant with a male gametic series of 203-44-45-206 and a female gametic series of 168—71-80-191 is 0.788. Ear No. 1800, which represents such a self- pollinated ear, has a correlation of 0.834+0.02, the deviation of 0.046 from 0.788 being no larger than is to be expected.
89356°—19—_6
82 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
This difference between the male and female gametes in the degree of reduplication could be brought about by a higher death rate pre- vailing in the pollen grains carrying white horny and colored waxy, the combinations that came from opposite parents. It might be urged that these combinations reacted in an unfavorable way, lessening the life of the pollen grain or so reducing it in vigor as to have a larger proportion of the ovaries fertilized by the parental, white waxy and colored horny combinations.
It would be necessary that the death rate be alike for the two com- binations, colored waxy and white horny, or the percentages of white and waxy would be found deficient. This is in itself an argu- ment against this explanation, since it seems improbable that CX and WH should happen to be equally weak. The ‘percentages of white to. waxy seeds for the three ears are sufficiently close approximations to the expected to indicate that the two combinations were retarded about equally.
Ear No. 1764 had 50.2 per cent waxy and 50.4 per cent white seeds, certainly very close to the expected 50 per cent. The reciprocal ear, No. 1799, had 51.4 per cent waxy and 53.2 per cent white seeds. The differences between white and waxy percentages of these two recipro- cals are not significant. The percentage of waxy seeds on the self- pollinated ear (No. 1800) is almost exactly the expected percentage, while the percentage of white seeds is in excess of the expected by more than three times the probable error. That the excess of white seeds on this ear is not brought about by a failure of the pollen grains carrying colored waxy combinations is demonstrated by the percent- age of waxy seeds, which is normal. In other words, if the high percentage of white seeds is due to a high mortality of the pollen grains carrying colored aleurone, this mortality must have been equal in the pollen grains carrying colored-waxy and colored-horny com- binations.
The expected grouping compared with that observed for the 755 seeds is as follows:
Number of seeds.
Class. ; CH. OXxE COVE. Wx 10S 9 0 SO ko ea eS Se AOR OnoLneoore Soo soo SSeobebuososccceucdosges ~ 484 82.5 82.5 106 Gieeaad DOS are ha a or Se Ste ee CB esac 476 64 88 127
As can be seen, there was a failure of both colored horny and col- ored waxy gametes, but greater in the colored waxy than in the col- ored horny, while a corresponding increase is noted in both the white horny and white waxy. combinations, though the increase is much larger in the latter case. The figures would seem to indicate that the
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 83
higher correlation was due to the weak growth of the pollen grains carrying the odd character combinations. If this be the case, it should also be observed on ear No. 1764, but not on ear No. 1799, as the male parent of this ear was making but one kind of pollen grains—white waxy.
The grouping for ear No. 1764 is as follows:
Number of seeds.
Class. CH. OX. WH. WX. IBDADOUNG | Gu boGondacdd ge oneas ese Sou oosuadocoonodedoLdbbacdouaoud 186.7 62.3 62.3 186.7 QSO IVC Ge rea ce re eee ee aire a mle eae fareterota ls siataienluaaicialslevela/aieieeis 203 44 45 206
These figures would certainly seem to indicate that the odd combi- nations CY and WH were in some way at a disadvantage when com- pared with CH and WY.
The grouping for ear No. 1799 is as follows:
Number of seeds.
Class. CH. CX WH. WX TP GOL KLIS hes Se lessee cease ica ie aca esol ane Mea cen a eet 191.3 63.7 63.7 191.3
ODE SESN eyo 20 Le eae iy SR Oe ea SO Og ee cbin ca e ae 168 71 80 191
The low correlation on this ear is obviously due to paucity of colored horny female gametes, a combination that would not be expected to be deficient. No question of the vigor of part of the pollen grains is concerned on this ear, since they were all alike. A shortage in the colored horny gametes was indicated on the self- pollinated ear (No. 1800), but not to the extent noted on ear No. 1799, while an increase was observed of the white waxy gametes on ear - No. 1800, which was also found on ear 1764, but not in such an increased degree as would naturally be expected.
Summing up the three ears, we find ear No. 1799 indicating that the female gametes were deficient in the colored horny combination, practically the expected proportion of white waxy gametes, and a slight excess of the two.odd combinations. The male gametes, as in- dicated on ear No. 1764, were in excess in both the colored horny and white waxy combinations and deficient in the odd combinations.
From these two ears we would expect the self-pollinated ear to be deficient in colored horny seeds, in excess in white waxy seeds. Using the zygotic ratios of the male and female parents as repre- senting the actual gametic ratios, we find the white waxy combina- tion in excess by 20 in the male gametes and equal in the female gametes; so we would expect an excess of about 20 in the self-polli- nated ear, and we find an excess of 21.
84 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The colored horny combination in the male gametes was in excess _ by 17 and deficient in the female gametes by 21; so a deficiency of 4 | would be expected on the self-pollinated ear, and we find a defi- ciency of 8. ;
The colored waxy combination in the male gametes is deficient by | 18; in the female gametes this same combination is in excess by 8; | so a deficiency of 10 would be expected in the self-pollinated ear, | and a deficiency of 18 is noted. |
The white horny combination is deficient by 17 in the male | gametes and in excess by 17 in the female gametes; so that they _ would be expected in the theoretical proportion on the self-pollinated | ear, and we find an excess of 6. This agreement of evidence derived | from so many different sources would indicate that the departures | observed were the result of a definite and unexpected gametic series | formed by the plant which bore ears Nos. 1799 and 1800, rather than | fluctuations due to chance. |
The three ears that were obtained when plants grown from white | waxy seeds were used as the male parent had a total of 1,293 seeds | with a correlation of 0.610+0.025, but since one ear of the three | has been shown to be of entirely different coupling this ear should | not be included in the totals. Omitting, then, this one ear, No. 1795, which is outstanding and does not belong to the series, the | total number of seeds then becomes 740, with a correlation of | 0.737+0.025—a deviation from the expected 0.8 of but 2.5 times the | probable error. |
Nine ears were secured from plants grown from the colored waxy | seeds as the male parent, and two ears were secured from plants — grown from the white horny seeds as the male. These ears are also shown in Table XXXVI. The correlation for the total number of | seeds is not significant. One ear, however, No. 1781, has a negative | association between C and H of 0.220+0.059, a deviation from a zero correlation by 8.7 times the probable error. This ear could in all - probability be looked upon as the result of chance fluctuation in — sampling, though closely approximating the 0.27 expected when a> plant heterozygous for the color factors C and Ff and horny endosperm texture with a 3-1-1-8 coupling between the factor C and waxy endosperm is crossed with a homozygous waxy plant heter- | ozygous for the two factors for color. |
As a test of the possibilities of securing a correlation when cross- | ing two plants, one heterozygous for endosperm texture and without | the factor for color C, the other homozygous for endosperm texture | and heterozygous for the factor C’, crosses were made between plants — from white horny seeds and plants from colored waxy seeds. These — crosses were made, using the colored waxy plants as the female parent | and also as the male parent. |
i) =
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 85
It is obvious that no coupling could occur in the gametes, but Col- lins (4) reported significant correlations on two ears representing a similar cross that as yet can not be explained. It would be possible, however, to obtain a correlation by crossing a plant grown from a white horny seed with a plant grown from a colored waxy seed where two factors are required to produce color, and the correlation is be- tween one of these color factors and endosperm texture.
