Promotion of Fruit Set and Reduction of Seed Number in Pollinated Fruit of Cucumber by Chlorflurenol1

Abstract Fruit development from pollinated flowers of cucumber ( Cucumis sativus L.) on early nodes inhibited fruit set on later nodes. Application of chlorflurenol (methyl-2-chloro-9-hydroxyfluorene-(9)-caroxylate) overcame this inhibition and increased the number of fruit which developed from both pollinated and nonpollinated ovaries. In nonpollinated flowers, chlorflurenol promoted fruit set through parthenocarpy. In chlorflurenol treated plants, approximately 80% of the fruit from pollinated flowers produced seed, while the remaining 20% were parthenocarpic. However, chlorflurenol reduced the quantity of seed in the nonparthenocarpic fruit by 30%. This included fruit set from flowers that had been pollinated up to 5 days before chlorflurenol application. Pollination tended to improve the effectiveness of chlorflurenol to increase fruit set.