Evaluation inheritance of drought stress tolerance score of bread wheat (Triticum Aestivum L.)

In order to increase drought tolerance in bread wheat, an appropriate breeding program based on inheritance of drought tolerance is recommended. In the present study, nine bread wheat cultivars and their F2 progenies were evaluated in a randomized complete block design under normal and drought stress conditions. Nine sensitivity/tolerance indices were calculated for studied genotypes and stress tolerance score (STS) was calculated using all indices. Inheritance of drought tolerance indices (STI, DRI and STS) were evaluated using half diallel design. Low Baker ratio for these indices showed that none-additive effects are more important than additive effects in genetic control of these indices. In addition, broad sense heritability was relatively high and narrow sense heritability was low for evaluated indices. Results of this research showed that selection for increasing drought tolerance in bread wheat should be postponed till late generations. Based on these results, bulk, single seed descent and double haploid are recommended methods for breeding for drought tolerance in this population.