Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. i | 30 U. S. DEPARTMENT OF AGRICULTURE. BUREAU OF PLANT INDUSTRY—Circular No. 120. ™ ih, IGEN PY 4 4 <¥ 4 we AA A - WILLIAM “X. PAYOR, Chief of Bureau. 22 Ke - MISCELLANEOUS PAPERS. Testing Cultures of Nodule-Forming Bacteria The Work of the San Antonio Experiment Farm in 1912 Inheritance of Waxy Endosperm in Hybrids with Sweet Corn Leaf-Cut, or Tomosis, a Disorder of Cotton Seedlings - Issued April 5, 1913. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1913. K. F. KELLERMAN S. H. HASTINGS G. N. COLLINS and J. H. KEMPTON 0. F. COOK BUREAU OF PLANT INDUSTRY. Chief of Bureau, WILLIAM A. TAYLOR. | Assistant Chief of Bureau, L. C, CorBETT. Editor, J. E, RocKWELL. Chief Clerk, JAMES EK. JONUS. [Cir. 120] : me [Cir. 120—A.] TESTING CULTURES OF NODULE-FORMING BACTERIA? By Ikari EF. KELLERMAN, Physiologist in Charge of Soil-Bacteriology and Plant- Nutrition Investigations, INTRODUCTION. The importance of leguminous crops 1n maintaining soil fertility or in rejuvenating overcropped and worn-out fields has long been recognized by practical farmers. Critical investigations carried on both in the laboratory and in the field have shown that this method of improving soil conditions is dependent chiefly upon the simultaneous development of a leguminous crop and the variety of bacteria which can produce root nodules and fix atmospheric nitrogen in suitable form for plant food. Although these nodule-forming bacteria are widely distributed in nature, there are regions where they are lacking, and they should be artificially introduced into the soil in these regions. This may be ac- complished either by transferring from 200 to 500 pounds of soil per acre from a field where the leguminous crop shows abundant root nodules to the new field where the same legume is to be planted, or by the application of artificially prepared cultures of bacteria to the seed before planting or directly to the field itself. Though inoculation by the pure-culture method has proved less universally successful than the soil-transfer method, the artificial cultures possess certain important advantages, especially the greater ease of their trans- portation and application, as well as their freedom from danger of intreducing weeds or plant diseases.? VARIATION IN INOCULATING POWER. A plausible explanation for the occasiona: failure of cultures of Bacillus radicicola to properly inoculate a crop is that the bacteria, though able to grow vigorously in the culture medium, have actually deteriorated in the essential quality of being able to infect the leguminous roots and to produce nodules. Testing the cultures at frequent intervals on potted plants in greenhouses or on small plats 1 Issued Apr. 5, 1913. Messrs. F. L. Goll and L. T. Leonard, scientific assistants, have assisted in working out _ the details of construction of the testing apparatus and its utilization in the laboratory. ~ 2 These facts are discussed in more detail in previous publications of the Bureau of Plant Industry. "> L®) [Cir. 120] 4 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. of leguminous crops in the field has been relied on to show which strains of bacteria had but a moderate or low inoculating power and which were most efficient. While these tests were useful, they were seldom entirely satisfactory, due to the frequency of chance inoculation of plants in either plats or pots by worms, insects, dust, and unsterilized water. It is obvious that tests of cultures should be carried on under sterile conditions, which should at the same time resemble as nearly as possible the soil and climatic conditions of nature. Although nod- ules have been produced frequently by growing sterilized inoculated seedlings upon sterilized agar media in flasks,! this method of testing cultures is undesirable on account of abnormal conditions. The use ef jars containing small quantities of sterilized soil has also been attempted,? but without success. During the last year numerous ex- periments have been conducted with a special type of jar supplied with a tubular neck near the bottom, and it is believed that with this simple apparatus accurate tests of the inoculating power of the bac- teria may be made at frequent intervals. TESTING THE INOCULATING POWER. A jar of the type shown in figure 1 is charged first with a layer of cinders or broken marble and then with coarse sand moistened with Sachs’s solution lacking in nitrogen compounds; the side tubulature is plugged with cotton wool; a narrow layer of cot- ton wool is drawn around the jar near the top; and over this a snugly fitting beaker is carefully slipped. The jar is now steril- ized in an autoclave at 20 pounds pressure for 30 minutes and 1s ready for use. To avoid cracking the jar the autoclave must be raised to the sterilizing temperature very gradually, and at the end of the sterilizing period the temperature must be allowed to fall very gradually. At least three hours should be consumed in this. process. By using ordinary bacteriological precautions it is possible to intro- duce sterilized seeds through the side tubulature and later inoculate them, with practically no danger of contamination. Black paper is then wrapped around the lower part of the jar to protect the growing roots from light. A slight circulation of air results from the proc- esses of respiration and photosynthesis within the jar, since both top and bottom offer opportunity for the passage of air through the cot- 1 Harrison, F. C., and Barlow, B. The nodule organism of the Leguminose—its isola- tion, cultivation, identification, and commercial application. Centralblatt fiir Bakteriolo- gie [etc.], Abt. 2; Bd. 19, No. 7/9, p. 264—272, 1907. Kellerman, Karl F. The present status of soil inoculation. Centralblatt fiir Bakteri- ologie [etc.], Abt. 2, Bd. 34, No. 1/3, p. 42-50, 1912. 