Evaluation of Bread Wheat Cultivars and Lines under Normal Irrigation and Drought Stress

The aim of this study was to evaluate and select bread wheat cultivars by some physiological traits under drought stress conditions. Experiments were conducted in the cropping years from 2018- 2019 and 2019-2020 in the farm of Agricultural and Natural Resources Research Center of Moghan in the form of split plots complete random block design with three repetitions. The Main plot covered the three irrigation regimes including control irrigation (without drought stress), medium drought stress (moderate drought stress) and full drought stress. Sub-plots included bread wheat cultivars and lines (Tirgan, Ehsan, Aftab and lines N-91-17, N-92-9 and N-93-17). The results showed that moderate and full drought stress caused a significant decrease in the number of days to germination, number of fertile tillers per plant, thousand seed weight, seed yield, proline content, catalase, leaf protein and leaf greenness index. Under moderate and full drought treatments, the seed yield declined (12.5 and 31 percent, respectively). Also, the results showed that moderate drought stress and full drought stress increased proline content and catalase enzyme activity and decreased leaf protein content and leaf greenness index. Considering the critical water conditions in the world and Iran, especially in Ardabil (Maghan) province, the introduction of cultivars that can reduce yield at least in low irrigation conditions are of great importance. Therefore, among the studied cultivars, the N-93-17 line and the Aftab variety are recommended for cultivation in the conditions of drought stress at the end of the season and the development of drought-resistant varieties.