INITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 1046 _ Contribution from the Bureau of Plant Industry, WM. A. TAYLOR, Chief, in cooperation with the Kansas Agricultural Experiment Station Washington, D. C. Ty agp May, 1922 RUST RESISTANCE IN WINTER-WHEAT VARIETIES By LEO E. MELCHERS, Plant Pathologist, and JOHN H. PARKER, in Charge of Crop Improvement, Kansas Agricultural Experiment Station; Agents, Office of Cereal Investigations | CONTENTS Scope of the Investigation ative “ ave x ° 4 Nive i 1 Review ofthe Literature . . : u + ° i - . . e 2 Nursery Experiments CANTER aS WaT OL Th Mean ROSES T ae cane URN eM eR AI Greenhouse Experiments . eT ett NRL eS NIM : 14 Comparison of Nursery and Greenhouse Results . ° x . - : we | Evidence of Specific Rust Resistance GRP AER RY APE SA aE Up Sa nN | Agronomic Value of Kanred Wheat 2 P . . s ° . . «| (26 Summary ° : Scimtp te rs ‘ : é a . Sake : . Ney-1 Literature Cited . WASHINGTON GOVERNMENT PRINTING OFFICK 1922 4 hi LIBRARY OF CONGRESS . RECEIVED JUN 261920 DOCUMENTS Bivisid sit Contribution from the Bureau of Plant Industry WM. A. TAYLOR, Chief, in. cooperation with the Kansas Agricultural Experiment Station Washington, D. C. Vv May, 1922 RUST RESISTANCE IN WINTER-WHEAT VARIETIES.! By Leo E. Metcuers, Plant Pathologist, and Joun H. ParKer, in Charge of Crop Improvement, Kansas Agricultural Experiment Station; Agents, Office of Cereal Investigations. CONTENTS. x Page. | Page. Scope of the investigation................... 1 | Evidence of specific rust resistance.......... 24 Review of the literature...................-. 2 | Agronomic value of Kanred wheat.......... 26 INUITSOLYIOXPOLUINOMES os rei Jace om cciew ce enecins 4)" Summary. 3: Stee = ct benoatatcccsccuc sme se seee's 27 Greenhouse experiments.................... 14 | Diteratureiciteds. s.scscccacmsaneececiccscecee 30 Comparison of nursery and greenhouseresults 23 SCOPE OF THE INVESTIGATION. A project to determine the rust resistance of existing varieties of winter wheats and to breed new varieties for rust resistance was begun in 1911 at the Kansas Agricultural Experiment Station, in cooperation with the Office of Cereal Investigations of the United States Department of Agriculture. The first two years were devoted to preparatory work, when no infection of stem rust was produced. The writers *? took charge of the work in 1913, and the data given herein are those obtained since that time. The investigation outlined in 1913 had two major purposes: (1) To study the rust resistance of about 130 varieties and strains of winter and spring wheats, particularly to the stem rust, Puccinia graminis tritict Erikss. and Henn.,? in the field and in the green- house; and (2) to study the inheritance of rust resistance in wheat and to produce hybrids adapted to commercial use. 1 Paper No. 183 of the Department of Botany and Plant Pathology and No. 136 of the Department of Agronomy, Kansas Agricultural Experiment Station. 2 The writers wish to acknowledge their indebtedness to Mr. Victor H. Florelland Mr. M. N. Levine, of the Office of Cereal Investigations, who assisted in the greenhouse studies and in other phases of the investigation. 3 Puccinia graminis tritici, as used in this bulletin, has reference to those strains of stem rust used in the experiments in 1915, 1916, and 1917. In 1915 a strain was used to which Kanred, P1066, and P1068 were-only partially resistant, while in 1916 and 1917 strains were used to which these varieties were very ’ resistant. The strains used in 1916 and 1917 may have been one or more,of the several strains which at present are known not to cause normal infection of these varieties. 79251—22— Bull. 1046——1 2 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. Climatic conditions at Manhattan, Kans., are generally unfavor- able for the development and spread of the stem rust of wheat; the development of a suitable technique for the production of severe epi- demics in the rust nursery was therefore an essential part of these investigations. Special attention was given to those varieties which are most. promising agronomically. If a seals of hard red winter wheat could be found which was. resistant to stem rust and suitable for Kansas conditions, breeding: for rust resistance would be much simpler than if it becomes neces- sary to cross with varieties of the durum or emmer groups. Hayes, Parker, and Kurtzweil (13)4 recently have found that “there is an indication of linkage of durum or emmer characters and rust. resistance, since the production of rust-resistant durums or emmers in the F, and F, generations is comparatively easy and the production of resistant common wheats much more difficult.” Moreover, the — only known rust-resistant varieties of the emmer or durum groups: are spring forms, a fact which complicates the task of obtaining a rust-resistant winter wheat from such a cross. Winter hardiness, high yield, and good milling quality also are essential for the success: of any variety of wheat in Kansas, which increased the complexity and difficulty of the problem. To obtain accurate information as to the resistance of existing varieties of winter wheat was, therefore, the first important step. REVIEW OF THE LITERATURE. Differences in the resistance of wheat varieties to rust were knowm to exist as early as 1841, when Henslow (15) observed that some wheats were injured less by rust than others. La Cour (23) and Little (26) made similar observations. Bolley (3) noted that hardy and ~ stiff-stemmed varieties with smooth, fibrous leaves seem to resist rust for a longer time. Anderson (1) observed that hard, flinty wheats are more resistant than others, believing that this mee be due to a larger proportion of silica in the plant. Cobb and Farrer (35) and Farrer (35) found that wheat varieties resist leaf rusts and stem rusts in different degrees. Hitchcock and Carleton (16) state that hard varieties of wheat suffer least from rust in Kansas and early varieties are likely to mature before being seriously injured. Henning (/4) and Eriksson and Henning (11) found that certain wheat varieties resisted different kinds of cereal rusts. It has long been known that some of the emmers (Triticum dicoc- cum) and certain varieties of durum wheat (Triticum durum) show marked resistance to stem