Effects of mycorrhizal symbiosis and seed priming on yield and water use efficiency of sesame under drought stress condition

•Seed priming and effect of mycorrhizal symbiosis on yield, harvest index, and water use efficiency of sesame.•Decreasing grain yield, harvest index and biological yield by reducing irrigation.•Increasing water use efficiency of grain, biological and oil crop yield by reducing irrigation.•Improving grain yield, harvest index and biological yield and water use efficiency for oil sesame by inoculation with Funneliformis species.•Superiority of F. mosseae compared to the Rhizoglomus intraradices.•High performance of mycorrhizal symbiosis under drought stress.•Positive effect of seed priming on the evaluated attributes. In order to study the effect of drought stress, seed priming, and mycorrhizal symbiosis on yield, harvest index, and water use efficiency (WUE) of sesame, an experiment was carried out based on the randomized complete block design as split-factorial arrangement with three replications at Agricultural Research Station of Haji Abad, Hormozgan- Iran, in 2014 and 2015. The results showed that grain yield, biological yield and harvest index were reduced by drought stress. On the other hands, WUE of grain, biological yield and oil product traits increased by drought stress. The highest efficiency of grain yield water usage, biological yield and oil product (0.39, 1.6, and 0.199 kg m−3, respectively) were obtained in the severe drought stress conditions. The results also showed that the highest grain yield, biological yield, and harvest index were related to the normal irrigation. In compared to the appropriate irrigation conditions, moderate to severe water stress reduced grain yield and biological yield rate by 39.4 and 26.7%, respectively. Mycorrhizal symbiosis improved all traits compared to the control group (no mycorrhiza). Inoculation with Funneliformis and Rhizoglomus fungi in optimum irrigation and stress conditions also improved traits compared to the control group.