Effects of ethephon treatment at pre-harvest stage on leave color, growth time, and sesame seed yield and quality (Sesamum indicum L.)

Abstract

The effect of ethephon spray on leaves at pre-harvest stage to accelerate the ripening process of capsules and sesame defoliation was studied. Sesame plant was treated with ethephon at concentrations of 0, 50, 100, 200, 300, 400 and 500 ppm when the capsules on plant began to mature, the seeds turned black. The results showed that ethephon treatment caused yellowing of leaves, accelerated defoliation and the growth time of sesame plants was shortened from 5 to 6 days compared to the control sample. In addition, the ethephon concentration of 50 and 100 ppm caused yellowing of leaves with chlorophyll index measured at 3 days after treatment was 13.5 and 12.7, respectively. At ethephone concentration of 200-500 ppm caused complete yellowing and defoliation of leaves in 3 days after treatment. The leaves of control sample were still green and had chlorophyll index of 22.2. Treatment of ethephon with concentrations of 50-300 ppm did not reduce the yield and lipid content in the seeds compared to the control sample, but from 400 ppm or more caused cracking of capsules, reducing yield and lipid content in the seeds. Ethephon treatment did not affect the number of capsules/plant, number of seeds/capsule, weight of 1000 seeds, protein content and seed color.