EXPLORING GENETIC VARIABILITY AND DIVERGENCE FOR YIELD IMPROVEMENT IN BREAD WHEAT (TRITICUM AESTIVUM L.)

Abstract

Genetic variability and divergence analysis play a crucial role in the improvement of bread wheat (Triticum aestivum L.) under diverse environmental conditions. The present study evaluated 30 genetically diverse wheat genotypes across three sowing environments (timely, late and very late) over two consecutive growing seasons (2023 to 2025). The experiment was conducted using a randomized block design with three replications, and eleven agro-morphological and yield-related traits were assessed. Significant variation among genotypes and environments was observed for most traits, indicating substantial genetic diversity. Delayed sowing negatively affected growth and yield traits causing significant reductions in plant height, spike length, grain weight and overall productivity. Estimates of phenotypic and genotypic coefficients of variation revealed moderate to high variability for key traits such as grain yield and biological yield, while heritability estimates varied across environments, with high values recorded for phonological traits. Correlation analysis indicated that grain yield was positively associated with effective tillers, grains per spike, spike length, and thousand-grain weight across environments. Principal component analysis explained over 85% of total variation, highlighting the major contribution of yield-related traits. Mahalanobis D² analysis grouped genotypes into distinct clusters, with clusters III and IV showing greater genetic divergence and superior performance. Traits such as days to maturity and flowering contributed significantly to genetic divergence under different sowing conditions. The findings suggest that selection of genotypes from highly divergent clusters with desirable traits can enhance breeding efficiency. Overall, the study provides valuable insights into genetic variability, trait associations, and selection strategies for developing high-yielding and climate-resilient wheat varieties.