UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA WHEAT PRODUCTION IN CALIFORNIA C. A. SUNESON and F. N. BRIGGS Rust-resistant Baart 38 (left) and rust-susceptible Baart BULLETIN 659 December, 1941 UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA CONTENTS PAGE Growing the crop 3 Diseases and insect pests 5 Harvesting and storage 6 Commercial uses of the California wheat crop 6 Varieties of wheat 7 Experimental data on wheat varieties 7 County yield trials 10 Milling and baking tests 12 Description of varieties 13 Summary 17 WHEAT PRODUCTION IN CALIFORNIA 1 C. A. SUNESON 2 and F. N. BRIGGS 3 Wheat, the most important food plant known to the white race, was first brought to California by the Spanish padres. The remains of club varie- ties resembling some still grown have been found by Hendry* in adobe bricks of mission buildings constructed between 1770 and 1800. More extensive wheat production in California began with the Gold Rush in 1849 and increased rapidly for about thirty years, until by 1890 Cali- fornia produced 41 million bushels, thus ranking second among the States in production. The encroachment of other crops and enterprises, and increases in land values, along with a necessary shift from extensive to more intensive agriculture, then brought a gradual decline, culminating in the production of only 4,200,000 bushels of wheat in 1913. Since that time the trend has been upward, with an average annual production of about 11,000,000 bushels between 1934 and 1939. This is less than half the present wheat requirements in California for human food and for feed for poultry and livestock. In recent years, cereal agronomists and plant breeders in California have been much concerned with the procuring and breeding of superior wheat varieties. The present bulletin contains up-to-date information on wheat improvement. Only general information on wheat production problems is given, because of the wide diversity of climate and soil in California. Also production practices are fairly well understood as a result of experiments and practical experience in each area. Local information on wheat production may be obtained from farm advisors in the respective counties. GROWING THE CROP Wheat production in California now follows two general cultural patterns, namely dry-land and irrigation farming. Common in the dry sections are alternate crop and fallow systems ; or short rotations, involv- ing wheat, a row crop or pasture, and fallow. Production of this type is generally on the poorer lands, whither wheat has been pushed by other crops that give greater acre returns. In such regions, fallowing, which 1 Received for publication March 21, 1941. Based on cooperative investigations with the Division of Cereal Crops and Diseases, Bureau of Plant Industry, United States Department of Agriculture. 2 Associate Agronomist, Division of Cereal Crops and Diseases, Bureau of Plant Industry, United States Department of Agriculture, and Associate in the Experiment Station. 3 Associate Professor of Agronomy and Associate Agronomist in the Experiment Station. * Hendry, G. W. The adobe brick as a historical source. Agr. Hist. 5:110-27. 1931. [3] 4 University of California — Experiment Station accumulates moisture and nitrogen and helps control weeds, is the most essential feature. Wheat also is grown under irrigation, chiefly where soils are unsuited to other field crops or where a rotation, a double crop- ping system, or erosion prevention is facilitated. Under irrigation, high yields are common ; and the elimination of the hazards from rust through production of resistant varieties should do much to further stabilize yields. Generally speaking, wheat gives best yields in California when sown in November, December, or January. It can be grown from sowing dur- ing any month, but for out-of -season plantings the cost of establishing stands and controlling weeds and diseases is generally far greater than the returns. The most essential consideration for growers appears to be seeding early enough to insure the maximum use of winter rainfall and to avoid excessive summer temperatures and warm-weather diseases. Wheat that heads during the winter months may fail because the flowers or developing grains are killed by frost. Rate-of -seeding experiments have demonstrated a rather wide lati- tude in quantity of seed that suffices. Rates above 75 pounds per acre are seldom justified except where weeds are serious. In this case thick stands of wheat compete with weeds more effectively. Wheat plants pos- sess a wide capacity for adjusting their tillering to occupy a land area to maximum production capacity for a given water and soil-nutrient supply. Much of the crop is broadcast, sometimes without subsequent harrow- ing, because of the persistent rains during the planting season. Drilling, when