rust. Carleton and Chamberlain (9) and Carleton (8) called attention to this in connection with the com- ‘The serial numbers (italic) in parentheses refer to “Literature cited” at the end of this bulletin. RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 5} mercial value of the durums. Carleton (8), in discussing the stem- rust epidemic on wheat in 1904, observed that no wheat varieties, with the exception of einkorn and some of the durums, spelts, and emmers, showed marked resistance under all conditions. He stated further, that during ordinary seasons when stem rust may be quite prevalent the hard-kerneled Russian winter wheats are considerably more resistant to rust than other varieties ordinarily grown. Bolley (4, 5), Biffen (2), and Nilsson-Ehle (33) were among the first to conduct wheat-breeding experiments with the definite object of obtaining rust-resistant varieties. No definite plan or method of study, however, was described until Johnson (20) explained the methods used for producing an artificial rust epidemic in Minnesota and furnished a working basis for the studies which have been made since in this country in breeding cereals for rust resistance. These methods are further described by Freeman and Johnson (12). They state that certain varieties, such as Extra Squarehead in Sweden, American Club in England, and Rerrarf and Ward’s Prolific in Aus- tralia, have been shown to be resistant to rust. They add, however, that some of these varieties can not be said to be universally rust resistant, as their behavior in different countries to different biologic forms of rust is variable. Field experiments have verified early observations that some of the durums and emmers are much more resistant than the common spring-wheat varieties. Stakman (37) found this to be true in both field and greenhouse experiments. Melchers and Parker (29, 31) recently have called attention to the resistance of three winter-wheat varieties to stem rust and leaf rust. Waldron and Clark (42) have described a variety of common wheat named Kota and stated that it was resistant to the strain or strains of stem rust prevalent at Fargo, N. Dak., Brookings, S. Dak., and St. Paul, Minn., in 1918. These authors state that “this resistance is decidedly greater than that possessed by the common spring wheats and second only to the more resistant durum wheats.’ Clark, Martin, and Smith (10) speak of the rust behavior of varieties of durum and common wheat grown during the seasons of 1914 to 1919 at several field stations in the northern Great Plains. They state that none of the varieties of common wheat grown is really rust resistant, but early-maturing varieties have ripened before the rust has developed extensively and are sometimes rust escaping. Most varieties of durum wheats are more or less rust resistant, as compared with common wheats. Acme, Monad, and D-—5 are known to be especially rust resistant. In years of heavy rust infection these varieties have produced the highest yields. When grown under comparable conditions in these and other experiments, the D-—5 variety shows the greatest resistance of all varieties to stem rust. 4 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. NURSERY EXPERIMENTS. METHODS AND MATERIALS. Because of the infrequent occurrence of natural epidemics of stem rust under Kansas conditions,® it was necessary to study varietal resistance in a rust nursery (Pl. I, figures 1 and 2), following the gen- eral plan suggested by Johnson (20). This rust nursery was located near Manhattan, Kans., on land which is low and slopes slightly - toward the south and west. Along the south side of the nursery is a hedge of common barberry bushes (PI. I, fig. 2). A large drainage ditch on the south side carried off the surplus water. Because of the likelihood of frequent heavy rains during the crop season, the ~ rust nursery was sown in slightly elevated plats, separated by de- pressed alleys, which received the surplus water and carried it into the main ditch. The rust nursery has been sown in various ways. At first a plat 1 rod square was used for each variety, but it was found impossible to produce severe epidemics of stem rust on large areas under Kansas conditions. The plats, therefore, were reduced to a single rod row and in 1915 to 5-foot nursery rows spaced 10 inches apart. The seeds are sown 3 inches apart in the row. A small hand plow was used for opening a furrow and a seeding board ~ with notches at regular intervals served to obtain uniformity in — spacing the seed. The spring varieties generally were sown during the last week in March or the first week in April in rows close to the winter-wheat rust nursery. The rust used in these experiments up to and including 1917 was obtained from the Minnesota Agricultural Experiment Station. In 1914, 1915, and 1916 the urediniospores came from greenhouse cul- tures of Puccinia graminis tritici, but in the fall of 1917 cultures were used from rusted wheat plants obtained in the field. These were found later to be a new strain of stem rust (30). The stock cultures of rust which were used in these field experiments were cultured on Improved Turkey (Kansas No. 2382), a variety which — has been found in these experiments to be very susceptible to stem rust. When the leaves produced uredinia which were sporulating abundantly they were used in one of two ways: (1) The leaves were clipped from the plants, placed in a few quarts of water, the urediniospores removed, and the liquid used as a spray on the wheat. plants in the rust nursery, or (2) the potted wheat plants bearing uredinia were used as centers of infection in the nursery. 5 The only natural epidemic known to the writers occurred in 1904. In 1915and1916stemrust waSvery prevalent in many fields in Kansas and in some instances there wasan appreciable loss. In 1919 stem rust was uniformly present in eastern and central Kansas, and although it was difficult to estimate the actual injury caused by stem rust it was one of several factors which reduced the yield and quality of wheat. Bul. 1046,"U. S. Dept. of Agriculture. PEATE Il Fic. |.—GENERAL VIEW OF THE WHEAT-RUST NURSERY. The investigation of the comparative rust resistance of varieties of wheat at the Kansas Agri- cultural Experiment Station was conducted here. The arrows indicate the location of rotary sprayers. FiG. 2.