Enhancing Growth, Flowering, Yield and Quality of Phalsa with the Foliar Spray of Naphthalene Acetic Acid (NAA) and Gibberellic Acid

Abstract

Phalsa (Grewia asiatica L.) is an important minor fruit crop valued for its refreshing fruits, but its productivity and fruit quality are often constrained by limited systematic management of plant growth regulators. To evaluate the effects of foliar sprays of Naphthalene Acetic Acid (NAA) and Gibberellic Acid on the growth, flowering, yield and quality of phalsa (Grewia asiatica L.), a field experiment was conducted at the Garden, Department of Fruit Science, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur (U.P.), during 2025-26. Ten treatments comprising NAA at 50, 75 and 100 ppm, GA₃ at 100, 150 and 200 ppm, three NAA + GA₃ combinations (50+100, 75+150 and 100+200 ppm), and one control (water spray) were evaluated in a randomised block design with three replications. Sprays were applied to uniformly maintained, regularly pruned sixty-five-year-old bushes that received the recommended dose of plant nutrients throughout the investigation period. Among all treatments, T₇ (50 ppm NAA + 100 ppm GA₃) was consistently the most effective, recording the maximum bush height (177.46 cm), number of shoots per bush (134.0), number of leaves per shoot (24.70), number of flowers per shoot (160.70), fruit yield per plant (3.05 kg), fruit diameter (1.14 cm), hundred-fruit weight (83.25 g), pulp weight (72.80 g) and pulp:stone ratio (6.97), together with the minimum number of days to flowering (35.37 days) and the lowest stone weight (10.45 g). T₇ also produced fruit of superior biochemical quality, with the highest total soluble solids (25.10 °Brix), reducing sugars (9.10%), non-reducing sugars (2.17%) and total sugars (11.27%), along with the lowest titratable acidity (2.51%). The results indicate that a combined foliar spray of 50 ppm NAA and 100 ppm GA₃, applied once before flower-bud initiation, can be recommended for improving growth, earliness of flowering, yield and fruit quality of phalsa cv. Sharbati under the agro-climatic conditions of the Indo-Gangetic plains of Uttar Pradesh.