The 2012 ASHS Annual Conference

Postharvest 1-MCP can inhibit development of the physiological storage disorder, superficial scald, in apple and pear fruit, but the extent of the inhibition can vary by cultivar. Whereas inhibition of scald in ‘Delicious’ apples after 1-MCP treatment is relatively persistent, scald can develop in ‘Cortland’ apples as the fruit recover from 1-MCP induced inhibition of ripening.  Multiple applications of 1-MCP to horticultural products are now permitted by a label modification of the commercial 1-MCP product, SmartFresh, and therefore such applications might be effective in improving scald control.  In this experiment, ‘Cortland’ apples were untreated, treated with the antioxidant inhibitor of scald, diphenylamine (DPA), on the day of harvest, or with 1 µL/L 1-MCP at different intervals after harvest.  Treatment times (days) were 1, 4, 7, 1+4, 4+7, 1+4+7, 7+14, 7+28, 7+42, and 7+84. Internal ethylene concentrations (IECs), flesh firmness, and accumulations of α-farnesene and conjugated trienols (CTols) were measured at harvest, at the time of treatment, and at 21, 42, 84, 126 and 168 days of air storage. IECs and α-farnesene accumulation were similar in untreated and DPA treated fruit, but inhibited by 1-MCP. However, differences among 1-MCP treatments became more persistent with increasing storage periods. Inhibition of both factors was greater in fruit treated on days 1, 4, 1+4, 4+7, 1+4+7, than on day 7 alone.  However, double 1-MCP treatments on days 7 and 14 increased inhibition of IECs, a-farnesene and CTol accumulations, but increasing the delay before the second 1-MCP treatment resulted in progressively less inhibition.