feasible, conserves seed and gives more uniform stands than broad- casting. Seedbed preparation, as regards time and depth of plowing and sub- sequent tillage necessarily varies considerably for different sections, soil types, and seasons. In cereal production, tillage, in addition to producing a satisfactory seedbed, serves to destroy weeds, incorporate plant mate- rial in the soil, conserve moisture, promote the activity of desirable soil organisms, and (if properly managed) reduce runoff and erosion. Con- tour tillage is desirable in areas subject to erosion. Under conditions of limited rainfall it is not desirable to incorporate too much straw in the soil because considerable water and nitrogen that are required by the wheat crop are utilized in decaying the straw. Be- cause of this, the burning of straw and stubble commonly results in greater yields of the succeeding crop, though continued adherence to such a practice hastens depletion of organic matter in the soil and tight- ening up of the soil structure. Experiments now under way suggest the rational use of nitrogenous fertilizer to promote decay of straw and Bul. 659] Wheat Production 5 other highly carbonaceous material in soils without materially reducing the yield of the succeeding crop. Most California soils devoted to wheat production respond to nitro- gen fertilizers, though in many cases the yields are not increased suffi- ciently to pay for the fertilizers and their application at the present low prices for wheat. Late winter applications appear most efficient; but costs of applying at the later date nullify the gain. Since nitrogen is a strong growth stimulant, one must always consider the danger of exhausting available moisture before maturity of the crop and of encour- aging lodging. Phosphorus and sulfur are also deficient on some Cali- fornia wheat lands. Soil deficiencies can best be determined by field trials in which the compared growth and yield of wheat are on fertilized and nonf ertilized areas. Chemical tests for soil deficiencies have gener- ally proved unsatisfactory. DISEASES AND INSECT PESTS Stem rust is the most important disease of wheat in California. The rust organism is carried through the summer, at the lower elevations, on volunteer wheat plants accessible to irrigation water, or on certain grasses, or the rust spores are blown in from mountain and coastal val- leys in the autumn. Often our winters are not severe enough to kill it. Thus the alternate host, the common barberry, is not essential to the maintenance of the rust organism in California. Given favorable tem- peratures and humidity, stem rust spreads rapidly in the spring, its spores being carried by the wind even to isolated mountain valleys. Whereas spread of rust is encouraged by damp weather, moderate tem- peratures, and wind movement, its development may be quickly arrested by dry, hot weather. Late-maturing varieties generally rust worse be- cause the organism has more time to develop spores to infest them. The recent release of California varieties resistant to stem rust should solve this problem. Leaf rust or stripe rust of wheat seldom reduce yields materially. At present only one smut of wheat is important in California — the so-called "stinking" smut or bunt. The spores are carried on the seed and they infect the germinating seedling. As the plant matures, smut balls develop in the head in place of the normal kernels. The disease may be controlled by seed treatment, using 2 ounces of copper carbonate dust per bushel or New Improved Ceresan (a mercury compound) applied at the prescribed rate of % ounce per bushel. With either of these dusts, some device must be provided for mixing seed and dust to insure com- plete coverage of all seeds. Most of the important varieties of wheat grown have been or will be crossed with resistant varieties and then 6 University of California — Experiment Station backcrossed to develop strains that are resistant to the most common race of bunt found here. Since some certain other races of bunt occur in Cali- fornia to which the ''smut-resistant varieties" are susceptible, seed of these varieties should be treated every second or third year as insurance against other races becoming established on the varieties that are resist- ant to the race now most common in California. Diseases of less importance are the foot and root rots, and septoria leaf spot. No practical control is known for these. A project looking toward transferring resistance to the hessian fly to certain California varieties is nearing completion. This is being carried cooperatively with the Bureau of Entomology and Plant Quarantine, U. S. Department of Agriculture. Although hessian fly is a serious pest only in the Bay region of California, the experience gained in breeding for resistance to this insect pest may well be useful