—ROw_OF BARBERRY BUSHES ADJACENT TO THE WHEAT-RUST NURSERY. Each arrow indicates the location of a rotary sprayer. Bul. 1046, U. S. Dept. of Agriculture. PLATE II. Fic. |.—REMOVABLE CANVAS COVERS USED IN THE WHEAT-RUST NURSERY TO RETAIN MOISTURE. A urediniospore sprayer is shown in operation. FIG. 2.—PoT CONTAINING RUSTED SEEDLINGS FROM THE GREENHOUSE. Used in establishing infection centers in the wheat-rust nursery. RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 5 When sprays of urediniospore decoction were used in the study at Manhattan, Kas., a small knapsack pressure sprayer was employed. All sprays were applied in the evening; if possible during periods of moist, cloudy weather. The plants were first sprayed with water and then with the urediniospore spray. Sprays of urediniospores were found to be unreliable, however, because of the hot dry winds which frequently occur in Kansas during the late spring and early summer. In order partially to overcome this difficulty, removable canvas covers were placed over a wooden framework which was built over the plats. These covers were used the day following the urediniospore sprays and aided materially in retaining moisture. They were easily handled by one man, being unrolled from a long strip of wood and drawn over the nursery plats, to be fastened at the corners as shown in Plate II, figure 1. Several attempts have been made to inoculate plants in the rust nursery in the fall. Not only was it difficult to obtain satisfactory infection, but it was of doubtful value in view of the fact that it is questionable whether stem rust lives over winter in Kansas to any ereat extent (17). On account of the unsatisfactory results obtained with the uredin- lospore sprays, the infection-center method of obtaining an epidemic was tried. This method is somewhat similar to inoculating plants in the field, but it is much simpler and more certain to give satis- factory results. The inoculated seedlings are carried from the green- house to the plats, where they spread the infection. Numerous infection centers were located in each plat, so as to provide ample spore material (Pl. II, fig. 2). Most of the rust cultures for these experiments were grown on seedlings in 24-inch flowerpots, two seedlings in each pot. Fre- quently 4-inch pots were used, as they held more seedlings and did not dry out so rapidly. It was found that if small galvanized-iron pans were placed between the rows of wheat in the rust nursery early in the spring and filled with pots of inoculated seedlings, a most successful center of infection could be established. (Pl. II, fig. 2). The pans were kept filled with water at all times. As soon as the seedlings died or the rusted leaves no longer produced urediniospores, the pots were replaced with a new set. In this man- ner the wheat plats were continually exposed to rust infection. It recently has been found that if plants in the heading stage are inocu- lated in the greenhouse and used in place of seedlings for the centers of infection, their usefulness in the field continues longer than that of seedling plants; hence, they are much more satisfactory. It was found also that wherever the centers of infection were located the rust obtained a start and spread rapidly from the centers to all adjacent plants. . 6 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. In 1914 only two urediniospore sprays were applied, one on April 19 and the other on May 23. Neither of these sprays was followed by any noticeable rust infection. Canvas covers were not used. In 1915 urediniospore sprays were given on April 20, 21, 27, and 29, and on May 7, 10, 20, 22, and 31. Inoculated seedlings were trans- planted into the soil in vacant rows, which were left for that purpose, this being the first attempt to use the infection-center method. Canvas covers were used and a severe epidemic was caused, as shown by the data on rust infection. In 1916 urediniospore sprays were given on April.6, 13, 14, 20, 25, 26, and 29, and on May 1, 4, 16, 19, and 27. Canvas covers were used. In addition to these sprays the infection-center method was employed. A severe epidemic resulted. In 1917 sprays of urediniospores were given on May 23 and 29, and on June 6. A few hand inoculations in the field were made in the spring, but the efforts were mostly directed toward establishing in- A,5percent. B,10percent. CC, 25 per cent. D, 40 percent. E,65 per cent. F, 100 percent. Fic. 1.—Scale for estimating rust, illustrating six degrees of rustiness used in estimating the percentage of stem-rust infection. The shaded spots represent rust, and the figures represent approximately the rust percentages computed on the basis of the maximum of surfaces covered by rust as shown in the 100 per cent figure (F). Figure F in the diagram represents 37 per cent of actual rust-covered Surface and is arbitrarily selected as 100 per cent. The other percentages are in terms of figure F. fection centers. It was evident from the results obtained that the latter method was sufficiently dependable to warrant the discontinu- ance of urediniospore sprays. | . The common barberry (Berberis vulgaris L.; see PI. I, fig. 2), planted south of the rust nursery plats, furnished some ecial infection in 1915, 1916, and 1917. Straw, bearing telia of stem rust, was placed around each shrub in the fall, so as to provide the necessary telio- spore material to infect the barberry leaves in the spring. The. final field notes were taken during the latter part of June or early in July, at the time the nursery was harvested. These included the percentage of stem rust, estimated in accordance with the scale shown in figure 1 and used by the Office of Cereal Investigations of the Bureau of Plant Industry, United States Department of Agri- culture. Notes on the type of head, plumpness of grain, and other characters also were recorded. See ; mete = - A ae ae eee eee Pinte zp ite anid iia si pian oe aa Saray = Bie aiegey e os See ye is ow ae SSM ate Gap Ae ea oR St ne ac as 51 RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 7 The varieties grown in the rust nursery included the commonly grown hard red winter wheats of the Crimean group, such as Turkey and Kharkof, and the varieties of soft red winter wheat