Division of Vegetable Crops and Floroculture, Indian Agricultural Research Institute, New Delhi-110012
Effects of plant regulators at varying concentrations were studied on the sex expression and sex ratio in the New Hampshire Midget variety of watermelon (Citrullus lanatus).
TIBA at 50, 100 and 200 ppm were found to be very efficacious in increasing the production of female flowers. The first female flower was produced by the above treatments comparatively at lower nodes. NAA and IAA significantly suppressed the number of male flowers while the effect of MH was inconsistent. GA at 25, 50 and 100 ppm increased the number of female flowers in one season.
TIBA at the lower three concentrations, viz. 50, 100 and 200 ppm, gave a significant increase in the number of fruits set and a high positive correlation was established between the production of female flowers and the fruit set. The above treatments remained outstanding in yield characters also and a significant increase in the total yield of fruits was recorded.
The studies indicated the possibility of modifying the sex expression and sex ratio and increasing the fruit yield in watermelon by spraying the plant regulators at the seedling stage, even under long day and high temperature conditions.
