SB 508 .W5 M4 Copy 1 INITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 1046 Contribation from the Bureau of Plant Industry, WM. A. TAYLOR, Chief, in cooperation with the Kansas Agricultural Experiment Station Washington, D. C. 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, OflSce of Cereal Investigations CONTENTS . ' Page Scope of the Investigation 1 Review of the Literature 2 Nuraery Experiments 4 Greenhouse Experiments 14 Comparison of Nursery and Greenhouse Results 23 Evidence of Specific Rust Resistance . . . / 24 Agronomic Value of Kanred Wheat .'26 Summary 27 Literature Cited 30 WASHINGTON GOVESNMENT PRINTING OFFICi:; 1922 LIBRARY OF CONG«gSS DOCUMENTS U»Vi«ION UNITED STATES DEPARTMENT OF AGRICULTURE s^J^'^^^u BULLETIN No. 1046 Contribution from the Bureau of Plant Industry WM. A, TAYLOR, Cliief, in cooperation with the Kansas Agricultural Experiment Station jTL^'^'Lrt. Washington, D. C. May, 1922 EUST 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 l Review of the literature 2 Nursery experiments 4 Greenhouse experiments 14 ■Comparison of nursery and greenhouse results 23 Evidence of specific rust resistance 24 Agronomic value of Kanred wheat 26 Summary 27 Literature cited 30 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 tritici 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. « The writers wish to acknowledge their indebtedness to Mr. Victor H. Florell and Mr. M. N. Levine, of the Office of Cereal Investigations, who assisted in the greenhouse studies and in other phases of the investigation. ' 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. DEPAETMENT OF AGEICULTUEE. 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 variety 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)* 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 F2 and F3 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 group& 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 known to exist as early as 1841, when Henslow (16) 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 might 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 (I4) 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 niunbers (Italic) in parentheses refer to "Literature cited" at the end of this bulletin. EUST RESISTANCE IN WINTER-WHEAT VARIETIES, 3". jnercial 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), Biff en (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 (4^) 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 AGEICULTURE. 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 Kansara 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. ' The only natural epidemic known to the -wTiters occurred in 1904. In 1915 and 1916 stem rust was very prevalent in many fields in Kansas and in some instances there was an 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. Bui. 1046,'U. S. Dept. of Agriculture. Plate I. Fig. I. — 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 tlie location of rotary sprayers. Fig. 2. — RowIOF Barberry Bushes Adjacent to the Wheat-Rust Nursery. Each arrow indicates the location of a rotary sprayer. Bui. 1046, U. S. Dept. of Agriculture. PLATE II. Fig. I. — 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 establisliing 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 great extent {17). On account of the unsatisfactory results obtained with the uredin- iospore 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 (PI. II, fig. 2). Most of the rust cultures for these experiments were grown on seedlings in 2|^-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. (PI. 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, 5 per cent. B, 10 per cent. C, 25 per cent. D, 40 per cent. E, 6u per cent. F, 1(W per cent. Fig. 1. — Scale for e.stimating 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 (Berheris vulgaris L. ; see PI. I, fig. 2), planted south of the rust nursery plats, furnished some aecial 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. 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 nurser}^. 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 (31) and to certain strains of stem rust (£9, 30) ; also between Marquis, Haynes Blue- stem, and Preston, varieties of spring wheat which are susceptible to stem rust. The Fi, Fj, and F3 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, Pl()68, and P1066, respectively. They have recently been given Cereal Investigations numbers as follows: C. 1. .51-16, C. I. .5879, and C. I. 5880, respectively. BULLETIN 1046, V. S. DEPARTMENT OF AGRICULTUEE. 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 {T. durum), emmer (T, dicoccum), and einkorn (T. 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. — Stevi-rust infection of wheat varieties after artificial inoculation in the nursery at Manhattan, Kans., in the years 1915, 1916, and 1917, together toith data on Icernel quality in 1916 and 1917. [Key to Symbols.— 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 better than good, G ± = variable quality (some fair to good, some good to excellent), P= poor, Vp = very poor.] Group i.