Determination of screening techniques to salinity tolerance in tomatoes and investigation of genotype responses

In order to determine the predictive screening parameters that can be applied at early development stages of tomato plants, 55 tomato genotypes were grown in nutrient solution with 200 mM NaCl. The relationships among the salinity scale classes based on the visual appearance and shoot Na+ accumulation, K+/Na+ and Ca2+/Na+ ratios and shoot-root dry weights were investigated. Tomato genotypes differed greatly for shoot Na+ concentration and salinity scale classes were significantly correlated with Na+ concentrations. Higher shoot Na+ concentrations indicated higher shoot damage. Shoot K+/Na+ and Ca2+/Na+ ratios were significantly correlated with the salinity scale classes. The higher shoot K+/Na+ and Ca2+/Na+ ratios indicated lower shoot damage. Tomato genotypes grown under 200 mM NaCI stress showed significant variations in shoot and root dry weights. However, no significant correlations were found between the shoot-root dry weight and the scale classes and Na+ concentration and the ion ratios investigated. These may indicate that plant shoot and root dry weights were independent of salt tolerance at the growth stage reached in this study. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.