in combating others. Other insects sometimes found in California wheat fields are straw worm, joint worm, and green bug (aphids) . HARVESTING AND STORAGE California farmers enjoy one natural advantage over most American wheat producers : they may spread both planting and harvesting over a considerable period without reducing the yield or quality of the crop. Harvesting with combines is almost universal. Handling, storage, and marketing in bulk would seem a desirable practice in effecting greater production economies. Because of existing investments in equipment and storage plants, this transformation will necessarily be slow. COMMERCIAL USES OF THE CALIFORNIA WHEAT CROP California-grown wheats have two principal uses: for human food and for poultry feed. As a rule, wheat shrunken by drought or diseases so that its weight per measured bushel is less than 56 pounds will not give a satisfactory flour yield. Variety, season, and region may influence that complex of chemical and physical properties called "quality." Un- fortunately no simple tests are available for predicting the baking response with certainty. For a true evaluation, each sample must be baked experimentally. Of course high protein content is generally con- ducive to a better loaf of bread, and very low protein content to the best pastry; but these generalizations are subject to occasional dramatic exceptions. Likewise the variety Baart usually makes a much better bread wheat than White Federation of like protein content, grown under the same conditions. In general, the protein test is not a very dependable measure of the quality of California-grown wheats. Bul. 659] Wheat Production 7 Standardization is the keynote of modern industry. The mills achieve it with a heterogeneous collection of wheats by blending, modifications in milling, variation in chemical treatment such as bleaching and oxida- tion, and use of adjuncts such as malt. The so-called "strong" wheats of the hard red classes seem necessary for blending with even the best Cali- fornia wheats; and since these cannot be produced successfully in Cali- fornia we must, apparently, be content with producing the best possible white wheats. VARIETIES OF WHEAT The numerous types of wheat known differ markedly in appearance, climatic adaptation, and commercial use. Within each of these types are numerous commercial varieties also more or less distinguishable from their kindred sorts in the above characteristics. Thus only certain adapted varieties of common white wheats, white club wheats, and hard red winter wheats are suitable for California. The hard red winter wheats are capable of enduring prolonged freezing or snow cover but do comparatively well only in the high mountain valleys. In the greater part of the state, certain spring varieties that make good winter growth when sown in November and December are desirable. Modern varieties are highly specialized selections adapted to a region but not to a country or a continent. To judge from experience in Cali- fornia with several thousand introduced varieties gathered from all parts of the world through the facilities of the United States Department of Agriculture and other agencies, we have obtained the better types for our conditions, and further gains are not likely to be achieved by this method, except to provide new parent material if new diseases or insect pests appear. Experimental tests indicate that the advantages of certain varieties over others, also proved and now extensively grown in Cali- fornia, are dependent on a very few major differences. More specifically, Baart, White Federation, and Big Club now comprise 60 per cent of our total wheat acreage. The transfer, by backcrossing, of the desired herita- ble characters of stem-rust resistance and smut resistance from non- adapted varieties to these three varieties probably will have sufficient practical value to increase their culture to 85 per cent of the total Cali- fornia acreage within five years. Other factors bearing on the adaptation of different varieties to California are mentioned later. EXPERIMENTAL DATA ON WHEAT VARIETIES 8 Wheat variety plot tests repeated under uniform conditions in a given field have been conducted at Davis each season, beginning in 1922. Table 5 Participating in the testing program were: V. H. Florell (1922-1928), and G. A. Wiebe (1929-1935), representing the United States Department of Agriculture; and W. W. Mackie (1922-1928), representing the University of California. ft R © DQ C "S *s 1 © 3 C O ° Jz 55 Q Light stem rust Leaf, stripe, and stem rust Heads of early varieties frosted Weed competition Excess winter rain Drought Root rot; stem rust Stand- dard error, bushels • 00 OS rH CO CO a 00 co os US CO CM CD CM CO to o t>. us CO US t-^- O rH CO rH If tD lO rjl K5 N * 2cm CcM OS os 00 »-i to o OO CO co o US ,-< •*»< OS CM CO CO CO CO 00 rH o oo o — i M N ^ * lO us M< O us o CO OS TJ< to us N tD r^ 00 >* Ifl O CO * M » <* N ^ pq OO N M tO lO to CO US CD OS oo N tO 1(5 N N ffi O K -3 1 N OO 18 W M CO US t»< US US ■«*< CO US CO CM US CM O 00 to CO CO CM US O CO ^H 00 Ol tO ■* M TK N M • CO to US ■<*< tM OS OS CO rH OS US O0 t~ OS OS CS . . t^ to . US Tr> CO CM US CO us US CM to oo to CO S O «« CM !