Drought Tolerance Levels of Turkish Melon Genetic Resources Using Morphological and Physiological Methods

Environmental factors such as drought, resulting from global climate change, have increasingly limited productivity in melon cultivation in recent years. Turkiye's geographical location and rich genetic diversity make it highly probable that drought-tolerant genetic material exists within this diversity. In this study, 192 melon genotypes were used, sourced from the cucurbit genetic resource collection of the Department of Horticulture at Çukurova University, which includes materials from various regions of Turkiye and around the world. In the pre-screening screening phase conducted in the first year of the research, 192 genotypes were grown under drought stress conditions created using 5% PEG 6000 for two months. Parameters such as stem length, stem dry weight, root dry weight, number of leaf, and a 0-5 scale were evaluated in the green parts and roots of the plants. A general decrease was observed in all parameters except root dry weight, where a 3% increase was noted in the average of the genotypes. In the special screening phase of the study, 15 genotypes selected based on the initial screening results were subjected to a second stress test under hydroponic conditions in a climate-controlled plant growth chamber using 8% PEG 6000, parameters such as visual scale evaluation (0-5), stem fresh and dry weight, root fresh and dry weight, stem and root length, number of leaf, leaf relative water content, relative water content, and electrolyte leakage were examined. All parameters showed varying degrees of reduction in the drought-stressed genotypes compared to the control groups, except for percentage change values. An increase in electrolyte leakage was observed compared to the control. As a result of the two different screenings, the drought tolerance levels of the melon genotypes were determined. Genotype Kav-248 was identified as the most drought-tolerant, while Kav-20 was found to be the most sensitive.