grown in eastern Kansas and other soft red winter-wheat districts. Some of the varieties were obtained from the Office of Cereal Investigations of the Bureau of Plant Industry and others from the agricultural experiment stations of other States. The strains grown under a pedigree number, and so designated in Table 1, represent pure-line selections made by Prof. H. F. Roberts, formerly of the department of botany, Kansas Agricultural Experiment Station. These strains were turned over to the department of agronomy in 1910, and seed was obtained from that department when the study of wheat varie- ties for rust resistance was begun. Not all the varieties have been grown throughout the period of experiment, because some of them were found to be of little or no agronomic value. Some were shown to be extremely susceptible to stem rust, and others were eliminated because of complete winter killing. A small number of spring- wheat varieties were grown, to obtain comparative data on rust infection. BREEDING PLAT. Certain varieties of spring and winter wheats were grown in a breeding plat each year to serve as material for crossing. The winter-wheat varieties were sown in the fall at the time the varieties were sown in the rust nursery. Considerable space was left between the rows of winter wheat, to allow for seeding spring wheats for crossing. Occasionally a few of the spring varieties bloomed at the same time as the winter wheats, thereby simplifying: the work of making the crosses. Generally, however, it was necessary to sow such spring varieties in the greenhouse about the first of February. These were transplanted to the breeding nursery in April and May, thus providing some of the spring-wheat plants, which were in flower at the same time as the winter varieties. Crosses have been made between Kanred (Kansas No. 2401), Kansas No. 2414, and Kansas No. 2415,° three closely related winter- wheat varieties which are resistant to leaf rust (3/) and to certain strains of stem rust (29, 30); also between Marquis, Haynes Blue- stem, and Preston, varieties of sprig wheat which are susceptible to stem rust. The F,, F,, and F, generations have been grown to maturity, and data on the inheritance of resistance to stem rust (Puccinia graminins tritici) have been obtained. These results, however, are not presented in this bulletin. These varieties have been known as P762, P1968, and P1066, respectively. They have recently been given Cereal Investigations numbers as follows: C, 1. 5146, C. I. 5879, and C, I. 5880, respectively. 8 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. RESULTS OF THE NURSERY EXPERIMENTS. The percentage of stem rust found on the varieties grown in 1915, 1916, and 1917 and the 3-year average for all varieties grown in all three seasons are shown in Table 1. Notes on the quality of grain also are given for the years 1916 and 1917. The varieties are arranged according to type and are grouped as to the characters, winter or spring, awned or awnless, glabrous or pubescent glumes, and soft or semihard to hard kernel. All of the winter-wheat varieties with the exception of Binkel Club are common wheats (Triticum vulgare). The spring grains include varieties of common wheat, as well as durum wheat (7. durum), emmer (T. dicoccum), and einkorn (7. monococcum). The “Identification numbers” include the ‘‘Pedigree number,” as used by Prof. H. F. Roberts; the ‘‘Kansas number,” which is an accession number assigned by the department of agronomy; and the C. I. number, used by the Office of Cereal Investigations of the Bureau of Plant Industry. TABLE 1.—Stem-rust infection of wheat varieties after artificial inoculation in the nursery at Manhattan, Kans., in the years 1915, 1916,-and 1917, together with data on kernel quality in 1916 and 1917. [Key To SymMBots.—Identification numbers (columns 1 and 3): C. I.=Cereal Investigations, H=hybrid, K=Kansas, P=pedigree. Rust infection (columns 5 to 7): T=trace, Wk=winterkilled. Quality of kernels (columns 9 and 10): E=excellent, F=fair, F—=poor to fair, F+—=a grade better than fair, F+— variable quality (some poor to fair, some fair to good), G=good, G—=a grade poorer than good, G+= a grade bes than good, G+=variable quality (some fair to good, some good to excellent), P=poor, Vp= very poor. Group 1.—AWNED, GLUMES GLABROUS, KERNEL SEMIHARD TO HARD. . : Quality of Stem-rust infection (per cent). ceraialst Season, class, and iden- | Kansas} C. I. 4 SS — tification number. No. | No. | Varietal name. | fies 1915 | 1916 | 1917 | aver- | 1916 | 1917 | age. 1 iar 8 4 5 6 7 8 9 10 WINTER VARIETIES. | Per |. ‘Per Per Per Common wheats: | cent. | cent. | cent. cent. P647 | 2356: Japan oeseee ses 40) |9.55 "Wiles | oe See Ros S| eee ISSA eee eee 25 |, 2°68 TWikes [a cane F-E> | eeeee Red Winter Java) 25 70 Wik ieee Ra esr eee eae Ose csete doce o 50>) S75=—1. >) AWikn co ceecesl et) ate Fee one eee 50 | 60 88 66 F+ F- Improved Tur- 50 57+ 58 | 55 Je Pp key. i Red Winter Java} 45 47 Wikio ee Gs |. See Lehane cane 2D 52 95 57.3 | G+ F— saree temas cmtcee 40 32 80 50.6 G F— Crimean........ 25 45 95— 55 F+ | G HRA: ie oss 40 30 |T t040 35 G G sihurce adleseeomenee 35+ 42 95 57.3 | G— F— is SR etree 40+| 65 98 67:6 || SE GUe Dae ee eee 45 60 WE |..:..00.|/0 2 eee La ake ares eae 65 48 90+] 67.6 G 1 Loe atte seme acc 65 54 65 61.3 | F— F-— Wilta 2a e eee 65+| 42 78 61.6 — i ee Been se oRCeeE eee 40 38 95 57.6 ie F NOT POVasenee eee 35 45+ 90 56.6| F— | F oth Seiveied cane conte 25 35 97 52.6 F P Beloglina...-....) 25+] 47 | 8 52 F— P RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 9 TABLE 1.—Stem-rust infection of wheat varieties after artificial inoculation in the nursery at Manhattan, Kans., in the years 1915 quality in 1916 and 1917—Continued. Group 1—AWNED, GLUMES GLABROUS, KERNEL SEMIHARD TO Harp—Continued. , 1916, and 1917, together with data on kernel 79251—22—Bull. 1046-2 | | | Stem-rust infection (per cent). Caality ot Season, class, andiden- .Kansas; C.I. | “ tification number. No. | No, | Varietal name. | event | 1915 | 1916 1917 | aver-:| 1916 | 1917 | age. 1 Hig 4 5 6 7 8 9 | 10 =a aie fe == WINTER VARIETIES— continued. | Pere le be, Per Per, || Common wheats—Con. L cent. | cent. | cent. cent. | | P751 Beloglina Wales 60 40 P F 40 SWike hoor ee (eee 60 88 60 F— | G— 40+ 95 56.6 | F— 48 65-++ 68 §4.3 | F— 122 67 50 49 F— ie 65+ 95 G5ea Ge F 40 | 70 43.3 122 ele 10 | 10 25.0 G E 12 C(t aes ee Chae ZABB | ae are Power Fife x 45 | 85 56.6) F+ F Jonathan. eRe ee See oe eral | eels | ercters cia ee ciao awake 45 50+} 95 63.3 F G IP TBE EAS Ae te Coker on Pee Re tee |< Same (2 ee ey 55—| 55—| 97 69 F— G— iat emer ee eer ne sae 2418 | sea se. [Bower oMifesci) nee: | 60+] 80+]........ | G— | G+ | Jonathan, | hea BE Silo aee an aos tiselisis acess lepers al giemnceeannes coe 60 | 65 70 6 | F—| F ESRI eran ees hos Seat \PeSecee Bosaaenasetsnee sae 60 | 48 90 66.0 P G BRBRO REE ase cate e 2409" | 16217) Burkey 2. tces- 20+ 40 50 36.6 P G BOSD sete imac ween PAGE Sense) eUCANCLS seaside | seer ccc 42 WOPE |S eae eG: F+ Le Seen ae ee ee Oia Bis aae a | Scottish Rank 40 | 45+ 88 57.6 | F— ie BRUG (Eee mee em Tee ghee melas an Bi apces HeGnC aCe 60+) 62 90 PULalh ele G Oost eee. 3|uawedos [Seeeecee ae Rate Oe leraepha tes 45+| 65—| 90 66.6| F— | F MOG ates SN Saco CLE GN eae Hicklingse- 222). See soe 75 MIG EE ae: TIS 3 SRS S oe BR Tel a oe ee Pre agi 35 | 82 Wile 3 Co ee PUOOSES so occ cele CALS Wisse cites Wietoria= =. ss 60+) 82+) 78 72.3 | G F HalOTse west e oecac| cee ncuee eoeee cal Renooe Hoeemaeenore 307) 75 50 61.6 F— F~ UGE Secor eeecenene| bacoueee | 5147 | Nebraska No. 28.|..-...-. 60 Wes eceeeees | WS esetsee A OMe on meee ate looser ae eel BOS LUE KO Ynale Common wheats: 4 IPUIS2 see meieieetal 23805 |Jaccmecyace tester cole coes 30 40 95+] 55 G G— P80 iS: sicia oe cei serene Sele Seen emcee Sooo eee eee - 80+ 40— 60 60 F F bart asaeeeransoascaa| 2441 1535) eb erdianskas-eaeepseseee 65 CORB Aeeeone F— P 4 PTL socieisnd eeee seal eet el Cees Lee cee meer eee ee 85 40— 95 73.3 Pp iB PUTAS: oom cicld qniceincee + basen cee ae ae Eee Gectee scene aese 40—| 65+ 85+] 63.3 | F+ G— PTO0re aaciepoceee ce 2402) Break ea Se terns sot epee beeeaee 65+ 90) 22S eee — | F+ BSUL: 2soeaoesle one [ete otal eee ete | oa tec eee 40—| 60+ 80 60 F— | F+ POO scaeaitsseeeeee 2403) ono tote | Gare eoele Sameecesee | emee se 65 OO Mite cesee F-— F PO80 shail 2405 eee ae North Allerton..| 40+] 68 75 61 P F- : Pl0G4255. 2 ssaeee eee 2440 | 6218 | Zimmerman..... 30+ 60+ 70 53.3 eo ey b P1092 TN SoS5 3 eee 2406 |) 6216) | ‘Currell22222 5-3 25+ 75 90 63.3 | G— P a Ki30. oar accu tebe eeeerone 1733 | Dawson Golden.|...-..-- 75-5 |) Wikebeaecees IF ia ctor = F | Chaff. | 4 IK SS. oie eas See sees | eae ee 1744 | Early Genesee |....... 77 Giant. Purple straw... -|25<...- 60 MUNGZ = oe eee oeeaee 67 Michigan Amber]|....-.- 80 Leto) (ees os ER Shoes 85 a Fultzo-Mediter- |....... 90+ | ranean. RAG Sok Soe eee lees 299%: | MIKOL0d sion - Sas os| eee 65 CPTF 8326 Sse ea |e erate Currell es. Fa eee 95— - Group 5.—AWNLESS, GLUMES PUBESCENT. j | WINTER VARIETIES. | | Common wheats: | | <4 PLOTS se see ZA08 se Seee ee Jones X Red Fife|......- 95 Wika|e2 eee 1 Sees sng GM ho weds ecdosaoss)|sescccce | 1933 | Tongs Winter |......- 90 VWs pececacs Pc jets tees : ia | | ife. | IDO oe Cosa eee | eee eee oe Mealy, {22 22 Seeclsaccece iti es WN ee ge mcus: 1 eee = — ! = Group 6.—AWNED, GLUMES GLABROUS (TRITICUM VULGARE, T. DURUM, AND HYBRIDS). 4 Sa ey + © ( & ( Z t CNS < wg ON WeLEtt 9 % d Ci iq, oS an Fic. 2.—KERNELS OF SUSCEPTIBLE AND RESISTANT WHEAT VARIETIES IN I9I7. PLATE VII. Bul. 1046, U. S. Dept. of Agriculture. “ASNOHNAAYS) ‘a1Nnj e199} OY} JAMO] OF Pasn st PF 4B JoVeM Jo Avads ouy W HHL NI SONIIGSSS GALVINOON| YOS GAS YSEWVHO LSION RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 13 All varieties of soft red winter wheat were found to be susceptible to stem rust. Plate V, A shows a typical plant of Mealy, a very ~ susceptible variety. Several of the varieties of spring wheat showed evidence of being resistant. Other varieties, such as Ghirka Spring (Pl. V, B), were found to be very susceptible. Black Persian was the only variety of common spring wheat which showed marked signs of resistance. Among the durum wheats, Beloturka (C. I. No. 1513), Iumillo (C. I. No. 1736), Kubanka (C. I. No. 2094), Monad (C. I. No. 3320), and D-5 (C. I. No. 3322) all proved rather resistant to stem rust. A hybrid between Iumillo and Preston (No. 3 X 122A12) also was very resistant. This hybrid resembles the durum parent in type of head. All of the strains of emmer gave some evidence of being resistant, as did the one strain of einkorn. Khapli emmer (C. I. No. 4013), although slightly rusted, never showed the large linear uredinia which develop on susceptible varieties. Usually a rather close relationship is shown between the extent of stem rust recorded and the quality of grain produced by a given variety. The grain of certain varieties, however, sometimes is severely injured by a medium quantity of rust, while other varieties with a higher percentage of rust infection will produce heavier grain. Kanred, P1066, and P1068 were all low in quantity of rust in 1916 and 1917, and all produced good heavy plump kernels. Factors other than rust infection, of course, influence grain quality, but it was very evident in 1916 and 1917 that the three rust-resistant varieties produced better grain than the similar but more severely rusted varieties grown in near-by rows. Typical kernels of resistant and susceptible varieties produced in the wheat-rust nursery in. 1916 and 1917 are shown in Plate VI. Table 2 presents data showing the percentage of rust infection on the varieties of which kernels are shown in Plate VI. The letters in the first column of the table correspond with those of figures 1 and 2 of the plate. 14 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. TABLE 2.—Stem-rust infection on susceptible and resistant varieties of wheat grown in the rust nursery at Manhattan, Kans., in 1916 and 1917. 1916. Identification. | 7 | | Rust in- ,7 | Pedigree or Name. Class. fection. vals in sathen | fig-1- | number. | | ..| Hard id spring... Se ediGuntum.seees .