Salinity tolerance screening in Iranian and Afghan melons (Cucumis melon) based on several associated morphological and physiological traits

Abstract

Abstract This study was carried out to investigate the effect of salinity on some physiological and morphological traits of native Iranian and Afghan melon cultivars using a split-plot experiment with a randomized complete block design and three replications. Two salinity levels (2 and 8 dSm-1 NaCl) and 39 cultivars from Iran and Afghanistan were utilized. This study was carried out to investigate the effect of salinity stress on growth and yield and recommend the tolerant genotype(s). PCA comparisons were done between biochemical and morphological parameters. The sensitive and tolerant cultivar was chosen based on proximity to high yield, morphological characteristics, and distance from stress indices. The biplot results showed a high correlation between vitamin C traits with soluble solids, proline, and relative water content and a negative correlation with Fv/Fm ratio. These indices are good indicators for identifying saline resistance cultivars. Salinity stress increased electrolyte leakage, proline concentration, total antioxidant activity, Na content, vitamin C, organic acid, and total soluble solids. In addition, salinity decreased the yield, mean fruit weight, firmness, fruit length, fruit width, internal cavity length, internal cavity width, flesh thickness and fruit peel thickness, Fv/Fm ratio, greenness index, relative water content, leaf K.. The highest concentrations of Na and K were found in the G-SHI cultivar under salinity, while the highest concentrations of Na and K were found in the Tork cultivar under non-saline conditions. Based on the results, two types of Tork and Zank melon were recommended to plant in saline conditions.