Exogenous regulators enhance strawberry yield under heat stress conditions

Abstract Climate change poses a growing threat to strawberry cultivation, a crop highly sensitive to elevated temperatures. Developing sustainable strategies to mitigate heat induced stress is crucial for maintaining yield and fruit quality. This study evaluated the effectiveness of different exogenous chemical treatments in enhancing heat stress tolerance across three strawberry genotypes RABI-3, BARI Strawberry-2, and BARI Strawberry-3 under prolonged summer conditions in Bangladesh. A two-factorial completely randomized design (CRD) was conducted from February 2024 to April 2025 with six treatments: control (water), abscisic acid (5 ppm), calcium chloride (10 mM), kaolin (5%), melatonin (10 ppm), and molasses (5%). Vegetative, physiological, biochemical, and yield parameters were analyzed, and treatment effects were statistically tested at 5% significance level. Kaolin application significantly improved vegetative growth (plant height and leaf number increased by 15–25% compared to the control) and enhanced photosynthetic activity and antioxidant capacity. The kaolin treated plants also showed a 20–30% yield increase with better fruit size, total soluble solids, and vitamin C content. Among genotypes, BARI Strawberry-3 demonstrated the highest tolerance and yield stability under high-temperature stress. These findings suggest that kaolin spray may offer a cost effective and environmentally sustainable approach to mitigating heat stress in strawberries, with BARI Strawberry-3 representing a promising genotype for future commercial cultivation in warming agro-climatic zones.