Effects of Aminoethoxyvinylglycine, Ethephon, and 1-Methylcyclopropene on Apple Fruit Quality at Harvest and after Storage

This study was conducted over two crop seasons using `Scarletspur Delicious' and `Gale Gala' apple trees (Malus ×domestica). The bioregulators aminoethoxyvinylglycine (AVG), ethephon (ETH), and 1-methylcyclopropene (MCP) were applied at various times before or after harvest. Fruit response was evaluated at harvest and after regular atmosphere (RA) and controlled atmosphere (CA) storage [2.0% oxygen (O2) and <2.0% carbon dioxide (CO2) at 0 °C] and quality of whole and juice apple products evaluated. AVG reduced starch loss and ethylene production, enhanced firmness, and reduced cracking in `Gale Gala,' but reduced sensory acceptance of apples and apple juice. ETH intensified starch loss, ethylene production, and reduced firmness, but did not affect `Gale Gala' fruit cracking. AVG followed by ETH reduced starch loss, ethylene production, and cracking and maintained firmness. This combination also aided in sensory acceptance of apples but reduced sensory preference of apple juice. Exposure to postharvest MCP improved flesh firmness retention and reduced ethylene production after both RA and CA storage. MCP either favored or reduced sensory acceptance of whole apples, depending on the particular season, but reduced sensory preference of apple juice. Sensory scores for `Scarletspur Delicious' apples were more strongly modified by bioregulators than were `Gale Gala' apples.