— Awned, Glumes Glabrous, Kernel SEMraARD to Hard. Season, class, and iden- tification number. Kansas No. C.L No, Varietal name. Stem-rust infection (per cent). Quality of kernels. 1915 1916 1917 3-year aver- age. 1916 1917 1 2 3 4 5 6 7 8 9 10 WINTER VARIETIES. Common wheats: P647 2356 2357 2368 2370 2376 2382 2383 2385 2386 2388 2390 2391 2398 2399 Japan Per cent. 40 25 25 50 50 50 45 25 40 25 40 35+ 40+ 45 65 65 65+ 40 35 25 25+ Per cent. 55 68 70 Per cent. Wk Wk Wk Per cent. ""m" 55 57.3 50.6 55 35 57.3 67.6 "'67.'6' 61.3 61.6 57.6 56.6 52.6 52 r+ F+ F± F F+ P G± P651 Russian P675 Red Winter Java do P678 75- Wk P693 1665 5592 60 67+ 47 52 32 45 30 42 65 60 48 54 42 38 45+ 85 47 88 58 Wk 95 80 95- Tto40 95 98 Wk 90+ 65 78 95 90 97 85 F- P706 Improved Tur- key. Red Winter Java P P707 P711 .G± ; F- P712 G I F- P717 1437 Crimean F+ G P721 G G P722 G- F- P732 F F P733 F- 1... P736 G 1 P P737 F- : F- P742 2434 1538 Ulta F- P P744 P F P745 2433 1539 Torgova F- F P746 F P P750 2411 1543 Belogltna 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, 1916, and 1917, together with data on kernel quality in 1916 and 1917 — Continued. Group 1. — Aavned, Glumes Glabrous, Kernel Semihard to Hard— Continued. Group ;?.— AwNED, Glumes Glabrous, Kernel Soft. ■Seasan, class, and iden- tification number. Kansas No. C.I. No. Varietal name. Stem-rust infection (per cent). Quality of kernels. 1915 1916 1917 3-year aver- age. 1916 1917 1 2 3 4 5 6 7 8 9 10 WINTER varieties— continued. Common wheats— Con. P751 P752 2427 1543 ' Beloglina Per cent. 25 40 50 35+ 30+ 30+ 35 20- 40 to 70 40 45 55- 60 60 20+ Per cent. 35 40 60 40+ 65+ 67 65+ 40 10 45 50+ 55- 60+ 65 48 40 42 45+ 62 65- 85- 82 82+ 75 77 85+ 5± 5± 50+ 60+ 78 45 65+ 70+ 85+ 40 60 45 Per cent. 60 Wk 88 95 68 50 95 70 10 85 95 97 80+ 70 90 50 70+ 88 90 90 75 Wk 78 50 Wk 85 15 5 to 25 85 78 Wk Wk 85 97 85 Wk Wk 95 88 70+ Wk 95+ 88 Per cent. 40 ""m" 56.6 54.3 49 65 43.3 25.0 56.6 63.3 69 65 66.0 36.6 "'"57.'6' 70.6 66.6 71.6 ""73.'3' 51.6 P F- F- F- F- F- P P G F+ F F- G- F- P P G F- P F- F+ G G F- F P753 G— P754 V P755 P P757 1 ... P P758 P759 2419 1544 Beloglina F p P762 2401 2436 5146 Kanred E P771 P772 Power Fife X Jonathan. F G P773 G— P774 2418 Power Fife X Jonathan. G + P877 F P882 G P889 2409 2404 2417 62i7 Turkey G P935 Bucanera F+ P951 P967 Scottish Rank 40 60+ 45+ 55 + 35 60+ 30 35- 25 45 40+ 25- 60- 30 45 40 40+ 30 65 P G P973 F PIOOO 2435 Hickling P P1003 P1008 2428 Victoria . F P1013 F— P1036 2412 2422 2415 2414 2416 2479 2478 5879 5880 1543 Romanella Fem or April.... P1038 65 18.3 20 53.3 66 . "es's' 69 66.6 F G+ G+ F- F- G- G- F- F F- G+ F- F+ F— P1066 G P1068 G P1078 Beloglina F- P1080 F PlUl P1119 1 P1128 1 F P1131 -- - - F P1134 P1161 2420 2410 1436 1787 5147 1558 5797 6213 6214 6474 1442 Crimean P K34 Nebraska No. 28. Turkey K570 P K2048 Alberta Red F K2101 Red Winter F K2123 Defiance Hard Winter. P2141 2413 30- 60- 60+ 61.6 G- F- F- K35 Kharkof F WINTER VARIETIES. Common wheats: P63S 2358 2365 "igsi" BinkelClub 68 90+ 90- " 88 95 85 90— Wk 70 Wk Wk Wk Wk Wk F G P F- F- P F P668 Michigan Bronze! Dietz Longberry' - - - P K51 C.I. 1945 Lancaster K36 2008 C.I. 1973 New Amber K47 2980 Longberry. Stoner 79251— 22— Bull. 1046- 10 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTUEE. Table 1. — Stem-rust infection of wheat varieties after artificial inoculation in the nurser-y at Manhattan, Kans., in the years 1915, 1916, and 1917, together with data on kernel quality in 1916 and 1917 — Continued. Group 3. — AwNED, Glumes Pubescent, Kernel Soft. Season, class, and iden- tification number. Kansas No. C.I. No. Varietal name. Stem-rust infection (per cent). Quality of kernels. 1915 1916 1917 3-year aver- age. . 1916 1917 1 2 3 4 5 6 7 8 9 F+ F+ F+ P G- 10 WINTER VARIETIES. Common wheats: P724 2392 Per cent. 40+ 20+ 25 Per cent. 50 45 50 85+ 65 Per cent. 68 . Wk 65 95+ Wk Per cent. 52.6 F P1071 P1082 1571 3277 Turkey p K49 Virginia p (?) Velvet Chaff Group |.— AwNLESs, Glumes Glabrous, Kernel Soft. WINTER VARIETIES. Common wheats: P718 2389 30 - 80+ 40 40- 65 40- 65+ 65+ 60+ 65 68 60+ 75 75+ 77 60 67 80 85 90+ 65 95- 95+ 60 70 95 85+ 90+ 80 90 75 70 90 Wk Wk Wk Wk Wk Wk Wk Wk Wk 55 60 "73'3' 63.3 '"m" ■■--■■■ 53.3 63.3 G F F- P F+ F- F- F- P F G- F Vp F- F+ F P G — P739 F P740 2441 1535 Berdiansk P P741 85 40- P P748 G— P765 2402 F+ P871 40- F+ P970 2403 2405 2440 2406 F P980 "62i8' 6216 1733 1744 1915 1923 1969 North Allerton.. Zimmerman Currell Dawson Golden 40+ 30+ 25+ F- P1064 F P1092 P K39 K38 Chafl. Early Genesee Giant. K42 K40 Fultz K52 Michigan Amber Poole C. I. 1979 K48 1980 2997 Fultzo-Mediter- ranean. Kofod K46 C. 1.3326 Currell Group 5.— AwKLESS, Glumes Pubescent. WINTER VARIETIES. Common wheats: P1073 K44 K50. j Jones X Red Fife 1933 1 Jones Winter t Fife. I Mealy , 95 Wk P- 90 Wk P 85 Wk P Group 6.— AwNED, Glumes Glabrous (Triticum vulgare, T. durum, and Hybrids;. SPRING varieties. Common wheats: C.I. 2958 H. 3X111.-.- H. 4X942.10. H. 6X2223... 