TABLE XXXVIII.—Correlation between the endosperm texture and the aleuron2 color of 22 ears of maize, the progeny of ear No. 1129 of the third generation
of the hybrid Dh 237. 7 COLORED HoRNyY X SELF.
Pedigree No. of— ; a Number of seeds. a ag Percentage ao e iS) of— ~ i H Progeny ear. Self-pollinated. 3 ¢ 5 ane 3 < Sel aot er eas : eae ee ule peels || ee) e (e) St Y mM io) ah S K faa i= = o S oO Ay i e 1 2 3 uf 5 6 q 8 9 10 11 12 13 TOAST AS 8 Bieta EUs aD ok Ov a 8 ee Le 296 24 41 42 | 189 | 0.450 |0.063 | 23.3 | 21.9 LDS are eta otra Sees cn sre etats ovellls aiig wicteia isn cieiareiahetere ats 752 | 107 71 87 | 487] .788 | .025 | 26.2 | 23.7 (ECU Se eae eS aa OL oo ES i ay 755 | 127 88 64 | 476 | .834 | .020 | 25.3] 28.5 ROTA ESS: OR Rep rek COTA LE Sen cio A 1,803 | 258 | 200] 193 |1, 152 HON AOL ileceetelees ese
WO Die rs ors 3 INOnNese 22s. UA Sa454 None....| 553 164 117 104 168 | 0.387 |0.050 | 48.5 50.5 PM Baas panna eee Ose a2 |. Boe aeec alee doz ==. 230 93 32 24 81 -810 | .036 | 50.9 54.4 1 DE ae ee doses eee) 1800 2242 1764.2... 510 191 80 71 168 700 | .034 | 51.4 5de2 POC ATs eee oe Stee et has eae: 1,293 |} 448 | 229] 199] 417 GIONS O25 ues sl|eeeeee COLORED WAXY X WHITE HORNY. AGG cece te ING ATS .3| aoomesede None....| 4382] 112} 102} 110] 108 | 0.038 |0.065 | 51.4] 49.6 M738 SSS Aee ee Gee CO a eee year a Ligier 144 33 35 42 34 |—.135 | .112 | 52.0 | 47.2 UNO See Ree eeu Ole ey sahein iy days ea ees Bias of sue HOM la Damour oo N14 nt. O09 Obi semee el liseesee WHITE HorRNY X COLORED WAXY. LUDA a ae INOne Yess te ase ee ce None....}| 448 95 | 120] 114| 119 —0.095 0.064 | 46.6] 48.0 Vi BOS aageSe eee GOeereme len cone ee cls dOn erly Ole 146 158 161 148 |— .082 | .055 | 50.4 49.6 WV BS Geneed Bee (OKRA a cleo ceess scllely(ices see 533 | 128 38 | 143] 124 |— .096 | .058 | 50.8} 50.0 LICH hes aes ee Tose do Bene None....] | 428 97 97 112 122 . 043 065 | 48.8 45.3 1 Re eee do seis vaecidtetess Dine sel, (400. 127 135 107 107 |— .036 062 | 49.2 55.0 Sloss ais cclsiec do. Sk aie Ghee) <4(7/ 105 137 128 107 |— .220 059 | 48.9 50. 4 SARE Seles Poe GOW Fe Fe eee Sree 8 Gonose Se SOlet 740) 1659) 1339) 119) |—121029))| 205601) 522 0h) = ib fa3 URS ees eee GOss lees ene ee do. 446 | 101 | 113] 110] 122 |— .004 | .064 | 47.3] 48.0 HSS cesar neces GORE saline: Satay oe douse al 1886 87 | 102 95 | 102 |— .044 | .069 | 47.2] 49.0 L010 (8 Se Cea I BB oe ora 4,398 |1,060 [1,165 |1,103 |1,070 |— .061 | .020 |......]......
86 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The assumption can then be made that the white horny plant is producing gametes (Hr, Chr, cHr, and chr, with a correlation be- tween C and H. Such a plant, if self-pollinated, would produce an all-white ear with 3 horny seeds to 1 waxy.
The colored waxy plant might be making gametes CRA Crh. A cross between a colored waxy plant of this nature and a white horny plant such as has been described would result in an ear with four classes of seeds: CH, 7; CX,5; WH,1; WX, 38; correlation, 0.615. In this case, however, the percentage of white seeds is but 25, and _ the correlation is 0.615, while in the two ears reported by Collins, one had 380.1 per cent white with a correlation of 0.3730.057, and the other had 48 per cent white and a correlation of 0.470.056. It is at once apparent that neither of these ears could be looked upon as approximations of the above zygotic arrangement.
From the second ear of the hybrid Dh 2387, No. 1130, from which the six classes of seeds were planted, three self-pollinated ears from colored horny plants were secured that had four classes of seeds (Table XX XIX). These three ears had a correlation of 0.7250.017, slightly lower than the expected 0.766. None of the three ears devi- ated from the expected in excess of three times the probable error, though all three were below the expected. As the result of crossing plants grown from white waxy seeds with plants grown from colored horny seeds of ear No. 1130, six ears were obtained by using the white waxy plants as the female parents, and five ears were obtained by using the white waxy plants as the male parents. These 11 ears are also shown in Table XX XIX.
