One 10‐inbred‐line diallel of maize (Zea mays L.) was evaluated for 2 years for resistance to second‐brood European corn borer [Ostrinia nubilalis (Hübner)], and a second 10‐line diallel was evaluated for 1 year for resistance to first and second broods. First‐brood evaluations were based on leaf‐feeding ratings in the pretassel stage, and second‐brood evaluations were based on plant‐cavity counts in mature plants. Variations attributed to general combining ability and general combining ability ✕ years were highly significant in the first diallel, but none of the F‐tests for specific combining ability were significant. Different levels of borer infestation in the 2 years probably affected the estimates of genetic effects. In the second diallel, variations attributed to general combining ability and specific combining ability were highly significant for both first‐ and second‐brood data. Also, heterosis was highly significant, with resistance being partially dominant. Inbred B52 contributed the most resistance to second brood, and CI31A and B49 contributed the most resistance to first brood. There are differences in the genes of the maize plant that condition resistance to first and second broods, but some genes may contribute resistance to both broods.
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Jennings et al. (1974) studied this question.