Performance evaluation of genotypes and crosses in bread wheat for grain yield and its constituent under terminal heat

Abstract

The experimental study involved 45 F1 hybrids, 10 parental lines, and 3 control varieties, totalling 58 genotypes of bread wheat. 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, Prayagraj, Uttar Pradesh. A Randomized Block Design with three replications was employed 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 indicated significant differences (α=0.05) across all 18 traits in both timely sown (E1) and late sown (E2) environments, as well as in the pooled mean, underscoring considerable genetic variability among the bread wheat germplasms. The genotypes SHUATS-W13, SHUATS-W12, SHUATS-W16, and SHUATS-W86 exhibited tolerance to terminal heat stress, as evidenced by their highest grain yields under both timely and late-sown conditions. These genotypes also showed superior values for key traits such as the number of productive tillers, test weight, chlorophyll content, canopy temperature deficit, and culm wall thickness. Among the forty-five bread wheat crosses, three (W66 × W13, W86 × W12, and W86 × W16) significantly outperformed the check varieties in terms of desirable traits and demonstrated higher grain yield per plant. These crosses show promising potential and may be recommended for cultivation in the eastern plains of Uttar Pradesh, as well as incorporated into future breeding programs to develop improved varieties.