Facilitation of Quality Seed Production of Sesame through Desiccation and Defoliation Using Chemical Agents

Loss of seed yield in terms of quantity and quality is very common due to the dehiscence of capsules at maturity and indeterminate growth habit resulting in non-uniform ripening of capsules in sesame. Desiccants are used to accelerate and standardize the drying of sesame plants, thus facilitating either mechanized or manual harvesting. This experiment was conducted to assess four chemicals (salt, ethephon, glufosinate-ammonium and pelargonic acid) at two different rates of applications as harvest aids (desiccants and defoliants) to facilitate the harvesting in seed-producing sesame cultivation. Among tested chemicals, ethephon 2,000 and 4,000 ppm, glufosinate-ammonium 1,400 ppm, pelargonic acid 30 and 40 mL L^-1 resulted in 100% leaf drying at one week after chemical application. Of all treatments, ethephon (2,000 and 4,000 ppm) and salt (45 g L^-1) applications gave the highest percentage of leaf falling. Glufosinate-ammonium 1,050 and 1,400 ppm, pelargonic acid 30 and 40 mL L^-1 showed a significantly higher percentage of pod drying, and pod splitting compared to other treatments. The application of these chemicals did not have a negative effect on seed germination and seed vigour. Thus, the application of glufosinate-ammonium (1,050 ppm) and pelargonic acid (30 mL L^-1) can effectively be used for the purpose of drydown in seed-producing sesame cultivations.