Effects of Harvest Maturity, Production Year, Storage Temperature, and Post-Storage Ethylene Conditioning on Ripening Capacity of 1-MCP Treated 'd'Anjou' Pears

A continuing challenge for commercializing 1-methylcyclopropene (1-MCP) to control superficial scald (SS) and extend storage life of 'd'Anjou' pear (Pyrus communis L.) is how to initiate ripening capacity (RC) in 1-MCP treated fruit following cold storage. 'D'Anjou' pears harvested at 3 maturities (H1 approximate to 66.7 N, H2 approximate to 58.0 N, and H3 approximate to 55.6 N) were treated with 1-MCP at 0.15 mu l L-1 and stored either at the commercial storage temperature -1.1 degrees C (1-MCP at -1.1 degrees C), or at 1.1 degrees C (1-MCP at 1.1 degrees C) or 2.2 degrees C (1-MCP at 2.2 degrees C) for 8 months in 2011 and 2012. Control fruit stored at -1.1 degrees C developed RC and significant SS within 7 d at 20 degrees C following 2-5 and 3-5 months in 2011 and 2012, respectively. While 1-MCP at -1.1 degrees C fruit developed neither RC nor SS for 8 months, 1-MCP at 1.1 degrees C fruit developed RC with relatively low levels of SS within 7 d at 20 degrees C following 5-8 and 6-8 months in 2011 and 2012, respectively. 1-MCP at 2.2 degrees C fruit lost quality (yellowing and decay) quickly during storage. Post-storage ethylene conditioning could not ripen 1-MCP at -1.1 degrees C fruit until 7-8 and 8 months in 2011 and 2012, respectively, however, ripened 1-MCP at 1.1 degrees C fruit following 4-6 months in both production years. H1 and H2 fruit were similar in responding to 1-MCP with respect to developing RC. 1-MCP treated H3 fruit developed RC following 7-8 months of storage at -1.1 degrees C in 2011 but did not develop RC for 8 months in 2012. In conclusion, storage at 1.1 degrees C can facilitate the initiation of RC in 1-MCP treated 'd'Anjou' pears with relatively low SS following 6-8 months of cold storage; PSEC can ripen the 1-MCP at 1.1 degrees C fruit following 4-6 months of cold storage. Late harvest may not be a useful protocol for ripening 1-MCP treated 'd'Anjou' pears due to an inconsistent efficacy among production years.