Experiments on the Inheritance of Niacin in Corn (maize).

In an earlier publication the writers (12) showed that the niacin concentration of dent corn behaved as a so-called quantitative character in inheritance, being determined by many genes of small individual effects. They also showed that niacin concentration could be modified rapidly by selection and saw no reason why hybrids with niacin concentrations as high as 50 micrograms/gram could not be developed. It was noted further that a second mode of inheritance had been reported (1, 9). In this, the starchy, Su, gene was dominant for lower niacin concentration over its su allele, just as it is dominant for starchy vs. sweet endosperm. We suggested that the influence of the Susu alleles on niacin concentration was a secondary or pleiotropic one. There also was a suggestion (inconclusive) that the alleles differentiating starchy and waxy (Wx wx) might operate similarly. Since our paper was written, workers at the Ohio Experiment Station have reported on niacin concentration in dent corn. Their earlier results (7) are open to some question because their material was open pollinated. Pollination accordingly could have been a differentiating influence, rather than environment as they concluded. Their later research was with handpollinated material. From this (4), they stressed the hereditary influence on niacin concentration, and suggested that it might be increased by breeding. GORFINKEL (5) also has reported practically complete dominance of the Su gene for lower niacin, and CAMERON and TEAS (3) have found the sugary types as conditioned at both the su and the du loci to be higher in niacin than the starchy types. LENG et al. (8) report the niacin concentration of sugary, waxy and dent kernels from segregating ears. Dent and waxy are not mutually exclusive, and neither are sugary and waxy. Their sugary class included the double recessive su wx kernels; whether or not their dent included waxy as well as starchy cannot be told. Correlations reported indicate a multiple effect of the su gene on both niacin concentration and carbohydrate formation, a pleiotropic action as postulated by RICHEY and DAWSON (12). LENG et al. (8) also state that unpublished data indicate no close relation between kernel size and niacin concentration, in agreement with the conclusion previously reported by RICHEY and DAWSON (12). 1Joint contribution from the Division of Cereal Crops and Diseases, Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Research Administration, U. S. Department of Agriculture; the Agricultural Experiment Station of the University of Tennessee; and the Department of Botany of Columbia University.