2 Wilson, J. K., and Harding, H. A. Method of keeping bacteria from growing plants. Science, n. s., v. 33, no. 849, p. 545, 1911. (Abstract.) [Cir. 120] TESTING CULTURES OF NODULE-FORMING BACTERIA. D ton wool. The leguminous plants grow well, and if the culture used for inoculating is in proper condition normal nodules are soon formed. By this procedure it has been possible to distinguish sharply be- tween the inoculating power of apparently identical strains of bac- Fic. 1.—Jars for testing the inoculating power of different strains of Baciilus radicicola. In the jar at the right are inoculated garden-pea plants, while at the left are uninocu- lated ones, each 8 weeks old. teria, and in future all stock cultures intended for distribution by the Office of Soil-Bacteriology and Plant-Nutrition Investigations to farmers and other experimenters in the United States will be tested in this manner. [Cir. 120] [Cir. 120—B.] THE WORK OF THE SAN ANTONIO EXPERIMENT FARM IN : i NOs By S. H. HastTines, Farm Superintendent, Office of Western Irrigation Agri- eulture. INTRODUCTION. The work of the San Antonio Experiment Farm is devoted to the investigation of agricultural prcblems peculiar to large areas in the southwestern United States, where the conditions of soil and climate are similar to those at San Antonio. The mcre important lines of work carried on are tillage and rotation experiments; breeding, variety testing, and different planting methods for cotton; variety Fic, 1.—View showing the buildings on the San Antonio Experiment Farm. testing of grain sorghum and broom corn; corn breeding and variety testing; a few forage-crop experiments; variety testing of peaches, plums, apricots, persimmons, grapes, walnuts, almonds, and other fruits, including Chinese dates. In addition to such horticultural work as is mentioned above, much attention is being given to finding stocks better adapted to the local conditions than those now used. lIssued Apr. 5, 1913. The San Antonio Experiment Farm comprises about 125 acres of land situated about 6 “miles south of San Antonio, Tex. The tract belongs to the city of San Antonio and is leased to the Department of Agriculture. About 80 acres of the land are under cultiva- tion, and 6 of these are irrigated. The farm is equipped with the buildings (fig. 1) nec- essary for storage, laboratory, and cffice purposes and for employees’ quarters. The experiment farm is under the direction of the Office of Western Irrigation Agriculture of the Bureau of Plant Industry and is maintained from the funds of the Department of Agriculture. Previous general reports on the work of the farm were published in 1908 and 1909 as Bureau of Plant Industry Circulars Nos. 13 and 34. kGing 120) 7 i ¥ ae — ~-+ > ee Ba = = - - z= — Oe OS eee mates + — $e 333 FS Henares aoe Se reer pee ee 8 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. The testing of trees and shrubs for ornamental purposes is being emphasized. The location of the experiments in 1912 is shown in figure 2. COOPERATIVE WORK. The following are the offices of the Bureau of Plant Industry co- operating in the work at San Antonio, the approximate area occupied by each being noted: The Office of Ac- climatization and Adaptation of Crop Plants and Cotton- Breeding Investiga- tions has about 11 acres devoted to corn and cotton. The Office of Foreign Seed and Plant In- troduction has ap- proximately 14 acres devoted to the test- ing of new plant in- troductions. The Office of Crop Phys- iology and Breeding Investigations has about 2 acres de- voted to testing the Texas wild peach (Prunus tewana) and its hybrids and to fig and pistache ex- periments. Ap- ante] 4 SAN ANTONIO EXPERIMENT rar LOD. tal | proximately 3 acres are used by the Fic. 2.—Diagram of the San Antonio Experiment Farm, Office of Corn In- showing the arrangement of the fields and the location of vestigations in test- the experiments in 1912. alee Ing corn varieties. About 14 acres are used by the Office of Alkali and Drought Resistant Plant Investigations in its work with pomegranates and olives. The Office of Cereal Investigations cooperates in the variety testing of grain sorghum and broom corn. CLIMATIC CONDITIONS. The first part of the season of 1912 was very favorable to crop erowth, and as a result the yields of early crops, such as corn, oats, [Cir. 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. 9 and sorghum, were good. The preceding winter was one of unusual severity and the amount of winter rainfall was somewhat above the normal. From June 23 until late in September practically no rain fell, the total precipitation for the months of July and August being only 0.33 inch. This continued drought of nearly three months cut the cotton crop short. The spring was late and consequently the corn and other early-planted crops were somewhat late in maturing. The total precipitation for the year, as measured at the farm, was 26.37 inches,! which is practically the normal for this section, but somewhat higher than the mean annual rainfall for the period 1907 to 1912, inclusive. The meteorological observations at the experiment farm are made in cooperation with the Biophysical Laboratory of the Bureau of Plant Industry. Table I shows the summaries for 1912 compared with the means for the six-year period 1907 to 1912, inclusive. TABLE I.—Summary of meteorological observations at the San Antonio EHaperi- ment Farm, 1907 to 1912, inclusive. PRECIPITATION (INCHES). Item. Jan. | Feb. | Mar. | Apr. | May.| June.j July. | Aug. | Sept.