Evaluation of tomato genotypes based on salinity stress tolerance indices at seedling stage

Salinity is one of the most significant environmental stresses for sustainable crop production in the world's agricultural lands. Tomatoes are sensitive to salinity, and it is possible to create a tolerant genotype by evaluating the diversity among tomato genotypes under salt stress and using this diversity in tomato breeding programs. Based on this, in the current study, 22 tomato genotypes were evaluated under salt stress in a randomized complete block design with three replications. In this research, different stress tolerance indices were used to evaluate genotypes under salt stress. Stress Tolerance Index (STI), Tolerance Index (TOL), Geometric Mean Productivity (GMP), Mean Productivity (MP), Harmonic Mean (HM), Yield (Y), Yield Stability (YSI) and Stress Sensitivity (SSI) were calculated based on the total dry weight under control and stress conditions. The results of analysis of variance and mean comparison showed that there is a statistically significant difference between the studied tomato genotypes for two traits, total dry weight and total fresh weight, in two conditions of salt stress and control. These results confirmed the existence of diversity between genotypes in their morphological characteristics. The YP trait showed the highest correlation (0.9) with the MP index and the YS trait showed the highest correlation (0.91) with the HM index, and these indices are suitable for evaluating tomato genotypes under salt stress in the seedling stage. Based on bi-plot analysis, the G10 genotype was the most tolerant genotype, and after that, the G2, G22, G19 and G5 genotypes showed tolerance to salt stress. The cluster analysis divided the genotypes into three separate categories, which showed different behaviors during the transition from a non-stressed environment to a stressed environment. Based on tolerance indices and grouping methods, genotype G10 was identified as a tolerant genotype to salt stress, which can be used as a parent in hybridization and selection of tolerant genotypes.