Physiological features of tolerance of tomato genotypes on high temperatures

Relevance. Tomato ( Solanum lycopersicum L.) is one of the most important vegetable crops in the world. With climate change, the development of heat-tolerant varieties has become a key research focus in tomato breeding. Heat tolerance is a phenomenon regulated by developmental stages, and its mechanism remains unknown. Tolerance at one stage of development may or may not be linked to tolerance at other stages. Studying the response of tomato genotypes and identifying key physiological traits associated with heat tolerance is highly relevant. Methodology. The experimental design of this study was completely randomized. Thirty-eight tomato varieties were categorized based on fruit type: cherry (<50 g), medium (50–<100 g), and large (>100 g). Data collection and statistical analysis were conducted using widely accepted methods. Results. The results showed that for effective selection of heat-stress-tolerant tomato varieties, it is essential to consider both the physiological responses of tomato plants to high temperatures and the genotypic specificity of each variety. Additionally, fruit size plays a role in productivity under elevated temperature conditions. A correlation was found between yield under control conditions and under high temperature conditions, indicating that varieties with high yield under control conditions may also perform well in terms of yield under high temperature conditions.