Niacin inheritance in maize.
Niacin concentration in corn has been found to be primarily a function of the genetic constitution of the endosperm, with practically no influence by kernel size or by differences in the physiology of the seed parent plants as between Su su and su su plants. Within starchy corn, niacin concentration was inherited as a quantitative, multiple‑factor character. Most crosses are basically intermediate between the parents with the seed parent exercising twice the influence of the pollen parent. Crosses among some inbreds resulted in concentrations definitely below those expected from parental values. This suggests that some lines are high in niacin because of recessive genes which are suppressed in the hybrid.
The sugary gene was simply recessive for high niacin to its starch allele, the concentration in sugary kernels averaging about 60% more than that of starchy sibs.
The niacin concentration of sweet corns was a poor criterion of what they transmitted to crosses with starchy corn, but this "inherent" niacin concentration of sweet corn could be estimated from crosses with starchy corn of known concentration.
The Su su locus interacted with the multiple‑factor system in determining final niacin concentration. Thus, sugary segregates from crosses of sweet corn with high niacin starch corn had higher concentrations than corresponding sugary segregates from crosses with low‑niacin starchy corn, the correlation for niacin in sweet and starchy kernels from segregating ears being 0.95 for 26 degrees of freedom.
The increase in niacin due to su was not strictly additive, that in the higher niacin strains being larger than that in the lower niacin strains, both absolutely and relatively. Different sweet inbreds differed in the degree to which they increased the niacin concentrations suggesting a possibility of su alleles differing in their niacin influence.
F.D. Richey and R.F. Dawson