Variation among highbush and rabbiteye cultivars of blueberry for fruit quality and phytochemical characteristics

Variability in soluble solids (SS), titratable acidity (TA), SS/TA, pH, total phenolic content (TPC), ferric reducing ability of plasma (FRAP), total monomeric anthocyanin content (TMAC) and levels of vitamin C were evaluated in a broad array of northern and southern highbush (Vaccinium corymbosum) and rabbiteye (Vaccinium virgatum) cultivars of blueberry, grown in different locations and years. When cultivars were grouped by decade of release, there were few significant overall trends observed over years in fruit quality and phytochemical content; however, individual cultivars varied significantly for all the traits analysed. Considerable overlap in most quality and phytochemical characteristics were found among cultivars of the three blueberry types, suggesting that genetic barriers do not exist among the various types of blueberries with regard to breeding cultivars with comparable sugar, acid and phytochemical properties. There were significant negative correlations observed between fruit weight and SS, TPC, FRAP and TMAC, suggesting that as breeders have been selecting for larger fruit, they have inadvertantly selected for tarter fruit with lower antioxidant capacity. However, SS was correlated positively with FRAP and TMAC, indicating that cultivars can be developed that have high antioxidant capacity and anthocyanin content, combined with high sugar content.