4783 4788 4789 Preston (Minn. No. 188). lumillo X Pres- ton. KubankaX Pres- ton. Kubankax Blue- stem. 35 40 85 53 25 40 80 68 60 48 G- G p p F- F- RUST EESISTANCE IN WINTER-WHEAT VARIETIES. 11 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 ivith data on Jcernel quality in 1916 and 1917 — Continued. Group 7.— AwNED, Glumes Pubescent. Season, class, and iden- tification number. Kansas No. C.I. No. Varietal name. Stem-rust infection (per cent). Quality of kernels. 1915 5 1916 1917 3-year aver- age. 1916 1917 1 2 3 4 6 7 8 9 10 SPRDfG VARIETIES. Common wheats: C. I. 2442 Black Persian... Per cent. — Per cent. 10 Per cent. 10 to 40 Per cent. 13 G 1" Group S.— AWNLES.S, Glumes Glabrous. SPRING VARIETIES. Common wheats: C. I. 1517 C. 1.3641 C. I. 2S73 Ghirka Spring. . Marquis Glyndon Fife (Minn. No. 163), ■ 35+ 50 98 61 25 65 95 61 25 45 85 51 F- G- P Group 5.— Awnless, Glumes Pubescent. SPRING VARIETIES Common wheats C. I. 2S74 Haynes Blue- stem (Minn. No. 169). 35+ 40 90 55 Group 70.— AwNED, Glumes Glabrous. Durum wheats: H. 3yi22A12 lumillo X Pres ton. Arnautka 5- 75 G- C. I. 1493 55 F C. I. 14Q4 do («) C. I. 1443 . . . Gharnovka • 40 G- C. 1. 1513 Beloturka G C. I. 1736 25 5- 60 6 25 5- 10 5— T~ 30 30 13 G C. I. 2094 Kubanka G C. I. 3320 G- C. I. 3320... Monad Selection Pentad (D-5)... G- C. I. 3322 G C. I. 5284 G Group /;.— AwNED, Glumes Glaprous, White. Emmer and Einkorn: C. I. 1522 White Spring Emmer. do C. I. 1524 5 T T 5 C. I. 4781 . . .do C. I. 1526 Yaroslav emmer Khapli emmer... Common einkorn C. I. 4013 . . T 8 T Tto35 C.I. 2433 o Heavy on base; on upper culms, trace. '• On necks. c Fairly heavy at base; on culms, trace, d Heavy on necks; on culms, trace. 12 BULLETIIsr 1046, U. S. DEPARTMENT OF AGRICULTURE . The names are those which appear in the records of the Kansas Agricultural Experiment Station. Most of the varieties in the bearded, glabrous-glumed, hard red-kerneled group are very sunilar to the well-known Turkey and Kharkof varieties. Nearly all the winter-wheat varieties proved to be very susceptible to stem rust (PI. III). Three of the pedigreed strains, however, were found to be remarkably resistant. These were Kanred and two un- named varieties, P1066 and P1068. These three pure-line selections differ morphologically from Turkey and Kharkof in the greater length of the short awn or beak found at the tip of the outer or empty glume. The average length of the beak in these three varieties is considerably greater than in the case of Turkey, Crimean, and Kharkof.^ The va- riety P762 (Kansas No. 2401) was named Kanred (from Kansas Red) and distributed to farmers in 1914. The other two resistant strains, Pi 066 and Pi 068, are very similar to Kanred; in fact, the three strains seem to be morphologically identical. They appear to differ slightly in certain agronomic characters, such as yield, winter hardi- ness, and grain quality. The experimental data which are available indicate that each of these other two selections is equal to Kanred in yield and other agronomic qualities, although they have not been grown as long in plats at the agronomy farm and have not been com- pared at the branch experiment stations or in cooperative experiments with farmers. These three strains did not attract any particular attention in 1915, as they seemed as heavily rusted (40 to 70 per cent) as many of the other varieties, but in 1916 and 1917 very different results were ob- tained.® They were almost free from stem rust (PI. IV). The estimated infections of rust on these three varieties in 1916 were 10, 5, and 5 per cent respectively, and in 1917 they were 10, 15, and 5 to 25 per cent, respectively, compared to the maximum figures of 95 to 98 per cent on other varieties in the same seasons. The only other variety of winter wheat which gave any evidence of resistance was Kansas No. 2390. The infection of stem rust on plants of this variety was estimated at 40 per cent in 1915, at 30 per cent in 1916, and as "Trace to 40 per cent " in 1917. This variety was much less heavily rusted than many other varieties in 1916 and 1917, but it does not appear to be nearly as resistant as Kanred, P1066, and P1068. 1 This distinguishing character was first called to the attention of the writers by Carleton R. Ball and J. Allen Clark, of the Office of Cereal Investigations. 8 In the Ught of present knowledge of the existence of several biologic strains of stem rust, with differ- ent infection capabilities, the results in 1915 are easily explained as being due to the presence in the rust nursery of one or more strains of stem rust which were able to attack these varieties. Bui. 1046, U. S. Dept. of Agriculture. Plate III. Typical Infection of Stem Rust of Turkey Wheat. This represents the susceptible strain of this vaiiely used as a checlj in the wheat-rust nursery in 1916. 