The Effects of Daminozide On Flower Production and Sex Ratios in Hydroponic Greenhouse Cucumbers (Cucumis sativus)

Plant growth regulators have been used to manipulate flowering in cucumber production.  We investigated the effect of early applications of daminozide, a plant growth regulator, on plant growth, flower production and sex ratios in hydroponically grown cucumbers.  Twenty-four cucumber plants were grown in Hailstorm, a recycled plastic media, irrigated by a closed hyroponic system.  Four groups of six individual plants, were subjected to differing growth regulator treatments. The treatment groups consisted of: 1) one application of daminozide (3750 ppm) at the two true leaf stage, 2) one application of daminozide (1875 ppm) at the two true leaf stage, 3) two applications of daminozide (1875 ppm) at the two true leaf stage and then again at the six leaf stage, and 4) no application of daminozide . Leaf numbers and vine heights were measured weekly throughout the experiment. The number and sex of the flowers were recorded weekly for a period of three weeks.  The results provide useful information regarding the applicability of incorporating daminozide applications in a hydroponic cucumber production system.