Abstract:

【Objective】 The introgression line population, which was developed from a salt-sensitive parent S. lycopersicum M82 and a salt-tolerance wild species S. pennellii LA716, was employed in this paper to identify QTLs conferring salt tolerance at the seedling stage. Meanwhile the primary genetic effect and interaction of some QTLs were also analyzed. 【Method】 Seedlings with four fully developed true leaves were transferred into hydroponic tanks containing 50 L of half-strength modified Hoagland solution. The same amount of salts was added every day to achieve a final concentration of 700 mmol?L-1NaCl + 70 mmol?L-1 CaCl2. After the final salt concentration was reached, the plants were evaluated using a scale of 0 to 10. Dunnett test was used for ANOVA analysis. 【Result】 Seven unambiguous QTLs (Stq2a, Stq2b, Stq6a, Stq7a, Stq7b, Stq8 and Stq10) located respectively on chromosome 2, 6, 7, 8 and 10 were identified, which were responsible for controlling salt tolerance at seedling stage and derived from wild relative S. pennellii LA716. The survival percentage increased by 18.9%-83.8% as compared to the control M82 under this salt stress. QTL possibly involved in IL6-4 and IL6-3 needed to be confirmed in the further experiments. Genetic analysis of some QTLs showed a significant dominant effect with the exception of Stq6b. The interaction of QTLs presented a typically less-than-additive but two QTLs located on chromosome 7 gave a reduced effect. 【Conclusion】 This is the first report to identify QTLs conferring salt tolerance from wild species S. pennellii LA716 at the seedling stage. These identified QTLs would provide a sound base for tomato breeding with salt tolerance.

Key words: tomato, introgression lines, salt tolerance, QTL mapping