Background

Cupressus chengiana?is mainly distributed in the Hengduan Mountains area in China. It is one of the Class II endangered plants, ex situ conservation is often used to the affected?C. chengiana?population due to the construction of the power station. However, population fragmentation and inbreeding in the ex situ conservation have led to decline in genetic diversity. It is therefore important to clarify the differences in genetic diversity between native populations and ex situ population.

Results

In this study, we used Genotyping-by-Sequencing to assess the genetic diversity of 30?C. chengiana?trees from four populations in the Dadu River Basin, southwest China, including one ex situ conserved population (DK) and three native populations (BW, SA, RJ). The results showed that compared with the native populations, the DK population showed higher genetic diversity. Among the three native populations, SA population may experience inbreeding and has low genetic diversity. The population structure analysis further revealed that the DK population had higher gene flow and lower differentiation than other three populations. For ex situ populations, the primary determinant of genetic diversity is the genetic variation present in the seedlings sourced from natural populations.

Conclusion

These findings support the feasibility of ex situ conservation for?C. chengiana?conservation. This study provides a scientific foundation for the preservation, management, and restoration of?C. chengiana, and would offer valuable insights for the conservation of other endangered plants.