>• t~ _ tO .-H rH ^H S t- rH 00 O &s to CO 00 to T* oo to soi uj^io 00 CO US ^ CM CO CM CM t>. us US O0 CM ■«*< CD O0 O0 CO TJ< CO CO rt< CM CO White Feder- ation (4981) "rjl US CO rH CO CO) t«- © US co S Ttl c<- a to so t~- O OS t~ t~- us to © f •* lO IO t- CO US CO oo US as CM tO y-< ■»* CM CO © S US CO <* tO ■# ^ * N W el os c3t© PQd to io o * « to o t>- us US 00 00 t> H OO tO (<5 N N tf to O CO OO US CO to I>. US US ■«*( CO Tt* US CO -r eo s? O CO to 00 N 115 » tO OO ^ rj CO US CO CO CO CM O" Pacific Blue- stem (4067) O CM 00 <-■ US O OS us o CM CO CO O O n o h « to to CO US ■«* CO CM CO CM OS CO CO CI CI to eo US •<*< CM rH CM •>* OS O OS CM Tfl CM CO CM CM CM I I e a > < a, J*. 8 s ft, « M >* W tO N N N N N N N OS OS OS OS OS OS 0O OS tM CM OS OS o CO as CO 02 CM CO CO CO OS OS * » CO N 0O » O CO CO CO CO CO CO * 8 .3* CM © 2 > A .g J | cu * > e Bul. 659] Wheat Production 9 1, giving the yields secured, includes only varieties of commercial inter- est in California at .this time. Numerous other varieties or experimental hybrids have proved deficient in yield or in some other vital character- istic. At the beginning of the testing period, Pacific Bluestem was the most extensively grown wheat variety in California. Obviously there are better-yielding varieties now, as is apparent from the yield figures shown. Individual plots have generally been % acre in size. In all the tests, four or more plots (replicates) of each variety have been grown each season. The wheat was sown from November through February, the time depending on seasonal conditions. Before 1937, a systematic planting sequence was used. Beginning with that year, varieties have been planted in random order in each replication, and noncropped alleys or borders between plots were eliminated in an effort to improve experimental tech- nique. This arrangement necessitated growing plots 12 feet wide from which a 9-foot swath was combined for yield determination. By cropping roadways at the end of plots for hay, all need for cultivation to control weeds has been eliminated. Plots have been harvested when all varieties were fully ripe. Seed plots have been grown independently of these yield studies, so that the slight mixtures obtained in moving from plot to plot are of no practical consequence. The experimental error (standard error) based upon the variation in yield among the different plots of each variety is estimated for each of the years. These error estimates apply to the average yield of the variety for the year shown. The reader should recognize that annual variety yields reflect relative yielding ability under only one specific environment. The chief cause or causes for the given annual responses have been supplied in the table, from the experimental records. This information is more vital than the actual yield in projecting the results for general use. Demonstrated high relative yielding ability alone does not permit choice of one or two varieties suited to the needs of all Cali- fornia farmers. Any one of our more prominent varieties might give the highest average yield during the next five-year period at Davis or on a vast number of other farms. Under certain other conditions a some- what different collection of varieties might enjoy a similar advantage. For that reason, farmers should choose among the known better-yielding varieties the one that most nearly meets all requirements, recognized or conceived as a result of local experience. Community accord in this choice will make the crop more marketable. To facilitate such choice, the appended description of varieties has been prepared emphasizing particularly the general similarity between California improved varie- ties bearing appended numbers and their familiar protovarieties. 