A SURVEY OF THE POSSIBILITIES AND METHODS OF BREEDING HIGH-NIACIN CORN (MAIZE)

Abstract

Sampling studies for niacin concn. showed 2-g. samples of shelled corn and 25-kernel samples from any part of an individual ear to be adequately representative. Vars. of white dent corn differ widely in their niacin concns., the southern vars. tending to be higher than northern vars. Extreme differences in production practices, such as fertilizer applications, green manures, etc., resulted in no significant differences in niacin content at reasonable corn yield levels. Differences in the niacin concn. of corn grown on different farms or in different states were either not significant or unimportant. Inbred lines differed widely in their niacin concn. the range for 24 established inbreds being from 13.9 to 53.3[mu]g./g. Single-cross and double-cross hybrids tended to be intermediate between the parents, with the seed parent exercising more influence than the pollen parent. A few exceptions to this condition suggest that complicating mechanisms may exist. The influence of the pollen parent, though less than that of the seed parent, is enough to require controlled pollination in any study of niacin concentration in corn. Two modes of inheritance for niacin concentration are indicated. One of these, multiple-factor inheritance, dominates control in the dent corn used. In addition, the effect of Su su alleles, as reported by Mather and Barton-Wright, appears to be pleiotropic with Su dominant for low niacin. Three generations of selection in selfed lines of the Huffman var. established 4 families at higher and 4 families at lower concns. The 15 S3 ears grown in 1946 and planted in 1947 to continue the 3 highest-niacin families, averaged 41,4[mu]g./g. This avg. concn. exceeded the individual concns. of all but one of the 1946 parent ears, and was nearly twice that (22) for the Huffman var. It was concluded that corn hybrids with niacin conens. as high as 50[mu]g./g. could be developed. Such hybrids would be useless, however, unless they also yielded well and had other desirable characteristics. Their development, accordingly, would be complicated.