Silicon supplements affect yield and fruit quality of cucumber (Cucumis sativus L.) grown in net houses

Silicon (Si) plays an important role in plant growth and development, but the uptake, accumulation in tissue, and beneficial effects of Si differ greatly between plant species. Net house experiments were conducted with Cucumis sativus L. ‘Shabah F1’ in 2013 and repeated in 2014 to determine the effects of Si supplementation on yield, fruit quality, and chemical composition. Diatomite (86-89% SiO2) was applied to cucumber plants three times at two-week intervals after two weeks from transplanting through either foliar spraying (50, 100, 200 mg/l or soil drenching in the root area (500, 1000 and 2000 mg/l). All treatments produced higher early and marketable fruit yield (number and weight) in both years. At all growth stages, application of Si significantly increased fruit firmness, but the effects of Si on total soluble solids varied depending on growth stage and concentration of Si. Significant differences among treatments for ascorbic acid content of cucumber fruits were found in 2013 but not 2014. Tissue analyses showed that Si-treated plants had more Si in the leaves and fruits (% dry wt.), and phosphorus and potassium (% dry wt.) in the leaves compared to untreated controls. We conclude that both foliar sprays and soil drenches of Si have the potential to increase cucumber yield and fruit quality in net house production. Key words: Cucumis sativus, diatomite, foliar spraying, soil drenching.