Harnessing Wheat's Genetic Diversity from Heat-Tolerant, High-Yielding Varieties

Abstract

The experimental study included 58 bread wheat genotypes of 45 F1 hybrids, 10 parental lines, and three control varieties. This research was conducted during the Rabi seasons of 2022-23 and 2023-24 at the Field Experimentation Centre within the Department of Genetics and Plant Breeding at SHUATS in Prayagraj, Uttar Pradesh. A randomized block design with three replications was used for the experiment. The parental lines included SHUATS-W8, SHUATS-W10, SHUATS-W12, SHUATS-W13, SHUATS-W16, SHUATS-W21, SHUATS-W66, SHUATS-W67, SHUATS-W86, and SHUATS-W87, which were crossed using a half-diallel cross design. The variance analysis showed significant differences (α=0.05) across all 18 traits in both timely (E1) and late sown (E2) environments, highlighting substantial genetic variability among bread wheat germplasms and indicating strong potential for selection-based improvement. Traits such as plant height, days to first heading, days to 50% flowering, days to maturity, and test weight showed minimal differences between GCV and PCV in both environments, indicating a lower environmental impact and a higher degree of genetic control over their expression. In contrast, traits like the number of grains per spike and chlorophyll content exhibited more significant GCV-PCV differentials, suggesting a greater environmental effect on their phenotypic traits. Notably, high heritability and significant genetic advance as a percentage of the mean were found for test weight, plant height, and days to maturity, emphasizing the influence of additive gene action and making these traits prime candidates for direct selection in breeding initiatives. Traits such as days to first heading and days to 50% flowering showed moderate GCV, high heritability, and moderate genetic advance, indicating a reasonable potential for genetic enhancement. The pooled mean analysis further confirmed that test weight and days to first heading displayed high genetic variability, heritability and genetic advance, positioning them as important targets for wheat improvement efforts.