Anthocyanin Content of Wild Black Raspberry Germplasm

Because of its intense anthocyanin pigments, black raspberry (Rubus occidentalis L.) has a long history of use as a natural colorant and dye. Recent studies showing black raspberries to be a rich source of anthocyanins and other dietary phytochemicals have led to renewed interest in breeding better adapted cultivars that meet the demands of these markets. Anthocyanin content is a critical indicator of fruit quality for fresh and processed markets. Previous studies characterizing black raspberry anthocyanins have focused on existing cultivars comprising a narrow genetic base; however, progress in breeding new cultivars with better adaptability and disease resistance will rely on the use of new germplasm sources. Using high performance liquid chromatography/diode array detector/ion trap mass spectrometer, we examined anthocyanin content and profiles in the juice of fruit from black raspberry seedlings representing 78 wild populations from across the species' native range over a two year period. Anthocyanin profiles were similar to those previously reported, however total anthocyanin content varied widely. Total anthocyanins in individual clones ranged from 39 to 996 mg/100 ml (expressed as cyanidin-3-glucoside) and averaged slightly higher in 2010 than in 2009. Black raspberry cultivars fell in the middle of this range, with individual wild clones ranging from less than one fourth to nearly three times the anthocyanin concentration of the industry standard, 'Munger'. Genetic diversity for anthocyanin content is present in recently collected wild black raspberry germplasm and should be carefully evaluated when using this material for breeding improved cultivars.