} Oct. | Nov. | Dec. | Total. | (eee eee EE ee ee eee Se eee eee EEE Eee Average, 6 years, 1907 to 1912, in- CIMSIVOs 2) a 0.54 | 2.23 | 1.66 | 2.96 { 2.47 | 1.28 | 1.54 | 1.63 | 1.15 | 2.60 | 2.52 | 1.88 | 22.46 For the year 1912...| .31 | 6.21 | 2.30 | 2.04 | 1.64 | 3.42} .08; .25 | 1.53 | 2.92 | 1.76 | 3.91 | 26.37 EVAPORATION (INCHES).? Average, 6 years, 1907 to 1912, in- elusive: ...2..:-- 2.72 | 3.12 | 4.68 | 5.32 | 6.63 | 8.40 | 8.69 | 9.39 | 7.31 | 5.23 | 3.21 | 2.38] 67.07 For the year 1912...| 2.35 | 3.35 | 3.05 | 3.88 | 7.39 | 7.02 |10.59 |10.65 | 8.52 | 5.41 | 3.23 | 1.83 67.26 DAILY WIND VELOCITY (MILES PER HourR).3 1911, highest......-- 10.4 |15.9 | 9.0 {10.6 Qe On 12 bes 12a: 6.6 8.5 9.5 es Dies | serene 1912, highest.......- 8.2 {11.2 6.4 6.0 | 5.9 8.4 7.3 7.6 6.5 7.6 yer SP Opal eee ee GIIEMOWESIES 22s sec 1.12 | 1.45°| 2.24 | 3.28 | 2.17 | 2.34 | 2.82 | 1.82']. 1.98 .86 | 1.06 A (asl lee eee 1912, lowest........ Bile tO2, Nee SON eed. [pearl 108. e388 2230) T4289) 76) Sl eae NOMI AVELASe 2.255. - 5.60 | 7.02 | 5.20 | 6.10 | 5.60 | 6.40 | 6.86 | 4.59 | 3.91 | 3.76 | 3.24 | 3.36 |..._... 3.50 | 2.68 | 3.23 | 2.92 | 4.27 | 4.83 | 3.75.| 3.84 | 2.68 | 2.80 |....... 1912, average......- 3.16 | 4.00 1 The rainfall in the city of San Antonio in 1912, as reported by the United States Weather Bureau, was 23.7 inches, which was 3.2 inches below the normal. 2 The evaporation measurements missing are as follows: 1909.—April, 2 days; June, 3 days; July, 6 days; August, 1 day; November, 1 day. a anuary, 7 days; February, 2 days; June, 3 days; July, 5 days; October, 4 days; December, ays. 1911.—April, 1 day; July, 2 days. 1912.—February, 2 days; April, 1 day; December, 2 days. 3 Wind velocities are reported for the years 1911 and 1912 only. 84899°—Cir. 120—18 2 10 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. TABLE I.—NSunemary of meteorological observations at the San Antonio EH.rperi- ment Faria, L907 to 1912, inclustve—Coutinued. TEMPERATURE (°F.). = | | | | Total em: Jan. | Feb. | Mar. | Apr. | May.| June.| July.| Aug.| Sept.| Oct. | Nov.| Dec.! for | | | period | | | Absolute manxi- | mum, 6 years, | 1907 to 1912, in- GIUSIMGa 2-2-4522 88.5 | 87.0-| 95.0 |102.0 |103.0 |108.0 |108.0 |105.0 |104.0 | 98.0 | 86.5 | 82.0 | 108.0 Absolute maxi mim, 191222522. 84.0 | 78.5 | 82.0 | 90.0 |103.0 |100.5 }105.0 |104.0 {101.0 | 94.0 } 84.0] 74.0] 105.0 Absolute minimum, 6 years, 1907 to 1912. melusive:...| 1250 4) 1320: | 34.0 |°38:0 | 39.0: | 5620)) 76420 | 6420} 4170" | 3220 De OR eligi) 12.0 Absolute minimum, 169) 2 a eee er 1655 }' 16..0)), 34.0 | 38:0) 4720) | 59:0 )| 6650) | 68.0 1154. bso On 2580 P2550 16.0 Mean, 6 years, 1907 : to 1912, inclusive.-| 54.1 | 54.7 | 65.0 | 68.6 | 75.2 | 82.7 | 85.2 | 85.3 | 80.3 |-69.6 | 59.6 | 50.2 €9.2 Mean, 1912......... 46.6 |.49.9 | 55.4 | 67.4 | 76.5 | 77.8 | 85.1 | 86.8 | 82.0] 71.8 | 59.4 | 48.6 iors} KILLING FROSTS. Last in spring. First in autumn. | = Length Years. Mini- Mini- ee ah le mum ; mum = Date. temper- Date temper- period ature. ature. °F el Days 10910 VFp js st ec et ee Ae ETOP Feb. . 8 29 Nov. 12 32 217 S105 55 cesar Ae peta ee ae ee Feb. 20 24 Nov. 14 29 268 ISTO) es me ek ee ar ea gS Feb. 25 30 Dec. 6 31 284 CIC Rpm eee ssacr ae OY een ne Ngee, aye eye, eee ee Cones: 26 Oct. 29 32 246 THU Ze eae ae ee EE me ee ee eee doses 29 Nov. 13 31 261 TES. 5, a rr co aS Feb. 27 30.5 | Nov. 2 29.5 245 ROTATION AND TILLAGE EXPERIMENTS.’ The rotation and tillage experiments, which are conducted on 82 plats of one-fourth of an acre each, were continued as previously, except that milo was substituted for corn on four plats and for oats on one plat. The results of the rotation exper mene indicate that crop rotation is an important factor in crop production in this section of Texas, the vields of crops grown in a suitable rotation being on the whole uniformly higher than when grown continuously on the same land. The average yields of all crops except cotton were the highest of any year since the work was started in 1909. Table IT gives the crops in the rotation experiments, the number of plats planted to each crop in 1912, the average yields per acre, and the highest and lowest yields per acre in 1912. 1These experiments are under the direct supervision of Mr. C. R. Letteer, assistant. [Cir. 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. 11 Tasie I1.—Average yields per acre of crops in the rotation erperiments, San “Antonio Haperiment Farm, 19122. | Yield in 1912. Average ‘ yield, 1907 aT = = ey to 1911, | Number . ee inclusive. of plats. Average. | Highest. | Lowest. QTM a rar si Se Scie, ey ante ea) s bushels. . 14.6 26 34.1 42.3 24.3 income Orversee oe See in ke pee eS COG keeles eee 5 40.0 52.0 O24 (QV NES:, (Ea WA Sy eee ee OWS sad 6.5 10 26.75 37.0 19.1 CAD OI Lh ees ee ae elf pounds. . 585.3 25 621.5 818.0 448.0 Sorghum: ENSTU TROYONE, ob RSH ey aa ele ere a eee a tons. . 4. 86 5 4.03 4.28 3.82 SSM MRO S As ee ogee Se eR TT ee hk Se dosese 2.06 3 4.68 5.49 | 4.16 \DAUISS, LINEN YZ AE eS Se ae doses . 83 4 2. 82 3.09 | 73 533 1 No oat yields in 1907 and 1908. 2 Seed cotton. 3’ Sorghum not planted in 8-inch drills in 1908. MANURING. The effect of barnyard manure on crop yields in the rotations was more noticeable this year than ever before. The average yield of corn from all plats where manure was applied at some time during the course of the rotation was shghtly greater than the average of corn plats in corresponding rotations not manured. The same was true of cotton, but manuring decreased the yield of oats for grain very noticeably. The oats on plats which had been manured grew very rank and lodged much more than on plats which had not been manured. The excessive vegetative growth and consequent lodging probably account largely for the decreased yield of grain. While the results indicate the value of barnyard manure, the dif- ference in favor of manure is much less on crops grown in a rotation than where grown continuously on the same land and manured each year. (See figs. 3 and 4.) Table III gives the yields for 1912 and the average yields for 1910, 1911, and 1912 of crops grown continuously on the same land manured + each year compared with plats not manured. TABLE III.