Abstract: In order to obtain the indexes which can be conveniently used to identify the drought tolerance of tomato rootstocks and to screen out tomato rootstocks with strong drought tolerance from thirtytwo tomato rootstocks, we measured the changes of root fresh weight, stem fresh weight, leaf fresh weight, leaf water potential, root activity both before and after soil dehydration treatment, then evaluated the drought tolerance of tomato rootstock seedlings through comprehensive comparative analysis. It was found that, with increasing the duration of soil dehydration, the average value of drought damage index of tomato rootstock seedlings increased, while the coefficient of variation of drought damage index decreased. However, after the seedlings were watered, the changes were opposite. In the regression model of drought damage indexes, only root fresh weight, leaf water potential before soil dehydration treatment and the relative increment value of root fresh weight were selected. Tomato rootstocks could be divided into three classes by clustering analysis based on each of all variable factors of the model. With the exception of the relative increment value of root fresh weight, the other factors had same results on the grouping. So root fresh weight and leaf water potential of seedlings before soil dehydration treatment could be used as convenient indicators identifying tomato drought tolerance, and 606, AnkaT, 060813 and 0301112 were screened out as droughttolerant rootstocks of tomato.

Key words: herb, soil enzyme activity, microbial diversity