5ul. 1046, U. S. Dept. of Agriculture. Plate IV. A Typical Plant of Kanred Wheat from the Rust Nursery in 1916. Note the very slight, rust infection. The other pure lines (P 1066 and P 1068) presented a similar appearance. Bui. 1046, U. S. Dept. of Agriculture. Plate V . Typical Rust Infection of i wo Varieties of Wheat in 1 91 6. A, Mealy, a susceptible variety of soft red winter wheat; B, Ohirka Spring wheat, also very susceptible. Bui. 1046, U. S. Dept. of Agriculture. PLATE VI. «^^ ^ :: * ^ TO. a*^^ — ~^ v^ ^:* A ~B c^ ^D E F ^ -X> ' ^^ ^. "*• /»# .^.v' .. ."^ y *t* .^ '" ,t >^ ^ '^ .-- V ~* -^ ^ -!*■ \ ler " "^ \ *^ ' ' \ ', <» ' ,.. '• ^ ^" » *\' . - -V ^ -^ '^ "^ "' V - -^ '\ ^! ' w ^— "IL-.^ • ■'" - ^^ \'>_-^ '-. _"~~ V ^ \ _^ V ^ '~— ■»-» '«»'■ «^ -^-- ^<* ^G H 1 J K L *.^v'^ *-5^ . ^ . ^ '■-'v«. > C- . ^ ^^ , ^V, •Xirf. jj i, -* « M N ^ p^ Q R Fig. I. — Kernels of Susceptible and Resistant Wheat Varieties in 1916. 1*— >«. ••«■ l^j^%i% ii^' -^ ^ • ^ V IT"""' ^- ^- ^"^ ^O'^), Kubanka -^^^r^l^^^Z:^^- and durum below) ZZlt^Jlr" r.*"™ " "'^ *''"^ "^y ^y'^bols (explained resut o"t:Sion'llti:eZf aTh^V^"^^? '''"'^ ''''' regarded as a corollary to the field re^l,t^^ ""^T *""''' ^^ frequently may cause a different interpretatioTof he refute ^ts S2d ^ *r ^^'"^ ™'y ^ ''^ '''^'^Ss ^^ inocufated A vaJety thouX th J'^t [ u'^t"^ "'^^'^ inoculated at another time, even kiectn '"'^ •" '"" '"'^ ^™^^ ^^"^^ "ay show a formal 18 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. 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. Kan- sas No. C.I. No. Varietal name. Stem-rust in- fection. Type ofin- fection.a Season, class, and identification Seed- hngs. Headed plants. number. d . fe'S ll tH CD a's m a a 1 ■ 03 03 ■WINTER VARIETIES. Common wheats:— Continued. P373 . . . 30 /30 \30 /30 t30 30 30 /30 130 30 30 30 30 30 13 29 28 30 28 22 23 30 30 30 29 30 3 6 3 6 S s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s R s s s s s s s s s s s s s s s s s s ■ ■ s" " "s" s s "s" "s" s s s s . s s s s s s s s s "s"" s "s" s s s "s" R s "s" s s s s s "s" s "s" s P647 2356 2357 2368 2370 2376 2382 2383 2385 2386 2388 2390 2391 2398 2399 Japan Purple color. 1j Russian P651 Do. P675 Red Winter Java do "3' 3 3 "3' 3 3 P678... P693 1665 5592 P706 P707 P711... Improved Tur- key. Red Winter Java '"9' 3 6 3 3 6 3 3 3 4 3 5 3 3 6 3 ■9" 6 3 3 6 3 3 3 4 3 5 3 3 6 3 Plant died. P712... P717 1437 Crimean. 30 1 27 P721 30 30 30 30 30 30 30 30 30 30 r30 \8 30 29 28 30 30 30 30 26 30 30 30 30 8 30 16 30 30 24 28 6 21 30 24 30 30 30 30 27 30 22 8 30 7 30 30 28 28 30 P722 P732 P733 . . . Purple color. P736 . . . P742 P744 2434 1538 ijlta. P745 P746... 2433 1539 Torgova P750 P751 •.. 2411 2427 1543 1543 Beloglina .....do P752.. 3 3 3 3 P753 f30 \30 30 30 30 t28 30 C242 f30 i30 30 30 30 30 30 {1 30 /30 \30 30 (30 f30 130 P754.. "■3' 6 6 3 ""3" 6 6 3 P755... Do. P757... P758 2419 1544 Beloglina P759... 3 d6. 3 3 3 P762 2401 2436 5146 Kanred P771 fPower Fife x \ Jonathan. P772... 3 3 6 3 3 3 3 3 6 3 3 3 P773 P774 2418 Power Fife X Jonathan. P877 Purple color. P882 P889 2409 2404 2417 6217 Turkey P935 Bucanera Scottish Rank... "3' 3 "3"; 3 P951 P967 6 3 6 3 P973 a The symbols indicate the type of infection, as explauied on page 22. b Under certain conditions some varieties produced a purple color surrounding the uredinia; where this was pronounced it is indicated in the table. c Since the completion of this work about 200 additional seedlings have been inoculated, with the same results. d Since these inoculations were made, many additional culms have been inoculated, with the same results. RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 19 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— Continued. Group ).— AwNED, Glumes Glabrous, Kernel Semihard to Hard— Continued. Kan- sas No. C.I. No. Varietal name. Stem-rust in- fection. Type of in- fection. Season, class, and identification Seed- lings. Headed plants. number. 'Zt P t-i'rt Uredinia small; resistant. 22 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. All the varieties of winter wheat used can be placed in one of two classes: (1) Those which fail to show visible signs of uredinia and (2) those entirely susceptible. Those of the first group are desig- nated by the symbol R, and those of the second group by S. Among the spring varieties there were different types of infection, these being represented by the symbols R^ to Kg and by S. Following is a description of the types of rust infection designated by the symbols: EXPLANATION OF SYMBOLS USED. R=Extremely resistant. Ri=No uredinia produced. Occasionally very small indefinite flecks, dead areas, or yellowish blotches occur. Signs of hypersensitiveness may be present. R2=Very rarely the occurrence of minute uredinia (0.1 to 0.5 mm.); presence of flecks, dead areas, or blotches. R3=Numerous minute to small uredinia (0.2 to 0.75 mm.); presence or absence of yellowish "islands" surrounding uredinia, or the occurrence of numerous yellow blotched areas surrounding or adjoining uredinia. R4=Uredinia numerous, variable in size and number (0.2 to 0.4 mm.); flecked or blotched, yellow areas present; yellow areas adjoining uredinia. R5=Uredinia apparently quite normal in size and shape, but presence of yellowish green areas surrounding or adjoining some uredinia indicative of slight resistance. S=Showing ordinary susceptibility; uredinia large, normal, vigorous. The inoculations of Kanred, P1066. and P1068 both in the seed- ling and in the heading stage produced consistent results, indicating extreme resistance. The hard and soft wheat varieties did not differ strikingly in susceptibility, except in the case of Kanred, P1066, and P1068. The other hard red winter wheats apparently were as susceptible as the soft red winter wheats, although Leach (^4) found a "decided correlation between the hardness and softness of wheat varieties and their relative susceptibility to Puccinia graminis tritici-compacti.