—Yield” for 1912 and average yields for 1910, 1911, and 1912 of crops on manured and unmanured plats planted continuously to the same crops at the San Antonio E.rperiment Farm. ; Ae Lae : Difference in fa- Manured. Not manured. vor of manuring. Crop. l i a ty: Average Average ; {O10 to, | 1912. | 1910 to" | tie, | T9009 | aor, 1912. 1912. oa Orns, 2 =. ede CABS Ooo ete eR are Rea les et ae 15.9 30.5 11.6 26. 6 4.3 3.9 Co TRIS OOM 8 id Date Sa Pa ge D2R OME ome ao 32 vival eects creep gee 19.5 (OHRID ooo ae cla ete a a a 455.3 072.0 397.3 474.0 58. 0 98. 0 1 The manure is applied at the rate of about 15 tons per acre. 2Corn and milo in bushels per acre; cotton in pounds of seed cotton per acre. 3 The plats from which dwarf milo yields are given had previously been planted to corn for three years. [Cir. 120] : a= 12 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. SUMMER FALLOWING. Three years’ results have now been obtained from the tests in summer fallowing land for corn, oats, and cotton. As in 1911, the vields of crops on land summer-fallowed the previous season were generally low, corn yielding at the rate of 24.7 bushels per acre, as compared with the average of 34.1 bushels per acre on the 26 plats in the rotation experiments. The corn on the summer-fallowed plat yielded the lowest, save one, of any of the 26 plats. Cotton on summer-fallowed land yielded at the rate of 448 pounds of seed cotton per acre, as compared with an average of 621.5 pounds per acre on the 25 plats of cotton, giving the lowest vield of the 25 plats. Fic, 5.—Cotton on plat B 5—5, land continuously cropped and not manured. This plat has yielded an average of 397 pounds of seed cotton per acre during the past three years. Compare with figure 4. (Photographed June 26, 1912.) Oats for grain on a fallowed plat yielded at the rate of 37 bushels per acre, the highest yield obtained from the 10 plats of oats. The average yleld from 10 plats was 26.75 bushels per acre. While the oats on summer-fallowed land yielded somewhat higher than the others, the increase was not sufficient to indicate that summer fallow- ing is a desirable practice under the conditions at San Antonio, even for oats. SUBSOILING. Subsoiling tests have been a rather important part of the rotation and tillage experiments. The results have been summarized and pub- lished in Circular No. 114 of the Bureau of Plant Industry. [Cir. 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. 13 The results from subsoiling in 1912: were corroborative of those of previous years, namely, that subsoiling does not materially in- crease the yields of crops, and in many instances decreases the yields, and that, owing to its being an expensive operation, it can not be rec- ommended as a regular farin practice in connection with corn, oats, and cotton in the San Antonio region of Texas. ROOT-ROT. Root-rot. a fungous disease of plants,? is doubtless one of the most 9 tes) 9 serious diseases with which farmers have to contend in the Black Lands of Texas. It affects such crops as cotton, cowpeas, and alfalfa, Fic. 4.—Cotton on plat B 5-4, land continuously cropped and fertilized each year with barnyard manure. This plat has yielded an average of 455 pounds of seed cotton per acre during the past three years. Compare with figure 3. (Photographed June 26, 1912.) but does no perceptible damage to plants belonging to the grass fam- ily, such as corn, oats, wheat, ete. In many cotton fields it causes the premature death of a large proportion of the plants. It was observed in 1912 that in a number of the rotations with cotton and corn the root-rot was much more widespread and did more damage to the cot- ton on plats which were spring-plowed than on plats which were summer or fall plowed. The same condition was apparent in 1911. It was also observed in 1912 that where cotton was grown in rota- tion with corn or oats the damage due to root-rot was much less noticeable than on plats continuously planted to cotton. 1 This disease is caused by Ozonium ominivorum. For an account of the disease and methods of lessening its damage, see the paper entitled ‘‘ The control of Texas root- ‘rot of cotton,’ in Bureau of Plant Industry Bulletin 102, Peir b20i] / aii i 14 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. HORTICULTURAL WORK." THE MEXICAN SEEDLING PEACH. The Mexican seedling peach trees? bore a heavy crop of fruit, and the early prospects were good that more data on the comparative Fic. 5.—English walnut grafted on native Texas black walnut in February, 1912. (Photographed August 28, 1912.) merits of different trees might be secured. The earher ripen- ing trees gave a heavy yield of good fruit, but the continued drought of midsummer dam-— aged all the peaches from the later maturing trees, making the tests with these trees nearly worthless. Nearly all the trees bore an exceptionally heavy crop, but they were not able to hold the fruit through such a long period of drought. The trees are becoming over- crowded, owing to their size and close planting, bringing out the point that to obtain the best results the distance be- tween the trees will have to be greater than is ordinarily adopted in more humid sec- tions. The trees were planted 16 feet apart, but it is now ap- parent that better results would be secured if they were 22 feet apart. The Office of Foreign Seed and Plant Introduction put in 324+ buds from what were considered the best 9 trees of the Mexican seedling orchard. These budded trees are to be distributed to cooperators in southwest Texas to test their value under varying condi- tions. | 1 The horticultural experiments were under the direct charge of Mr. R. E. Blair, scien- tific assistant. 