SAMPLING STRATEGY FOR PRESERVATION OF GERM PLASM FROM DAVIDIA INVOLUCRATA
珙桐种质资源保存样本策略的研究

Davidia involucrata is a monotypic genus that is a relict from the tropical flora of the Tertiary Period. As a plant endemic to China, it is classified as a first-grade state protection plant. An analysis on genetic diversity and genetic variation within and among populations from five natural populations of D. involucrata was conducted using RAPD marker based on 11 polymorphic random primers. The results showed that populations of D. involucrata had rich genetic diversity, but those significant differences among populations accounted for 26% of the genetic variation. Two large provenance plots in the southeast and northwest were established for the study. Based on cluster analysis of genetic diversity of populations of D. involucrata and curve analysis of the genetic markers, we put forward a sampling strategy for the preservation of germplasm of D. involucrata. For on-site preservation, three populations should be selected for each of the following areas: Wenxian County in Gansu Province, Emeishan in Shichuan Province and Fanjingshan in Guizhou Province. Each population to be preserved should occupy a minimum 3 hm 2. Off-site preservation should sample a minimum of 30 individuals from each of the following populations: Wenxian County, Emeishan and Shennongjia (in Hubei Province) and Fanjingshan for a total of 150 individuals. Individuals should be planted at a minimum space of 30 m. Also, we suggest that two off-site preservation areas should be established: one in the southeast and one in the northwest regions of China.