The 6-ear group had a correlation of 0.809+0.01, which is a very close approximation of the expected 0.8. None of the individual ears of this group deviated from the expected correlation by as much as three times the probable error.
The ears of the 5-ear group had with one exception lower correla-
tions than the lowest obtained in the 6-ear group. The correlation _
for the five ears was 0.76+0.01, which differs from the 0.809 correla- tion obtained in the reciprocal ears by 0.049-+-0.015. None of the ears in the 5-ear group deviated by as much as three times the prob- able error from the expected correlation. These two groups, together with the three self-pollinated ears from the colored horny plants, are certainly very close approximations of the expected results where the coupling is of the form 3-1-1-3. The individual ears exhibit a re- markably uniform grouping of the four classes of seeds.
Crosses were also made between plants from the colored waxy seeds and plants from the white horny seeds, which should result in ears with no correlation.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE.
87
TABLE XXNXIX.—Correlation between the endosperm texture and the aleurone color of 14 ears of maize, the progeny of ear No. 1130 of the third generation
of the hybrid Dh 237.
{Lines bracketed together indicate ears borne on the same plant.]
COLORED HORNY X SELF.
Pedigree No. of—
Number of seeds. S Percentage umber of seeds Cor- mad ian Self-pollinated. Hon able Progeny Recipro- W+x| &tror ears. cal cross. 3 fe} Total.|WX.|WH.| CX.| CH. Waxy.|White. 1 2 3 4 dD 6 q 8 9 10 11 12 13
TSAQ Rees ees Selita | ete aN yas 2 aay 308 38 46 37 | 187 | 0.615 10.060 | 24.3 27.5
1 yey ee aes] ee (OOS Be iad eae are se ell Sl are a 721 83 97 72 | 469 | .695] .084] 21.5 25.0
SEAS NR (6 1 ce RN St RN COT [Re 563 76 56 56 | 375] .740] .0385} 23.5 23.5
TNO Ca api seese al rset se ee ok syne 1,592 | 197 | 199} 165 |1,031 C20 OL |e 22a 75 | 2409 COLORED HORNY XK WHITE WAXY.
TERY Ae eae INNES D/eslosebenbeoc 1804. .... 545 | 193 78 67 | 207 | .768 |..027 | 47.8 49.8
ISO alge Gell ae dows a a eae None....| 415] 153 67 55 | 140] .706} .037} 50.1 53.0
1846 res Exe dons see ESS a ee do....| 621] 219 80 86] 236] .765 | .025]} 49.2 48.2
1840 ees OK o ee i ice set hy Soe eee 581 | 222 79 77 | 203 | .754 | .027 } 51.4 51.8
1854 ance dont es Gaos 1816. .... 614 | 223 76 83 | 232] .784].024} 49.8 48.7
TOES | reps eee alec cet a | afte ae 2,776 {1,010 | 380} 368 /1,018 | .760 | .012] 50.1 52.0 WHITE WAXY X COLORED HORNY.
1804......- IN ONG Peers |e R aerate LS3Sese= 363 | 132 47 34 | 1504 .850 | .027 | 45.7 49.3
TSOG RE Bese GO nese ae None....| 435} 180 52 57 | 146] .799 | .027 | 54.5 53.3
WOT 52 hela oe Gon ees Vase oe SR SS 0.. 275 95 32 41 | 107] .775 | .037 | 49.5 46.2
TS1O aS eae Gore nies |e tee esas (op eee 441 | 183 60 55 | 143 | .776 | .028 | 54.0 55.0
ESTDE ee ae ae (6 (0) Bear Pe ee Be 1849..... 465 | 164 60 53} 188} .814 ] .025 | 51.0 48.2
UM Beoanec 1S a ss eee ens 1854..... 515 | 215 57 65 | 178} .824 | .023 | 54.3 52.8
TOLLS eater | Sameer 2,494 | 969] 308 | 305} 912] .809 | .011 | 51.0 51.2 CoLORED WAXY X WHITE Horny.
18184. B53 Allliwhite jie. 0222222 URS Bee 7541 185 | 182{ 181] 206 | 0.074 |0.049 | 48.6 48.7
S20 Eee SS ales One eee ete None.. 207 57 52 47 51] .686 | .C95 | 48.0 49.8
1 tc Diy aes Bae ees Olt SSF [oss Sens 1836..... 542} 136] 1385] 157 | 114 |—.155 | .057 | 53.8 50.0
IDSs obese INONCG2 ee eeecweenes 1S35e Rose 584 | 139} 148) 129) 168] .100°} .055 | 46.0 49.2
CEO Gala Sees eee see ties | es cre pagans | isc meee 2,087 | 517} 517} 514} 539} .042 | .029 | 49.6 49.4 WHITE HORNY X COLORED WAXY.
142 7( See ae ALL Ways al eseeeae eke 1818 eee = 644 |. 170 | 163 | 140] 171} 0.119 |0.053 | 48.2 oileya
B20 a eeee ONCE selec None....| 511] 134] 128] 142] 107 |—.117 | .059 | 54.0 51.3
lisa ee ae PAU Wayne cence ales Gorse. 4341 116 98 | 100] 120] .173 |} .063 | 49.8 49.3
1834......]... (6 OY ype | Pee ar Fa do....] 511] 128] 128] 122] 13837 .043} .060 | 49.0 50.5
1835 See aaleee (6 Foyt OE EMA Be Ba a 18254 e5 503 | 125] 131] 129] 118 |—.068 | .060 | 50.5 56.9
1836272 2 secloee Goer rea ee Se 1822 ane 297 58 91 69 79 |—.156 | .077 | 42.8 50. 1
PNG Gale ree ce sree mt erst ree mre THE Sh ek me 2,900 |} 731 | 739 | 702] 728 013 | .025 | 49.4 50. 6
As the result of such crosses 10 ears were obtained, 4 with the colored waxy plants as the female parent and 6 with colored waxy plants as the male parent (Table XX XIX). The highest correlation
88 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
secured was 0.173+-0.063 on ear No. 1833, which can not be considered significant, being less than three times the probable error.
