Mitigating gibberellic acid-induced effects on dormancy, shoot growth, and fruit development in persimmons when used to delay harvest

• GA₃ extends harvest of ‘Rojo Brillante’ persimmon and stabilizes market prices. • The optimal treatment is 30 mg L⁻¹ GA₃ applied 20 days before colour break. • Repeated GA₃ sprays enhance response but delay dormancy and reduce flower quality. • Yield losses in the following year increase with cumulative autumn treatments. • GA₃ or Promalin at budburst raised growth and fruit set, mitigating yield losses. The large-scale production of ‘Rojo Brillante’ persimmon in Spain relies on gibberellic acid (GA₃) applications to delay harvest and stabilize market prices; however, the optimal concentration and timing of these treatments remain unclear. Spraying 10 to 50 mg L -1 GA 3 showed that the response saturates at 30 mg L⁻¹ when applied between 20 days before and the onset of fruit colour break. Nonetheless, this treatment delays harvest by only ∼10 days, which is insufficient to effectively manage the national production (∼500,000 t). To enhance their effectiveness, growers often apply 30–50 mg L -1 GA 3 up to three times, but this practice also delays leaf abscission and bud dormancy, reduces the fulfillment of chilling requirements, and impairs flower quality, ultimately causing substantial yield losses in the following season. Because these treatments are applied annually, their negative effects accumulate over time. In this study we demonstrate that applying GA₃ (25 mg L⁻¹) or Promalin© (10 mg L⁻¹) at budbreak, when the first leaf primordia become macroscopically visible, mitigates these carryover effects of autumn GA₃ treatments on subsequent yield. Spring applications increased vegetative growth by 48% and ovary weight at petal fall by 81%, which in turn increased fruit set (26% more fruits per tree) and fruit size at harvest (25% increase), with no significant differences between the two products. This approach provides a practical and sustainable strategy to improve persimmon yield and fruit quality while minimizing the long-term drawbacks associated with autumn GA₃ applications.