Stone fruit ripening and 1-methylcyclopropene

Apricot (cv. Canino), nectarine (cv. Flavortop), and plum (cv. Red Rosa) were treated with concentrations of 0.01, 0.1 or 1 mul l(-1) 1-methylcyclopropene (MCP) for 20 h at 20degreesC and their ripening followed with or without storage. Ethylene production of unstored apricots and nectarines was not inhibited by MCP. Fruit softening was slower in all stone fruits treated with MCP. In apricots the rate of softening was inversely proportional to MCP concentrations, with 1 mul l(-1) remaining the firmest of all treatments. Fruit decay in apricots after 30 days of 0degreesC storage was higher in control fruits than in fruit treated with MCP, and was also affected by concentration, with 1 mul l(-1) showing no decay. Following storage, ethylene production was lower in all MCP treated fruits. Adding exogenous ethylene during storage helped to alleviate storage disorders in nectarines. It appears that ethylene is required in apricots and nectarines to coordinate proper ripening, particularly after storage.