2 The seed from which these trees were produced was collected in Mexico by Mr. Gilbert Orderdonk, under the direction of the Office of Foreign Seed and Plant Introduction. They are listed under S. P. I. Nos. 9320 and 9521. [Cir. 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. — 15 } OTHER PEACH VARIETIES. In the variety peach orchard on Field Al, where there are 35 varieties of peaches, set out in 1906, an unusually heavy crop of fruit set. Even the northern peaches in most instances were heavily loaded for the first time in the history of the orchard. This shouid not be taken as an indication that this class of peaches is adapted to these conditions. Those belonging to the South Chinese type are the most reliable bearers. Of the varieties on trial the following have proved to be the best: Pallas, Honey, Im- perial, and “Triana. ~The wild peach from China (Amygdalus davidiana) is proving to be excep- tionally good for peach stock, but there is difficulty in securing seed, as thus far it has not fruited here, with the exception of two fruits which ripened in 1912. PLUMS. The tests of plums include 16 varieties that have been under trial since 1906. The tests so far con- ducted indicate that the plum is probably the most reliable fruit for the San Antonio section. The American-Japanese hybrids bear somewhat more heavily than the pure Japanese sorts. The plums that have proved the best adapted to the conditions at San Antonio | are the Gonzales, Burbank, Wick- a i son, Terrel, El Paso, and Trans- Fic. 6.—Xenia grape grafted on native : mustang grape in February, 1912. (Pho- parent. I nt tographed June 28, 1912.) NATIVE TREES AND SHRUBS. Much work has been done on the domestication of native trees and shrubs suitable for use as grafting stock (fig. 5) or for crossbreeding. [Cir. 120] 16 CIRCULAR NO, 120, BUREAU OF PLANT INDUSTRY. Hybridization and grafting work has been done on the peach, plum, persimmon, and grape. Successful crosses between the native Prunus texana and the peach and plum have been made. The grafting of the better types of grapes on the native mustang grape has been done successfully (fig. 6). Some attention is also being given to grafting the English walnut on the native black walnut. PERSIM MONS. The propagation of persimmons has been tried, a special effort being made to utilize as a stock the native Texas persimmon (Dios- pyros texana), which grows so abundantly and persistently on the semiarid lands of western Texas and in the limestone canyons. This tree has long been regarded as a probable stock for the Japanese persimmon, but until recently it was impossible to produce a union. Successful results have lately been accomplished by inarching with Diospyros texana seedlings small enough to be handled in pots. In this method of inarching, the small native seedling is transferred to a paper pot after most of the soil has been removed from the roots, and the pot is filled with sphagnum. It is necessary that the pots be small and light, for under normal summer conditions the wind would prevent securely fastening a heavy pot in position long enough to permit the formation of a union. The stock and scion will com- monly unite in about 30 days, but as the persimmon grows rather slowly even more time is desirable. Until this method was devised, no successful Diospyros kaki plants had been produced on LD. texana stock. A few crown grafts were made to start, but no others. Budding has been attempted repeatedly by shield, patch, flute, and ring methods, with no success whatever. The following combina- tions have been successfully accomplished here by the inarch method described : D. kaki on D. texana stock. D. virginiana on D. tewzana stock. D. texana on D. kaki stock. D. texana on D. virginiana stock. A small planting of varieties of Japanese persimmons worked on the native stock is to be made under dry-land conditions as soon as the trees can be propagated. Several have already been set to orchard positions. As most species of the Japanese persimmon suffer from chlorosis on the soils of the San Antonio region, it is believed that the use of this resistant stock may be a remedy for this trouble unless the scion proves to rapidly outgrow the stock. [Cir, 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. 17 ORNAMENTAL PLANTS. Ornamental trees and shrubs suitable for the San Antonio section have been tried in large numbers. Particular attention is also being given to native trees and shrubs not already known or whose desir- able qualities are not fully appreciated. In addition to the native trees and shrubs, about 100 varieties of roses and a collection of bam- boos, palms, yuccas, agaves, and many others have been assembled. FORAGE CROPS. The results of all the forage-crop experiments conducted at the farm from 1908 to 1912, inclusive, have been assembled and published as Circular No. 106 of the Bureau of Plant Industry. This circular contains an extensive discussion of the results with the forage crops tested during the past five years. For this reason, only brief men- tion will be made here of the main features of the work in 1912. Among the more conspicuous new forage crops that are particu- larly well adapted to the section may be mentioned Canada field peas and Sudan grass. So far Canada field peas have given a higher hay yield than oats, and apparently there is at least one variety that will stand nearly, if not quite, as much cold. Last winter there were on trial three lots, known as S. P. I. Nos. 30307, 18806, and 30134. Dur- ing the winter there was a minimum temperature of 15° F. Nos. 30307 and 18806 were almost completely killed out, but, while the plants on the other planting (No. 30134) were killed nearly to the ground, new growth was put out and a grain yield of 14 bushels per acre was obtained. As a winter cover crop this is the most promising that has been tested. 