SOFTENING AND ETHYLENE PRODUCTION OF KIWIFRUIT REDUCED WITH 1-METHYLCYCLOPROPENE

Kiwifruit soften rapidly in response to exogenous ethylene and susceptibility increases with advancing fruit maturity. Premature softening at 0°C is undesirable and can result in significant economic losses. Strategies are needed to reduce rate of fruit softening during storage. Kiwifruit were exposed to 0, 1, 10 and 100 µL.L^-1 1-methylcyclopropene (MCP) for 16 h then maintained at 20°C after harvest or at 0°C for 1 month before transfer to 20°C. MCP reduced ethylene production and softening in fruit maintained at 20°C after harvest, with only minor differences between treatments on fruit from 0°C. The MCP effect tended to be concentration dependent. Fruit were exposed to either 10 µL.L^-1 MCP immediately after harvest and treated with 10 µL.L^-1 ethylene after different times at 20°C or 0°C, or treated with MCP and ethylene on removal to 20°C after different times at 0°C. When applied at harvest MCP had little effect on C2H4 induced softening after fruit removal from 0oC. However when MCP was applied after fruit removal from 0oC and then challenged with C₂H₄, softening rate was reduced to a level similar to controls and fruit treated with MCP alone.