| Hard red winter...... Softreduwinterteacesee eer ee meee 1917 | Ae P58 ce cee | ss eee es ee A ee ac Bese ea Hardired\ winter nee: tae-eenceeeeceneee 95 Bis cane PTO). he cen Stes See Se eae Ee ee Pee eae te are Oeste Jelowe 22 cee eee eee Ce eee 70 Clin Lyne eas Keanredin notes oe ee eee elo eee GOztae st teeta ee eee eee Trace Dee. PGB weici Scr penis crete cleo eae ee rere ee ence eve GOs ei Pers lec eatiae aan oe ereal 90 | DI Mecy Pees Ree See ee ease Paha ea ee oo 4 Goleta ee eee 70 Nees Pil Q3S 2 ce Ael as cee doen acne ee Reco ae ane le tone GO sca 4s al ees eon eee ne ee 85 Gre: PAOB4 Aad oe ete oe ee i ee Sr es eee eran ae GOs ei.3 Asses ees eee eee 70 TBE Ae se POG Ge Reece poe cae ee oes peal emcees enes eh hen 6 Vo pe ees: Sree ema et 5 | Oe ES P1068! Sei] f's 6 ee oe eee ce Oe ey GO sie ogee 8 eee ees eee 5 Sion ee = LEAK eee ee es ne ee Dace Sobaonnlsesoe Okc ee pee an ee ene ae AGS oe | 85 Ke sapetine Kans: 2048.) Alberta Red_..2....-.-2..--e51-|-Lse- COasse bh Pedi eae st eee ee ed 88 Tene Minn. 169..! Haynes Bluestem.............-- heElerderedhsp rin pst. e-eseye sm mnae aaa 85 Mires. C2094 59 Kennan eee hee ee | Durum. 252s SER e ee ees | 10 Nese, PTT en crc | eee ee ere mien pee ee me eee leHardredawinters-2s2 205900 Se eeem enema | 40 Ota: GTS BO 77ioclis SERe S OAR Re aed, eS ise Softred winters sees see eee | 95 GREENHOUSE EXPERIMENTS. To check the nursery results similar experiments under controlled conditions were conducted in the greenhouse. INOCULATION METHODS, Nearly all the varieties, both winter and spring, which were used in the field were inoculated in the seedling and heading stages in the greenhouse. Careful records of the inoculated plants of each variety have been kept and their behavior compared with the behavior of the same variety in the field. The number of plants which can be grown under greenhouse conditions is more or less limited, and for this reason conclusions from such experiments should nae be drawn with caution. INOCULATION OF SEEDLINGS. In inoculating seedlings the first leaf was inoculated and all others were trimmed off. The uredinial material came from stock cultures grown on Improved Turkey (Kansas No. 2382), or some other sus- Percentc 65 diportenn Shite ys eH hed 1s as Wes Spica inte Nirciasents 8? RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 5 sceptible variety. The inoculation method used was described by Melchers (28) and was a modification of the method proposed and used by Kellerman (22) and Carleton (7) in their studies of cereal and other rusts. This is a satisfactory method where the supply of rust is limited, as there is little chance for loss of spores. The spore supply was collected in a Petri dish and applied to the seedlings by means of a flattened or a rounded needle. The leaves to be inocu- lated were first thoroughly dampened by stroking them several times between the fingers previously moistened in water. Tap water was used with satisfactory results, although Melhus and Dur- rell (32) have shown that tap water may have a toxic effect on the germination of certain kinds of rust spores. In the studies in the greenhouse the seedlings were grown in 24-inch pots, illustrated in figure 2. Fifteen pots, each containing 2 seed- lings, or 30 seedlings in all, constituted one series of each variety. Fie. 2.—Seedlings grown to determine rust resistance of wheat varieties under greenhouse conditions. Pots 1 and 2 contain seedlings of a susceptible variety used as a check; Nos. 3 to 6 contain seedlings of _ P1068. Each of the two seedlings in each pot is trimmed to a Single leaf blade which is inoculated. In most cases it was not necessary to inoculate more than one series of plants, but if the results were at all doubtful a second series was inoculated. Hundreds of inoculations weré made on seedlings of Kanred, P1066, and P1068. Two to four seedlings of Improved Turkey (Kansas No. 2382) were used as checks for each series. After inoculation, the seedlings were kept in damp chambers for 48 hours, after which they were removed and placed on the green- house bench. Bell jars were first used, but these proved impracti- cable. An inexpensive and effective damp chamber, shown in Plate VII, was devised. It consisted of a galvanized-iron washtub with a pane of glass for a cover.°® About one-quarter of an inch of water was placed in the bottom of each chamber, to keep the air saturated. The chambers were kept in the shade, so as to maintain a temperature of 50° to 70° F. In warm weather, a spray of water was directed upon the damp cham- bers to reduce the temperatures. Difficulty was experienced during 9 Cylinders made of galvanized iron (without permanent top or bottom), with a diameter of 15 inches and a height of 12 inches, have been used more recently. A removable piece of glassis used foratop. If these cylinders stand on damp sand, sufficient moisture is supplied to keep the chamber saturated, and the potted seedlings do not stand in water. Damp chambers of this type have proved very Satisfactory. 16 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. the first year in carrying the cultures through the summer, on account of the prolonged periods of temperatures ranging from 100° to 110° F. It was found that sprays of water directed upon the chamber not only cooled the air in the greenhouse but in addition kept the tem- perature in the damp chambers within a few degrees of that of the water itself. By such means a difference of 11°C. between the tem- perature inside and that outside the chambers was obtained, as shown by some of the readings at different dates during July and August. Johnson (21) found that the maximum temperature at which ure- diniospores of Puccinia graminis would germinate in a normal manner was about 88° F., though the experiments of the writers have shown that temperatures of 80° to 95° F. do not prevent normal infection. However, temperatures of 65° to 70° F. are believed to be the most favorable for inoculations with stem rust. ‘These methods have been satisfactory in every respect; 100 per cent of infection always was obtained on plants of susceptible varieties, including checks, and it is believed the notes on resistance or susceptibility are as depend- able as can be obtained under greenhouse conditions. The methods described, however, might not give as satisfactory results with other cereal rusts. . INOCULATION IN THE HEADING STAGE. One plant of each variety which was grown in the rust nursery was allowed to develop to the heading stage in the greenhouse. One seed was sown in each pot in October. It has been found that by main- taining the proper temperature, either spring or winter wheat can be matured and normal