1-MCP efficacy in extending storage life of ‘Bartlett’ pears is affected by harvest maturity, production elevation, and holding temperature during treatment delay

• ‘Bartlett’ IEC was affected by harvest maturity and production elevation.
• 1-MCP efficacy was determined by fruit physiological stage.
• 1-MCP efficacy was reduced in fruit at late harvest.
• 1-MCP efficacy was reduced in fruit from high production elevation.
• 1-MCP efficacy was reduced by high holding temperature during treatment decay.

The efficacy of 1-methylcyclopropene (1-MCP) in extending storage life of the Pacific Northwest ‘Bartlett’ pear is inconsistent. The effects of harvest maturity [H1: flesh firmness (FF) ≈ 83.6 N; H2: FF ≈ 74.8 N], production elevation (E1 ≈ 150 m; E2 ≈ 610 m), and holding temperature (0 and 5 °C) prior to application of 1-MCP have been measured with respect to ethylene production, fruit quality, and storage disorders of ‘Bartlett’ fruit during 6 months of storage at −1.1 °C. 1-MCP at 0.3 μL L−1 for 24 h at 0 °C inhibited ethylene production, FF and green color losses, senescence disorders, and friction discoloration for H1 fruit from both elevations. However, 1-MCP efficacy was reduced moderately in E1H2 fruit and reduced to a greater extend in E2H2 fruit. Internal ethylene concentration (IEC) at harvest was not detected in H1 fruit from either elevation, but it accumulated in E1H2 and E2H2 fruit (E2H2 > E1H2). The holding temperature at 5 °C but not 0 °C for 12 d between harvest and 1-MCP treatment increased fruit IEC and ethylene production rate and reduced the fruit response to subsequent 1-MCP treatment. The fruit physiological stage at the moment of 1-MCP treatment determined the efficacy of 1-MCP in extending the storage life of ‘Bartlett’ pears. 1-MCP retarded development of ripening capacity and 10–14 d at 20 °C were needed to ripen 1-MCP treated ‘Bartlett’ pears to optimum eating quality following 5–6 months of cold storage.