Plant Growth Regulators Modify Fruit Set, Fruit Quality, and Return Bloom in Sweet Cherry

Sweet cherry ( Prunus avium L.) is a valuable fruit crop worldwide. Farmers’ incomes are closely related to quantity and quality, yet these can be highly variable across years. As part of broader project for optimizing set quality in sweet cherries, this study was conducted evaluate the potential various plant growth regulators (PGRs) improving quality. Cytokinins, gibberellins, auxin, polyamines were used as treatments. Treatments applied foliar sprays at full bloom ‘Bing’ three low-productivity genotypes, ‘Regina’, ‘Tieton’, ‘PC8011-3’. We assessed set, return from each treatment. 4-chlorophenoxyacetic acid (4-CPA) increased by 53% 36% respectively. The combination gibberellin (GA) 3 + GA 4/7 more effective than other isomers alone. Cytokinin treatments had slight adverse effects or no effect on except CPPU. In ‘PC8011-3’, both N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) 4-CPA enhanced ≈81% 100% compared with untreated control. response trees polyamine depended properties cultivars treatment concentration. Foliar application , N-phenyl-N'-(1, 2, 3-thiadiazol-5-yl) urea (TDZ) has negative bloom, whereas 1 increase yield flower buds. These results suggest that PGRs may have varied work needed develop practical programs security.