The results obtained from the progeny of the two ears, Nos. 1129 and 1130, of the hybrid Dh 237 were, with a few exceptions, fairly close approximations of the expected results on the assumption that the gametes were formed in a series of 3-1-1-3.
SECOND GENERATION OF THE CROSSES BETWEEN THE TWO HYBRIDS DH 234 AND DH. 237.
Aside from the two first-generation hybrids between the Algeria and the Chinese varieties of maize, Dh 234 and Dh 237, and their im- mediate progeny, the result of self-pollination or crosses between two plants of the same hybrid there were 34 ears, the result of crossing the two first-generation hybrids. Seventeen of these ears were all colored with both horny and waxy seeds.
Three of these all-colored ears were grown the following season. One ear, resulting from using the hybrid Dh 234 as the female parent and the hybrid Dh 237 as the male parent, was renum- bered cross Dh 330 and grown under that symbol. The other two ears grown were the result of using the hybrid Dh 237 as the female parent and the hybrid Dh 234 as the male parent. These two ears were known as crosses Dh 333 and Dh 334. The female parent of the cross Dh 333 was used as the male parent of the cross Dh 330. :
On each of these three all-colored ears there are 16 classes of zygotes, only 6 of which will exhibit, when self-pollinated, ears with all 4 classes of seeds, colored and white horny and colored and white waxy.
All 6 of these classes of zygotes when planted and self-pollinated are expected to have horny and waxy seeds in the proportion of 3 to 1, while 4 of the 6 are expected to have colored and white in the pro- portion of 83to1. The remaining 2 classes are expected to have colored and white seeds in the proportion of 9 to 7. |
For the 6 classes of zygotes, 4 very different degrees of correla- tion are expected, in the following proportions: Four ears with no correlation between the colored aleurone and horny endosperm, 3 ears with a correlation of 0.766 between colored aleurone and horny endosperm, one with a correlation of 0.744 between colored aleurone and waxy endosperm, and one with a correlation of 0.380 between colored aleurone and waxy endosperm. Of the 16 zygotic combina- tions represented on the all-colored ears, only 2 classes of seeds could be distinguished, namely, horny and waxy. These were planted separately.. |
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 89
When the colored horny plants are crossed with the colored waxy plants, 6 of the 16 zygotic combinations are expected to exhibit all 4. classes, and since there are three classes of waxy, 14 combinations result, as shown in Table XLII. Of these 14 ears, 12 are expected to have colored and white in the proportion of 3 to 1 and horny and waxy seeds in equal numbers, while the remaining 2 ears are expected to have colored and white seeds in the proportion of 9 to 7, with equal numbers of waxy and horny seeds. The 14 classes of ears are ex- pected to be divided into five groups, with different degrees of cor- relation, as follows: Twenty ears with no correlation, 27 ears with a correlation of 0.615 between colored and horny, 9 with a correla- tion of 0.270 between colored and horny, 9 with a correlation of 0.615 between colored and waxy, 3 with a correlation of 0.270 between col- ored and waxy. The classes of zygotes are represented in Table XL.
TaBLeE XL.—Classes of zygotes on the all-colored ears resulting from crossing the hybrids Dh 234 and Dh 237.
Hybrid Dh 234. Gametes. CRH. | CRh. Cr iH. Crh. SMO ee (ok oe, OP Al Give Duin Yearly, Ol 6@ii Outs @ TUCR DRE Ts PUTER ne! dete La ui 6) 6) @ RCH Eee 2 ys SAS BVA de ra eR MERE Sih eh Q) @) @) BOR Be 0) ise ee a BB or Ae Oe A AI (3) : (5)
The italic letters in the column boxes of the table represent the gametic combinations formed by the hybrid Dh 234, and those in the left-hand column represent the gametic combinations formed by the hybrid Dh 237. The figures 3, 1,1, and 3 preceding the italic letters in the left-hand column indicate the proportion in which each of these gametic combinations are formed in the hybrid Dh 237. Owing to the reduplication of certain combinations, resulting in an association of the color factor C and the endosperm texture //, there was no reduplication in the hybrid Dh 234.
Each circle in the table represents one of 16 zygotic combinations formed by crossing the two hybrids Dh 234 and Dh 2387. The circles are numbered for convenience of reference. Thus, owing to the reduplication, the zygotic combinations represented by circles 1, 2, 3, and 4 are present on the ears three times as often as the com- binations represented by circles 5, 6, 7, and 8. It must be borne in mind that two factors are required to produce colored seeds; these factors are represented by the letters C and R. The endosperm tex- tures horny and waxy are represented by the letters HW and h.
Taste XLI.—Evpectation of seed classes resulting from the self-fertiliz ation of
90 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
Table XLI shows the expected result of self-fertilizing the 16 classes of zygotes in Table XL. When horny and waxy seeds are both present on a self-pollinated ear the expected proportion 1s always 3 horny seeds to 1 waxy, within the range of chance fiuctua- tion.
the zygotes enumerated in Table XL.
Circle. Class of seeds. | Circle. Class of seeds. INOFeeec ge acces All colored. horny. Nos. 8 and 14...--- 3 colored to 1 white, all waxy. INOS 2andloseecnee Allcolored, horny, and waxy. ,|| No. 11............. 9 colored to 7 white, all horny. Nos. 3 and 9.......| 3 colored to 1 white, all horny. |} Nos. 12 and 15..... 9 colored to 7 white, horny, and Nos. 4,7,10,and 13.| 3 colored, 1 white, horny and waxy.
waxy. NO: 16.2... se52 250 9 colored to 7 white, all waxy. aloe Gases oaralae see All colored, waxy.
The following list shows the circles that would have four classes of seeds when self-pollinated, together with the degree of correla- tion expected :
Circles Nos. 4 and 7, no correlation.
Circle No. 10, correlation, colored and waxy, 0.744. Circle No. 12, correlation, colored and waxy, 0.880. Circle No. 18, correlation, colored and horny, 0.766. Circle No. 15, correlation, colored and horny, 0.570.
The proportions in which the different degrees of correlation are expected are as follows:
INOFCOrTe Ta GI OTA a eS eee ee ee ee re 4 ears. Correlation between colored and horny, 0.766_____________ 3 ears. Correlation between colored and horny, 0.570_____________ 3 ears. Correlation between colored and waxy, 0.744_____________ 1 ear. Correlation between colored and waxy, 0.380_____________ 1 ear.