3 Excellent results were obtained with Sudan grass in both 1911 and 1912. The yield of Sudan grass in 1912 was 5.66 tons per acre, based on the weights from a one-tenth-acre plat. Sorghum planted in the same way on the rotation fields gave a yield of 4.68 tons per acre. A rate-of-seeding test consisting of seven one-tenth-acre plats of Sumac sorghum in 8-inch drills was conducted, as there is a variance of opinion among farmers as to the best rate, quality of forage and yield considered. The rates varied from 26 to 174 pounds per acre. The highest yield was obtained from the plat seeded at the rate of 88 pounds per acre, or slightly more than 1} bushels. The quality of the forage was apparently equal to that produced by the heavier seedings and better than that in the thinner seedings. Japanese sugar cane, which has been grown here for the past three seasons, gave a yield in 1912 of 13.08 tons per acre, the average yield for the past three years being 12.84 tons per acre. This crop is grown under irrigation, 84899°—Cir. 120—13——3._. LS CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. VARIETY TEST OF COTTON.’ A variety test of cotton was conducted with seven varieties and five selections of Triumph. Sixteen-rod rows of each variety were planted in triplicate. Table IV gives the results of the test. TABLE IV.—Yields obtained in a variety test of cotton at the San Antonio Experiment Farm, 1912. end . Percentage. Variety. cotton pemacre-|- Lint= | Stand Pounds. \VGHEGIRD Bison On Spe peeeaaoee see ee Sosa ahr aanee cc RBe aca ope aaodoee a Soon 735 32. 4 100 Ae OOO Driump hy) 2.2. Aee wdc fe -< ois cinta tates eta te etna eee he | 635 35.5 90 IVOUMONOSCE A creo Se eos occ eg tie oe cree eee ra Sees Sein ee eines 580 37.6 97 Seo 0 (Pru ph) base -ocist oo pet Se ee ee | 580 3758 89 IL GCTEN ST aga ee a nr Oe ee ae eM er oy ea RC Le Spe | 525 34. 2 i ROM CCI Mite occ 2 2 ooo c ss se cease Ss oc Se Meters ee macnn ae ee ee | 525 32.8 89 URI, SeNeral SCCM Je 45.22 ase starok Sects Desa ca nes ae Se pime aoe = ene ee | 520 37.2 93 TU AT Ose ee ack wate) t wtarare aia PapeR > Shia ae le ns een ee Se ee oe ee 496 27.8 87 SINE HDDS 5s sie tees te ge ic sh ee an Seger eR pe | 480 37.9 87 ETT aM CDAN Carte noe fot cto eee 3 oY. Senate Rae eee eee 480 38. 2 94 INCA NS ees ee eos are rara as Sle iSins ele She aya ace ee a= echoes = ce ae chen ee ere | 410 35.7 80 SENEEa (0 01220 (1 poi eee i ec ec Se ret one cine ea 335 34.0 69 1 Percentage of stand determined from an actual count of the plants in each row. 2 Lint very short. 3 Lint but little better than Triumph. As is shown, the Vergatus gave the highest yield, but the lint was very short, making it an undesirable variety. GRAIN SORGHUMS. The experiments in grain sorghums reported on last year? were continued. Both variety and time-of-planting tests were made. Table V gives the average yields of the varieties for three plantings. TABLE V.—Yields obtained in a variety test of grain sorghum at the San Antonio Hxrperiment Farm in 1912. cee Bushels Tow Bushels Variety. per acre. Variety. per acre. AD WVaTuelil Opec sre cee ee See 50.5 |/ "White sorghum... 02:-.-5 5: 222-22 25-- 25.4 Simuarcenel malts ae oe Bob sees Seca Se AG2 Si] |) WW CesG Ue spe eer a eee ee 22.6 Biackhullkaolianes.. -2 s.2222.-2-2422. 36.5 || Standard Blackhull kafir..-.:..-.....-. 19.9 SUG AN CUT ey eee eos See 3s] ||pRedukatire case aaceee oe ees 19.9 Dwarf Blackhull kaoliang....-.......- ZO gall ces cee eee ee eee 11.7 IB TOWNE KAO LaT Cem sere yn eee rae PHY) ; : _ The sorghum midge did not appear this season until somewhat later than in previous years, so with .the earler maturing varieties, 1 The variety test here reported is additional to an extensive series of experiments with cotton conducted by the Office: of Aecclimatization and. Adaptation of Crop Plants and Cotton-Breeding Investigations, the results of which will be reported elsewhere. 2U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 237, entitled “ Grain-sorghum production in the San Antonio region of Texas.” : [Cir. 120] WORK OF THE SAN ANTONIO EXPERIMENT FARM IN 1912. 19 such as milo, plantings made as late as April 1 gave heavier yields than earlier plantings. This was due largely to the fact that there was a poor stand in the earlier plantings. GRAIN-SORGHUM YIELDS COMPARED WITH CORN. Two varieties of grain sorghum, Dwarf milo and Sudan durra, were grown in comparison with 42 of the most common types of Texas corn. Sudan durra gave a yield of 57 bushels per acre and Dwarf milo 638 bushels per acre, while the best strain of corn gave a yield of 40 bushels per acre, with an average of about 30 bushels for the field. Fig. 7.—Dwarf broom corn on the San Antonio Experiment Farm. An average yield of 657 pounds of brush per acre was obtained from plantings made on three different dates in 1912. (Photographed June 15, 1912.) DISTRIBUTION OF SORGHUM SEED. More than 150 requests for grain-sorghum seed were received from near-by farmers, and 209 packages were sent out to 103 of these. The varieties distributed were Dwarf milo, Sudan durra, and Dwarf Blackhull kafir. Much interest is being shown by the farmers in western Texas in the production of this grain crop, since the corn yields have been low during the past four years. y BROOM CORN. In connection with grain-sorghum tests, three varieties of broom corn were planted, Dwarf broom corn (fig. 7) being planted on three [Cir. 120] ! 