Effect of foliar spray of potassium nitrate on growth, flowering and yield of rejuvenated custard apple (Annona squamosa L.) cv. Balanagar

Abstract

The present investigation entitled “Effect of Foliar Spray of Potassium Nitrate on Growth and Yield of Rejuvenated Custard Apple (Annona squamosa L.) cv. Balanagar” was conducted during 2024 at the All India Coordinated Research Project on Arid Zone Fruits, Department of Horticulture, MPKV, Rahuri. The study aimed to evaluate the influence of pruning and foliar application of potassium nitrate (KNO₃) on the growth, flowering and yield in 32 years old rejuvenated custard apple orchard. The experiment was laid out in a Factorial Randomized Block Design with two replications and 18 treatment combinations across six pruning levels and three foliar sprays of KNO3. Foliar spray was applied twice-at flowering and fruit set stage. Two years after rejuvenation, the maximum plant height (484.00 cm), plant spread (255.75 cm EW), (246.67 cm NS) and shoot length (112.25 cm) were recorded in T6 [Control without pruning] while T5 [Recommended practice of 25% pruning] recorded the highest number of shoots per tree (252.00) and yield (17.94 kg/tree). The earliest flowering (34.87 days) recorded in T4 [Retention of main trunk including primary branches and basal portion of secondary branches 10-15 cm]. Among the foliar sprays, S2 (KNO3 2%) significantly enhanced plant height (322.24 cm), plant spread (EW) (212.36 cm), number of shoots (203.42), days to flowering (39.67 days) and yield (15.09 kg/tree). The findings indicate that T5S2 [25% pruning with KNO3 2% spray] is most effective for improving growth and productivity in rejuvenated custard apple trees.