CHANGES MACRO AND MICRO ELEMENT LEVELS IN MELON GENETIC RESOURCES GROWN UNDER DROUGHT CONDITIONS

Abstract

Drought stress, an increasingly prevalent abiotic factor due to global climate change, poses a significant threat to agricultural productivity, particularly in arid and semi-arid regions. This study investigated changes in macro and micronutrient concentrations of 15 melon (Cucumis melo L.) genotypes subjected to drought conditions to evaluate their tolerance mechanisms. The genotypes, selected from diverse genetic resources across Türkiye, were grown hydroponically under controlled climate conditions using 8% polyethylene glycol (PEG 6000) to simulate drought stress. Nutrient analyses were conducted on root and shoot tissues, focusing on macro (P, K, Ca, Mg, S) and micro (Fe, Zn, Mn, B, Cu) elements. The results demonstrated considerable variation among genotypes in their response to drought. On average, phosphorus (P), calcium (Ca), and sulfur (S) exhibited the most significant reductions among macronutrients. At the same time, manganese (Mn), zinc (Zn), iron (Fe), and copper (Cu) were the most affected micro-elements. The drought-sensitive genotype 'Kav 20' observed the most pronounced nutrient decreases. In contrast, genotypes 'Kav 248' and 'Kav 265' showed better retention of essential nutrient levels under stress, indicating higher tolerance. Furthermore, genotypes 'Kav 183' and 'Kav 190' were more negatively impacted due to significant Fe and Zn concentrations decline. These findings highlight the critical role of nutrient retention, particularly of Fe, Zn, and Mn, in drought stress resilience. Differences in the ability of melon genotypes to maintain adequate nutrient levels under stress conditions suggest that nutrient homeostasis is closely linked to drought tolerance. The results contribute valuable insights for selecting and developing drought-resilient melon cultivars through physiological and nutritional profiling.