Female Flower Induction on Androecious Cucumber, Cucumis sativus L.1

Abstract

Ethephon applied as a foliar spray caused an androecious (all-male) line of Cucumis sativus L. to produce pistillate flowers analogous to those of monoecious phenotypes. The degree of conversion depended on the concentration of ethephon and stage of growth at the time of application. In the greenhouse, a concentration of 50 ppm applied at the 3- or 4-leaf stage was the best treatment for induction of pistillate flowers without marked inhibition of growth.

Phenotypic Stability and Ethylene Evolution in Androecious Cucumber1

“…This low rate of ethylene evolution from androecious plants suggests either a deficiency or partial block in ethylene production. Pistillate flowers are induced on androecious plants by exogenous applications of ethephon, an ethylene releasing compound, causing an expression of monoecy (2). Conversely, staminate flowers are induced on gynoecious plants by exogenous gibberellin treatment which results in monoecious expression (14,15).…”

“…Sex expression of cucumber has been investigated primarily in monoecious and gynoecious phenotypes (1,3,4,10,11,13,17,18,19). Few experiments with androecious phenotypes have been reported (2,9,20). In a study (4) on the effect of daylength on sex expression, 25 monoecious cucumber cultivars were classified according to their response to daylength, as daylength insensitive, short day sensitive, and long day sensi tive.…”

“…Exogenous applications of ethephon (17) or enrichment with ethylene (12) caused female expression on monoecious plants. Finally, foliar applications of ethephon to androecious plants caused pistillate flower production re sulting in monoecy (2). Short day conditions increased ethylene evolution and female expression (19), probably explaining the association of female expression with short daylength.…”