Table XLII shows the expected results of crossing colored horny with colored waxy plants when the ears obtained exhibit four classes of seeds, the expectation being that these ears are to have horny and waxy seeds in equal numbers.
TABLE XLII.—E«vpectation of seed classes resulting from the crossing of colored horny with colored wary maize plants whose ears exhibit four classes of seeds.
l Circle. Color. | Texture. Correlation. s |
Number 4 X 8.........- 3 colored, 1 white... ...--| Horny and MARY =: None. INUHIben yy MiSs eee ee CO sooo SS ee ee eet Gh es at Sa Do. Nii ber 12 Saie ee ee hee Gowess ek set ah ae ee 5 (0S ae mice Do. Number dS XC 8= 2 as alae Se 0222 35 Besa ee. ee SE Goria Fe. Do. Number 10 X 14........ Be SACO aoe eae ete | eae doeeesi so osees Colored and waxy. 0.615. INUmM bernt2 Kelas | eee COLT eer ieee Re es oe a be ae (6 (ESN Do. Numberi3 X14. 24 1 ae Se ge en ee .do.............| Colored and horny, 0.615. ING bersl Ss Sola see Pe eee GO. eee oe SoA te ee ERE CG ss Do. Number4 s¢1622 24242 2/2254 ees Beets eee ee Cot Sanaa SNOneS IN Dery x<elOb. en eee Po La ieee PE a tee MA SR SIere Same RE AS Gos Gee at Do. Number 10 16222. * 4)/52.22 cB Le ee Ny aa = IED Oh cat Sider ba luh estas do ee Colored and waxy, 0.615. Number 12 X 16.......- Sicolored 7 white <3 |ee do........-....-| Colored and waxy, 0.270. NimberdS <162 525 3 colored, liwihttetstes a espa do.............| Colored and horny, 0.615.
Numbers osxel6s 9 colorediw whitees-o-- ses oho se do.............| Colored and horny, 0.270.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. O01
The proportions in which the different degrees of correlation are expected where colored horny is crossed with colored waxy are as follows:
INGE OERE Labi ee eat eras neue alee rer ae Sak 20 ears. Correlation between colored and horny, 0.615 _________-___ 27 ears. - Correlation between colored and horny, 0.270_-___________ 9 ears. Correlation between colored and waxy, 0.615___~_-__-_____ 9 ears. Correlation between colored and waxy, 0.270____________ 3 ears.
It can readily be seen that a very large number of individuals would be necessary to determine whether the ratios, together with the expected degrees of correlation, were obtained in the correct pro- portions. The results obtained from the cross Dh 333 can be dis- posed of rather easily, since only four self-pollinated ears were se- cured from the colored horny group (Table XLIII). With three of these ears it is not possible to accurately determine the degree of correlation to which to refer them, since the number of individuals is small. The fourth ear seems to have rather too high a degree of correlation between colored and horny to be referred to the expected 0.766, but the chances of such a deviation being due to an error in sampling are about 5.5 in 10. It can therefore be assumed that the four ears secured from the cross Dh 333 do not in any way conflict with the expected results.
The remaining crosses, Dh 330 and Dh 384, have a slightly larger number of ears with which to further test the fit of observed to theory, but it is not the number of ears, which indeed are far short of sufficient numbers to make an accurate test of proportions, but from the way in which they are related that the most interesting results are obtained.
Taste XLIII.—Correlation between the endosperm texture and the aleurone color in four ears of maize, the progeny of colored horny seeds of cross Dh 333 self-pollinated.
Number of seeds, Percentage of—
Progeny ear. S| OE | Total.| WX. | WH. | cx. | cH, |W+*.| error. | waxy. | white.
| f | | Be J |
1 2 3 4 5 6 | 8 9 10 ICE Bs Go aoonceusodsooccUbedas 337 16 53 78 190 | —0.153 | 0.103 27.9 20.5 eke Se sooerepecesdooasnaode 261 14 55 41 151 | — .032 117 21.1 26.4 LO QS. Pe oe aa creme ee ee cial e dike 33 2 3 9 19 . 169 270 33.3 15.2 eC isa seSacncosbobbciook oceae 424 58 47 39 280 . 800 031 2 24.7
At first glance the degrees of correlation obtained with the cross Dh 330 by pollinating the colored waxy individuals with the colored horny individuals and the reverse, together with the few self- pollinated horny plants, seem to very nearly approximate those ex-
92 - BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
pected on theory, as all of the correlations obtained could be re- ferred to some of the expected degrees of association.
The first ear shown in Table XLIV, No. 1856, has an exact recip- rocal in ear No. 1877, and the self-pollinated colored horny parent is ear No. 1878, both of the same table. All three of these ears show practically no correlation, and the Mendelian ratios approximate the expected. proportions. This group can be said to fulfill the ex- pected results where either circles 4, 7, 12, 15 are crossed with circle 8, or where circles 4 or 7 are crossed with circle 16 (Table XLIT).
The second group.-consists of ear No. 1860, its exact reciprocal ear No. 1874, together with the self-pollinated colored horny parent ear No. 1875 (Table XLIV).
TABLE XLIV.—Correlation between the endosperm texture and the aleurone color of 12 ears of maize, bhe progeny of the cross Dh 330.
COLORED WAXY X COLORED HORNY.