10 University of California — Experiment Station COUNTY YIELD TRIALS The applicability of comparative yields, as established at Davis, to the varied soil and climatic conditions obtaining throughout California deserves consideration. During the period 1929-1939, numerous yield trials were conducted in twenty-six wheat-growing counties, the total number of tests in a county during the period bearing a general relation to the importance of wheat in that county. In the summary of data given in table 2, only comparable plots replicated at least three times have been considered. These, generally a rod long and three rows wide with rows spaced a foot apart, are commonly called nursery plots. Because of non- TABLE 2 Average Comparative Yields of Varieties Expressed as a Per Cent of Comparable Yields of White Federation, in County Nurseries During the Period 1929-1939, and in Plots at Davis County nurseries Plots at Davis Variety Number of compari- sons Per cent of White Federation yield Number of compari- sons Per cent of White Federation yield 117 109 67 50 50 103.6 93.4 95.7 89.1 104.2 14 18 14 17 12 102.6 Baart 91.0 95.2 92.9 Poso 104.9 uniformity of varieties tested, all comparisons have been made in rela- tion to White Federation. Only the five most extensively tested varieties permit comparison. The average of county results embodying a consid- erably larger number of comparisons is, nevertheless, similar to the Davis averages given in table 1. This fact is not surprising; although California, is large, the principal production areas have the same hazards. Some brief statements about variety testing seem appropriate here. Although local differences in adaptation (mostly differences in the rela- tive importance of production hazards) occur in different sections of the state, it is not generally possible to determine these in yield tests of short duration. Any variety test has two important limitations : (1) it is not possible to test several varieties in comparative field experiments with- out experimental errors due to differences in treatment and soil; and (2) when only a few plots (three or even five of each variety) are used, the calculated experimental error is usually so high that only large differ- ences between varieties are significant. Also the season may not be normal. A large and very accurate yield difference, for instance, may be O) » W Ttl O O CM CO co ic o OS t~ Hi O CO CM us 00 t- © 00 OS CO 0 o fe OS CM OS OS »o fe O .O kO CO 00 O OS o CO >C OS CO CO 00 H CO . 3 1 & is o •©■ •2 E* II •s a a2 a: *■* ' o «*-. a a o ■ 3 S 8 ' 2 a "S 3 g a © 1 M ■3 5*1 * II 3^ 4i g *e3 3o 13 -3 > > h n m | o oS 8 Q w • <-> Xfl ,2 2o o -tS ©08 « •♦* fc. 1 IS ** -r 2 s 1? bo — ' oJ .3 as 2 gag Iflj fill 03 II C £ 12 University of California — Experiment Station established between two varieties equally susceptible to rust, in a season when rust develops later than usual and one variety was early enough to evade the rust, whereas the other was caught. The most important con- sideration then is not whether these two varieties differed by one sack or ten sacks in yield in that season, but whether rust normally comes early or late and whether some other condition might adversely affect the early variety in another season. Growers should learn to recognize reasons for differences in yield. TABLE 4 Disease-Resistant Varieties Produced by Backcrossing Compared with Commercial Types of These Varieties Familiar to Most California Farmers* Item Baart Baart 38 White Federation White Federation 38 Acre yield (bushels) Weight per bushel (pounds) Date headed Plant height (inches) Analysis of wheat: Flour yield (per cent) Protein (per cent) Carotinoid content (parts per million) . . . Index of particle size Doughball time (minutes) Gassing power of flour — 3 hours (millimeters) Baking test (bread): Baking valuef Baking value when oxidized X 35.8 61.8 April 18 42 74.4 11 5 2 01 23 54 36.9 62.2 April 18 42 73 1 12.1 2.35 23.6 55 223 98.0 107.0 236 100 102 5 35.4 60.3 April 14 37 73.3 10.8 2.35 13.4 136 86.5 92.0 April 14 37 73.4 11.0 2.24 13.2 146 304 90.0 99.0 * Agronomic data based on three-year average; quality data on a single crop. t Single-figure value determined from loaf volume, grain, texture, and color scores of bread. % Two milligrams potassium bromate added for each 100 grams flour. MILLING AND BAKING TESTS Results of rather detailed quality tests with comparably grown mate- rial, are given for the more prominent varieties for the period 1936-1938, in table 3. These results, given here for the technical worker, were ob- tained in the United States Department of Agriculture laboratory main- tained cooperatively by the Bureau of Plant Industry and the Agricul- tural Marketing Service. The quality differences shown are considered f airly characteristic for the varieties and for seasonal variations. None of the bread baking values shown are comparable with those of our better bakery breads, which are made from blends including hard red wheats, as pointed out elsewhere. The pastry-making qualities of the varieties Bul. 659] Wheat Production 13 are shown by the yellow loaf cake and the cooky factor scores. Cooky factors of 5 or greater are generally considered satisfactory for cooky making. For cake use, low-protein flours of nongranular nature (larger index of particle size) are more desirable. In some seasons many varieties usually grown for poultry feed may develop characteristics that make them suitable for milling, provided a sufficient supply is available. Supply is