Effects of Late-Season Drought Stress on some Physiological Traits, Yield and Yield Components of Wheat Genotypes

Drought, one of the environmental stresses, is the most significant factor restricting plant production in the majority of agricultural fields of the world. Wheat is generally grown on arid -agricultural fields. Drought often causes serious problems in wheat production areas. In order to investigate the effect of late season drought stress on some physiological traits, yield and yield components of seen wheat genotypes and experiment was conducted in Seed and Plant Improvement Institute, Karaj, Iran during 2012-2013 growing season. Six wheat lines and one cultivar as control (C -85-D8, C-85-D9, C-85-D13, C-88-D5, C-88-D6, C-85-D12 and Pishgam cultivar) were evaluated in two separate normal and drought stress conditions (no irrigation at 50% pollination stage) using a split plot layout based on randomized complete block design with three replications. According to the results, drought stress decreased 1000 -seed weight, seed number per ear and final seed yield. In addition, drought stress was responsible for cons iderable reduction in chlorophyll content, photosynthesis rate, stomatal conductance and transpiration. Moreover, there was significant difference between wheat genotypes so that C-85D-13 and C-85D-9 genotypes showed the highest compatibility with drought stress conditions. In addition, the results showed that Pishgam cultivar was a suitable cultivar for both normal and stressed conditions.