Effects of ethylene on the production of female flowers by “burpless hybrid” cucumber (cucumis sativus l.) in vitro

To investigate the role of ethylene in sex expression by cucumber (Cucumis sativus L.) in vitro, whole seeds of ‘Burpless Hybrid’ were explanted onto modified Murashige and Skoog (MS, 1962) medium supplemented with various concentrations of Ethephon (2-Chloroethyl phosphonic acid, Ethrel®), an ethylene releasing compound (0.0, 1.0, 2.0, 5.0, and 10.0 mg/l). Exogenous Ethephon significantly increased the incidence of female flowers and reduced the number of male flowers, especially at 10.0 mg/l (8.5 female flowers/tube vs.0.0 female flowers/tube for control). Control expiants (0.0 mg/l Ethephon) produced only male flowers (2.8 male flowers/tube). This information will be useful for researchers interested in studying flower induction, development, and sex regulation in vitro.