Effect of High Temperature and Humidity on Seed Production and Mother Bulb Harvesting of Onion

This study was undertaken to determine the effect of high temperature, high humidity and high temperature plus high humidity on seed production and mother bulb harvesting of three onion (Allium cepa L.) cultivars of early cultivar ‘Shinsunhwang’, intermediate cultivar ‘Maebsihwang’ and late cultivar ‘Chunjudaego’. At 32 days after treatment, onion plants were harvested and measured mother bulb parameters such as bulb height, diameter, weight and number, and seed yield. The results show that bulb height of the high humidity and high temperature plus high humidity treated plants significantly affected, but bulb diameter, weight and number were unaffected. Significantly decreased bulb yield in the late cultivar ‘Chunjudaego’ would be caused by the reduced bulb height, diameter, weight and increased bulb number. Compared to control, high temperature, high humidity and high temperature plus high humidity treatments significantly decreased seed yield of three onion cultivars such as early, intermediate and late. Especially, onion seed yield of the late cultivar ‘Chunjudaego’ under high temperature and high temperature plus high humidity treatments were considered to be more damaged compared to other cultivars.