Effect of GA₃ and NAA on Growth and Yield of Cabbage

Cabbage (Brassica oleracea var. capitata L.) is an important winter vegetable in Bangladesh; however, its yield remains considerably lower compared to that of major cabbage-producing countries. This study aimed to assess the effects of gibberellic acid (GA₃) and naphthalene acetic acid (NAA) on cabbage growth and yield, as well as to identify optimal application rates. The experiment was conducted using a randomized complete block design (RCBD) with eight treatments, including different concentrations of GA₃ (50, 75, and 100 ppm) and NAA (40, 60, 80, and 100 ppm), along with a control, at the Horticulture Farm of BARI, Gazipur. Findings revealed that GA₃ at 75 ppm significantly improved plant height (23.00 cm), total number of leaves (62.33), head diameter (22.60 cm), and yield (102.40 t ha⁻¹), achieving a 33.39% increase over the control. NAA at 60 ppm also showed notable, albeit slightly lower, improvements. Both growth regulators were effective in promoting earlier head formation and maturity. The results confirm that the exogenous application of GA₃ and NAA enhances vegetative growth and yield attributes in cabbage. Based on the findings, applying GA₃ at 75 ppm is recommended to maximize cabbage production under similar agro-ecological conditions. This study provides practical guidance for improving cabbage yield through the targeted use of plant growth regulators.