seed developed in the greenhouse. Hutcheson and Quantz (18) have shown that temperatures from 55° to 70° F. are best suited to this purpose. In the experiments of the writers, where plants were grown to the heading stage, a night temperature of about 50° F. was maintained, but not infrequently the night tempera- ture during the early stages of growth fell as low as 35° or 40° F. The temperature was kept below 75° F. during the daytime whenever possible. The plants were inoculated as soon as the heads were well out of the boot and the neck or peduncle exposed, as illustrated in Plate VIII. Two to six culms of each variety were inoculated with stem rust.. In. the case of Kanred, P1066, and P1068 the inoculations included a much larger number of plants. Ip some cases the culms of these three varieties were reinoculated a number of times, so as to expose them to infection as often as possible and at different periods of development. The uppermost leaf blade and the sheath of each culm of all varieties grown were thoroughly inoculated, as were the necks, glumes, and awns. These plants were then placed for.a period of 48 to 72 hours in a specially constructed galvanized-iron damp chamber, similar to the one described by Parker (34). This damp chamber is of sufficient Bul. 1046, U. S. Dept. of Agriculture. PLATE VIII. METHOD OF INOCULATING WHEAT PLANTS AT THE TIME OF HEADING AND SEEDLINGS AT THE INOCULATING STAGE. PLATE IX Bul. 1046, U. S. Dept. of Agriculture. -AyIprumny Jo velZep YSTY & UTEJUTEU YOIM puv Jo}eAM Jo ued oyL ‘AJWIL ONIGVAH Lv GALVINOON| SLNVWId LVAHM 404 G4asn YSaEWNVHO LSIOW IWLAIN-LSSHS a9uv 7 PLATE X. Bul. 1046, U. S. Dept. of Agriculture. “AWIL SONIGVAH LV GALVINOON| SLNV1d YO4S GASf) SYUAEWVHO LSIOW Ga1000D-YsaLVM 3947 Bul. 1046, U. S. Dept. of Agriculture. PLATE Xl. Fic. |.—RuUST RESISTANCE OF TWO VARIETIES OF WINTER WHEAT IN I918. Seedling leaves of P1056 (A) and Kanred (B), both inoculated on April 22 and photographed on May 11. Compared with the rusted leaves of the susceptible check (shown at the left of each group) these leaves are seen to be entirely free from flecks and uredinia. — Fig. 2.—RustT SUSCEPTIBILITY OF TWO VARIETIES OF SPRING WHEAT IN I917. Seedling leaves: C, Arnautka (C. I. 1493), inoculated on March 29 and photographed on April 19; D, hybrid 3 & 122A12, showing normal uredinia in this stage, inoculated on April 4 and photo- eraphed on April 27. Although known to be resistant to some strains of stem rust in the field, these two varieties show visible signs of infection when inoculated with the same strain of rust used with A and B (fig. 1, above). COMPARATIVE RUST RESISTANCE OF SOME WINTER AND SPRING VARIETIES OF WHEAT. RUST RESISTANCE IN WINTER-WHEAT VARIETIES. aly size to accommodate about 72 plants. About half an inch of water was kept in the bottom of the chamber and a pan of water was sus- pended from the top. A cloth wick was placed over this pan and was allowed to hang down on two sides, as shown in Plate IX. This helped to keep the air saturated. A glass top allowed sufficient light to enter the moist chamber, so that the plants did not become etiolated during the incubation period. On warm days a stream of water was allowed to flow over the top, as illustrated in Plate X. This helped to maintain a cool temperature within the chamber. Cloths were hung over the outside walls to help distribute the water evenly. An overflow pipe in the pan at the bottom of the chamber carried away the surplus water. The inoculated plants were placed on inverted empty flowerpots, to avoid setting them in water. RESULTS OF THE GREENHOUSE EXPERIMENTS. The results obtained from greenhouse inoculations are shown in Table 3. Very heavy infection always was obtained on the checks and the susceptible varieties, but in the case of Kanred, P1066, and P1068 no uredinia appeared. Some of the spring-wheat varieties also showed only slight to moderate infection. The peduncles, glumes, and awns of all susceptible varieties were just as readily infected at heading time as were the seedlings. In the case of the three resistant varieties, if any portion of the head becomes infected it is the awn. No signs of infection, however, could be noticed on regarded as a corollary to the field results, however. It is hardly infection. 18 TABLE 3.—Results of inoculating wheat varieties with stem rust in the greenhouse at the Kansas Agricultural Experiment Station at Manhattan, Kans., in the winter of 1916-17. [Key to identification numbers (columns 1 and 3): C. I.=Cereal Investigations, H=hybrid, K= Kansas P=pedigree.] Group 1.—AWNED, GLUMES GLABROUS, KERNEL SEMIHARD TO HARD. BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. | Season, class,and | Kan- C.1 { | identification sas woe Varietalname. | number. No. : | | WINTER VARIETIES. |. Common wheats:— Continued. SoBe aetetee eel ene elagaiees | aeencsel| ae eae ae ee pate PG6ATEe < Sale 2300 Naess Japaneate tee IP65IzEe es & ho Paty fo Sak RuSsianee see See TVA eas eee | 2368) |ieee ee ‘Red Winter Java’ IRGTSeeee cee ee DEY AVN Sas eae Al tah ee Ol reaa ane ae 1 251 RA a 23176) |/ il 665s eas nae a oneal) P06 2%. ene bid 9382 | 5592 Improved Tur- | ey. EY (Vy feet een ae Ieee eeeen Red Winter Java a The symbols indicate the type of infection, as expl ; of resistance or hypersensitiveness. This evidence of resistance is illustrated in Plate XI. All the spring-wheat varieties which the writers have studied and which are classed as highly resistant show such reactions to rust infection, and almost always very distinct uredinia, though frequently small, are formed in inoculated seedlings of these varieties. Kanred, P1066, and P1068 are unique in their behavior toward Puccinia graminis tritici, as hundreds of seedlings and of culms in the heading stage have been inoculated with this strain of rust and not a single uredinium ever has been observed. The entirely rust- - free and unflecked inoculated leaves of Kanred and P1066 are illus- trated in Plate XI, fig. 1, A and B. These varieties may be said to be immune” from this particular stem rust, if it be assumed that the controlled conditions provided in the greenhouse are as favorable and that exposure to infection is as severe as under natural field conditions, and that seedling inoculations are as severe a test as can