Responses of Six Wheat Cultivars to Terminal Water Deficit

In order to evaluate the morpho-physiological and biochemical responses of six wheat (Triticum aestivum L.) cultivars to late season water deficit stress, this experiment was carried out in controlled conditions at College of Agriculture of Shiraz University, Shiraz, Iran during 2013-14. The experimental treatments were water deficit (50 and 100% F.C.) and wheat cultivars (Sirvan, Chamran, Shiraz, Marvdasht, Hamoun, Pishtaz). The results showed that water deficit significantly reduced flag leaf area (7.23%), number of grains per spike (17.37%), 1000 grain weight (20.88%), grain yield (17.73%), biological yield (15%), and harvest index (10.75%) and increased the chlorophyll content (14.48%) in all wheat cultivars. Significant differences were found in physiological responses among wheat cultivars. Under water deficit stress, Sirvan and Chamran cultivars had significantly higher growth and yield compared to other wheat cultivars. Water stress increased the activity of catalase, peroxidase and superoxide dismutase and this increase was significantly higher in Sirvan and Chamran cultivars. It could be concluded that in Sirvan and Chamran cultivars the increased antioxidants activities led to the partial amelioration of the adverse effects of water deficit, resulting in greater grain yield and yield components, compared to the remaining genotypes.