Effect of drought stress on quantitative and qualitative traits of two forage sorghum cultivars in Jiroft region

To evaluation the effect of different drought stress levels on yield and yield components of two forge sorghum cultivars vic. Speedfeed and Pegah, an experiment was conduct in Agricultural and Natural Recourses Research Center of Jirof in 2014. Experimental design was split plot based on randomized complete block in three replications. The main plots were three irrigation levels including 33, 66 and 100% of plant water requirement and sub plots were forage sorghum cultivars. Drought stress affected significantly on all studied traits such as fresh and dry forage yield in both cultivars. Also, drought stress caused decrement in total fresh yield in forage sorghum. In intensive and moderate drought stress fresh forage yield decreased up to 47 and 17% comparing to normal irrigation, respectively. Pegah cultivar in both stressed and none-stressed conditions had higher yield than Speedfeed. Raw protein, fiber and ash percentage increased by improvement in drought stress condition. Also, these qualitative traits in Pegah were better than Speedfeed. In deficit water condition in forage sorghum cultivation, it is possible to use drought resistant cultivars and decreasing of irrigation intervals especially in sensitive plant stages and harvest higher amounts of forage yield.