important, since all varieties differ in certain inherent qualities as well as seasonal qualities, and mill- ing and trade requirements necessitate extensive testing and blending to attain certain performance standards. Baart is popular as a quality wheat because of better-than-average flour yields, better-than-average seasonal constancy of physical characteristics, and ability to give similar bakeshop responses under a variety of treatments. Detailed agronomic and quality results for the commercial and back- cross-derived strains of White Federation and Baart are given in table 4. The results suggest that the theoretical assumptions connected with the backcrossing method of breeding are essentially correct ; no appreciable differences as regards agronomic, milling, or baking behavior were noted between the old and the new strains. DESCRIPTION OF VARIETIES A key to principal varieties grown in California is presented (p. 14) as an aid in identification. To use this key, make the first comparison between the parallel left hand columns, choosing the heading descriptive of the sample to be identified. Proceed under this heading to the next indention to the right and repeat, if necessary, until a single differentiat- ing character specific to only one variety permits definite identification. Baart was introduced from Australia by the U. S. Department of Agriculture in 1900 and was first distributed in this country by the Arizona Agricultural Experiment Station. It is now the most extensively grown variety in Arizona and California, and is very popular in the central section of Washington and in other western states. It is the only widely grown bearded variety in California and is also readily identified by its unusually large kernels. This variety, once called Early Baart, must be considered as intermediate in maturity among the varieties now grown. The plant is perhaps too tall, and the straw somewhat weak. Though not a top yielder, it remains popular with both dry-land and irrigation farmers because it can produce relatively plump grain under adversities of drought or disease. High bushel weights are characteristic, and the milling and baking quality for bread is considered better than that of any other California variety. Small premiums commonly are paid for it. 14 University of California — Experiment Station Key to Varieties of Wheats Commonly Grown in California Spike (head) compact (club wheats) Palea (papery inner chaff) practically as long as lemma (shell or chaff surrounding the kernel) Big Club Palea noticeably shorter than lemma Poso Spike lax ("common" wheats) Spike awned (bearded) .Baart Spike awnless or tip-awned (beardless) Awnless Glumes (outer chaff of mesh, or spikelet) white or yellowish Spike slightly compact at tip ; occasional very short tip awns Onas Spike more lax White Federation Glumes brown or reddish Kernels soft Federation Kernels semihard to hard Ramona Strongly tip-awned (short beards in the upper part of the head) Glumes white or yellowish, glabrous (smooth) Shoulders of glume wide and distinctly notched Pacific Bluestem Shoulders of glume medium-wide to wide, not notched Eachis (stem of head) slightly pubescent on margin Escondido Eachis strongly pubescent on margin Bunyip Glumes brown or reddish, pubescent (velvety or hairy) Sonora Baart 38 is a stem-rust and bunt-resistant strain, developed at' the California Agricultural Experiment Station by backcrossing, and re- leased in 1939. The source of disease resistance and the breeding method were as follows : [ (Martin X Baart) X Baartf] X [ (Hope X Baart) X Baart 4 ] . The superscript in the pedigree indicates the number of back- crosses. Stated in another way, the method involved crossing bunt-resist- ant Martin with Baart and selecting plants resistant to bunt for backcrossing to Baart. This procedure was repeated for a total of six backcrosses, resulting in recovery of true Baart types with Martin bunt resistance. A less extended program of transferring the rust resistance of Hope to Baart was similarly executed. Derived Baart types resistant, respectively, to bunt and rust were then crossed, and 157 lines, resistant to both diseases but otherwise like Baart, were composited in 1938 and given the name Baart 38. Baart 38 is expected to replace the old commer- cial variety. Since, however, one can usually not be distinguished from the other in the absence of disease, farmers interested should obtain seed from fields "Calapproved" under the California Approved Seed Plan. Bunyip was distributed in California by the Sperry Flour Company from increase of a small sample obtained in the Australian exhibit at the 1915 Exposition in San Francisco. During the last ten years it has slipped from second to third place among California varieties in impor- Bul. 659] Wheat Production 15 tance. This variety has