Study the effect of deficit irrigation on yield, quality characteristics and water use efficiency of three cultivars of soybean in Moghan plain

Water deficit is the main factor that limit growth of plants, so achieving optimal performance under water deficit condition requires the selection of a suitable variety is due to the circumstances of each region. According to this, an experiment was conducted in a split plot arrangement based on randomized complete block design with three replications on soybean in Moghan plain at 2015 and 2016 years. Main-plots were Normal irrigation (IR1), 80 percent of full irrigation (IR2), 70 percent of full irrigation (IR3) and 50 percent of full irrigation (IR4) respectively, Cultivars included Williams (Cul1), M9 (Cul2) and Zan (Cul3) as a sub-plot. The results of comparing the means of data demonstrated that deficit irrigation decreased yield, yield components, percentage of seed oil of all cultivars. Also, the highest its characteristics (yield 4000 kg/hectare, Number of pods per plant 127.33, Number of seeds per plant 240, 1000 seeds weigh 300 gr, biomass 8900 kg/hectare, percentage of seed protein 25.3, WUE (yield) 0.95 and WUE (grain oil) 0.23 kg.m-3) observed in Williams cultivar under normal irrigation and the lowest values for these traits were obtained in Zan cultivar at IR3 and IR4 treatments. Also, the lowest protein content obtained in normal irrigation in the Williams cultivar and the highest that observed in the M9 cultivar at treatment IR4, respectively. Therefore, in order to this results Williams was the best cultivar under normal irrigation and water deficit conditions about yield and M9 was the sensitive variety to the deficit irrigation in Moghan Plain.