Genetic Variability and Heritability in Bread Wheat (Triticum aestivum L.) Germplasm Across Sowing Environments

Abstract

Genetic variability is a fundamental prerequisite for successful plant breeding and crop improvement. This investigation assessed genetic variability parameters, including genotypic and phenotypic coefficients of variation (GCV and PCV), heritability, and genetic advance in 40 geographically diverse wheat (Triticum aestivum L.) genotypes across three sowing environments (normal, late, and very late sowing). Pooled analysis of variance revealed highly significant differences among genotypes for all morphological, yield-attributing, and quality traits, indicating the presence of substantial genetic variability in the experimental material. PCV values were consistently higher than GCV values for all traits, though the narrow gap between them suggested a predominance of genetic control over environmental influence. Heritability estimates ranged from 63.37% (seed yield per plant) to 95.55% (iron content in seed), indicating strong genetic control for most traits. Genetic advance as a percentage of mean (GAM) was highest for 1000-seed weight (24.70%) and effective tillers per plant (21.36%), suggesting that these traits are governed predominantly by additive gene effects and can be effectively improved through simple phenotypic selection. Results indicated that traits such as days to maturity, zinc content, and seed yield per plant exhibited high heritability coupled with low GAM, suggesting significant non-additive gene action. These findings provide valuable insights for designing effective selection strategies in wheat breeding programmes aimed at improving yield and nutritional quality across variable agro-climatic conditions in India.