awnleted spikes and brown-striped glumes. It is of medium height and matures slightly earlier than Baart. Under most California conditions, average yields are similar to those of Baart, though Bunyip is more liable to injury from hot winds or drought. It almost equals Baart for breadmaking. Big Club is a survival of the Spanish era; but the acreage of this vari- ety is steadily declining. It is a tall, late-maturing, leafy club wheat with long club-type kernels. It has a capacity for high yield, but because of its late maturity is often severely damaged by rust or drought. When its kernels are plump it can be used in either bread or pastry flours, accord- ing to its texture and protein content. Big Club 37, developed by backcrossing, is indistinguishable from Big Club except for having the resistance of Martin to bunt. Additional breeding work now nearing completion will yield a Big Club type having the bunt resistance of Martin, the rust resistance of Hope, and the hes- sian-fly resistance of Dawson. This multiple-resistance wheat will go forth under its established name with an appended number showing when breeding improvements were terminated. Under such a breeding scheme, farmers can accept an improved variety with full assurance that no material changes have been made except for those originally specified. Each appended number has distinct significance, with which farmers should familiarize themselves. Federation, introduced from Australia by the U. S. Department of Agriculture, was first distributed in Oregon in 1920. It is widely grown in Oregon, Washington, Idaho, and other western states. In California, it is sometimes confused with White Federation, though the two can readily be distinguished in either the field or the sack. Federation has a dark-brown glume at maturity, is rather late in ripening, and has a soft grain. Its susceptibility to mildew and to stem rust are distinct disad- vantages. Most California farmers now growing it can probably find a superior substitute. Escondido, a moderately stem-rust-resistant wheat of the Defiance type, selected by the California Agricultural Experiment Station, was first distributed in 1928. It is an early variety with rather long heads, awnleted at the tip, and fairly hard kernels. Now grown mostly in south- ern coastal counties, where it has afforded some protection from stem rust, it will probably be replaced rather rapidly by the more positively rust-resistant Baart 38, and by White Federation 38. Galgalos is grown from either fall or spring plantings in northern California counties. It is a white wheat characterized by pubescence on leaves and glumes, brown glumes, and a very weak straw. Its reputation as a good bread wheat has no doubt helped sustain it. 16 University of California — Experiment Station Onas, another Australian introduction, first distributed by the Cali- fornia Agricultural Experiment Station in 1923, is now grown on rela- tively few acres but in widely dispersed sections of the western states. It has strong stems, fairly large leaves, white glumes, a rather dense head (sometimes slightly awnleted), and soft kernels. It matures somewhat late. Under favorable conditions it produces very well, but is often pinched by hot winds or rust. Pacific Bluest em was first established in California in the Gold Rush era, under the name White Australian. It has been widely grown in Cali- fornia, Washington, Oregon, Idaho, and Montana; but in all these states the acreage is declining. In California the variety is now prominent only in the Sierra Nevada foothills, on the north coast, and in northern coun- ties. It is the best wheat-hay variety grown in California, being leafy, tall, and late, with awnlets only at the tip of the heads. The kernels are above average size and if plump are generally in demand for milling. This variety will survive rather low winter temperatures. Pacific Bluest em 37 was developed at the California Agricultural Ex- periment Station in a backcrossing program designed to recover the bunt resistance of Martin. It does not differ appreciably from Pacific Blue- stem in any other respect. Poso, developed at the California Agricultural Experiment Station from a cross, Little Club X Clarendon, was first distributed in 1930. Its short stiff straw, short heads, small kernels, and early maturity readily distinguished it from other club varieties. It averages higher in protein than Big Club. It is particularly well adapted to the Sacramento Valley. Poso 41, soon to be released, will be resistant to hessian fly. It was devel- oped by crossing (Dawson X Poso) X Poso 5 . Bamona, developed from a cross, Hard Federation X Bunyip, made in 1917, was first distributed in 1935. It is a bronze-glumed, hard-kerneled variety with fair milling quality. It is very early, heading a full month earlier than Pacific