U* »c 4/ e Of %tfS\ Division of Agricultural Sciences UNIVERSITY OF CALIFORNIA- ONA HEAT C. A. SUNESON - C.W. SCHALLER CALIFORNIA AGRICULTURAL EXPERIMENT STATION BULLETIN 742 ^•NAS 53 is the cumulative product of several breeding projects which have corrected many of its original weaknesses yet have retained the out- standing attributes that make it an important variety. Onas 53 matures moderately late. Its straw is of medium height, fairly stiff, and relatively leafy. Its spikes are rather dense and awned and have white glumes. The kernels are soft, white, and of medium size. Quality studies indicate that Onas wheat when low in protein produces good cookie and pastry flour; when higher in protein can be used successfully in blends to produce bread flour. In general, its milling properties are less satisfactory than its baking responses. This wheat combines resistance to the races of stem rust and bunt (stink- ing smut) now prevalent in California. It is more resistant to stem rust than any other variety now grown. Morphologically it differs from the com- mercial Onas by the presence of awns on the head. Tests have shown that the awned form has a 7 per cent advantage in kernel weight and a pound advantage in test weight, resulting in higher yields and better milling quality. In all other respects it is identical to the variety now being grown. THE AUTHORS: C. A. Suneson is Research Agronomist (U.S.D.A.) and Associate in Agronomy, Davis. C. W. Schaller is Assistant Professor of Agronomy and Assistant Agronomist, Davis. ONAS 53 WHEAT C. A. SUNESON C. W. SCHALLER The Development of Onas Wheat years, however, the relative position of More than thirty years have elapsed varieties may differ. An analysis of these since the original release of Onas wheat yield positions shows that although Onas by the California Agricultural Experi- possesses a high capacity for yield, its ment Station in 1923. During this time performance between years and locations its general worthiness as a commercial fluctuates more than that of White Fed- variety has been demonstrated not only eration. Such fluctuations may result in California but also in other western from moisture and heat stresses on varie- states. ^ es °f tater maturity. Introduction in United States. Onas Adaptability. Onas has become well wheat was produced in 1915 by a farmer established in three extremely dissimilar in South Australia from a cross, Feder- production areas in California: the ation x Tarragon. It was introduced into Salinas basin, the Mother Lode wash, the United States by the United States and a portion of Fresno County. It pres- Department of Agriculture in 1918. Fob ently comprises about 7 per cent of the lowing experimental tests, the California California wheat acreage. The variety is Agricultural Experiment Station released g rown un der irrigation in Arizona and and recommended it for production in Montana, and with natural rainfall in California in 1923. Subsequently, several Idaho and Washington. Such widespread other western experiment stations have and diverse adaptation is in itself an joined in recommending it. indication of merit and is further cause Average yields. Onas has continued for seeking to improve the variety by its successful competitive performance backcross breeding, at Davis as indicated by the following average yields for the thirty-two-year Breeding Programs period— 1922-1953: Bushels per acre Backcross breeding has been widely Onas 46.8 used in California ( Briggs and Allard, White Federation 46.7 1953 ). 2 It can be likened to the succes- " aart 4 ">.0 s j ve steps by which our successful ma- After 1941 the above comparisons were chines are continually being improved, between Onas 41, White Federation 38, These are research, testing, and ultimate and Baart 38. Recent state-wide tests at substitution of improved parts. Four 105 locations during the years 1948- such programs to improve Onas have 1952 gave the following average yields been undertaken and completed by Cali- when stem rust was not a factor: fornia breeders. From the first three pro- Bushels per acre g rams me improved seed stocks are al- Q nas 41 30 7 ready in use in California or elsewhere White Federation 38 29.4 in the western region. High average yields are desirable and ° nas 41 - This variet y was produced indicate adaptability. In each of the from crossing (Martin x White Feder- ; . ation 3 ) x Onas*'. (The numerical super- 1 This paper is based on cooperative investi- • . j .v i r . • x i .T . c t n i r> j script denotes the number oi times the gations with the Section oi Cereal Crops and £. Diseases, United States Department of Agri- 2 See "Literature Cited" for citations referred culture. to in the text by author and date. [3] recurrent parent was used for back- crossing.) This project was completed in 1941 with the compositing of 115 F 3 lines having resistance to bunt (stinking smut). This transfer of bunt resistance has been duplicated with ten other Cali- fornia varieties. These breeding programs and com- panionate seed treatment improvements have practically eliminated wheat smut from California. Such breeding programs have controlled bunt, but they