Aminoethoxyvinylglycine (AVG) is a plant growth regulator widely used in apple production to delay ethylene-mediated ripening and improve fruit quality. This has become a key tool for delaying ripening, optimizing harvest time, and reducing preharvest drop. The development of an organic AVG is key for organic apple production, where growers currently lack effective tools to delay ripening and manage fruit quality, both at harvest and postharvest. A new organic-compliant formulation, Retain® OL, was developed to meet the needs of the organic industry. To assess the potential of organic AVG, field trials were conducted over three seasons in commercial Gala and Honeycrisp orchards. Different application rates were tested, and fruit samples were collected at preharvest, harvest, and postharvest intervals. Fruit maturity and quality attributes including flesh firmness, skin color, Index of Absorbance Difference (IAD), starch index, total soluble solids (TSS), among others were measured. Postharvest evaluations continued for up to nine months in controlled atmosphere (CA) storage. Retain® OL application effectively delayed fruit maturity in both Gala and Honeycrisp apples in a dose- and timing-dependent manner. Treated fruit exhibited higher firmness at harvest and after extended storage. IAD values were consistently improved, indicating a slower ripening process and delayed loss of chlorophyll. In Gala, red skin color development was maintained or enhanced, whereas Honeycrisp showed a slight reduction in coloration. The starch index was higher in the untreated control at both preharvest and harvest stages, indicating more advanced ripening. Total soluble solids (TSS) showed variable responses across seasons, influenced by treatment rate, timing, and cultivar. Depending on these factors, TSS levels were maintained, improved, or slightly reduced compared to the control. This study provides new insights into the pre- and postharvest effects of Retain® OL. Overall, organic AVG demonstrated benefits comparable to the conventional formulation, offering a valuable tool for harvest management in organic apple production. These findings support the integration of organic AVG into organic systems to enhance harvest flexibility, improve storability, and increase overall fruit marketability.
