Effect of Heat Stress on Yield and Its Components of some Egyptian Wheat Cultivars

Two field experiments were conducted during (2019/2020 and 2020/2021) seasons in Abu El Matamir region, Beheira Governorate, Egypt to evaluate the yield and its components of four Egyptian wheat cultivars (Gemmeiza-11, Giza-168, Sids-12 and Bani Sweif-5). Plant phenology and grain development traits including (days to anthesis, days to maturity, plant height and grain filling duration) and grain yield and its components traits (spikes number /m 2 , grains number /spikes, grain weight, grain yield, straw yield, biological yield and harvest index) were studied. The analysis of variance indicated that there were highly significant differences between cultivars for most of these traits in both seasons under both normal and heat-stressed conditions. Related to plant phenology and grain development traits, the highest cultivar under heat-stressed conditions at most of these traits was Giza 168 whereas Bani Sweif 5 was the lowest. Concerning grain yield and its components traits, the highest cultivar under heat-stressed conditions for spikes number /m 2 , grain yield, straw yield and biological yield was Bani Sweif 5. Giza 168 was the lowest for grain weight, grain yield, straw yield and biological yield. These results revealed that Bani Sweif 5 cultivar can be used for heat stress programs in wheat.