Combining Ability Analysis for Grain Yield and Its Contributing Traits in Maize (Zea mays L.)

Abstract

The present investigation was carried out at Agricultural Research Station Peddapuram during the Rabi season of 2025–2026 to evaluate combining ability, genetic variance components and progeny contributions for grain yield and 12 yield-attributing traits in maize (Zea mays L.). The experimental material, comprising 56 genotypes (17 lines, 2 testers, 34 Line × Tester crosses and 3 standard checks), was evaluated in an Alpha Lattice Design with two replications. Analysis of variance for combining ability revealed highly significant differences among treatments, parents and crosses for all 12 quantitative traits. Estimates of genetic variance components indicated a predominant role of non-additive gene action (dominance variance, σ²D) for grain yield per plant (σ²SCA = 314.209 vs. σ²GCA = 302.820; GCA/SCA ratio = 0.964), hundred-kernel weight, ear length and flowering parameters. Conversely, plant height (GCA/SCA ratio = 1.296), ear height (2.160) and ear girth (1.287) were predominantly governed by additive gene action. Among the female parents, inbred line PL 23689 proved to be the most outstanding general combiner (overall GCA score = 12), exhibiting significant positive GCA effects for grain yield per plant (64.260**), kernels per row (6.789**), ear length (3.860**), kernel rows per ear (1.016**) and ear girth (0.798*). Line PL 23688 also showed high GCA for yield per plant (38.427**). Among testers, LM 14 was identified as a superior combiner for grain yield (9.486**) and ear girth (0.684**). Cross combinations PL 23687 × LM 13 (SCA = 34.152**) and PL 23705 × LM 14 (SCA = 22.681*) recorded the highest significant positive SCA effects for grain yield. Promising general combiners PL 23689 and PL 23688 are recommended for population improvement, while high SCA hybrids should be advanced for further yield evaluation trials.