1-Methylcyclopropene Preharvest Application and Its Effect on Storability of 'Comice' and 'Bose' Pears

Sprayable formulation of 1-methylcyclopropene (1-MCP) was tested as a preharvest application on European pears to determine the best timing and rate of 1-MCP application for maintaining fruit firmness and quality of trees during harvest and in storage after harvest. Two rates of 1-MCP, 0.06 and 0.13 g.L-1 active ingredient (a.i.) (minimum and maximum rates, respectively), were sprayed 1 week and 2 weeks before commercial harvest on two cultivars, Bosc and Comice, in 2017 and 2018. After 2 months in cold storage (0 +/- 1 degrees C), differences in fruit firmness of both cultivars were observed among treatments. For 'Bose, fruit treated with both rates 1 week before harvest were 50% firmer than nontreated control fruit. For `Comke', fruit treated with the maximum rate both 2 weeks and 1 week before commercial harvest were 46% and 31% firmer than nontreated control fruit, respectively. However, after 4 months in storage, no differences in fruit firmness of both `Bose and 'Cornice' were observed among treatments. The sprayable 1-MCP application applied 2 weeks before commercial harvest also affected the fruit firmness on trees. The maximum rate of 1-MCP treatment consistently maintained the fruit firmness by 5.0 N compared with fruit treated with the minimum rate and nontreated controls. This effect was significant until 1 week after commercial harvest for both cultivars and until 2 weeks after commercial harvest for 'Bose. The poststorage fruit firmness and overall eating quality of `Bose were unaffected by the maximum rate of 1-MCP application as well as the extended harvest time. However, for 'Cornice', the overall eating quality was negatively impacted by 1-MCP treatments. This study suggests that the maximum rate (0.13 g.L-1 a.i.) of 1-MCP application 2 weeks before commercial harvest maintains the fruit firmness of 'Bose' for at least 2 weeks more and offers an extended harvest window for better preharvest manage-ment. Furthermore, this treatment improves the physiological fruit quality such as senescence scald during the poststorage period without significantly affecting the poststorage ripening of `Bose after 4 months of storage.