Influence of foliar-applied urea, zinc sulphate and PGPR on phenology and initial fruit development in mango (Mangifera indica L.) cv. Langra

Abstract

The productivity of the mango (Mangifera indica L.), an economically significant fruit crop, is profoundly influenced by the timing of early fruit development and flowering phenology. The aim of this study was to evaluate the impact of foliar application of urea, zinc sulfate, and PGPR on the phenological traits of the mango cultivar Langra. In a Factorial Randomized Block Design (FRBD) experiment, 27 treatment combinations were established, incorporating three doses of zinc sulphate (0%, 0.5%, 1.0%), urea (0%, 2%, 4%), and Plant Growth Promoting Rhizobacteria (0%, 0.5%, 1%). There were two applications of foliar sprays: one at the start of the floral bud and the other when 50% of the flowers had opened. Days to 50% panicle emergence, 50% flowering, first fruit set, and first panicle emergence were all recorded. The combined foliar application of nutrients and PGPR had a positive effect on all phenological parameters, even though the results were not statistically significant. The treatment T27 (4% urea + 1% ZnSO₄ + 1% PGPR) had the earliest panicle emergence (24.5 days), 50% emergence (6.0 days), 50% flowering (11.0 days), and the earliest first fruit set (45.0 days). These improvements may be due to better nutrient absorption, hormonal control, and increased assimilate translocation that come with integrated nutrition management. The study's results show that when applied to mango cv. Langra, urea, zinc sulfate, and PGPR may help fruit grow faster, make flowers bloom at the same time, and speed up reproductive phenology. Using this integrated foliar feeding method, commercial mango orchards could make a lot more fruit.