ASSOCIATION OF ZEIN CLASSES WITH MAIZE KERNEL HARDNESS

The association between maize kernel vitreosity (hardness) and the com position and content of alpha-, beta-, and gamma-zeins was investigate d. F-2 populations from two pairs of reciprocal flint X floury crosses were fractionated according to density by flotation in sodium nitrate solutions. Zeins were extracted from these fractions and quantified b y reversed-phase highperformance liquid chromatography. Statistical an alyses indicated that F-2 genotype affected all zein classes. In addit ion, direction of cross affected alpha- and 16-kDa gamma-zeins, and th e individual ears from which F-2 samples were obtained affected alpha- , beta-, and gamma-zein amounts and compositions. The strongest appare nt correlation was a decrease in amount of 16-kDa gamma-zein as kernel density increased in F-2 kernels from the Papago Flour (floury)X Ross Early Flint (flint) cross. alpha-Zein levels correlated positively, b ut to a lesser extent, with kernel density in Fz kernels from the Papa go Flour (floury)X Kantz Flint (flint) cross. In the reciprocal F-2 po pulation, however, zein class and kernel density were not significantl y correlated. Thus, while zein classes appear to relate to kernel hard ness variation in specific normal maize genotypes, we found no consist ent relationship between individual or total zeins and kernel density across all populations.