Study of Transferability of Rubus Microsatellite Markers to Hybrid Boysenberry

Boysenberry, a Rubus hybrid between loganberry and a trailing blackberry, possesses distinctive polyphenol compounds, which have demonstrated positive biological effects on human health. Several new boysenberry genotypes have recently been developed from mutation breeding technology. In this study, a total of 103 SSR markers developed from expressed sequence tag (EST) and genomic libraries in blackberry and red raspberry were tested for cross-amplifications in 10 boysenberry genotypes. All primer pairs successfully produced amplification products, ranging from 1 to 4 loci per primer. Eleven polymorphic SSR markers (RH_MEa0007aB01, RH_MEa12cE03, RH_MEa14bF07, RH_MEa15aD04, RH_MEa13cF08, ERubLR_SQ01_N03, ERubLR_ SQ053_H01, ERubLR_SQ191_A05, RubfruitG7, Rubusr43a, and RiM019) were detected among boysenberry genotypes, while polymorphic loci were not detected in 92 markers. Polymorphism information content (PIC) and genetic diversity (GD) values ranged from 0.160 to 0.580 and from 180 to 0.640, with average values of 0.359 and 0.407, respectively, in the 11 polymorphic markers. According to a cluster analysis, all the mutant boysenberry genotypes can be classified into one category. Although the level of genetic diversity revealed by SSR markers in 10 boysenberry genotypes was low, these SSR markers will be useful for future genetic diversity, cultivar identification, QTL mapping, and gene cloning studies in boysenberry.