^' A greater variation occurred among the varieties of durum spring wheat. Beloturka (C. I. No. 1513) seemed to behave very much like the three resistant winter-wheat varieties, in that no uredinia were formed. In more recent work, however, in which the same strain of rust was used, Beloturka (C. I. No. 1513) occasionally has shown a few very small uredinia. vSome of the durum varieties show^ed more or less uniformly the same type of infection (R2 or R^) as in the case of Kubanka (C. I. No. 2094), Arnautka (C. I. No. 1493), D-5 (C. I. No. 3322), and Gharnovka (C. I. No. 1443). A Poulard wheat (C. I. No. 4384) manifested a high degree of resistance. Among the emmers there was more or less similarity in the type of infection. The type of infection fluctuated in both of these groups, showing that various factors may affect the infection results. Two . White Spring emmers (C. I. Nos. 1524 and 4781) showed the R, and R4 types of infection, while another White Spring emmer (C. I. No. RUST RESISTANCE IN WINTER- WHEAT VARIETIES. 23 1526) and Khapli emmer (C. I. No. 4013) seemed to show more con- sistently the type designated as R3. Khapli emmer (C. I. No. 4013) is the only variety of spring wheat so far studied that under all conditions seemed to exhibit a high degree of resistance in the field and in the greenhouse. Even this variety, however, may be classed at times as R, instead of R3. The seedlings of the so-called wild wheat of Palestine, Triticum hermonis Cook (C. I. No. 3109), really a form of emmer, all proved to be susceptible. The purple color mentioned under "Remarks" occurred in some varieties and surrounded the uredinia. It does not appear con- sistently in any one variety. Environmental conditions seem to affect its production. COMPARISON OF NURSERY AND GREENHOUSE RESULTS. In general, the results of the greenhouse inoculations were similar to those produced under field conditions in the rust nursery. All of the winter-wheat varieties were found to be susceptible except Kanred, PIO66, and PIO68. Kansas No. 2390, which appeared to be partially resistant in the rust nursery, gave no evidence of being resistant in the greenhouse. In the nursery, results on rust behavior usually are obtained on varieties in the heading stage, but in the greenhouse the seedling stage is most commonly used. Determining the resistance of varie- ties as seedlings is the most convenient method, particularly when a number of distinct biologic strains of rust are being used. It perhaps is the most severe test that can be given a variety and should always serve as a check on nursery results. The results thus obtained, however, scarcely can be considered as the sole criteria of the actual field resistance or susceptibility of a variety; in fact, plants showing certain effects when inoculated in the seedling stage in the green- , house may respond very differently to the same rust when they are subjected to it in the heading stage under field conditions. No definite statements as to the cause of these differences can be made at this time. The same factors causing resistance or susceptibility may operate in all stages of growth, but the reaction of the host and parasite at various stages of development may be different. It is possible that time of maturity may have an important influence on the extent of the rust on a given variety, but if the rust is epidemic before the plants reach the heading stage there can be no doubt as to the plants having been exposed to infection. The differences perhaps are due to complex factors in the developmental stages in a variety, which may cause a different response to rust infection. To whatever cause these differences in behavior in the seedling and heading stages may be due, the behavior of any variety 24 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. under field conditions is of first importance from the agronomic and plant-breeding viewpoint. The growing of wheat varieties in the rust nursery places them under conditions at least as severe as those to which a commercial field is subjected in a natural epidemic. Field tests must finally determine the value of any variety. EVIDENCE OF SPECIFIC RUST RESISTANCE. In the studies made of the resistant varieties, Kanred, P1066, and P1068, it was noted that their reaction to rust infection was entirely different from