Chemical interventions for advancing the fruiting season of sugar apple (Annona squamosa L.) cv. balanagar

Abstract

Fruits of ‘Balanagar’, the most commonly grown cultivar of sugar apple (Annona squamosa) in India, come to harvest during the rainy months of September-October. Advancing its fruiting to early summer would be advantageous for better fruit quality. Since flowering in sugar apple occurs on current season growth arising naturally after leaf fall during late winter, attempt was made to advance the fruiting season by defoliating the trees using chemicals, well before the natural leaf fall during December - January. The chemical defoliants urea (5%, 10% & 15%) and ethrel (2000ppm, 3000ppm & 4000ppm) and bud sprout promoter KNO3 (5%, 10% and 15%) were sprayed during first week of October for two consecutive years (2016-17 and 2017-18). Maximum defoliation (97%, 96.5%) was recorded for ethrel @ 4000ppm during both the years. Early sprouting (26 days, 16.1days) and flower initiation (35 days, 23.03 days) were recorded in trees sprayed with urea @ 15% for both the years, respectively. Earliest harvest was from trees treated with urea @ 15% (290 days) and ethrel @ 4000ppm (285 days). Fruit yield per tree was not affected by any of the treatments. Defoliation with different chemicals significantly influenced vegetative and reproductive growth of sugar apple cv. Balanagar leading to early fruit harvest by 5-6 weeks.