Effects or 2-chloroethylphosphonic Acid on Sex Expression and Yield in Muskmelon

Effects of 2-chloroethylphosphonic acid (Ethrel) to he setting ratio of female flowers on the main stem and also on the firs node of lateral branches of muskmelon were investigated. Ethrel concentration sprayed was 200, 250 or 300 ppm, and leaf stage treated was one-, two- or five-leaf stage. Two cultivars, Harukei No. 1, a spring type, and Marunishi No.3, a summer type, both belonging to Earl's Favotrite strain, were used. 1. Plant height was suppressed by Ethrel treatment in each plot, but their final height was not differed from the control plot except in plots treated at five-leaf stage. 2. Ethrel treatment at three- or five-leaf stage induced the setting of female flowers on the main stem with reduction of male flowers on it. Treatment at one-leaf stage only reduced male flowers on the main stem, inducing no female flower. .....