Combining Ability in Diallel Crosses Involving Maize (Zea mays L.) S1/S9 Lines

Abstract

Twelve maize (Zea mays L.) inbred lines were evaluated for combining ability using a half-diallel mating design. The parental lines were crossed to generate 66 F₁ hybrids, which were assessed along with their parents and a standard check across two environments in a randomised complete block design with two replications. Data were recorded for days to tasselling, days to silking, days to maturity, plant height, ear height, number of ears per plant, cob length, cob diameter, kernel rows per cob, kernels per row, 100-grain weight, grain yield per hectare, shelling percentage and protein percentage. Pooled analysis of variance revealed significant environmental effects for all studied traits, indicating the influence of testing locations on trait expression. Significant variation among genotypes, parents, hybrids and parent-versus-hybrid contrasts indicated substantial genetic variability in the experimental material. Combining ability analysis revealed significant general combining ability and specific combining ability effects for most traits, suggesting the involvement of both additive and non-additive gene action. Dominance variance was generally higher than additive variance, indicating the predominance of non-additive gene action for most traits. Among the parents, KDM-926B, KDM-895A and V-351 showed desirable general combining ability for earliness-related traits, whereas KDM-926B, KDM-914A, KDM-340A and V-351 were identified as useful general combiners for grain yield and related traits. Several cross combinations expressed desirable specific combining ability effects for yield and component traits. The results indicate that the evaluated germplasm contains useful parental lines and cross combinations for maize hybrid breeding programmes.