20 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. different dates and the others on two. The average yields from these plantings were as follows: Dwarf broom corn, G.I. No, 442_=_.-._ -__ 657 pounds per acre. Broom corn;. G.ck: INOW 2AS 04 eee 640 pounds per acre. Standard broom corn, G. I. No. 446_____---- 730 pounds per acre. The brush was of fair quality. PUBLICATIONS. As rapidly as results of a conclusive nature are secured from the experiments at the farm they are prepared for publication. In this way the facts brought out in the experimental work are promptly made available to the farmers of the region. During the year 1912 three publications dealing in detail with some of the problems under investigation were prepared. The first of these? treats of the pro- duction of grain sorghum, the most important grain crop of the re- gion; the second? reports the results of five years’ experimentation with forage crops, and the third* deals with the effects produced on crop yields and soil moisture by the practice of subsoiling. Similar papers dealing with other problems will be issued from time to time as the experimental results warrant publication. 1U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 237, ‘‘ Grain- sorghum production in the San Antonio region of Texas,’ by Carleton R. Ball and Stephen H. Hastings. 2U. S. Department of Agriculture, Bureau of Plant Industry, Circular 106, ‘“‘ Report of the forage-crop work at the San Antonio Experiment F'arm,” by 8S. H. Hastings. 31. S. Department of Agriculture, Bureau of Plant Industry, Circular 114, article enti- tled ‘‘ Experiments in subsoiling at San Antonio,” by S. H. Hastings and C. R. Letteer. [ Cir, 120] hin 20——C.\] INHERITANCE OF WAXY ENDOSPERM IN HYBRIDS WITH SWEET CORN.* By G. N. Cotiins, Botanist, and J. H. Kempton, Assistant, Office of Acclimatiza- tion and Adaptation of Crop Plants and Cotton-Breeding Investigations, INTRODUCTION. As soon as European settlers in America became familiar with the different varieties of maize, the obvious classification of varieties _ based on the character of the seeds came into use. In very early literature we find such terms as flint, dent, and sweet referred to as representing classes already well known. The popular classification was crystallized into formal descriptions by Salisbury in 1849, but it was not until 1884, when Sturtevant extended the classification and applied as technical names Latin equivalents of the popular names, that the classification was generally recognized by scientific writers. With the exception of pod corn, which is known only as a curiosity, these groups are all distinguished by the texture or composition of the endosperm. The discovery in China of a type of maize with a new form of endosperm added another member to this long-estab- lished series.’ BEHAVIOR OF THE HYBRIDS. The waxy endosperm, characteristic of this Chinese variety, has never been observed in any American variety, while in all of the im- portations of this Chinese variety nothing but waxy seeds have been observed. When crossed with varieties that have a horny endosperm the waxy endosperm is completely recessive, the immediate result of the cross being seeds that are indistinguishable from those of horny varieties. In the second generation of crosses segregation appears to be complete, and the proportion of waxy to horny seed approximates the Mendelian monohybrid ratio, 1:3, with small, though significant, deviations. Detailed results of a series of crosses between waxy and horny are given in another place.’ In a general way waxy endosperm may be said to behave lke sweet endosperm, which has also been found to be recessive to horny _1Issued Apr. 5, 1913. 2 Collins, G. N. A new type of Indian corn from China. U.S. Department of Agricul- ture, Bureau of Plant Industry, Bulletin 161, 1909. : ° Collins, G. N., and Kempton, J. H. Inheritance of waxy endosperm in hybrids of Chinese maize. IV* Conférence Internationale de Génétique, Paris, 1911, p. 3847-357, 1913. * [Cir. 120] 21 ae A eat LIE re en eee en ee a FEED SESS CE SE EE DEI ELE IRE ie CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. in the first or Xenia generation and to segregate as a monohybrid in the following generation. Since both sweet and waxy endosperms are recessive to horny, it became of interest to know what a hybrid between sweet. and waxy would produce. Six such crosses were made in the season of 1911. In every instance the resulting ears were all horny, the endosperm in every way resembling the horny endosperm of ordinary varieties. This synthetic production of horny endosperm from nonhorny varieties at once suggests the idea that both sweet and waxy endo- 4 HORNY C HORN, C2 OWELT -~ ee (3 HORNY TOTAL J SWEET 3 WAKY 1? Fic, 1.