OBJECTIVETo study the genetic relationship and diversity of 3 species which belong to Tripterygium.

METHODSamples were collected and divided into 4 types: typical T. wilfordii, typical T. hypoglaucum and their middle type according to morphological characters, and T. regelii. RAPD markers were used to measure the genetic relationship and diversity of 110 individuals from 22 natural populations in China.

RESULT AND CONCLUSION10 primers were selected from 100 ones screened. A total of 128 bands were scored and 123 of them were polymorphic. Cluster analysis indicated that all the samples could be divided into 3 parts: 5 individuals from T. regelii gathered closely and were separated from other population and formed single branch. All 4 populations from T. hypoglaucum gathered directly. The middle type showed a nearer relationship with T. wilfordii than with T. hypoglaucum, although there was genetic differentiation between populations from middle type and those from T. wilfordii. The middle type has more diversity than T. wilfordii. The distance between different middle type populations and T. wilfordii was different. The existence of middle type populations between T. wilfordii and T. hypoglaucum suggested that the 2 species should be combined into one species. Considering all populations except T. regeli, the generic differentiation among populations was significant and the genetic diversity existed mainly among different populations. So samples of Tripterygii should be collected from different ppopulations for the reservation of the genetic diversity.