Modulating Physiological Resilience and Yield Recovery in Senile Mango (Mangifera indica L.) Orchards Through Differential Rejuvenation Intervals

Productivity in old and senile mango (Mangifera indica L.) orchards declines markedly due to reduced physiological efficiency. The present study investigated how differential rejuvenation intervals modulate physiological resilience and yield recovery in senile mango trees. Rejuvenation was imposed by heading back trees at 1.5–4.5 m and completing the process over 1, 3, or 5 years. Sequential rejuvenation over 3 years significantly enhanced tree survival (90%) and vegetative vigor, reflected in greater increments in tree height, twig number, twig length, girth, and canopy spread. This treatment also recorded the highest cumulative mean fruit yield over 8 years, demonstrating superior yield recovery as compared with 1‑ and 5‑year schedules. Physiologically, 1‑year rejuvenation, despite increasing immediate light penetration, induced substantial stress, evidenced by a ~ 30% reduction in photosynthetic rate and stomatal conductance during the first season. In contrast, trees rejuvenated sequentially over 3 years maintained stable gas exchange with non-significant reductions, indicating improved physiological resilience. Antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)—showed sustained upregulation under 3‑ and 5‑year rejuvenation, whereas a transient spike followed by decline was observed under 1‑year rejuvenation, further suggesting stress-induced imbalance. Fruit quality attributes—including fruit weight (252.4–311.8 g), total soluble solids (15–18 °Brix), titratable acidity (0.20–0.23%), and vitamin C (27.91–33.33 mg 100 g⁻¹ pulp)—remained unaffected by rejuvenation intervals. Sequential rejuvenation over 3 years effectively modulates physiological resilience, enabling sustained recovery of growth and productivity in senile mango orchards.