Study of Rubus chamaemorus Population Genetic Structure in the Eastern Baltic Region

Cloudberry (Rubus chamaemorus L.) is a dioecious, perennial plant that grows in the boreal climate zone. For the first time, intraspecific genetic variability of 174 individual cloudberry plants from 25 locations in Lithuania, Latvia, Estonia, and Belarus was examined. Genetic variation was assessed using microsatellite markers specific to the Rubus genus. Although high heterozygosity was observed across all sampling sites, allelic richness, the Shannon diversity index, and the number of unique genotypes revealed a geographic gradient in genetic diversity across the Eastern Baltic region, with the highest values in Estonia and the lowest in Belarus. Cluster analysis identified ten genetically distinct groups, revealing patterns of population differentiation. Principal coordinates analysis further demonstrated that some sampling sites were genetically distinct despite geographic proximity. PERMANOVA indicated that most genetic variation occurred among individuals within sampling sites rather than among sampling sites, despite the predominantly vegetative reproduction of this species. These findings improve our understanding of the intraspecific diversity and genetic structure of the cloudberry population at the southern edge of the distribution of the species, suggest factors shaping genetic structure, and provide valuable insights for conservation and management of this ecologically and economically important species.