Combining ability and trait heritability are critical parameters for developing maize hybrids with stable performance under variable production environments. This study evaluated 19 elite female and 4 male maize inbred lines crossed in a North Carolina Design II mating scheme, generating 76 hybrids along with two standard checks. The hybrids were tested in an alpha-lattice design under both optimum and low-nitrogen (N) conditions. Analysis of variance revealed that both additive and non-additive gene actions significantly influenced grain yield and associated agronomic traits. Notably, inbred line L7 exhibited consistently positive and significant general combining ability (GCA) effects for grain yield across both N regimes, underscoring its potential as a key parental line. Grain yield heritability ranging from 49% under low-N to 51% under optimum N, suggesting that genetic improvement through hybridization and selection are feasible under contrasting fertility conditions. The identification of superior female and male lines highlights valuable parental resources for breeding maize hybrids with enhanced tolerance to N stress. These findings provide a basis for developing resilient and high-yielding hybrids suited to diverse production systems, particularly in low-input environments.
Additive; General combining ability; Gene action; heritability; specific combining ability