Evaluation of genetic diversity effects on morpho-physiological and antioxidant responses in different species of Aegilops under drought stress

This experiment was conducted to investigate the effect of drought stress on photosynthetic pigments contents, biomass of roots and shoots, total protein content and antioxidant enzymes activity and non-enzymatic antioxidant of six species of Aegilops genus along with two drought resistant and susceptible wheat cultivars as checks in a factorial based on randomized complete block design with three replications. Drought stress treatments were applied at three levels of non-stress (FC=100%), moderate stress (FC=50%) and severe stress (FC=25%) conditions. Ae. caudata, Ae. triuncialis and Ae. cylindrica were ranked higher than resistance cultivar, Sirvan, as check in term of root fresh and dry weights under stresses. The highest total chlorophyll content was related to Ae. cylindrica, Ae. umbellulata and Ae. caudata in stresses. Carotenoid showed decreasing trend in all studied species except for Ae. umbellulata, and Ae cylindrica had the highest amount at both stress and non- stress conditions. The highest SOD under severe stress was observed in Ae. crassa and Sirvan as resistant cultivar. Maximum APX under severe stress was observed in Ae. triuncialis and Ae. caudata and the lowest activity was in Ae. neglecta. The highest level of GPX was observed in Ae. triuncialis, Ae. caudata and Sirvan cultivar under drought stress. Also the maximum CAT enzyme under severe stress was observed in Ae. triuncialis, Ae. caudata and Ae. crassa, respectively, and Ae. umbellulata and Darya cultivar had the lowest amount of CAT enzyme. In conclusion, because the three species Ae. caudata, Ae. triuncialis and Ae. cylindrica had the highest amounts for the traits associated with increased drought tolerance, including root volume, carotenoid, CAT, GPX and APX enzymes, and also these species were same in having CC genome. Therefore, it seems that the CC genome could have a high potential for future wheat breeding programs in increasing of drought tolerance.