Enhancing Growth and Quality of Cabbage (Brassica oleracea var. capitata L.) through Foliar Application of Plant Growth Regulators under Eastern U.P. Conditions

The investigation was carried out during the rabi season of 2023–2024 at the Vegetable Research Farm, Department of Horticulture, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi (U.P.), India. Cabbage (Brassica oleracea var. capitata L.), a commercially important cole crop, has its productivity enhanced through the application of plant hormones. The objective of the study was to assess the impact of foliar application of plant growth regulators as gibberellic acid (GA₃) and naphthaleneacetic acid (NAA), on the vegetative growth, yield attributes and quality traits of cabbage. The experiment followed a randomized block design comprising nine treatment combinations with three replications, using the cultivar ‘Golden Acre’. Treatments consisted of GA₃ at 60, 90, 120 and 150 ppm; NAA at 40, 80, 120 and 150 ppm, along with a control, sprayed at 30 and 45 days after transplanting. Statistically significant variations (p < 0.05) were noted across all treatments. GA₃ at 90 ppm recorded maximum plant height (32.83 cm), canopy spread (53.78 cm), leaf dimensions and wrapped leaf count (52.08), along with superior net head weight (1091.69 g), total biomass (1730.69 g), chlorophyll concentration (SPAD 70.13) and vitamin C content (34.22 mg/100 g). NAA at 80 ppm also showed favourable performance, improving head size, foliage growth and nutritional quality. Conversely, the untreated control exhibited the lowest values. Overall, the data suggest that appropriate use of GA₃ and NAA particularly at 90 ppm and 80 ppm, respectively, substantially enhances cabbage growth, productivity and quality through physiological modulation.