anything that had been observed in any other variety. Such varieties as Khapli emmer (C. I. No. 4013), White Spring emmers (C.I.Nos. 1524 and 1526 and Minnesota No. 1165), and the re- sistant durums Kubanka (C. I. No. 2094) and Arnautka (C. I. No. 1493) are known to show resistance in the seedling stage in the greenhouse as well as under field conditions. Their resistance in the seedling stage is shown by the formation of relatively sm;ill uredinia, surrounded by yellow or yellowish white areas, the occur- rence of minute brown or yellowish dead areas, the presence of yellowish islands, or other characters generally regarded as indicativ3 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, i» The word "immune" is here used to mean freedom from any macroscopic evidence of rust infection or to designate the inability of the rust fimgus 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 (PI. 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, 4^), 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 strams 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 seasons and in various sections of the country. 26 BULLETIN 1046, V. S. DEPARTMENT OF AGRICULTURE. RESISTANCE TO LEAF RUST. Observations (31) 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 been manifested also in experimental field sowings made in the States of Alabama, California, Missouri, North Carolina, 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 (19) 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 EUST RESISTANCE IX WIXTER-WHEAT VARIETIES. 27 crop as a result of the production of Kanred wheat would be $21,000,- OOO. A statement of the agronomic value of this variety will be found in Circular 194 of the United States Department of Agriculture. Although the problem of breeding wheat for resistance to stem rust has been greatly complicated by recent discoveries of a number of distinct biologic strains of rust which are present in the several grain- :growing regions, Kanred wheat in the future probably will prove of great value as a parental variety in crosses, for it certainly contains factors for resistance to some strains of leaf rust and stem rust. There is good evidence that these factors are transmitted in wheat hybrids in the same general way as the factors for other characters. Kanred wheat is being used by the Tennessee Agricultural Experi- ment Station as the rust-resistant parent in a series of crosses with adapted varieties of soft red winter wheat, in the hope of producing varieties of soft red winter wheat resistant to leaf rust and otherwise equal to the best varieties now being grown, which are often severely damaged by leaf rust. Kanred also has been used at the Kansas and Minnesota Agricultural Experiment Stations as a parent in a large number of crosses. It is too early to make any predictions as to the value of any of these hybrids, although several of them appear promismg. SUMMARY. (1) Field experiments to determine the resistance to black stem rust (Pvccinia graminis tritici) of about 100 varieties and strains of winter wheat, many of them pure-line selections, and of a few varieties of spring wheat, were conducted in a rust nursery at Manhattan, Kans., in 1915, 1916, and 1917. Greenhouse experiments were conducted during the winter of 1916-17, using the same varieties. Special methods were developed for producing rust epidemics under the pre- vailing climatic conditions of Kansas. (2) In the rust nursery severe epidemics were produced each season, and the percentage of rust infection probably represented the maximum rust attack which the varieties would encounter under field conditions. (3) All the winter-wheat varieties grown were found to be suscep- tible to stem rust except Kanred and two very similar pure-line selections, P1066 and P1068. These three varieties were found to be resistant. Another pure-line strain, Kansas No. 2390, gave evidence of being partially resistant. (4) Plumpness of kernels usually is reduced by severe rust attack. The three resistant varieties produced grain of good quality in 1916 and 1917, when other varieties grown under the same conditions but much more severely rusted produced very badly shrunken kernels. 28 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTUEE. (5) Several varieties of spring wheat proved rust resistant under the conditions of these experiments, though the Black Persian was the only spring-wheat variety of the common or bread-wheat group (Triticum vulgare) which was found to be resistant. Of the varieties of durum or macaroni wheat (Triticum dwum), Beloturka (C. I. No. 1513), lumillo (C. I. No. 1736), Kubanka (C. I. No. 2094), Monad (D-1), and Pentad (D-5) showed definite signs of resistance to stem rust. A hybrid of lumillo X Preston, resembling the durum parent, also was found to be rust resistant. All of the strains of emmer and einkorn grown gave some evidence of resistance. (6) In the greenhouse experiments the plants were studied for rust resistance at two stages of growth, viz, as seedlings and at