Assessment of Mean Performance and Genetic Variability in Maize Single Crosses

Maize is the stable crop critical for ensuring food security in Africa, yet its productivity remains limited by low-yielding varieties, biotic and abiotic stresses. This study evaluated mean performance, genetic variability, heritability, and genetic advance in maize single crosses. Fifty genotypes, including 48 F ₁ crosses derived from 24 inbred lines and two testers, plus two commercial checks, were evaluated at Ambo and Holeta using an alpha lattice design with two replications. Combined analysis of variance revealed a significant genetic difference (p ≤ 0.01) among genotypes for all studied traits except for plant aspect. The location x genotype interaction was significant for grain yield, plant height, ear height, ear diameter, and thousand-kernel weight, indicating that the performance of hybrids for these traits varied across the tested environment. Crosses L23 x T1 (10.17 t/ha) and L11 x T1 (9.5 t/ha) outperformed the commercial checks. Genetic variability analysis showed moderate GCV and PCV for ear height, while grain yield, ear per plant, and ear aspect exhibited medium variability, suggesting sufficient variability for these traits. Broad sense heritability ranged from low to very high across traits, with ear height showing high heritability and genetic advance as the present mean (GAM), indicating additive gene action and scope for subsequent genetic improvement. The results of this study suggest that traits such as ear height, plant height, and grain yield can be effectively improved through phenotypic selection. The identified superior crosses provide promising materials for developing high-yielding, stable maize hybrids for Ethiopian highlands.