Comprehensive study on combining ability, heritability and genetic advance for important morphological and biochemical traits in bread wheat (Triticumaestivum L.)

In this study, 15 genetically diverse wheat genotypes (10 lines and 5 testers) and their 50 F₁ hybrids were evaluated using a randomized design for 13 morphological and 2 biochemical traits under normal environmental conditions. Analysis of variance (ANOVA) revealed highly significant mean squares for both general combining ability (GCA) and specific combining ability (SCA) across all traits, indicating the involvement of both additive and non-additive gene actions. Among the parental genotypes, PBW-343, DBW-39, K-402, K-1317, KRL-210, and K-68 exhibited strong and consistent GCA effects, highlighting their potential as promising general combiners. For the hybrids, HD-3086 × HD-3171, K-402 × K-9107, K-1317 × K-9107, HD-2967 × K-0307, and K-402 × K-68 showed significantly positive SCA effects for grain yield per plant, suggesting a predominance of non-additive genetic variance in these crosses. In addition, high broad-sense heritability estimates were observed for plant height (77.32%), biological yield (59.52%), and grain yield per plant (68.76%), indicating substantial genetic control over these traits. Moderate heritability was recorded for spike length (32.26%), days to maturity (22.78%), and phenol color reaction (18.00%). Although no trait exhibited high genetic advance as a percentage of the mean, moderate genetic gains were observed for harvest index (11.72%) and grain yield per plant (13.15%), reflecting the influence of additive gene action and a significant proportion of fixable genetic variance.