Effect of Late Preharvest Deficit Irrigation on Physiological and Agronomical Responses in 'Regina'/Gisela 6 Sweet Cherry (Prunus avium L.) Cultivar

This study evaluated the impact of deficit irrigation during preharvest on the physiological and productive responses of 'Regina'/Gisela 6 sweet cherry. After harvest, deficit-irrigated trees were water recovered, and physiological variables were measured. Fruit condition was evaluated after 45 days of cold storage. The experiment was carried out during the 2023-2024 season in an orchard located in La Araucan & iacute;a, Chile. At 37 days after starting treatment (DAST), deficit irrigation (DI) depressed stem water potential (Psi s), photosynthesis (Asat), stomatal conductance, and intercellular CO2 concentration with respect to controls (WI). Findings suggest that stomatal behavior was near-anisohydric on a temporal scale. Carbon partitioning into sorbitol was favored over sucrose in DI leaves, indicating improved osmoprotection. At 51 DAST, water-recovered DI trees had a Psi s equivalent to WI trees but lower Asat. Chlorophylls (SPAD) remained unaffected throughout the trial. Treatments produced similar yields, whereas DI inhibited trunk cross-sectional area growth. The DI treatment had no effect on any of the fruit quality traits other than size. Similarly, fruit condition following 45 days of cold storage was not influenced by reduced irrigation. The physiological and productive responses of 'Regina'/Gisela 6 sweet cherry trees to preharvest deficit irrigation increased water productivity in the field.