Enhancing parthenocarpy and fruit set in sugar apples through gibberellic acid induction

Abstract

Abstract: In sugar apple cultivation, the implementation of manual pollination is imperative to enhance fruit set. However, this methodology concurrently leads to an elevation in seed count and in overall production expenses. As a potential solution, growth regulators have been employed across various crop types to augment fruit yield and to facilitate the development of seedless fruits. In order to achieve this goal, a range of concentrations (0, 250, 500, 750, and 1.000 mg L-1) of gibberellic acid (GA3) were administered to sugar apple trees during the flowering stage, specifically when the flowers were in the female phase. Subsequent applications were carried out at intervals of 7, 14, 21, and 35 days after the initial treatment, targeting already established fruits. After a span of thirteen weeks, the utilization of GA3 exhibited multiple benefits. Notably, it led to a considerable increase in fruit set, reaching up to 75%. Furthermore, GA3 induced parthenocarpy in sugar apples, triggering fruit development without fertilization. Additionally, the application of GA3 had a positive impact on key fruit attributes, including diameter, fresh weight, and soluble solids content. It is important to note, however, that the resultant fruits displayed a thicker peel and lower pulp content. Notwithstanding, the ratio of peel to pulp escalated proportionally with the concentration of GA3 applied. To further enhance the physicochemical characteristics of sugar apples, it is recommended to explore doses exceeding 1.000 mg L-1 as well as consider the synergistic effects achievable through a combination of different growth regulators. In conclusion, the outcomes unequivocally demonstrate that GA3 induces parthenocarpy in sugar apples and effectively enhances fruit set.

Keywords

• Annona squamosa L.
• fruiting
• GA3
• growth regulator