The endosperm protein patterns of an exotic maize mutant genotype (BOL II), with opaque and soft endosperm, and a single hybrid (paternal) line of maize cv. BR201, with hard and vitreous endosperm, were evaluated using PAGE and laser densitometry. The protein patterns of the F1, F2 and F3 generations from these crosses and other exotic genotypes were studied. Results showed that endosperm density is a monogenic trait. Analyses for the F3 generation revealed a possible association between the polypeptide pattern obtained for the endosperm and its opaque/vitreous phenotype, which may serve as a molecular marker for this trait