Bluestem, a characteristic that may result in frost injury at heading time. For this reason early planting should be avoided. On the other hand, very late planting is also undesirable, since Ramona is highly susceptible to stem rust. Although it is becoming popular, its principal use will probably be in conjunction with a later variety to spread the harvesting operation, or as an early crop where double-crop- ping is contemplated. Sonora 37 does not differ from the old pubescent, brown-glumed, sof t- kerneled variety Sonora, long known in California, except that the smut resistance of Martin has been incorporated by backcrossing. Because of very weak straw, Sonora wheat is not generally popular. Bul. 659] Wheat Production 17 White Federation, introduced from Australia by the U. S. Department, of Agriculture, was first distributed from the Plant Introduction Garden at Chico in 1920. Despite poor milling quality, it has continued to in- crease in popularity in this state ; its acreage is now about equal to that of Baart. The variety is moderately early, has a stiff straw, white glumes, and short, hard kernels. It has given high average yields in most parts of California. Although little of the grain is used in milling, it is popular as a poultry feed. White Federation 38, developed in a breeding program parallel to that shown earlier for Baart 38, was first released in 1939. The variety is a composite of 182 lines having the appearance and common characteris- tics of the White Federation variety, but is resistant to stem rust and to bunt. This improved type will probably replace the standard variety rapidly ; but inasmuch as the two cannot be distinguished, growers should obtain "Calapproved" seed, which is known to have originated from the disease-resistant stock. Several other varieties may be encountered in California. Among the hard red winter wheats adapted only to northern mountain valleys, Oro, because of its stiff straw and its bunt resistance, is perhaps the most desirable of the Turkey-type wheats. Among the white winter wheats Bex, an early, stiff-strawed, bronze-colored, smut- and shatter-resistant variety has given best results in recent tests. Florence (also called Qual- ity or Burbank) wheat, as grown in southern counties, is badly mixed, and does not compare with the new California varieties in resistance to stem rust. Filer aw (also known as Thompson or Crawford), long grown near Napa, has stiff straw and a large thick head from which grain is rather easily shattered by wind. SUMMARY California produces less than half the wheat required for food and for animal feeds. Expansion of acreage, however, except perhaps at the expense of barley, is not economically desirable at present prices ; but more economical and dependable production through the use of im- proved varieties and better methods is possible. The wheat crop is grown under a great diversity of elevations, tem- peratures, and moisture conditions. In the principal valleys, December seeding and May or June harvest are characteristic. Common white wheats (represented by such varieties as Baart and White Federation) and white club wheats (of which the Big Club variety is most prominent) are most generally grown, although some hard red winter varieties are grown in mountain valleys. 18 University of California — Experiment Station The principal production hazards are drought, frosts at the heading- stage (producing sterile heads) , stem rust, smut, and strong winds (caus- ing shattering). Proper choice of varieties and good management pro- vide partial or complete protection against all these. Comparative yields of the important varieties, as determined at Davis, are presented for 1922 to 1940. Pertinent to these yield differences are certain production hazards, also reported. The varieties are described and representative milling and baking data are included. The authors do not consider yield trials to be a satisfactory base for predicting future performance either at the point of determination or elsewhere. The higher-yielding varieties in any one experiment are determined by such factors as date of seeding, diseases, and seasonal environment. The inclu- sion of factors contributing resistance to stem rust and smut in Baart 38 and White Federation 38 is expected greatly to increase the acreage of these already popular varieties. Some of the poorer-yielding varieties, such as Pacific Bluestem and Big Club, have advantages for hay or pasture use that justify production in certain situations despite their lower grain yield. The backcrossing procedure now used to improve California wheat varieties is described. Data are presented to show that, except for the disease resistance added, no material differences in the appearance or reaction of the original susceptible varieties have resulted. 15ff»-3,'42(7110)