Population genetic structure of the endangered tree species Taxus wallichiana Zucco in the Western Himalayas

Taxus wallichiana Zucco (Taxaceae), commonly known as Himalayan yew, is a long-lived, dioeceous tree species distributed sparsely in the higher elevations of the Himalayan ranges. The species has become endangered and listed in the threat category of IUCN and Convention on International Trade on Endangered Species of Wild Flora and Fauna (CITES). Random Amplified Polymorphic DNA (RAPO) was used to study the genetic structure of severely restricted populations of this species, which would be useful in devising suitable conservation strategy. Analysis of molecular variance (AMOVA) revealed 89.95 per cent within population and 10.05 per cent between population components of variation. The Wright's fixation index (F_ST) or its analogue and migration rate (Nm) based on different methods revealed similar results. Rate of migration (Nm) varying from 1.00 to 1.30, indicated exchange of genetic material among the populations. However, FST that ranged from 0.16 to 0.21, suggested existence of genetic structuring. UPGMA dendrogram based on pair-wise CST values and Mantel's correlation (r = 0.47, P < 0.01) showed that genetic structure followed spatial distribution.