https://doi.org/10.37229/fsa.fjh.2025.09.17

This experiments were carried out during the two summer seasons of 2022/2023 and 2023/2024 at the Horticulture Research Farm of El- Baramoon, Horticultural Research Institute, Agriculture Research Centre, Dakahlia Governorate, Egypt. The study examined the effects of two plant spacing’s (75 and 100 cm) and foliar spraying with potassium silicate, salicylic acid, and glycine betaine, each at 100 and 200 ppm on bottle gourd under high temperature stress. The results showed that the plant spacing 75 cm gave the highest fruit length, number of fruits and total yield, due to increased plant density. While, plant spacing 100 cm gave the highest vine length, number of branches and leaves, fruit diameter and fruit weight. The results indicated that potassium silicate, at 200 ppm, enhanced length and diameter of fruits, total yield, potassium and silicon content, while glycine betaine at 200 ppm improved vine length, number of branches and leaves, nitrogen and phosphorus concentrations. The study showed that sowing bottle gourd seeds at 75 cm spacing with foliar spraying with potassium silicate at 200 ppm maximized the total yield, while spraying with glycine betaine at the same rate improved the vegetative traits and fruit nutritional value. Wider plant spacing 100 cm combined with potassium silicate at 200 ppm maximized seed yield/plant, while salicylic acid at 200 ppm was most effective in improving 100 seed weight. Interaction effects suggest that optimal plant spacing can enhance the efficacy of certain foliar treatments. These findings highlight the potential of integrating optimized plant spacing with specific foliar application to enhance both productivity and nutritional value of bottle gourd under high temperature.