Effect of Foliar Feeding of Plant Growth Regulator and Nutrients on Phenological Attributes of Guava (Psidium guajava L.) cv Apple Colour

Guava, (Psidium guajava L.), small tropical tree or shrub of the family Myrtaceae, cultivated for its edible fruits. Guava trees are native to tropical America and are grown in tropical and subtropical areas worldwide. Nutrients and PGR play a crucial role in flowering and fruit production and their deficiency can significantly impact the yield, productivity, and quality of fruits. Therefore, keeping these points in view, the present investigation was carried out on a 10-year-old guava plant in a high-density plantation (3x3) at the Fruit Research Station Imaliya, Department of Horticulture, J.N.K.V.V., Jabalpur (M.P.) during the mrig-bahar season of 2022-23. The study employed a Factorial Randomised Block Design (FRBD) with 20 treatment combinations involving Plant Growth Regulators (PGR) like salicylic acid and various nutrients, replicated three times. Results indicated that the combination of salicylic acid (200 ppm) + borax (0.5%) significantly influenced several phenological parameters. This treatment resulted in the earliest flower bud initiation (18.33 days) after foliar application, the highest average number of flower buds per shoot (7.05), minimum days to 50% flowering (33.67 days), maximum average number of flowers per shoot (6.95), the highest fruit set percentage (92.18%), the highest fruit retention percentage (81.23%), and the lowest fruit drop percentage (18.77%). The application of salicylic acid at 200 ppm in conjunction with borax at 0.5% (S2 M4) followed by salicylic acid at 300 ppm with borax at 0.5% (S3 M4) demonstrated exceptional efficacy in significantly optimizing phenological parameters when compared to the control.