Evaluation of Wheat (Triticum aestivum L.) Genotypes under Pre- and Post-anthesis Drought Stress Conditions

The responses of yield and yield components of 24 advanced bread wheat genotypes to pre- and post-anthesis drought stress conditions were studied at Ardabil Agricultural Research Station during the 1997-2000 cropping seasons. Results showed that genotypes produced signif icantly lower spikes No./m2, seeds No./spike and grain yield under prethan in post-anthesis drought stress conditions. However, an average of 1,000 kernel weight of genotypes under pre-anthesis was higher than under non-stress and postanthesis drought stress conditions. Selection based on TOL and SSI identified the drought tolerant genotypes with low grain yield. However, selection based on MP, GMP and STI identif ied drought tolerant genotypes with a high yield. Genotypes No. 13, 14 and 21 were determined as desirable genotypes based on their high grain yield under non-stress, preanthesis and post-anthesis drought stress conditions. The interaction eff ect of genotype x year was signif icant for membrane stability and membrane damage, however, the interaction eff ect of genotypes×stages of measurement (booting and heading) were not signif icant. On the basis of these results, genotypes No. 13, 14 and 21 with low membrane damage were also identified as drought tolerant genotypes. It can be concluded that the laboratory test can be an useful tool in a breeding program for improving drought tolerance in wheat