Effect of drought stress and foliar nutrition of iron nano-chelate and fulvic acid on grain yield and fatty acids composition in seed oil of two sesame cultivars

Evaluation the effect of drought stress and foliar nutrition of iron nano-chelate and fulvic acid on grain yield and fatty acids composition in seed oil of two sesame cultivars was conducted during a factorial split-plot experiment based on randomized complete block design with three replicates in 2017 in the Research Farm Shahed University of Tehran. The experimental factors included drought stress in three levels: full irrigation as control, irrigation up to 50% seed ripping, and flowering, as well as four treatments of foliar nutrition by iron nano-chelate and fulvic acid in Dashtestan and Halil cultivars. The results showed that the drought stress reduced grain yield and also, seed oil content. The highest grain yield was observed in full irrigation (2303.3 kg/ha) and the co-application of iron nano-chelate and fulvic acid (2246.4 kg/ha). Halil cultivar had the highest mean of the total number of capsules (81.19), number of seeds per plant (4786.1), 1000-grain weight (3.21 g), grain yield (2172.7 kg/ha), and biological yield (13534.6 kg/ha) in compared with Dashtestan. The highest oil and protein yield were observed in full irrigation and irrigation up to 50% seed ripping. Irrigation cut off at 50% flowering and seed ripping had the highest oleic and linoleic fatty acids compared to the control treatment, but the highest palmitic and stearic fatty acids were obtained in full irrigation treatment (10.86 and 10.73%, respectively). Halil and Dashtestan cultivars had the highest unsaturated and saturated fatty acids, respectively.