Managing ‘Bartlett’ pear fruit ripening with 1-methylcyclopropene reapplication during cold storage

•‘Bartlett’ pear ripening was assessed following fruit exposure to 1-MCP.•Ethylene production post storage varied with storage time and 1-MCP concentration.•1-MCP reapplication based on fruit ethylene production capacity was effective.•Reapplication success depended on initial and reapplication 1-MCP concentrations.

Repeated low-dose 1-MCP-applications were evaluated during cold storage of ‘Bartlett’ pear fruit to overcome long-term ripening inhibition of a high dose 1-MCP treatment at harvest. Fruit were exposed to 1-MCP at 0, 0.42, 4.2 or 42 μmol m−3 at harvest in year one, and to 0, 0.42 or 42 μmol m−3 in year two, and then stored in air at 0.5 °C. In year two, fruit exposed to 1-MCP at 0.42 μmol m−3 at harvest were retreated during cold storage once (after 38 days) or twice (after 38 and 68 days), when ethylene production in samples removed from cold storage exceeded 0.014 ηmol kg−1 s−1 within 7 days at 20 °C. 1-MCP was re-applied once at 0.42 or 4.2 μmol m−3 or twice at 0.42 or 4.2 then 42 μmol m−3. In year one, fruit treatment at harvest with 4.2 or 42 μmol m−3 1-MCP provided similar ripening delay during 120 days in storage followed by 7 days at 20 °C, while fruit treated with 0.42 μmol m−3 1-MCP was not different from the control. In year two, fruit treated at harvest with 0.42 μmol m−3 1-MCP and retreated with 0.42 μmol m−3 (when ethylene production was already high) did not delay subsequent fruit ripening. Fruit treated at harvest with 42 μmol m−3 1-MCP or with 0.42 μmol m−3 at harvest and then +4.2 + 42, had similar peel yellow color, TA and SSC, but higher firmness after 180 days storage, compared to control fruit after 60 days storage. After 180 days storage, the severity of superficial scald, senescent scald and core browning on fruit treated only at harvest with 42 μmol m−3 were lower than on control fruit and similar to on fruit treated with 0.42 μmol m−3 at harvest and then retreated with +4.2 + 42. Therefore, a low dose application of 1-MCP at harvest followed by reapplication with higher doses based on fruit ethylene production capacity after removal from cold storage can extend ‘Bartlett’ pear storage life while allowing ripening to occur after mid-term storage. The efficiency of this procedure will depend on timing and 1-MCP reapplication concentration.