Title: DELAYED 1-MCP APPLICATION EFFECT ON POSTHARVEST FIRMNESS AND SCALD CONTROL OF MCINTOSH AND CORTLAND APPLES
Abstract: The objective was to test the efficacy of 1-MCP when applied at 1, 4, 7, or 10 days after harvest. At harvest, internal ethylene (IEC) was undetectable in most fruit. There was a large increase in concentration at 7 days after harvest and an additional increased at 10 days in `McIntosh'. In Cortland, IEC was very low or undetectable until 10 days after harvest. After 4 months in CA storage, firmness of untreated `McIntosh' fell below 53 N. 1-MCP applied 1 day after harvest maintained firmness more than later applications. Application at 4–10 days was also effective with little difference between the three dates. 1-MCP was most effective on `Cortland' when applied 1–7 days after harvest. At 10 days, there was a loss of efficacy in maintaining firmness. Similar results occurred after 7 months of CA storage. Superficial scald of `McIntosh' was very mild with <1% of the fruit being affected after 220 days storage and 7 days at 20 °C. Untreated `Cortland' fruit had the greatest incidence of scald with most of the fruit being affected by 200 days. 1-MCP was not effective in preventing scald in `Cortland'.