Assessment of Genetic Diversity and Interspecific Relationships of the Genus Viburnum Inferred from Start Codon Targeted (SCoT) Polymorphism Markers

ABSTRACT: The genus Viburnum (Adoxaceae) comprises deciduous broad-leaved shrubs with a thicket-like growth habit, and globally about 150–200 species are recognized. In Korea, several native Viburnum taxa have recently been listed as threatened, emphasizing the need for robust genetic information to support conservation and management. This study aimed to evaluate genetic diversity and interspecific relationships among 33 Viburnum taxa and to establish a practical framework for their identification and management using start codon targeted (SCoT) markers. SCoT markers were chosen because they are easier to apply than simple sequence repeat (SSR) and generally provide richer nuclear variation than chloroplast DNA (cpDNA), offering a simple yet informative tool for distinguishing closely related members of this shrub genus. Seventeen SCoT primers produced 489 polymorphic bands, revealing substantial nuclear variation among the 33 Viburnum taxa. An unweighted pair-group method with arithmetic mean (UPGMA), we grouped the 33 accessions into four major genetic clusters, and this clustering pattern was in good agreement with the structure inferred from principal component analysis. These clusters highlighted the genetic isolation of the V. plicatum group and the close affinity of the V. carlesii complex, while also indicating complex relationships among East Asian species. In contrast, V. plicatum formed Cluster IV, highlighting the taxonomic positions of these lineages and their potential priority for conservation and breeding. Overall, the results demonstrate that SCoT markers provide an efficient, operationally simple system for discriminating between closely related accessions and major genetic lineages within Viburnum. The SCoT-based approach developed here provides baseline information for species and cultivar identification. It also supports germplasm conservation and the selection of genetically divergent parents for future breeding programs.