GENETIC ANALYSIS OF SOME BREAD WHEAT GENOTYPES UNDER DROUGHT STRESS IN SANDY SOILS

A half diallel cross was performed between six bread wheat (Triticum aestivum L.) genotypes, Line Yr5, Shandwell 1, Gemmeiza 11, Misr 4, Sakha 95, and Sids 14 during the 2022/2023 winter season. The resulting 15 F1 crosses were evaluated during the 2023/2024 season under normal irrigation and drought stress conditions using strip plot design in RCB arrangement with 3 replications at Khattara Research Station, Sharqia, Egypt, to calculate mean performance, drought stress tolerance measurements, effects of general and specific combining abilities, mode of gene action, and heritability. Results cleared that mean squares due to genotypes, parents, and crosses, and parents vs. crosses were highly significant for most studied characters under both conditions. Moreover, general and specific combining abilities mean squares were highly significant for most studied characters under two conditions. The highest heritability in the narrow sense (Tn) was observed for number of days to heading, number of days to maturity, and plant height under both conditions. Additionally, under normal irrigation conditions, heritability was also high for the number of spikes plant-1, weight of thousand grains, and the number of grains spike-1. On the other hand, chlorophyll content showed moderate heritability under specific conditions, including grain yield plant-1 and the number of spikes plant-1, along with the number of grains spike-1 and the weight of thousand grains under drought stress conditions. In contrast, the heritability for grain yield plant-1 under drought stress conditions was low.