RESUMEN
Psammosilene tunicoides is one of the main ingredients of the "Yunnan Baiyao". P. tunicoides is an endangered species included in the secondary protection list in China Plant Red Data Book as well as the endemic species in Southwest China. Its natural resources could not meet the needs of pharmaceutical production. Construction of core collection of P. tunicoides will lay the foundation for germplasm improvement and molecular breeding. The sequence variation of the key enzymes gene locus (β-AS) were carried out to survey the population structure and population history of the species. Among the 11 populations across its geographical range, 36 haplotypes were identified. The levels of haplotype diversity (Hd=0.905) were high, while the levels of population differentiation (GST=0.280) were low. Analysisof molecular variance (AMOVA) indicated that a significantly greater proportion of total genetic variationpartitioned among populations thanwithin populations (values of 77.43% and 22.57%, respectively). These results in combination with the star-like phylogenetic network analysis indicate that Hap1 as an ancestral haplotypewas shared in four populations, Hap2, Hap4, Hap15 and Hap16 are occurred in two populations, the remains as private haplotype only distributed in single population. The strategy of core collection was constructed in order to maximumpreserve genetic diversity of P. tunicoides.