Combining ability among provitamin A‐enriched maize inbred lines and heterosis of their hybrids for grain yield and agronomic traits

Studying the combining ability of pro‐vitamin A enriched yellow maize inbred lines ( Zea mays L.) provides valuable information on the breeding potential of these lines for developing high‐yielding and biofortified maize hybrids with desirable agronomic traits. Twelve pro‐vitamin A‐enriched yellow maize inbred lines were crossed using a half diallel mating design with the objective of identifying the best combiners to use as testers and selecting the highest‐performing hybrids for grain yield with desirable traits. Sixty‐eight F 1 hybrids along with checks were evaluated across three environments at mid‐altitude agroecology of Ethiopia during the 2022 main cropping season. Combined analysis of variance revealed significant differences ( p ≤ 0.01) due to hybrids, environments, and hybrid × environment interactions for grain yield and agronomic traits, indicating that genotypes performed differently across environments. Eight hybrids were selected based on superior mean yield performance (6.92–7.95 t ha − 1 ), providing yield advantages of 15.6%–32.7% over the best check, warranting promotion to the next stage of hybrid evaluation. Analysis of variance for general combining ability (GCA) and specific combining ability showed significant differences ( p ≤ 0.001) for all traits studied, indicating that these traits are controlled by both additive and non‐additive gene effects. Inbred lines L2, L6, L8, L10, and L12 exhibited high, positive, significant GCA effects on yield and other traits. Inbred lines L10 and L12 showed the best combiners for most traits and exhibited high GCA effect for yield. Their crosses generated the top yield performance and negative contributions to foliar diseases. Thus, these inbred lines can be used as testers for future provitamin A maize breeding program in the mid‐altitude agroecology of Ethiopia.