No abstract

Panax vietnamensis Ha et Grushv. is a precious medicinal species native to the tropical forests of Vietnam. Due to habitat loss and over-harvesting, this species is endangered in Vietnam. To conserve the species, we investigated genetic variability and population structure using nine microsatellites for 148 individuals from seven populations across the current distribution range of P. vietnamensis in Vietnam. We determined a moderate genetic diversity within populations (HO = 0.367, HE = 0.437) and relatively low population differentiation (the Weir and Cockerham index of 0.172 and the Hedrick index of 0.254) and showed significant differentiation (P < 0.05), which suggested fragmented habitats, over-utilization and over-harvesting of P. vietnamensis. Different clustering methods revealed that individuals were grouped into two major clusters, which were associated with gene flow across the geographical range of P. vietnamensis. This study also detected that ginseng populations can have undergone a recent bottleneck. We recommend measures in future P. vietnamensis conservation and breeding programs.

Cinnamomum balansae Lecomte (Lauraceae), an economically important forest tree, is distributed in the tropical forests of central and northern Vietnam, which has been threatened in recent decades due to the destruction of its habitat and over-exploitation. The genetic diversity and population structure of the species have not been fully evaluated. We used a set of 15 microsatellites to analyze 161 adult trees from 9 different populations, representing the geographical distribution of C. balansae. Ninety-two different alleles were identified. Here our results showed a low genetic diversity level with an average H o = 0.246 and H e = 0.262, and a high level of genetic differentiation (F ST = 0.601). The bottleneck tests indicated evidence of a reduction in the population size of the two populations (TC and CP). Additionally, all three clustering methods (Bayesian analysis, principal coordinate analysis, and Neighbor-joining tree) were identified in the two genetic groups. The Mantel test showed a significant positive correlation between genetic distance and geographic distance (R 2 = 0.7331). This study will provide a platform for the conservation of C. balansae both in ex-situ and in-situ plans.

No abstract

Tacca chantrieri is a useful medicinal plant native to lowland tropical forests in northern Vietnam. However, it is threatened with extinction owing to habitat fragmentation and overexploitation. Genetic diversity in 5 natural populations of T. chantrieri was examined using 20 ISSR primers polymorphism. Our study showed that average PIC was 0.253 (0.018 - 0.460) and average PPB was 62.49 % (40- 85.71). 5 populations had modest genetic variability (Na = 1.384, Ne = 1.32, Ho = 0.182, He = 0.178 and I = 0.258) and the species level had a low value (Na = 1.892, Ne = 1.744, Ho = 0.293, He = 0.389 and I = 0.549). The lowest levels of genetic diversity were detected in Cuc Phuong population (Na = 1.135, Ne = 1.021, Ho = 0.091, He = 0.078 and I = 0.116) and the highest levels were detected in Ba Vi population (Na = 1.555, Ne = 1.436, Ho = 0.247, He = 0.242 and I = 0.350). A substantial positive connection between genetic distance and geographic distance was discovered using the Mantel test (R2 = 0.5086). The implications of the results of this study to conserve the genetic resources of T. chantrieri were discussed.