be given to a variety. They are certainly more strikingly resistant to Puccinia graminis tritici than any other varieties of common wheat (Triticum vulgare) which have been studied by the writers. Because of this specific behavior these varieties have been used as differential hosts in separating certain biologic strains of stem rust of wheat. The inoculation studies with these varieties have been carried over a long period, including every month in the year, 10 The word ‘‘immune” is here used to mean freedom from any macroscopic evidence of rust infection or to designate the inability of the rust fungus to sporulate. RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 25 under various temperature conditions and at various stages of development of the plant. \The work has been done by different persons at different agricultural experiment stations and always with the same results. The only visible evidence of infection in the seedling stage has been the occasional appearance of very indefi- nite, scarcely visible, whitish flecks, generally less than 0.1 millimeter in diameter. These indefinite flecks are not similar to the areas or flecks occurring on the seedlings of the resistant emmers and durums (Pl. XI, fig. 2, C) and are very much less conspicuous. In this respect these three varieties of winter wheat are distinct in their behavior. The behavior of Kanred, P1066, and P1068 in the nursery and field is not greatly different from that in the greenhouse. ‘Table 1 shows that these varieties had very low percentages of stem-rust infection, varying in 1916 and 1917 from a trace to 10 per cent. In 1915 the percentages recorded were higher. In view of present knowledge of the existence of several distinct biologic strains of wheat-stem rusts (38, 39, 40, 41), this rather heavy infection very _ probably was due to the use of one or more biologic strains of stem rust similar to, if not identical with, the one recently described by the writers (30). When mature culms of the three resistant varieties were inoculated in the greenhouse with cultures of Puccinia graminis tritici, a response on the part of the host to the rust infection was only occasionally visible. Slightly yellowish or brownish white minute dead areas were sometimes vaguely visible, indicating that infection had occurred but that the organism had ceased to develop. The results reported in this bulletin establish the fact that Kanred and two other very similar pure lines of hard red winter wheat are - resistant to certain biologic strains of black stem rust. More recent studies (25, 30, 41) have shown that these varieties are not resistant to all the known strains of stem rust. Extensive field observations made in 1919 and 1920 have indicated, however, that Kanred is much less severely injured by most of the stem-rust strains occurring in Kansas than are Turkey and Kharkof, the other varieties commonly grown. Reports from Wisconsin, Alabama, _ Nebraska, New York, Illinois, Missouri, Iowa, California, and New ‘South Wales: (Australia) indicate that these three varieties have shown resistance to stem rust, while the Minnesota and the South Dakota agricultural experiment stations report them rather severely rusted, although in South Dakota Kanred showed less rust than Turkey. Because of the existence of distinct strains of stem rust it is probable that the behavior of these varieties will vary in different feasons and in various sections of the country. 26 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. RESISTANCE TO LEAF RUST. Observations (37) made at Manhattan, Kans., during the 5-year period from 1915 to 1919, inclusive, and field notes recorded in all sections of the State in 1919, 1920, and 1921 show that these three pure lines of Crimean wheat are remarkably resistant also to leaf | rust (Puccinia triticina) as it occurs in Kansas. Mains and Jackson (27) also have found these three varieties to be very resistant to leaf rust under field conditions and where the plants were approaching the heading stage. According to these workers, however, seedlings of these varieties do not prove to be resistant to leaf rust when inoculated and maintained under greenhouse conditions. The resistance to leaf rust has eon manifested also in experimental field sowings made in the States of Alabama, California, Missouri, North Ghrokay North Dakota, Oregon, South Dakota, Tennessee, Texas, Virginia, and Wisconsin, and also in New South Wales, Australia. Present knowledge of the leaf-rust problem and the records from a wide range of sowings subjected to severe epidemics of leaf rust indicate rather definitely that Kanred, P1066, and P1068 will maintain this high degree of resistance under a wide range of conditions. It should not be supposed, however, that the resistance of these varieties to leaf rust will be absolute under all conditions or in the presence of all the biologic strains of leaf rust which may exist. AGRONOMIC VALUE OF KANRED WHEAT. Kanred wheat presents a unique combination of desirable agro- nomic characters, a fact which is of even greater significance than its resistance to rusts. Jardine (/9) described the origin and history of Kanred wheat and called attention to its higher yield, earliness, and cold resistance. Call and Salmon (6) state that ‘‘at Manhattan, the average pro- duction of Kanred has been 4.5 bushels per acre more than Turkey and 4.7 bushels more than Kharkof.”’ It has outyielded these varieties in every season but one and in that season (1914) practically equaled the others. Salmon (36) presents further experimental data on the superiority of Kanred and gives statements regarding the value of Kanred from a large number of farmers who have grown the new variety. It is estimated that at least 1,500,000 acres were sown to Kanred wheat in Kansas in the fall of 1920, and it is expected that within a few years this variety will occupy a large percentage of the hard winter-wheat acreage of Kansas. If the area sown to Kanred should reach 7,000,000 acres and the yield should be increased 3 bushels per acre, with wheat selling at $1 per bushel, other factors re- maining unchanged, the annual value added to the Kansas wheat © RUST RESISTANCE IN WINTER-WHEAT VARIETIES. Dit crop as a result of the production of Kanred wheat would be $21,000,- 000.