بررسي اثر تنش گرمايي بعد از گرده افشاني بر ارقام گندم و جو

The Effect of Heat Stress After Anthesis on Grain Yield of Wheat and Barley Cultivars

In order to study the effects of heat stress after anthesis on six wheat (Stork, Showa, Green, Star, Chamran and Fong) and two barley (Jonob and Sarasary 6) cultivars, two field experiments were conducted in delayed and optimum sowing dates. Plants in delayed sowing date experienced heat stress in after anthesis growth stage. Study of stress tolerance index (STI) and stress susceptibility index (SSI) for grain yield and grain weight indicated that the highest and the lowest STI for grain yield was in Jonob and 00 cultivars, respectively. Green and Stork STIʹs had the highest and the lowest grain weight, respectively. Stork and Jonob were sensitive and insensitive cultivars to heat stress respectively. Higher SSI for grain weight in late maturity cultivars such as Green and Star was related to the delay in anthesis and contact of grain growth period with heat stress, In early mature cultivars such as Fong with early anthesis, grain growth period was before heat conditions, while stress susceptibility for both grain yield and grain weight was the highest in Fong cultivar.