Pedigree No. of— mt Number of seeds. A . Rereeiiaes Self-pollinated. a = E Progeny ear. e s g o on ic} o aS Se ® SS Ray B ° S 3 Py ice las, lec loee ee ele 1 2 3 4 5 6 7 8 9 10 11 12 13 TSO6 Soe aeee UY ieee aaellocsecraoon A Siideecee 525 69 74 | 170} 212 | 0.075 10.067 | 45.6 | 25.4 1860 Nee caer: IS 75 ace oe | eee mens eyes ese 649 | 119 45 | 170] 315] .653] .039 | 44.6} 25.3 SGUe Se sa INIOH EWE Saal Bos were oS Gy Ale ees 450 51 58 | 153] 188] .034] .074 | 45.4] 24.2 lee eSseauses Bae GOressecleeaeaeeace None....| 679 72} 102} 234) 271 |—.114]} .059 | 45.0} 25.6 ES60 5S ace S75 Se veinnleG Se toerseel ae do....| 739] 143 38 | 237) 321] .670]| .081 | 51.4] 24.5 COLORED HORNY X COLORED WAXY. 1S7 eee | All waxy..| None....| 1861..... 81 10 11 23 37 | 0.188 [0.053 | 40.6 | 25.9 ISG ee as eae ae STORE ees AS6OE S322 137 25 16 46 50} .259 | .120} 51.8} 29.9 ILY(seeoopece INOne2 2-5. None....| None....| 377 86 36 | 115] 140] .491 | .064} 53.4] 32.4 CVA (heseasenc All waxy..| 1878..... TS56seee2 424 51 50 | 175] 148 |—.074 | .076 | 53.3 | 23.9 COLORED HoRNy X SELF. ISTE SORA BASS | Sa taseaaebs aes 8 Sinaia, Bee 716 | 104} 194 47 | 371 | 0.605 |0.042 | 21.1] 41.6 TRS fie Spee Caeser ONES Soul SEAS eae Ee eee er 496 32} 104 90 | 270 |—.040 |} .080 | 24.6] 27.4 ISP Baca booallead Os Has SA See a aosis Merescmsnae 136 19 42 9 66 | .588 | .077 | 20.6 | 44.8
Since the self-pollinated ear from the colored horny parent of the above reciprocals had approximately 9 colored to 7 white seeds with a correlation of 0.605 between C’ and H, it could have come only from circle 15 (Table XL). The expected correlation upon self-polli- nating circle 15 is 0.570, of which 0.605+.0.04 can reasonably be con- sidered an approximation.
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 93
There are three classes of waxy seeds with which circle 15 may be. crossed that will result in ears with four classes of seeds. These seeds are represented by circles 8, 14, and 16 in Table XL. Circle 8 can be eliminated, since a cross between it and circle 15 would result in an ear with no correlation. The choice lies between 14 and 16. The result of crossing circles 15 and 14 would be an ear with a cor- relation approximating 0.615 between C and H. This is a fairly close approximation to the 0.653+-0.039 obtained with ear No. 1860, but the correlation of 0.259+0.12 obtained with the exact reciprocal of ear No. 1860, namely, No. 1874, is a very close approximation to the expected 0.270, when circles 15 and 16 are crossed. In this case, as is Shown on page 90, the expected ratio of colored to white seeds is 9 to 7, while on the ear concerned, No. 1874, the colored seeds are approximately three times the number of white seeds. The corre- lation of 0.259 certainly can not be looked upon as a chance fluctua- tion from the correlation 0.615 expected when circles 15 and 14 are crossed. A case parallel to this is found in the cross Dh 334. The colored waxy parent pollinated by the colored horny is represented by ear No. 1902, the exact reciprocal is ear No. 1917, and the self- pollinated colored horny parent is ear No. 1918 (Table XLV).
TABLE XLV.—Correlation between the endosperm texture and the aleurone color of 10 ears of maize, the progeny of the cross Dh 334.
COLORED Waxy X COLORED HoRNy.
Pedigree No, of— bd Number of seeds. NM fg PERE Self-pollinated. a ; tela ox S| 3 Progeny ear. A z % S = & 3 4 eee ee tele. lias ea Pas ain care ease iinlesr at ie 1 2 3 4 5 6 vi 10; il 12 13 1 Sea ans eae ONS Saectere 1903 Ke eo NOR 2 ae) 765 | 166 49 | 249] 301 |0.640 |0.038 | 54.3] 28:1 O04 None...... None....}| None....| 443 57 58 162 166 | .002 | .073 | 49.5] 26.0 TOOG ae O23 Bone ee laos doOeesce 19222 .2- 315 40 41 112 116 | .076 | .085 | 50.1] 27.6 LOUG DSS occ ODS eet 1910..... 1924..... 485 71 32 | 146 | 236 | .563 | .042 | 44.7] 21.3 COLORED HORNY X COLORED WAXY. OARS oc pos All waxy..| 1918..... 1902S eee 452 80 40 | 170] 162] .348| .067 | 55.3 | 26.5 O22 ewiccmeeee pee CGA KAGE 1923..... 1906..... 421 56 53 156 160 | .040 | .046 | 49.4] 26.5 NODA AE Sele site cta| siete OSes a2 1925...-. 1909..... 415 83 25 125 182 | .658 | .049 | 50.6 6.9 COLORED HORNY X SELF LOLS SR oaaoe oot Clie caltcloatocece calluteeuseces 46 47 | 206 | .628] .054 | 27.0] 26.6 M23 cae sere hiall sts OMS staal] sciciectelsie su le wierele ofeicse 399 42 71 81 | 205 199 | .077 | 30.8 28.8
UTS Boe GOscO Hee emeod aoonodcsd lbobosonoue 59
te ee en ee a ee ee ee
— 94) BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The self-pollinated colored horny ear had approximately 3 col- ored seeds to 1 white and a correlation of 0.628+0.054 between C and H. This correlation is about midway between that expected for self-pollinating circles 13 and 15, though it is slightly closer to the latter. Self-pollinating circle 15 would have an expected ratio of 9 colored to 7 white seeds, but since the ear in question is a fairly close approximation to the ratio of 3 colored to 1 white it fits the expected proportions when circle 13 is self-pollinated.
Assuming the plant in question to be the result of planting circle 13, there are two classes of waxy seeds with which it may be crossed that will result in ears with four classes of seeds. These classes are represented by circles 14 and 16.
The ears secured by either cross would be alike, both having 3 colored seeds to 1 white and a correlation of 0.615 between C and H. Ear No. 1902, with a correlation of 0.640.038, is a close approxima- tion to the expected results on this basis, but the exact reciprocal ear, No. 1917, with a correlation of 0.348+0.067, can hardly be looked upon as approximating the expected 0.615. This correlation is much closer to that expected when circles 15 and 16 are crossed, but the ratio of white to colored seeds would in that case be as 7 to 9, and the observed ratio is a close approximation to the 3 to 1 ratio. In both the cases where the reciprocals differ in the degree of correla- tion the lowest correlation is found where the colored horny plant served as the female parent, indicating a higher correlation in the male gametes. This tendency has been observed with ear No. 1764 (Table XX XVIII), where a significant difference was observed in
_reciprocals, and also with ears Nos. 1804, 1815, and 1816 (Table
XX XIX), where smaller differences in this direction were observed.
