Evaluation of water stress tolerance, dry forage yield and biochemical traits of five alfalfa cultivars

One of the important activities to achieve drought tolerant cultivars is screening and selection of cultivars, based on yield and biochemical characteristics. A split-plot experiment arranged in a randomized complete blocks design with three replications has been carried out in Safiabad Agricultural Research Center during two growing seasons (2017-19). The main plots are consisted of different irrigation regimes based on crop’s water requirement (25%, 50%, 75%, and 100%) and sub plots include five levels of alfalfa cultivars (Baghdadi, Nikshahri, Yazdi, Omid, and american Mesa-Sirsa). Results show that drought stress due to irrigation regimes have resulted in a significant reduction of forage dry matter yield and considerable changes of soluble sugar, glutation peroxidase, and catalase in alfalfa leaves. However, it has not greatly affected total protein. For forage dry matter yield, the highest statistical class belongs to Baghdadi cultivar under 100% water requirement supply treatment (2.824 t.ha-1). The lowest statistical class for forage dry matter yield has been observed in Yazdi and Mesa-Sirsa cultivars under 25% water requirement supply treatment (0.598 and 0.546 t.ha-1), respectively. Among the cultivars, examined in this experiment, Yazdi has been identified as a drought tolerant cultivar due to the stability of dry forage yield as well as high leaf antioxidants content.