the time of heading. The results were very similar to those in the field experiments. All the winter-wheat varieties were susceptible except three— Kanred, P1066, and P1068. Kansas No. 2390, which ap- peared to be somewhat resistant in the field, showed no evidence of resistance at either stage of growth in the greenhouse. Most of the spring-wheat varieties which the field experiments had shown to be resistant also gave more or less evidence of resistance under green- house conditions. This was not true, however, of einkorn. (7) Although the results obtamed in the field and those in the greenhouse agree fairly well, final conclusions as to rust resistance of a variety should not be drawn from greenhouse tests alone. The com- bined evidence from nursery experiments and inoculations of seed- lings and of plants in the heading stage under greenhouse conditions is much more likely to agree with actual field trials, which must always be the final test of the practical value of any variety. (8) The behavior of the rust parasite on the inoculated plants of the three resistant varieties^Kanred, P1066, and P1068 — seems to be different from that in other varieties described as resistant. In most other varieties prominent flecks are nearly always present in 8 to 12 days after inoculation, and most frequently small uredinia are pro- duced. In these three varieties, however, flecks are very rarely visible, and in no instance have even the most minute uredinia been observed. (9) Reports from Alabama. California, Illinois, Iowa, Missouri, Nebraska, New York, Wisconsin, and New South Wales indicate that these three varieties are resistant to stem rust; but Minnesota and South Dakota report them rather severely attacked by stem rust. The occurrence of distinct strains of stem rust complicates the prob- lem of predicting what their behavior may be during different seasons. Present knowledge of the distribution of stem-rust strains and whether they occur each season in definite regions is so limited that the resist- ance or susceptibility of those wheats in any region may differ from season to season. RUST RESISTANCE IN WINTER- WHEAT VARIETIES. 29 (10) The very light infection of leaf rust in sowings made in Ala- bama, Arkansas, California, Missouri, North Carolina, North Dakota, Oregon, South Dakota, Tennessee, Texas, Virginia, and Wisconsin, and in New South Wales has proved that these three varieties are extremely resistant to leaf rust also. Present knowledge of the leaf-rust problem indicates rather definitely that these varieties will maintain this high degree of resistance under a wdde range of condi- tions. (11) Kanred, one of the three rust-resistant pure lines, has an" unusual combination of desirable characters. In Kansas it yields from 3 to 5 bushels more per acre than either Turkey or Kharkof, the varieties commonly grown. It ripens a little earlier, thus escaping some of the damage from drought and hot winds during the ripening period. Kanred also seems to be more winter hardy in Kansas than other varieties and survives the severe winters with less loss from winterkilling. In milling and baking quality it apparently is equal to Turkey and Kharkof, varieties of hard red winter wheat which have established a world-wide reputation for quality. (12) Experiments and the experience of large numbers of farmers have shown that Kanred is adapted to other sections of the hard winter-wheat area, and it is now rapidly being introduced and widely grown in Oklahoma, Texas, Nebraska, eastern Colorado, and some other States. (13) Kanred wheat is believed to have considerable potential value also as a parental variety to be used by plant breeders in com- bining its rust resistance and other valuable characters with those of the varieties of other classes of wheat adapted to the several wheat- growing districts. LITERATURE CITED. (1) Anderson, H. C. L. 1890. Rust in wheat. Experiments and their objects. In Agr. Gaz. N. S. Wales, V. 1, pt. 1, p. 81-90, ilkis. (2) BiFFEN, R. H. 1907. Studies in the inheritance of disease resistance. In Jour. Agr. Sci.^ V. 2, pt. 2, p. 109-128. (3) BOLLEY, H. L. 1889. Wheat rust. Ind. Agr. Exp. Sta. Bui. 26, 19 p., 9 fig. (4) 1905. Experiments and studies upon wheat. In No. Dak. Agr. Exp. Sta. 15th Ann. Rpt. 1904, p. 34-51, 1-5 fig. (on pi.). (5) 1909. Some results and observations noted in breeding cereals in a specially prepared disease garden. In Amer. Breeders' Assoc. Rpt.^ v. 5 (1908), p. 177-182. (6) Call, L. E., and Salmon, S. C. 1918. Growing wheat in Kansas. Kans. Agr. Exp. Sta. Bui. 219, 51 p., 11 fig. (7) Carleton, Mark Alfred. 1903. Culture methods with Uredinea?. In Jour. Appl. Micros, and Lab. Methods, v. 6, no. 1, p. 2109-2114. (8) 1905. Lessons from the grain-rust epidemic of 1904. U. S. Dept. Agr., Farmers' Bui. 219, 24 p., 6 fig. (9) and Chamberlain, Joseph S. 1904. The commercial status of durum wheat. U. S. Dept. Agr., Bur. Plant Indus. Bui. 70, 70 p., 1 fig., 5 pi. (10) Clark. J. Allen, Martin, John H., and Smith, Ralph W. 1920. Varietal experiments with spring wheat on the northern Great Plains. U. S. Dept. Agr. Bui. 878, 48 p., 2 tig., 3 pi. Publications on cereals in the Great Plains area, p. 48. (11) Eriksson, Jakob, and Henning, Ernst. 