have not changed the many characters which indi- vidualize the varieties in appearance, performance, and production. Thus, in 136 comparisons between Onas and Onas 41, almost identical yields of 52.6 and 52.7 bushels respectively were obtained (Suneson, 1947). This can be expected wherever six or more backcrosses are made, and numerous lines are blended to constitute the improved variety. These are basic procedures in all the present California wheat-breeding programs. Awned Onas. This variety resulted from crossing Baart x Onas 9 with con- tinuous selection to recover awns. This created an awned form of a previously awnless variety. Tests showing a 7 per cent advantage in kernel weight and a pound advantage in test weight for the awned type have been reported (Sune- son, et at., 1948). The reality of these advantages for awns has been further emphasized by more recent tests in nearly all parts of California. This strain has lately become popular in Arizona. Onas 49. This variety consolidated the two previous breeding gains. In this case the mating was Awned Onas x Onas 41 2 . This strain has served as the experi- mental prototype of Onas 53 in numer- ous tests and on a limited commercial acreage. Table 1. Breeding and Testing Schedule for Production of Onas 53 Year Winter planting Summer planting* Crosses or lines advanced Preparatory period 1939-1944 Evaluating the parent, Kenya (Calif. 3098) Crossing period 1944 Onas 41 X Kenya 2 1945 Fi F 2 X Onas 41 6 1946 BCF, BCF 2 X Onas 41 9 1947 BC 2 F t BC 2 F 2 X Awned Onas 19 1948 BC 3 F, BC 3 F 2 XOnas41 20 1949 BC 4 F X X Onas 49 BC 5 F X X Onas 49 42 BC 5 F, X BC 4 F 2 f 10 Final selection period 1950 BC 6 F! BC 6 F 2 164 1951 BC 6 F 3 t BC 6 F 4 257 1952 BC 6 F 6 (Breeder's seed) 250 Seed increase 1953 Foundation seed (6 acres) * Stem rust selection in every summer planting. t Progeny considered equivalent of BCe. % Duplicate plantings for agronomic and bunt selection. F denotes filial generation; BC denotes backcross generation. [4] THE DEVELOPMENT OF ONAS 53 WHEAT Parentage. Onas 53 was produced on a schedule given in table 1. For general- ization it can be regarded as coming from Kenya x Onas 49 7 , although Onas 49 did not exist as such until 1949. To produce it required 114 actual crosses each producing 5 to 16 seeds; growing two crops during each of seven years; providing selective rust epidemics after every backcross and twice after the last backcross; providing a bunt test for elimination of susceptible progeny in 1951; continuous selection directed to- ward recovering the Onas type; and terminal blending of 250 F 3 lines to con- stitute Onas 53. For all this about 73,000 individually spaced plants were grown and observed from 1945 to 1953. Kenya parent. The Kenya (Cali- fornia 3098) parent deserves mention. Introduced from Australia, it was first tested in 1939. During subsequent test- ing it exhibited a better and genetically different reaction to prevalent stem rust races (races 17 and 56) than the variety Hope. Hope was already in wide use as a rust-resistant parent in our breeding programs. Therefore the opportunity to apply the old adage of "not putting all the eggs in one basket" was evident. Furthermore, it was recognized that this transfer could be made without intro- ducing new test races of rust, and that the resulting Onas 53 would possess re- sistance to the prevalent stem rusts in California and to some other races against which Hope's resistance was not effective. Thus, Onas 53 was conceived and produced before any real California need for its genetically different rust re- sistance existed. Meanwhile, world-wide reports show that races of stem rust capable of attacking Hope (and varieties CHARACTERIZATION OF ONAS 53 CHARACTER RESPONSE Agronomic: Winter growth Average total, low growing, good tillering Maturity One to 12 days later than Baart Shattering Average loss slightly greater than for Baart Frost Above average hardiness (spring types) Heat Good tolerance if soil moisture is available Test weight Average equal to White Federation Plant parts: Kernels White, soft, ovate, open crease, medium-sized Heads Oblong, denser than Baart, awns on glumes Stems Medium height, fairly stiff, large Leaves Larger than average, dark green Roots Good penetration and extension Disease reactions: Stem rust Resistant to all races recently prevalent in California Leaf rust Moderately susceptible (race 1 1 most common) Stripe rust Resistant to most races Bunt Resistant to most common races in California Mildew Occurrence rare on this variety Septoria leaf spot Most resistant of all California varieties Yellow dwarf virus Less than average damage [5] derived from it) are spreading, and that the Kenya parent (and Onas 53) are genetically protected from many of these new rust races. Resistance to Stem Rust Nature of stem rust in California. This disease affords a constant threat to wheat production in California. The per- sistance of the red spore stage through- out the year on the commercial wheat crop, volunteer wheat plants in irrigated crops, and on certain grasses serves as source material for potential rust epi- demics. Rust is killed in the winter only