Corn Hybrids for the South

by MERLE T. JENKINS

PROGRESSIVE farmers in all parts of the South want to know what is being done to develop corn hybrids suited to their soil and climate and whether adapted hybrids can duplicate in their fields the outstanding performance of those in the Corn Belt. Encouraging answers can be given them.

The Department of Agriculture is conducting corn-improvement programs in cooperation with 12 State agricultural experiment stations. Five are in the South—North Carolina, Tennessee, Mississippi, Louisiana, and Georgia. Informal cooperation is maintained with all other southern stations that have corn-improvement experiments.

Because corn hybrids are produced by crossing inbred lines, the general quality of a group of hybrids depends upon the characteristics of the parent lines. Outstanding, or elite, inbred lines are isolated only infrequently, and the numbers and relative superiority of elite lines isolated depends largely upon the total number of lines examined and tested.

The early inbreeding programs in the South, like those in the Corn Belt, were small. The elite lines that founded the present hybrids in the Corn Belt were developed as a result of the greatly expanded inbreeding programs organized in the early 1920's. Similar expansion of the southern corn-breeding programs occurred in the late 1930's and early 1940's, but was relatively less extensive than that in the Midwest. The group of elite lines that is beginning to emerge from the expanded programs promises a marked improvement in hybrids for the South in the next few years.

Another prime factor in developing outstanding Corn Belt corn hybrids was the exchange of breeding materials among the cooperating experiment stations. The Purnell Corn Improvement Conference, which functioned from 1926 to 1932, and its successor, the Corn Improvement Conference of the North Central Region, organized in 1937, promoted the exchange. In 1933 a series of uniform tests of hybrids involving a group of elite lines contributed by the different cooperating experiment stations was organized to promote further the wide use of the best of the available breeding material. U. S. Hybrid 13, a direct result of the first of these uniform tests, is the most widely grown hybrid in the country. Many other Corn Belt hybrids involve a relatively small group of elite lines; the uniform tests aided materially in identifying them.

The Southern Corn Improvement Conference was organized in New Orleans, in November 1939, at the instigation of Fred H. Hull of the Florida Agricultural Experiment Station. Uniform tests of crosses among lines grown in the South were organized in 1941 to further the ready interchange of breeding materials; the first tests were made in 1942.

The uniform tests bring to light and permit the selection of parent lines whose hybrids perform satisfactorily over a wide range of growing conditions. Numerous advantages derive from this procedure. Uniform tests in different States give an opportunity to find out how the new kinds perform in different kinds of soil and climate in the same season. We thus get in one season results that are somewhat comparable to those from tests in each of several seasons at a single location. Hybrids involving parent inbred lines whose crosses perform satisfactorily under a wide range of conditions are not likely to perform badly under some peculiar or unusual set of conditions. The identification of these widely adapted parent lines permits simplification of the hybrid corn program as a few widely adapted hybrids can be made to serve a whole region.

Many of the promising new experimental hybrids of the South involve this new crop of elite lines. Outstanding white lines among those of suitable maturity for the area in which Neal Paymaster is adapted are T61 and T13 from Tennessee, and NC34, NC37, and NC45 from North Carolina. T61 probably has more yield factors than any other southern inbred line, but it is subject to root lodging. Outstanding yellow inbred lines of suitable maturity for the same general area are C1.21 and CI.7, developed by the Department, Ky35-7 from Kentucky, NC7 and NC 13, developed in North Carolina, and Kys, developed in Kansas.

Experience has amply demonstrated that crosses among lines of widely diverse origin usually have the most vigor. The outstanding hybrids of the Corn Belt usually involve lines originating from more than one State program. In all probability, the same will be found to hold true in the South. The promotion of free interchange of breeding materials sponsored by the Southern Corn Improvement Conference stands directly to benefit every southern corn grower by providing him with better hybrids than he would have otherwise.