This study aims to update the genetic diversity of seagrass which is used to evaluate the healthy, reaching to the conservation of seagrass beds from Viet Nam.

Theoretical results: i) The present study together with literature reviews indicate that the total area of seagrass beds from Southern Viet Nam is 10,832.1 ha. 2,562 ha (or 19.1%) of seagrass coverage has been lost. ii) The occurrence of Halophila major is updated for almost all off-shore islands and open-water areas . H. major SL type formed a distinct clade, neither H. ovalis nor H. major. This proposed hybridization is the only population found in Pacific Ocean. iii) Based on the analyses of 10 loci of SSRs from eight Thalassia hemprichii populations indicated that: overall genetic differentiation among them is low, eight populations formed two clusters, one including the hard bottom populations and one including the soft bottom populations. The genetic diversity from eight populations suggests that three populations (Cam Ranh, Ninh Thuan and Phu Quoc) need protection priority. and iv) For Enhalus acoroides, population at Phu Quoc showed genetically difference to populations in Central Viet Nam. Significant isolation by distance at a significance level of 95%. Gene flows between Khanh Hoa and Ninh Thuan are stronger than other locations. The genetic diversity from six populations suggests that two populations at Khanh Hoa (Hon Khoi and Cam Ranh) populations at Ninh Thuan and Phu Quoc need protection priority.
 
Applied results: The outcomes of this study may be the scientific baseline to evaluate the seagrass healthy, and for conservation as well as rehabititation

- Scientific papers in referred journals (list):
Nguyen XV, Lau VK, Nguyen-Nhat NT, Nguyen TH, Phan KH, Dao VH, Ho DD, Hayashizaki K, Fortes MD, Papenbrock J. (2021). Update of seagrass cover and species diversity in Southern Viet Nam using remote sensing data and molecular analyses. Regional Studies in Marine Science 44: 101803. doi: 10.1016/j.rsma.2021.101803.
Nguyen XV, Nguyen-Nhat NT, Nguyen TXT, Dao VH, McDermid SK, Papenbrock J. Microsatellite-based analysis of the genetic diversity and population structure of the seagrass species Thalassia hemprichii from Southern Viet Nam. Aquatic Botany 178: 103497. doi: 10.1016/j.aquabot.2022.103497.
- Other products (if applicable): Four specific reports, SSRs database from two species including Thalassia hemprichii and Enhalus acoroides, maps of 10 seagrass beds, ITS sequences were submitted.