Response of Gynoecious Cucumber Hybrids to Foliar Application of Silicon Dioxide Nanoparticles under Heat Stress Conditions

• Wasan Owda Khalid *1 Idrees Hussein Mola Salih 2

  Author

The present study aimed to evaluate the response of five gynoecious cucumber hybrids to foliar application of silicon dioxide nanoparticles (SiO₂-NPs) under heat stress conditions and to identify the most effective hybrid–SiO₂-NP combination for improving vegetative growth, fruit characteristics, and yield. This study was conducted in the greenhouses of the College of Agriculture, University of Anbar, during the spring season of 2025–2026 to evaluate the response of five gynoecious cucumber hybrids to foliar application of silicon dioxide nanoparticles (SiO₂-NPs) under heat stress conditions. The experiment was arranged in a randomized complete block design (RCBD) using a split-plot arrangement with three replicates. Cucumber hybrids were assigned to the main plots, while three concentrations of SiO₂-NPs (0, 50, and 100 mg L⁻¹) were allocated to the subplots. Vegetative growth traits, total number of flowers, selected fruit characteristics, and yield were evaluated. Significant differences among the hybrids were observed for plant height, dry weight, fruit diameter, rind thickness, and yield, whereas internode length, stem diameter, and total number of flowers were not significantly affected. Foliar application of SiO₂-NPs improved most of the studied traits, with the concentration of 100 mg L⁻¹ producing the greatest enhancement in vegetative growth and yield. In contrast, the highest rind thickness was recorded at 50 mg L⁻¹, while fruit diameter was not significantly influenced by the applied concentrations. The interaction between hybrids and SiO₂-NP concentrations was significant for most of the evaluated traits. Hybrid H1, particularly when treated with 100 mg L⁻¹ SiO₂-NPs, exhibited superior performance in several vegetative growth traits and yield. These findings suggest that foliar application of 100 mg L⁻¹ SiO₂ nanoparticles may be adopted to improve cucumber productivity under greenhouse heat stress conditions.

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