Effect of Genotypes, Ethephone and Boron and Their Interaction on Sex Expression and Yield of Summer Squash

A pot experiment was conducted in lath house at the College of Agriculture, Kerbala on March, 10^th /2016 and on September 16^th,2016 for spring and fall seasons respectively to study the effect of genotype (local Mullah Ahmed and hybrid), ethephon (0, 50, 100 and 150  mg.l^-1 ), boron (0 and 30 mg.l^-1) and their interaction on sex expression and yield of the summer squash plant. A factorial experiment within a completely randomized design was adopted. Plants were sprayed with ethephon at 4-5 leaf-stage and boron was sprayed at 6-8 leaf-stage for spring and fall seasons. The results showed that the hybrid genotype significantly surpassed in most floral growth characters and yield (female flowers, sex ratio, fruit number and plant yield) in both growing seasons whereas the local genotype significantly surpassed in male flower. Ethephon at 150 mg/L^-1 was superior in yield characters (fruit weight, fruit number and plant yield), while ethephon at 0 mg/L^-1 gave a higher number of male flowers in both growing seasons. Boron spraying significantly surpassed in all yield characters (fruit weight, fruit number and plant yield) in both growing seasons. The interaction between genotype and ethephon significantly affected all floral growth characters, whereas it had no significant effects on all yield characters in both growing seasons. The interaction between genotypes and boron showed a marked effect on all floral growth characters, while it had no significant effect on all yield characters in both growing seasons. The interaction between ethephon and boron achieved a significant effect on all yield characters, whereas it showed a significant influence on the sex ratio during spring season only.