This difference may be due to a higher death rate for the pollen grains bearing the character combinations resulting from different parents, or it may be that such pollen grains are less vigorous or that the male gametes are not being formed in the expected proportions.
The remaining ear of cross Dh 330 that resulted from pollinating colored horny individuals by colored waxy is ear No. 1876. There is no reciprocal of this cross nor is there a self-pollinated ear from the colored horny parent. The ratio of white to colored seeds is rather closer to a 8 to 1 than a 7 to 9, and the correlation, 0.491 +0.064, though low, may be looked upon as an approximation of the expected 0.615, when circles 13 and 16, 18 and 14, or 15 and 14 are crossed.
Of the three self-pollinated ears of the cross Dh 330, one ear, No. 1875, has already been discussed. Ear No. 1878, having no signifi- cant correlation, could be the result of self-pollinating circles 4 or
7, Ear No. 1882, with an approximate ratio of 9 colored to 7 white
seeds and a correlation of 0.538 between ( and HZ, is a very close ap-
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 95
proximation of the expected 0.570 when circle 15 is self-pollinated. The remaining ears of the cross Dh 334 also seem to approximate the expected correlations.
Ears Nos. 1906, 1904, and 1922 are all close approximations to the expected results of crossing circles 4, 7, 12, or 15 with circle 8 or 4 or circle 7 with 16. Ears Nos. 1906 and 1922 are exact reciprocals, and as such agree as well as could be expected. The colored horny parent of these last-mentioned ears had a self-pollinated ear, No. 1923, which could have been the result of the self-pollination of circles 4 or 7, so that ears Nos. 1906 and 1922 are probably the result of crossing circles 4 or 7 with circles 8 or 16. Ears Nos. 1909 and 1924 are exact reciprocals, and with the self-pollinated ear from the colored horny parent, No. 1925, make a complete group. The self- pollinated colored horny parent is a very close approximation to the result expected when circle 13 is self-pollinated. The reciprocals, Nos. 1909 and 1924, are in fairly close agreement with each other and are close approximations to the expected result of crossing circle 13 with either circle 14 or 16.
SUMMARY OF THE CORRELATIONS BETWEEN ENDOSPERM TEXTURE AND ALEURONE COLOR.
The preceding experiments were undertaken in the spring of 1910 with the view to determining whether the previously observed coherence between endosperm texture and aleurone color could be referred to the 3-1-1-3 reduplication series of Bateson and Punnett. The intention was to obtain a number of individuals large enough to determine definitely the degree of reduplication, as well as to decide whether all plants gave the same reduplication ratio.
The experiments have now been carried to the third generation, and the degree of correlation with 17,015 seeds has been found to be 0.762+0.0057. This correlation is a very close approximation to the 0.766 expected if the reduplication was of the series 3-1-1-3. Some plants have been found, however, which gave reduplications other than 3-1-1-8, and it is possible that succeeding generations of these will throw additional light on this complicated subject. In some cases the departures could be readily explained by slightly modifying the theory proposed by Punnett as to the type of cell division, which resulted in the 3-1-1-3 ratio, but in other cases an extremely complicated theory of cell divisions would be required to give an adequate explanation of the observed ratios.
To explain the aberrant cases by Morgan’s linkage hypothesis, we would be forced to believe that at least one of the characters was insecurely located on the chromosome, since with the widely different: correlations obtained it is necessary to assume that the mutation of the locus of at least one of the characters is of frequent occurrence.
96 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
With a new series of hybrids between these same varieties compris- ing some 20,000 seeds, a correlation has been obtained which more nearly approximates a 4-1-1-4 than a 3-1-1-3 gametic series. The correlation for these last hybrids differs from that obtained in the original crosses by more than eight times the probable error. From this we must conclude that the correlation between the same char- acters differs widely in different families, though the individuals within a family seem to approximate the same mean.
We must further conclude that the association between these two characters in maize does not. always fit the arbitrary series of 3 to 1, 7 to 1, etc., proposed by Bateson, but that in some instances the couplings more nearly approximate the intermediate points of this series, such as 4 to 1, 5 to 1, etc.
It is not intended to imply that the: reduplication found in the gametes is the direct result of unequal cell division, although the observed results can be explained on such a hypothesis. The assump- tion that for the higher coupling ratios segregation must take place before synapsis in order to permit of the proper number of cell divisions seems thus far unwarranted by any cytological evidence.
A study of the Mendelian behavior of the aleurone color has led to the realization that since characters are the result of many factors more or less independent the correlations must also be between these invisible factors rather than between the visible characters. |
The fact that correlations are between factors which can be de- tected only when in combination with certain other factors permits of many different degrees of correlation and lessens the degree of confidence to be placed in conclusions regarding both the factorial composition and the correlations or couplings. There is danger of explaining aberrant Mendelian ratios by the predication of correla- tions and to explain aberrant coupling ratios by assuming changes in the factorial composition. Because of this fact, great care must be given to the analysis of correlated characters from the standpoint of their Mendelian behavior, since much depends upon the number of factors involved.
Reciprocal crosses between plants heterozygous for endosperm texture and aleurone color and plants homozygous for the recessive characters waxy endosperm and colorless aleurone have shown in many cases that certain character combinations are deficient in the male gametes. It is suggested that this deficiency may be due to a higher death rate, less vigor, or a failure of the plant to produce these odd combinations in the proper proportions.
If we can assume that correlations are the result of unequal cell division, we can further assume that the reduplicated character com- binations are also the most vigorous. Thus the tubes from the pollen | grains bearing the reduplicated characters may grow more rapidly ~
INHERITANCE OF WAXY ENDOSPERM IN MAIZE. 97
than the pollen tubes from the grains bearing the odd combinations. Such a difference in the rate of growth would not occur in the female gametes, and they would be present in the theoretical proportions unless a differential death rate supervened.
Tt does not seem unreasonable to believe that any reaction, which causes the more rapid division of the cells bearing the correlated characters, may also cause the gametes with these same combinations to be more vigorous. In most cases when an ear is pollinated there are enough pollen grains on each stigma to insure the presence of all gametic combinations, and if any difference in the rate of growth prevailed for a certain gametic combination most of the seeds would be fertilized by that combination.
CONCLUSION.
