Study of Physiological, Growth, and Yield Responses of Sesame to the Application of Potassium Nano-Fertilizer, Foliar Application of Fulvic Acid and Chitosan under Drought Stress

This experiment works on the physiological, growth, and yield responses of sesame to the application of potassium nano-fertilizers, chitosan, and fulvic acid under drought stress in Semnan Agricultural and Natural Resources Research Center as a factorial split-plot based on randomized complete block design with three replications in 2019. The experimental treatments include drought as the main plot (normal irrigation, irrigation cut offin 70 and 60 BBCH as moderate, and severe stress, respectively) and potassium nano-fertilizer (0, 1.5, and 2.5 per thousand) and foliar application (control, chitosan, fulvic acid, and 50% of chitosan+ fulvic acid) as sub-plots.Application of potassium nano-fertilizer under normal and stress conditions significantly cuts chlorophyll b and total, leaf area index, number of capsules, 1000-seed weight, and oil percentage.The highest grain yield belongs to the application of 1.5 and 2.5 per thousand nano fertilizers, using fulvic acid alone or in combination with 50% chitosan (2516, 2277.5, 2506.6, and 2313.2 kg/ha, respectively). The highest oil content has been in 1.5 and 2.5 per thousand nano fertilizer application under normal irrigation, which has increased 13.2% and 15.4%, respectively. Foliar application of fulvic acid with nano potassium fertilizer (1.5 per thousand) under severe drought stress show the highest activity of antioxidant enzymes catalase, peroxidase, ascorbate peroxidase, and superoxide dismutase. In general, the results show that the application of 1.5 per thousand nano potassium fertilizer and combined foliar application of chitosan and fulvic acid under severe drought by improving physiological traits, manage to modify the adverse effects of drought, increasing growth, yield, and quality indices of sesame.