Objective By comparing and identifying the drought tolerance of eight main tomato varieties cultivated in Xinjiang during the seedling stage, various drought tolerance indicators were analyzed to screen for varieties with superior drought tolerance, to provide a theoretical foundation and scientific basis for future breeding improvements in tomato drought tolerance.

Methods Eight major tomato varieties in Xinjiang were subjected to different levels of drought stress during the seedling stage. Seventeen indicators, including plant height, stem diameter, malondialdehyde, and proline, were measured in both the control and treatment groups. Principal component analysis and membership function analysis were used to evaluate the drought tolerance of the eight tomato varieties comprehensively.

Results Under drought stress, morphological indicators such as plant height, stem diameter, and leaf area of each variety showed varying degrees of change, while physiological indicators including soluble sugars, proline, malondialdehyde, and antioxidant enzyme activities also exhibited regular responses. Principal component analysis transformed 16 single indicators into 7 comprehensive indicators, with a cumulative contribution rate of 80.28%. The comprehensive evaluation D-value indicated that the fresh-eating tomato variety 'Yuanyi 504' and the processing tomato variety 'Tunhe No. 8' had significantly better drought tolerance than other varieties of the same type. Cluster analysis classified the 32 treated materials into 6 major groups.

Conclusion Plant height, stem diameter, malondialdehyde, and proline can be used as key indicators for drought tolerance. Two varieties, 'Yuanyi 504' and 'Tunhe No. 8', were identified as having strong drought tolerance.