Preharvest Application of 1-Methylcyclopropene (1-MCP) to Schedule the Harvest and Maintain the Storage Quality of ‘Maxi Gala’ Apples

This three-year study in southern Brazil assessed the effectiveness of the preharvest spraying of 1-methylcyclopropene (1-MCP; Harvista™ 1.3 SC) in reducing the fruit drop, delaying the maturity, and maintaining the postharvest quality of ‘Maxi Gala’ apples. 1-MCP was sprayed at 0, 75, 125, 175, and 225 mg a.i. L−1 seven days before the anticipated harvest time (DBAH). Aminoethoxyvinylglycine (AVG; Retain®), a commercial control, was applied at 124 mg a.i. L−1 28 DBAH. After harvest, the fruit were stored for seven months under a controlled atmosphere (CA; 1.5 kPa O2 and 2.5 kPa CO2 at 0.8 ± 0.6 °C/RH of 94–95%), followed by seven days of shelf life (23 ± 1 °C/RH of 70–80%). Increasing 1-MCP concentrations significantly reduced preharvest fruit drop, and 1-MCP at 175 and 225 mg L−1 was more effective over time than AVG. While 1-MCP, like AVG, delayed red color development, fruit treated with 175 and 225 mg L−1 still achieved over 44.5 N firmness after CA storage, even when harvested 28 days after spraying, allowing for red color development and an average 12 g fruit weight increase. 1-MCP at ≥75 mg L−1 was more efficient than AVG in maintaining flesh firmness, while at 225 mg L−1, it also preserved higher titratable acidity and a lower soluble solid content after CA storage. Thus, the preharvest spraying of 1-MCP is a valuable tool for growers to schedule the harvest and maintain the postharvest quality of ‘Maxi Gala’ apples.