Inheritance of Resistance to Aflatoxin Production in the Cross Between Corn Inbreds B73 and LB31

Abstract

ABSTRACT The inheritance of resistance to aflatoxin production in corn (Zea mays) caused by the fungus Aspergillus flavus was studied following inoculation in progeny derived from the cross between the susceptible inbred B73 and the resistant inbred LB31. In 1993, the susceptible parent B73 (P(1)), resistant parent LB31 (P(2)), F(1), F(3), and BCP(1)-selfed generations were evaluated. In 1994, the study was expanded to include the F(2), BCP(1), and BCP(2) generations. Aflatoxin concentrations were higher in 1993 than 1994. Generation mean analysis showed that additive and dominant gene action were important for resistance to aflatoxin production. Potence ratios indicated dominance for resistance in both years. In 1993, aflatoxin values of the F(1) generation were significantly lower than the calculated mid-parent values, indicating dominant gene action favoring resistance. In 1994, values of the F(1) generation were not significantly lower than the calculated midparent value. The frequency distributions of aflatoxin values for families of the F(3) and BCP(1)-selfed generations were skewed toward the resistant parent, also indicating dominance. Heritability based on a progeny mean basis of F(3) families representing the additive variance plus one-fourth of the dominance variance was estimated at 66% over both years combined. Based on these results, selection for resistance to aflatoxin production in progeny derived from the cross between B73 and LB31 should be effective.