Effects of Indole-3-Acetic Acid on the Growth Parameters of Citrullus lanatus (Thunberg) Matsum and Nakai

Effects of Indole-3-Acid (IAA) on Citrullus lanatus plant height, leaf number, branching and flower production were studied in order to evaluate the optimum concentrations required for growth and development. Foliar application using five different concentrations [1, 5, 10, 20 and 0 ppm IAA] was conducted twice at two weeks interval. The results suggest that as IAA concentration increases, plant height decreases with an optimum concentration of 5 ppm IAA. Mean plant height was also significantly different. More so, optimum concentration for leaf production and branching varied with varietal difference. Results obtained for number of branching suggest that 1 ppm IAA is optimum for variety A and 10 ppm is optimum for varieties B, C and D. Although flower production was poor during the study, high flower production is recorded for plants in 20 ppm IAA at 6 weeks after planting for all the varieties. This work establishes the inducing effects of different IAA concentration, which may be exploited for the commercial production of C. lanatus. Keywords : Watermelon (Citrullus lanatus), Indole-3-Acetic acid, Growth parameters, Leaf production, Plant Physiology.