Tailor-Made Sorghums

by JOHN H. MARTIN

THE FIRST grain sorghums that reached the United States from Africa more than two generations ago could not be harvested and threshed without a lot of hand labor. They grew 4 to 6 feet tall; some had bent heads, and they were not suited to the combine. Engineers and plant breeders joined forces to solve the difficulty. They improved the combined harvester-thresher. It was made lighter and mounted on rubber tires; it could be transported easily, so that operators from the Wheat Belt could move westward into the grain-sorghum region for the autumn harvest. The breeders produced tailor-made new varieties that could be combined. Together the improvements saved seven-eighths of the man-hours needed to harvest the grain by hand and thresh it later. Consequently, during the War, when labor was scarce, many farmers were able to grow eight times more sorghum than if they would have had to depend on hand labor. The extra grain contributed materially to the supply of feed and industrial alcohol. Besides, harvesting with combines saved about two dollars an acre in harvesting costs—a total saving of some 12 million dollars a year.

Even more impressive is the story of six varieties, distributed since 1940, that were grown on 7 million acres by 1944—Martin, Plainsman, Westland, Midland, Caprock, and Bonita. They comprise 80 percent of the sorghum harvested for grain in the United States. They have erect heads and usually grow to only 2 to 3, feet, so that harvesting is easy. Altogether, these developments of a generation have given the Great Plains a crop that is as important to that area as corn is to the more humid Corn Belt.

Combines were not used for harvesting any crop in the Southern Great. Plains until about 1918. In 1920, J. B. Sieglinger selected some dwarf, erect-headed plants from the progenies of a cross between milo and kafir that grew at the United States Southern Great Plains Field Station at Woodward, Okla. Nobody had bothered much about such plants before. They were nondescript, unprepossessing hybrids no taller than wheat plants, although both parents stood 4 to 6 feet, and the milo parent had crooknecked heads. But from his selections Sieglinger bred Beaver and Wheatland, which were distributed to growers in 1928 and 1931. The value of Wheatland for Kansas was quickly recognized after small fields of several new varieties were harvested with a combine.

Two quick-maturing combine-type varieties, Colby and Day, originated at Woodward, were distributed later in Kansas and Nebraska after tests of numerous similar strains. The new varieties, especially Wheatland, soon were grown extensively, but they had some serious faults. All were susceptible to milo disease, or pythium root rot, which was first observed in 1925. Also, like their milo parent, they were subject to chinch bug injury. There was a need also for kinds that matured earlier than Wheatland and Beaver, but later than Colby and Day.

The Agricultural Experiment Stations of Kansas, Texas, Oklahoma, Nebraska, Colorado, and New Mexico, cooperating with the Department, set out to breed better kinds. Pythium-resistant offspring of Wheatland were tested extensively. One, named Westland, was distributed in Kansas in 1942 and grown on a million acres by 1944.

A Texas farmer, W. P. Martin, found a promising plant in his field of Wheatland in 1936. When tested in a nursery, it was found to resist pythium root rot. It was increased, given the name of Martin, and distributed in 1941. By 1943 it was grown on 3 million acres, and has been the leader since then. Like Westland, it matures earlier than Wheatland. Martin has reddish-yellow grains somewhat smaller and harder than those of milo. The heads are upstanding. and open enough to dry quickly, so that combine operators can even start harvesting it soon after it has been dampened by dew or rain. Martin's early maturity permits it to be grown as far north as South Dakota, yet it is the leading grain sorghum in southern Texas (where the crop is harvested in early summer), other parts of Texas, and Oklahoma.

The breeding work at the Texas Agricultural Experiment Station, at Lubbock and Chillicothe, produced three varieties that were released between 1941 and 1943. Plainsman and Caprock were developed from milo kafir crosses by R. E. Karper and D. L. Jones. The third, Bonita, was selected from a Chiltex-hegari cross by J. R. Quinby. Plainsman and Caprock mature later and yield better than Martin and Westland when everything is favorable, but are not so well suited to dry conditions or short seasons. Bonita has found an important place in north-central Texas, where chinch bugs may work havoc with other improved kinds.

Meanwhile, a new disease, charcoal rot, appeared. It can cut the yield of all the new kinds and cause their stalks to fall down after they ripen but before the grain is dry enough for combining. Martin is particularly susceptible. A condition called weakneck also causes ripe stalks to fall over and be lost at harvest.