Evaluation of droght tolerance of new wheat genotypes under water stress conditions

To evaluate the drought tolerance of new wheat genotypes to terminal water stress in field conditions, an experiment using a split plot design based on compelet randomaised block design with three replications was conducted in Torogh Agricultural Research Station (Mashad) in 1382-83. Irrigation treatments with two levels were allocated in main plots: I1- full irrigation (100% water use in different development stages) and I2- water stress (withdrawal of irrigation from anthesis stage to maturity with prevention of precipitation using mobile rain shelter). Number of 16 elite wheat genotypes suited for cold regions of Iran and Khorasan province (C-82) were allocated in sub plots. Results showed that, irrigation treatment had a significant effect on grain yield (GY), harvest index (HI), No. of spike per m2 (S.m-2), No. of grain per spike (G.S-1) and thousands kernel weight (1000 KW). There was significant differences between genotypes. C-82-5 was a high yielding genotype in both conditions (control and water stress) and had optimum level of HI, G.S-1 and 1000 KW. The tolerance of genotypes to water stress was evalovated with different drought tolerance indices, such as stress tolerance index (STI). Results showed that, C-82-5 was a high yielding genotype with more tolerance to terminal water stress.