Alteration of Sex Expression in Cucumber Due to Changes in Temperature, Light Intensity, and Photoperiod1

Abstract

Five pickling cultivars and a breeding line of cucumber ( Cucumis sativus L.) were grown under varying environmental conditions to determine the influence of light and temperature on sex expression. More staminate flowers were produced under 17,200 lux light intensity than 8,600,12,900 or 25,800 lux, whereas more pistillate flowers reached anthesis under the highest 2 light intensities. A gynoecious line, MSU 713-5, produced no staminate flowers under varying light intensities, however gynoecious hybrids did. Altering the length of the photoperiod or red and tarred light exposure at the end of the light period had no influence on sex expression. Few staminate flowers were produced when the plants were grown at a constant 16° or 22°C, but all lines or cultivars produced some staminate flowers at 30°. The largest number of pistillate flowers reached anthesis at 26° or 30°. Temperature influenced sex expression more than light intensity or photoperiod.