Fruit Ripening and Quality Profile of 64 Cultivars in Three Species of Blueberries Grown in Tokyo

The growth and fruit quality of sixty-four blueberry cultivars were evaluated in a three-year trial in Tokyo, Japan where three species of blueberries can be grown. Cultivars belonging to 3 species were classified into a RB group that inclueded only rabbiteye blueberry cultivars and a HB group that included both northern highbush blueberry (NHB) and southern highbush blueberry (SHB) cultivars but excluded ‘Pearl River’, a pentaploid SHB cultivar, based on principal component analysis of their traits. SHB distributed the bottom part of HB group in the scatter diagram of eighteen characteristics of fruits with small fruits, low percentage of citric acid content, high sugar-acid ratio and high malic acid percentage. The correlations between individual parameters of characteristic showed that the harvest day of cultivars was influenced by the earliness of flowering day and the day that coloration started. In the NHB group, positive correlations between the harvest day and the fruit weight, between the harvest day and organic acid content, between the harvest day and citric acid content were observed. Negative correlations between harvest day and sugar-acid ratio were also observed in the NHB group. Cultivars with useful characteristics for blueberry breeding were evaluated from this study.