Abstract: Some species of the genus Paris are of high medicinal value . Severe human activities particularly over-harvesting have led to recent declines of their population size and fragmented habitat patches . Inter-simple sequence repeat markers ( ISSR) were applied to investigate the genetic diversity of eight populations of Paris polyphylla in Yunnan and Sichuan Provinces. Fourteen primers resulted to a total of 251 bands from the eight populations, of which 235 were polymorphic, which showes a high level of genetic diversity in this species . A relatively high level of genetic diversity was revealed: PPB
= 93 . 63% , HE = 0 . 2204 and HO = 0. 3532 at the species level; PPB = 50. 45%, HE = 0.1405 and HO = 0.2194 at the population level. The GST= 0. 3625 indicated a high degree of genetic differentiation among populations . Genetic variation occurred mainly within populations . In UPGMA cluster analysis the six populations of P. polyphylla var. yunnanensis were divided into two clades , and P. polyphylla var. yunnanensis is more related to P. polyphylla var . stenophylla than to P. polyphylla var . pseudothibetica . In this paper , some conservation concerns were discussed which would be helpful for the conservation and sustainable utilization of this medicine resources.

Key words: Paris polyphylla