Determination of development levels of some eggplant species under in vitro salt stress conditions

This study was carried out to determine the effects of different sodium chloride (NaCl) concentrations on the germination, morphological, and physiological characteristics of different eggplant species and varieties in vitro conditions. The experiment was carried out at the Plant Tissue Culture Laboratory of Prof. Dr. Saadet BÜYÜKALACA of Horticulture Department of Cukurova University (Adana, Türkiye). Four different eggplant varieties (Topan 374, Amadeo F1, HAWK and AGR-703) were used as plant materials. The Murashige and Skoog (1962) medium was supplemented with varying NaCl doses (0, 50, 100, 150, 200, 250, and 300 mM). The effects of salinity on germination percentage (%), mean germination time (days), germination rate, shoot and root fresh-dry weights (g), shoot and root lengths (mm), and relative water content (%RWC) were evaluated. The results revealed that increasing NaCl concentrations significantly reduced germination percentage and biomass accumulation, extended germination time, and decreased RWC values in all genotypes. The interaction between cultivar and salt concentration was statistically significant for all parameters. Among the genotypes, Amadeo F1 exhibited the highest shoot and root fresh-dry weights and shoot–root lengths, indicating strong morphological tolerance to salinity. AGR-703 had the highest RWC (94.00%), the shortest germination time, and the highest germination rate, showing superior physiological adaptability to salt stress. Topan 374 showed moderate tolerance, whereas HAWK had the lowest performance in all traits and was identified as the most salt-sensitive genotype. Multivariate analyses (PCA and Heatmap) explained 82% of the total variance within the first two principal components and effectively differentiated the genotypes. In conclusion, this study showed that there is a clear genotypic variation in response to salinity stress in eggplant. The Amadeo F1 and AGR-703 genotypes can be considered as promising parental materials for breeding programs aimed at improving salt tolerance in eggplant. Keywords: Eggplant, In vitro Salt Stress, Germination, Morphological and Physiological Traits, PCA