Gene Action in Oh45 and Oh45B Crosses of Zea mays L
1972
Findley, W. R. | Dollinger, E. J. | Eberhart, S. A.
Experiments were conducted to study types of gene action contributing to yield increases obtained by substitution of inbred Oh45B for inbred Oh45 in the pedigree of certain double-cross corn (Zea mays L.) hybrids. Estimates of mean, additive, dominance, additive ✕ additive, additive ✕ dominance, and dominance ✕ dominance gene effects, and deviations due to linkage and/or higher orders of epistasis were obtained. Generations P₁, P₂, F₁, F₂, F₃, B₁, B₂, BS₁, and BS₂ were grown for inbred lines WF9, Oh51A, Oh26, and Hy each crossed with Oh45 and Oh45B. Grain yield, kernel weight, ear length, and ear diameter were studied. Crosses involving Oh45 showed an average yield heterosis of 95%; whereas, the heterosis for Oh45B crosses was 136%. Differences in average yield of the Oh45 and Oh45B families were due primarily to dominance effects. The addition of digenic epistatic effects did not improve the predictive ability of the model even though epistatic effects were statistically significant. Most of the variation among generation means was accounted for by the mean, the additive effect, and the dominance effect for all attributes studied. Deviations from the digenic model were non-significant, except for grain weight in one family and for ear diameter in two families.
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