Temporary Reduction and Control of Female Flower Expression in Cucumber (Cucumis sativus L.) by Application of 1-Methylcyclopropene

A combination of phytohormones and ethylene, a key regulator of sex determination, induces female flowers in cucumber plants. Several inhibitors of ethylene biosynthesis or action affect plant sex determination. However, the use of ethylene inhibitors to control sex determination in commercial cucumber production has not been reported. 1-Methylcyclopropene (1-MCP), a commercial ethylene antagonist that inhibits ethylene signaling, is used to maintain the freshness of many harvested horticultural products. In this study, we evaluated the effect of 1-MCP on the sex ratio in cucumber plants to reduce production of cucumber fruit by inducing male flowers and reducing labor time for harvest. A concentration-dependent induction of male flowers was observed. Dose-response curves were obtained from the male flower induction rate (MFIR) and the range of nodes producing male flowers induced by 1-MCP treatment. We applied these models in independent experiments to predict the number of nodes and emergence day of male flowers induced by 1-MCP treatment and confirmed that the prediction fitted the results. Based on these results, production of cucumber fruit could be controlled by 1-MCP treatment and temporary excess labor for harvest could be avoided by using this model.