Varieties Produced From Composite Crosses

The late Dr. H. V. Harlan, during a third of a century of breeding barley, conceived the idea of improving varieties by combining hybridization and natural selection. These efforts were known as composite crosses, and many parent stocks were used. Hybridization produced the diverse germ plasm upon which natural selection could act. Dr. Harlan had shown earlier that when pure varieties were mixed, natural selection was a powerful force in eliminating poor varieties and preserving well adapted ones, although not always the highest yielding ones.

Composite crosses of both spring and winter types, the two main kinds grown in the United States, were distributed to experiment stations to be grown in bulk plots without selection for a number of years. After 5 to 6 or more years, when nearly all the different types were fixed, and natural selection had played its part, desirable plants were picked from these plots and .tested. Several new varieties originated from them. Compana is an example. It was selected and tested cooperatively by the Department and the Montana station and released in Montana in 1941. By 1945 it was sown on 90 percent of the barley acreage in that State.

S. C. Litzenberger, of the Montana station, describes Compana as a spring type that is two-rowed, semismooth-awned, drought resistant, early maturing, and suitable for combining. The seeds are large, plump, and thin-hulled, and 2 to 4 pounds a bushel heavier in test weight than Trebi or Glacier. It is recommended for the nonirrigated lands, where it has yielded up to a third more than Trebi or Horn. On irrigated lands its yield equals that of Trebi, but it is more subject to lodging. It resists nuda loose smut, and grasshoppers hurt it less than other commercial varieties. Compana has a relatively short and weak straw and these characteristics are its two major faults under Montana conditions.

Another barley from a composite cross is called Rojo, meaning red. It was released in 1943. C. A. Suneson of the Department reports that at the experiment station at Davis, Rojo yielded 16 percent more, over 12 years, than Atlas, the commonly grown variety. For California, the difference is 12 percent. It is a spring type, six-rowed, smooth-awned barley, resistant to scald and net blotch. Rojo is desirable for hay because of its smooth awns, relatively disease-free leaves, and stiff straw. The spike is distinctly red, but under some conditions the kernels may develop a less attractive gray color. Some difficulties have been reported in removing the awns from it at harvest. It is now grown only in California.

New varieties of winter barley, which is much less widely grown in the United States than the spring type, also have been produced by selecting from composite crosses. G. K. Middleton, working in North Carolina, I. M. Atkins in Texas, and D. D. Hill and others in Oregon have released kinds developed in the cooperative programs. Davidson is one. It was released in North Carolina in 1939. At the Statesville station, Davidson tops the yield of the older varieties tested, having averaged 44.2 bushels over 14 years. It is said to resist all forms of smut, but is susceptible to mildew. The straw is stiff, the kernels large and plump.

Texan was introduced in Texas in 1941. It is well adapted to the blacklands of central Texas, where it yields about 3 bushels more than Wintex or others. It is six-rowed, smooth-awned, resistant to mildew, and a winter-type variety. Texan lacks strength of straw and tends to lodge on rich 'land. It is sufficiently winter-hardy for the blacklands and is used for grazing. It is also grown in the Mississippi Delta and Arkansas.

On the Pacific coast, Santiam and Cascade, also winter-type varieties, were released by the Oregon station at Corvallis in 1939 and 1945. Santiam surpassed the varieties grown in western Oregon at the time it was released, but no doubt it will give way in turn to Cascade, a still better kind. The main disadvantage of Santiam is that its straw is so tall and weak that it lodges on rich soil. Cascade is shorter and has a stiffer straw. It is suited to harvesting with combines, as it will stand without shattering after ripening. In 5 years of tests at Corvallis, Cascade produced 14 bushels more an acre than Santiam.