Ye-Rim ChoiP, Tae-Hee Kim, Hee-joo Choi, Ara Cho, Hee-Young Gil

Division of Forest Biodiversity, Korea National Arboretum, Pocheon, Korea

Rhaphiolepis indica var. umbellata (Rosaceae) is an evergreen coastal shrub distributed in southern Korea and China. Owing to its high tolerance to harsh coastal environments, it is widely used in restoration and landscaping. Recently, however, the increasing introduction of foreign plant materials has raised concerns about potential genetic contamination of native populations. To provide a scientific basis for regional genetic resource management, we investigated genetic diversity and population structure of this species. A total of 105 individuals from 12 populations in Korea and China were analyzed using a high-quality reference genome (752,519,896 bp) generated by PacBio long-read sequencing. Multi-sample genotyping identified 15,751 high-quality single nucleotide polymorphisms (SNPs). Genetic diversity analyses showed that Korean populations exhibit higher genetic diversity than Chinese populations. Population structure analyses based on ADMIXTURE and principal component analysis revealed clear genetic differentiation between Korean and Chinese populations, whereas no distinct genetic structure was detected among Korean populations, indicating geographic homogeneity. From the genome-wide SNP dataset, 31 candidate loci were initially selected, and these markers are suggested to be effective in discriminating Korean genetic resources from Chinese populations. Overall, our results demonstrate that Korean populations maintain high genetic diversity without regional structure, yet remain genetically distinct from Chinese populations. This study provides valuable genomic resources and molecular tools to support sustainable restoration and conservation management in Korea.

This research was funded by Scientific Research Grants (KNA 1-2-51-26-3) of the Korea National Arboretum.