A thorough understanding of the laws of heredity is essential in determining the most effective methods of breeding plants and ani- mals with the special characters that are needed for purposes of com- mercial production under different environmental conditions. It is of general interest to practical breeders at the present time to know the extent to which it is possible to rely upon the application of the Mendelian principles of heredity. Assurance has been given by cer- tain writers that analysis and recombination of characters of varie- ties by the Mendelian methods could be substituted to advantage for the methods of selection that have been considered as the most effective means of obtaining improved strains. ~
An adequate investigation of the current theories in regard to the laws of heredity requires the detailed analysis of results derived from the study of large numbers of individuals. In this respect the seeds of maize offer unusual opportunities. Instead of a single offspring, or a few, from 400 to 800 seeds result from a single application of pollen, and the technique of hybridization is extremely simple. In addition to the ease of manipulation and the relatively. large num- bers obtained, maize seeds offer the further advantage of several alternative characters which permit rapid and accurate classification. This makes possible the definite determination of questions which depend upon the regularity of the proportions in which the charac- ters are represented in the various hybrid stocks.
With these possibilities in view, the experiments reported in this bulletin were undertaken in 1910, to analyze further the inheritance of contrasted characters and to obtain a clearer understanding of the nature of the interrelations or correlations between such charac- ters. The characters chosen were the waxy endosperm texture found in a variety of maize from China and the colors of the aleurone cells with which this endosperm texture was known to be associated.
89356°—19——7
98 BULLETIN 754, U. S. DEPARTMENT OF AGRICULTURE.
The results of this analysis show that the number of seeds with the waxy endosperm reappearing in the perjugate generation of waxy X horny crosses is less than the expected for a simple Men- delian character, but this deviation, though significant, is too small to warrant the predication of additional factors. In making this determination, more than 100,000 seeds were classified, and it has been possible therefore to establish*the actual percentage within 0.3 of 1 per cent.
The same material was used to test the inheritance of aleurone color, which also was found to depart from the theoretical ratios. Unlike the waxy endosperm texture, no definite trend above or below the expected ratios was observed, but many abnormal ratios were obtained which necessitated further refinements in the factorial analysis of this character.
From the results of the Mendelian analysis of aleurone color and endosperm texture it must be concluded that in many cases uniform Mendelian reactions are obtained which allow certain predictions to be made with respect to the behavior of these characters in subsequent generations. But that these predictions based upon the gametic an- alysis will be uniformly fulfilled must not be supposed. As we have seen, aberrant behavior is far from uncommon, increasing with the progress of investigation and the refinement of analysis. The fact is coming to be appreciated that instead of a few simple unassociated factors most characters are composed of many complex units which may no longer be considered singly but that their interrelations or correlations must be taken into account.
_ The present investigations show that certain of the more definitely
alternative characters of maize are subject to variation or fluctuating behavior that renders these supposed Mendelian factors too irregular to justify a belief that the very definite relationship predicted in the- ories of gametic coupling could exist between such characters. There can be little doubt, however, that at least with several combinations of characters the gametic ratios are to a certain extent regular, but that these ratios fit any arbitrary series is not so well demonstrated.
For the breeder of crop plants where most of the desired characters are almost infinitely complex, seldom alternative, and often intangi- ble, Mendelism seems to have little of practical value to offer, whether the attempt of some investigators to so extend the theory to embrace such characters be approved or not. While Mendelism may assist in making desired combinations, there is nothing to show that it can serve as a substitute for selection either in finding the best stocks or in preserving them from subsequent deterioration.
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LITERATURE CITED.
BATESON, WILLIAM, SAUNDERS, EpitH R., and PUNNETT, R. C. 1906. Experimental studies in the physiology of heredity. Rpts. Evol. Comm., Roy. Soc. Rpt. 3, 53 p., 4 fig. CASTLE, W. E., and PHILLIPs, J. C. 1914. Piebald rats and selection. Carnegie Inst. Washington Pub. 195, 56 p., 2 pl. Bibliography, p. 31. Cotuins, G. N. 1909. A new type of Indian corn from China. U. S. Dept. Agr., Bur. Plant Indus. Bul.,161, 30 p., 2 pl. 1912. Gametic coupling as a cause of correlations. Jn Amer. Nat., v. 46, no. 550, p. 569-590. | 1918. Mosaie coherence of characters in seeds of maize. In U. S. Dept. Agr., Bur. Plant Indus. Cir, 182, p. 19-21. and Krmpron, J. H. 1912. An improved method of artificial pollination in corn, U. S. Dept. Agr., Bur. Plant Indus. Cir. 89, 7 p., 2 fig.
1913. Inheritance of waxy endosperm in hybrids of Chinese maize. In 4th Conf. Intern. Génétique Compt. Rend. et Rapp., 1911, p. 347-357. 1913. Inheritance of waxy endosperm in hybrids with Sweet corn. Jn U. S. Dept. Agr., Bur. Plant Indus. Cir. 120, p. 21-27, 1 fig. ELDERTON, W. P. 1902. Tables for testing the goodness of fit of theory to observation. In Biometrica, v. 1, pt. 2, p. 155-1683. HERON, DAVID. 1911. The danger of certain formule suggested as substitutes for the correlation coefticient. In Biometrica, v. 8, pt. 1/2, p. 109-122. Morgan, T. H. . 1911. Random segregation versus coupling in Mendelian inheritance. In Science, n. s., v. 34, no. 873, p. 334.
PEARL, RAYMOND, and MINER, J. R. 1914. A table for estimating the probable significance of statistical con- stants. In Maine Agr. Exp. Sta. Bul. 226, p. 85-88.
PEARSON, KARL.
1900. On the criterion that a given system of deviations from the prob- able in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling. In Phil. Mag. and Jour. Sci., s. 5, v. 50, no. 302, p. 157-175.
YULE, G. U.
1900. On the association of attributes in statistics. Jn Phil. Trans. Roy. Soc. London, s. A, v. 194, p. 257-319.
1912. On the methods of measuring association between two attributes. In Jour. Roy. Statis. Soc, v. 75, pt. 6, p. 579-652, 3 fig. Dis- cussion, p. 643-652. References, p. 641-642.
1914. Fluctuations of sampling in Mendelian ratios. In Proc. Cambridge Phil. Soc., v. 17, pt. 5, p. 425-482.
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