Effect of Different Concentrations of Brassinolide on Some Growth Parameters of Cucumber Plants (Cucumis sativus L.)

Abstract

This study evaluated the physiological response of local cucumber (Cucumis sativus L.) seedlings to varying concentrations of brassinolide under controlled greenhouse conditions. Conducted at the Department of Life Sciences, Al-Mustansiriya University, the experiment utilized a completely randomized design featuring six treatments with seven replications. Plants were treated with foliar sprays of brassinolide at concentrations of 0 (control), 1, 2, 3, 4, and 5 mL/L 32 days after planting. Evaluation at 20 days post-spraying revealed significant dose-dependent increases across all measured vegetative parameters. Foliar application of 5 mL/L brassinolide yielded the highest performance, producing an average of 15 leaves per plant, a leaf area of 37 m², a shoot dry weight of 3.4 g, and a root dry weight of 3.1 g. These results demonstrate the efficacy of brassinolide in enhancing early vegetative development and biomass accumulation in cucumber crops.