Genetic analyses were carried out to determine inheritance of resistance, heterotic effects and reciprocal effects for resistance to the spotted stem borer, Chilo partellus in three maize crosses. Resistance was found dominant over susceptibility. Highly significant heterosis was detected for percentage dead hearts. Both additive and nonadditive gene effects were important in the inheritance of resistance to C. partellus in all crosses. Additive gene effects were highly significant for all the three resistance parameters: leaf-feeding, dead hearts and stem tunnelling. However, a high magnitude of nonadditive (dominance and epistatic) gene effects were detected for dead hearts. No cytoplasmic effects were detected in reciprocal crosses between resistant and susceptible maize lines, suggesting that the resistance to C. partellus is conferred only by nuclear genes. Recurrent selection methods should be used to accumulate alleles for resistance. Resistant F1 hybrids could be developed between resistant and susceptible lines in reciprocal combinations.
