Inheritance of Test‐Weight Components in Normal, Opaque‐2, and Floury‐2 Corn (Zea mays L.)1

Abstract

Diallel mating systems were used to study kernel‐endosperm properties in normal corn (Zea mays L.) and its opaque‐2 and floury‐2 endosperm mutants. Seven parental lines were involved. Each line had five endosperm versions: original normal, opaque‐2, normal derived from opaque‐2 backcross population, floury‐2, and normal derived from a floury‐2 backcross population. All 21 possible single crosses and reciprocals were made among the seven lines within each of the five groups. The opaque‐2 and floury‐2 groups gave similar responses, each decreasing test weight, 500‐kernel weight, and kernel density; and increasing number of kernels per 100 g and percent kernel breakage. Addition of opaque‐2 and floury‐2 genes changed the means of the kernel traits but did not change appreciably the combining ability of the lines. Additive gene effects accounted for a larger part of the variation among crosses than nonadditive effects in the inheritance of the kernel traits. Phenotypic and genetic correlations among test weight, kernel density, and kernel breakage were high; chemical components were correlated poorly with physical kernel traits.