Evaluation of the extent of genetic variability and associated traits of bread wheat (Triticum aestivum L.) genotypes under heat and drought stress environment conditions

Drought and temperature are the two important abiotic factors that limit wheat yield and endanger productivity. The success of crop improvement with enhanced grain yield under drought and heat stressed conditions depends considerably on the extent of genetic variability in a crop species. The present study was carried out to determine the level of genetic variation and associations of yield and yield attributing traits among 55 bread wheat genotypes under drought-stressed and heat-stressed conditions. In the current investigation, we evaluated fifty-five bread wheat genotypes under two sowing dates: timely and late sown conditions, with restricted irrigation at different plant growth stages. Under different environmental conditions, there were notable genetic variations for the studied attributes. The highest value for GCV and PCV was observed for Harvest index% (25.8 and 34.3 respectively). High GCV, PCV, heritability and genetic advance as% of mean showed by two traits, viz., biological yield and seed yield per plot; heritability and GA (%) of mean were observed to be high for seed yield per plot, number of seeds per spike and biological yield. Genotypes UP 2425, WH 1025, HD 2985, HS 490, AKAW 3717 and HI 1544 had high stable yields under most of the conditions. The identified traits and genotypes were drought and heat stress tolerant and could be exploited to develop novel genotypes for drought and stress tolerance.