when temperatures are low enough to kill the leaves and stems of the host. A combination of favorable spring temper- atures and humidity in the over-wintering area results in a rapid increase of spore numbers. At that period successively established red spore generations can re- produce every eight days. The spores are spread by the wind and can be directed over the entire state from localized centers. Prior to 1941, a constant widespread prevalence of wheat stem rust in Cali- fornia produced moderate or severe losses in about one of every four years. Damage from rust is increased by heat, drought, wind or lodging, and is ex- pressed primarily through reduced ker- nel weight. In extreme situations almost complete losses occur, but the common loss specifically attributable to stem rust rarely exceeds 50 per cent. Since 1941 widespread use of varieties deriving their resistance from Hope has minimized losses from stem rust. The variety Hope has remained resistant con- tinuously since 1929 and the variety Kenya since 1939. This fact and the con- stancy of race identifications from Cali- fornia' indicate that neither the origin of new races through hybridization (which may occur when the sexual gen- eration of stem rust develops on barberry 3 Identification reported by Dr. E. C. Stak- man, University Farm, St. Paul, Minnesota. bushes), nor spore migration from other wheat-growing areas where such hybrid- ization has occurred has been of conse- quence in California since 1941. This stability is fortunate but not positive pro- tection. There is good suggestive evidence that recent rust damage to the improved vari- eties White Federation 38, Baart 38, and Ramona 44 has not resulted from newly introduced rusts, but rather from muta- tions (sports) within the long prevalent races 17 and 56. All of the named im- proved varieties possess only a part of the total genetic resistance of Hope and were never totally free of rust. Conse- quently, change toward greater suscepti- bility was favored — a factor which ac- counts for our recent breeding programs to utilize both the full resistance of Hope and of other genetic systems, such as Kenya. It should be evident from the discus- sion that our climate and irrigation make stem rust a major disease of wheat in California; that it has been under prac- tical control for twelve years as a result of earlier breeding programs for develop- ing resistance; and that Onas 53 was produced, in part, to increase and broaden our security from attack by stem rust. Recommended Use It is believed that Onas 53 should re- place all of the present Onas acreage and some of the acreage now occupied by each of the other important varieties. The yield, quality, and production secur- ity obtainable with Onas 53 is unques- tionably better than with any other strain of Onas. Recommended trial areas in- clude all irrigated lands where early maturity is not essential and where aver- age losses from shattering are not high, and dryland farms with demonstrated capacity to mature wheats slightly later than Baart. On the latter, particularly, November or December planting will prove best. The growth, strain character, [6] maturity, and high-yielding capacity of resistant varieties grown in California) Onas 53 make irrigation and fertilization becomes established in California and necessary. Onas 53 remains resistant, most wheat If a rust race capable of attacking growers operating on irrigated land or varieties deriving their rust resistance in humid areas would do well to shift to from Hope (which includes all rust- Onas 53. LITERATURE CITED Briggs, F. N., and R. W. Allard 1953. The current status of the backcross method of plant breeding. Agron. Jour. 45(4):131-38. SUNESON, C. A. 1947. An evaluation of nine backcross-derived wheats. Hilgardia 17(15) : 501-10. Suneson, C. A., B. B. Bayles, and C. C. Fifield 1948. Effect of awns on yield and market qualities of wheat. U.S.D.A. Cir. 783. 8 p. 10w-2,'54(2679)M.H. [7] AGRONOMY TRAINING leads to many careers AGRICULTURAL INDUSTRIES RESEARCH ORGANIZATIONS GOVERNMENT AGENCIES FARMING Agronomy deals with the production and improvement of field crops, pastures, and rangelands. Agronomic crops are grown on more than half of California's agricultural land. Trained agronomists are needed to produce more foodstuffs, handle speciality crops, develop improved varieties, devise and apply scientific methods. Training at Davis has special advantages: Instructors who are leaders in their fields, and are active in research on today's farm problems. The University farm, for practice and ex- periment in one of the nation's richest farm areas. Modern facilities, for better study and re- search. An uncrowded campus, with many new buildings. Letters and Science college on the same campus, broadening the scope of education. FOR FURTHER INFORMATION on agronomy write to Maurice L. Peterson, opportunities chairman, agronomy depart- ment. on entrance write to Howard B. Shontz, requirements office of the registrar. on college see your County Farm Ad- opportunities visor for college entrance counsel. University of California * Davis, Calif. 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