Morpho-physiological Responses of Tomato Genotypes Under Saline Conditions

Salinity is a complex abiotic stress that affects physiology and biochemistry of plants and significantly reduces both crop yield and quality. Considering the global increase in soil salinity, it is required to develop salt-tolerant cultivars for various crops. Solanum lycopersicum L. is an important Solanaceous crop with a diverse level of genotype dependent salt tolerance. However, the evaluation of salt tolerance in tomato genotypes or screening for traits utilized reliably for breeding against salt tolerance is scarcely reported. Thirteen different genotypes of tomato were exposed to salinity with three simulated soil NaCl levels (0, 75 and 150 mM) in a complete randomized design with three pots per treatment. Morpho-physiological traits (fresh and dry weight of shoot and roots, chlorophyll content, Na+ accumulation, K+ content, Na+/K+ ratio, proline content and percent ion leakage) were measured to determine the extent of salt tolerance. Different genotypes, salinity levels and their interaction significantly influenced both the observed morphological and physiological traits of tomato. Fresh weight of shoot and root, dry weight of root and shoot, chlorophyll content, K+ content and proline content were significantly increased by Rio Grande genotype, while higher Na+ content and percent ion leakage was observed in Early King genotype. Among all tested genotypes, Rio Grande and Red Star were found salt tolerant and Early King and Vigo were found the most susceptible tomato genotypes.