Effect of Gibberellin and Nitrogen Fertilizer on Growth and Zucchini (Cucurbita pepo L.) Yield In Tropical Regions

Zucchini is the Cucurbitaceae family and rich in nutrients. In Indonesia, cultivation of zucchini is still low and zucchini has the potential to be developed. Improvement of cultivation technology is required to ensure optimal growth and yield of zucchini. The research to study effect of gibberellin and nitrogen fertilizer on growth and yield of zucchini plants. Was conducted from July to October 2023 in Batu City, East Java, Indonesia. The Research was a factorial experiment using a randomized complete block design with two factors, first factor was gibberellin concentration with 3 treatment levels (0, 150 and 300 ppm) and the second factor was the dose of nitrogen fertilization with 5 treatment levels (50, 100, 150, 200 and 250 kg/ha). The observation data results were analyzed using analysis of variance (ANOVA) and continued honest significant difference test HSD at 5% error level. To determine the relationship pattern between observation variables, regression test was conducted. The results showed that significant effect of gibberellin and nitrogen fertilization on growth and yield of zucchini plants. There were increasing in plant length, number of leaves, leaf area, fresh weight, dry weight, number of fruits and fruit weight. Nitrogen fertilization caused increasing in plant length, number of leaves, leaf area, fresh weight, dry weight, number of fruits, fruit weight and chlorophyll index. The results of this study revealed that gibberellin and nitrogen fertilization positive effect in increasing the growth and yield of zucchini plants. Based on the results of this study recommended that the optimum gibberellin and nitrogen are 150 ppm and 150-250 kg/ha.