Genetic diversity and population relationships in wild Korean black raspberry (Rubus coreanus Miq.) based on microsatellite markers: establishing a fruit tree breeding strategy

The importance of involving genetic diversity in breeding has been emphasized for the sustainable and stable utilization of crop genetic resources and preparation for unpredictable future environments. The black raspberry fruit from the genus Rubus is highly consumed owing its flavor and health benefits, but the genetic basis of its cultivars is very limited with insufficient genetic information available. Therefore, breeding programs must focus on the exploitation of genetic diversity of wild crop relatives. We assessed the genetic diversity, population differentiation, and genetic structure of 11 wild relatives of R. coreanus Miq. using 10 microsatellite markers to collect valuable genetic information and propose enhanced strategies for development of breeding populations. The observed and expected heterozygosity were 0.493 and 0.520, respectively. Genetic differentiation among the populations was 0.109. The Mantel test confirmed that wild R. coreanus populations differentiated following isolation by distance. Moreover, Bayesian clustering analysis showed that R. coreanus populations consisted of three genetic clusters, distribution of those showed a geographical tendency. Based on the genetic diversity, private allele frequency, and genetic structure results, we suggest to preferentially include the Chiak, Hamyang, and Jeju populations for construction of a breeding population of the Korean black raspberry.