Efficacy of Foliar Application of Ga₃ and K on Growth and Biochemical Parameters of Two F1 Hybrid Parthenocarpic Cultivars of Cucumber

The experiment was conducted in anti-insect net house for three consecutive years (2013–2016) with the goal of improving the growth and biochemical contents in two F1 cultivars of cucumber, ‘Sevenstar’ and ‘KUK 9’. Treatment was given in the form of foliar spray containing different concentrations of gibberellic acid (GA₃) [0.005 g·dm⁻³ (G₁), 0.01 g·dm⁻³ (G₂), and 0.015 g·dm⁻³ (G₃)] and potassium [1.0 g·dm⁻³ (K₁), 2.5 g·dm⁻³ (K₂), and 5.0 g·dm⁻³ (K₃)] alone and as combinations. All the treatments significantly enhanced plant growth and yield over control. The combination K₂G₂ showed a marked increase in growth parameters (leaf area, flower number, total dry matter production, growth rate, net assimilation rate) and biochemical attributes (total sugar content, starch, protein). The cultivar ‘KUK 9’ had more increased parameter values than the ‘Sevenstar’. This study provides a direct evidence of the beneficial role of the application of potassium and gibberellic acid on growth, biochemical attributes, and yield of cucumber.