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Paclobutrazol Influences Vegetative and Reproductive Growth, Physiology and Quality of Watermelon Hybrids

Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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(Received: March 15, 2023; Accepted: April 25, 2023)


Paclobutrazol (PBZ) is a member of the triazole plant growth inhibitor group that is responsible for controlling plant height and inducing flowering. An experiment was, therefore, conducted to examine the foliar application of PBZ at various concentrations to control the vigorous growth of watermelon seedlings in a greenhouse. The first factor was the concentration of PBZ at 0, 250, 500, 750 and 1000 ppm as a foliar spray, and the second factor was hybrids of watermelon i.e. GE344, GE341 and SSH348. Foliar application of PBZ reduced plant height and unwanted vegetative growth in tested watermelon hybrids. The reduction in plant height for 250 ppm was almost 14.26% compared to the non-treated plants; however, 1,000 ppm, showed extremely the shortest plant. With the increase in PBZ concentration from 0 to 1,000 ppm, plant height and leaf area were reduced. Results also indicated that in all three hybrids the highest relative chlorophyll content, number of the female flowers, fresh and dry root weights, root diameter and TSS (% Brix) were found in the application of 250 ppm compared to other PBZ concentrations. Maximum fruit firmness was obtained at 500 ppm of PBZ. Among the hybrids, the GE344 produced significantly highest relative chlorophyll content, TSS%, fruit weight and fruit firmness. Considering the above results, 250 ppm of PBZ is recommended for commercial production of watermelon in greenhouse.
Key words : Paclobutrazol, concentration, watermelon, growth, quality