—Diagram showing the gametie composition of second-generation hybrids between waxy and sweet varieties of maize. sperms represent an imperfect development through the loss or fail- ure of some element or hereditary factor and that what is lacking in the sweet is supphed by the waxy, and vice versa. It has often been suggested that sweet endosperm resulted from a failure of com- plete development of horny endosperm, but no suggestion has been made regarding the nature of the deficiency. It now appears that what is lacking in a sweet variety is supplied by the waxy, and, con- [Cir. 120] WAXY ENDOSPERM IN HYBRIDS WITH SWEET CORN. 23 versely, that what is lacking in the waxy 1s supplied by a sweet variety. While the horny seeds resulting from the cross between sweet and waxy were indistinguishable from ordinary horny seeds, it was, of course, to be expected that differences would appear in the progeny. Four of the six ears obtained as a result of the crosses made in 1911 were selected for planting in 1912. The ancestry of these ears is as follows: Dh221. White Chinese (waxy) X Voorhees Red (sweet). Dh209. White Chinese (waxy) X Black Mexican (sweet). Dh216. White Chinese (waxy) X Black Mexican (sweet). Dh207. White Chinese (waxy) X Black Mexican (sweet). The same individual plant was not used as the parent of more than one cross. From these 4 ears 55 ears were produced in 1912. Every ear bore seeds of all three classes—horny, sweet, and waxy. The entire 55 ears had 22,132 seeds, of which 57.4 per cent were horny, 24.8 per cent sweet, and 17.8 per cent waxy. These proportions approximate the 9:4:3 Mendelian ratio involving two factors. Since in the first generation sweet combined with waxy produced horny, it has been assumed that something necessary to produce horny is lacking in both the sweet and the waxy, and an attempt has been made to analyze the behavior of these hybrids with this idea in view. The residual factor which when it occurs alone is assumed to cause the sweet character will be called S, while Y will be used to indicate the factor of the waxy character. Small letters, s and a, are used to denote the absence of these factors. Since in both sweet and waxy the alternative factor necessary to produce horny is assumed to be lacking, the gametes produced by sweet varieties will be repre- sented by Sa and the gametes produced by varieties with waxy endosperm by sX. The synthetic horny will then be represented by a combination of these, or SvsY. Assuming a chance recombination of these factors in the gametes derived from these synthetic horny seeds, the gametes will be of four kinds. Both the sweet and the waxy may be present (S.1’), or the sweet may be present without the waxy (Sw), or the waxy without the sweet (s1’), or both may be absent (sa). At fertilization each of these kinds of gametes may unite with any one of the four corresponding kinds derived from the other parent, producing 16 zygotic combinations. The formation of these combinations is represented in the conventional diagram, figure 1. The four classes of gametes from one parent are given in the horizontal row at the top, and the same four classes from the other parent in the vertical row at the left. Each gametie combina- tion from the top is repeated four times in the squares below, while [Cir. 120] a ere ee eS SR RS SS er +a oe ae Pee es = abet Se eae ne ee = ae ai — =a ; - mot . ee 24 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. each combination at the side occurs four times in the corresponding horizontal row of squares. Thus each of the squares represents the result obtained by combining the gametes representing the horizontal and vertical rows that intersect at that point. In all cases where both S and XY occur together the seed should be horny, where only S occurs the seed should be sweet, when only XY occurs it should be waxy, and in ene square (No. 16), where neither S nor XY occurs, no predic- tion can be made, since this is presumably a new condition. Leaving the nature of the seed from square 16 out of considerate for the present, it can be seen that there are 9 squares in which both S and XY occur (horny), 3 in which X alone occurs (waxy), and 3 in which S alone occurs (sweet). With respect to the horny and waxy seeds, these numbers approximate the ratios that were actually ob- tained, there being roughly 9 horny seeds to 3 waxy, but the sweet seeds occur as 4 instead of 3 out of every 16. We must therefore assume that the new type, swaa, represented in square 16 and contain- ing neither the sweet nor the waxy factor is or resembles sweet. Careful scrutiny of the sweet seeds failed to show any consistent differences that would allow another class to be separated, but if the present method of looking at the cross is to be of use it should be possible to detect the differences between the ordinary sweet seeds and this new class by analytical breeding. One way to test the theory that this new class of apparently sweet seeds really lacks the element ordinarily concerned in the production of the sweet character is to cross it with pure waxy. The cross of sweet and waxy has heretofore always produced horny, but if this new class lacks the factor for sweet, the cross should have the gametic composition represented by squares 12 and 15 and should result in waxy instead of horny seeds. Another test could be applied by cross- ing the new class with ordinary horny varieties. The first genera- tion of this cross should be horny, but the formula of gametic com- position, S.’szv, would be the same as for the synthetic horny, and in the second generation 3 out of every 16 seeds should be waxy. Thus, if the present assumption regarding the nature of this class is correct we may expect two apparent anomales, not observed hith- erto, viz, waxy seeds as the immediate result of crossing sweet and waxy, and waxy seeds in the second generation of a cross between sweet and horny. COMPARATIVE WEIGHT OF HORNY, SWEET, AND WAXY SEEDS. The view that waxy as well as sweet endosperm may be compared to incomplete stages in the production of the horny endosperm 1s strengthened by the relative weights of the sweet, waxy, and horny seeds where all three classes occur on the same ear. The horny seeds [Cir. 120] WAXY ENDOSPERM IN HYBRIDS WITH SWEET CORN. DHS) are the heaviest, followed by the waxy and sweet.