1896. Die Getreideroste. Jhre Geschichte und Natur sowie Massregeln gegen dieselben. vii, 463 p., 5 fig., 13 col. pi., 1 col. tab. Stockholm. Litteraturverzeichnis, p. 446-457. (12) Freeman, E. M., and Johnson, Edward C. 1911. The rusts of grains in the United States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 216, 87 p., 2 fig., 1 pi. Bibliography, p. 79-82. (13) Hayes, H. K., Parker, John H., and Kurtzweil, Carl. 1920. Genetics of rust resistance in crosses of varieties of Triticum vulgare with varieties of T. durum and T. dicoccum. In Jour. Agr. Re- search, V. 19, no. 11, p. 523-542, pi. 97-102. Literature cited, p. 541-542. (14) Henning, Ernst. 1894. Nagra ord om olika predisposition for rost a sad. In K. Landtbr. Akad. Handl. och Tidskr., arg. 33, p. 205-217. (15) Henslow, J. S. 1841. Report on the diseases of wheat. In Jour. Roy. Agr. Soc. England, V. 2, p. 1-25. 30 RUST RESISTANCE IX WINTER-WHEAT VARIETIES. 31 (16) Hitchcock, A. S., and Carleton, M. A. 1893. Preliminary report on rusts of grain. Kans. Agr. Exp. Sta. Bui. 38, 14 p., 3 pi. (17) 1894. Second report on rusts of grain. Kans. Agr. Exp. Sta. Bui. 46, 9 p. (18) HuTCHEsoN, T. B., and Quantz, K. E. 1917. The effect of greenhouse temperatures on the growth of small grains. In Jour. Amer. Soc. Agron., v. 9, no. 1, p. 17-21, 1 fig., 2 pi. (19) Jardine, W. M. 1917. A new wheat for Kansas. In Jour. Amer. Soc. Agron., v. 9, no. 6, p. 257-266. (20) Johnson, Edward C. 1911. Methods in breeding cereals for rust resistance. In Proc. Amer. Soc Agron., V. 2 (1910), p. 76-80. (21) 1912. Cardinal temperatures for the germination of uredospores of cereal rusts. (Abstract.) In Phytopathology, v. 2, no. 1. p. 47. (22) Kellerman, W. A. 1903. Uredineous infection experiments in 1902. In Jour. MycoL, v. 9, no. 65, p. 6-13. (23) La Cour, J. G. 1863. Sygdommene i kornet og midlerne derimod. Zn Tidsskr. Land0kon., Raekke 3, Bd. 11, p. 249-264. (24) Leach, Julian G. 1919. The parasitism of Puccinia graminis tritici Erikss. and Henn. and Puccinia graminis tritici-compacti Stak. and Piem. In Phyto- pathology, V. 9, no. 2, p. 59-88, pi. 4-6. (25) Levine, M. N., and Stakman, E. C. 1918. A third biologic form of Puccinia graminis on wheat. In Jour. Agr. Research, v. 13, no. 12, p. 651-654. (26) Little, W. C. 1883. Report on wheat-mildew. Jour. Roy. Agr. Soc. England, ser. 2, v. 19, p. 634-691. (27) Mains, E. B., and Jackson, H. S. 1921. Two strains of Puccinia triticina on wheat in the United States. (Ab- stract.) In Phytopathology, v. 11, no. 1, p. 40. (28) Melchers, Leo E. 1915. A way of obtaining an abundance of large uredinia from artificial culture. In Phytopathology, v. 5, no. 4, p. 236-237. (29) and Parker, John H. 1918. Three varieties of hard red winter wheat resistant to stem rust. (Ab- stract.) In Phytopathology, v. 8, no. 2, p. 79. (30) 1918. Another strain of Puccinia graminis. Kans. Agr. Exp. Sta. Circ. 68, 4 p. (31) 1920. Three winter wheat varieties resistant to leaf rust in Kansas. In Phytopathology. v.lO, no. 3, p. 164-171, 3 fig. Literature cited, p. 171. (32) Melhus, I. E., and Durrell, L. W. 1919. Studies on the crown rust of oats. Iowa Agr. Exp. Sta. Research Bui • 49, p. 115-144, 6 fig. BibUography, p. 143-144. (33) Nilsson-Ehle, H. 1911. Kreuzungsuntersuchungen an Hafer und Weizen. II. In Lunds Univ. Arsskr., n. f., afd. 2, bd. 7, nr. 6, 84 p. Literaturverzeichnis zu der Einleitung, p. 20. 32 BULLETIN 1046, U. S. DEPARTMENT OF AGEICULTUEE. (34) Parker, John H. 1918. Greenhouse experiments on the rust resistance of oat varieties. U. S. Dept. Agr. Bui. 629, 16 p., 2 fig., 3 pi. Literature cited, p. 16. (35) Rust in Wheat Conference. 1891-92. Report of the proceedings, 2d-3d session, 1891-92. Sydney (N. S. Wales), Adelaide (S. Australia). (36) Salmon, S. C. 1919. Establishing Kanred wheat in Kansas. Kans. A'gr. Exp. Sta. Giro. 74, 16 p., 7 fig. (37) Stakman, E. G. 1914. A study in cereal rusts. Physiological races. Minn. Agr. Exp. Sta. Bui. 138, 56 p., 9 pi. BibUography, p. 50-54. (38) and Hoerner, G. R. 1918. The occurrence of Puccinia graminis tritici-compacti in the southern United States. In Phytopathology, v. 8, no. 4, p. 141-149, 2 fig. (39) Levine, M. N., and Leach, J. G. 1919. New biologic forms of Puccinia graminis. [Preliminary paper.] In Jour. Agr. Research, v. 16, no. 3, p. 103-105. (40) and Piemeisel, F. J. 1917. Biologic forms of Puccinia graminis on cereals and grasses. In Jour Agr. Research, v. 10, no. 9, p. 429-496, pi. 53-59. (41) United States Department op Agriculture. 1920. Kanred wheat epoch-making for Kansas ... Jn U. S. Dept. Agr. Weekly News Letter, v. 8, no. 6, p. 6. (42) Waldron, L. R., and Glare, J. A. 3919. Kota, a rust-resisting variety of common spring wheat. In Jour. Amer. Soc. Agron., v. 11, no. 5, p. 187-195, pi. 7. 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