Clonal Propagation System Using Plant Tissue Culture and ex vitro Rooting in Japanese Wild Vaccinium and Blueberry Cultivars

Abstract

In vitro shoot proliferation and ex vitro rooting of Japanese wild Vaccinium species and blueberry cultivars were investigated. Multiple shoot induction and proliferation were highest in medium with 5 mg・L −1 zeatin and multiple shoots were obtained with a 5.6-40.6% induction rate. The most efficient proliferation was obtained by subculturing multiple shoots at 2-3-month intervals. Rooting occurred early when the plants were treated with indole-3-butyric acid (IBA), and the rooting rate increased by raising the IBA concentration. The light condition had no effect on IBA-treated shoots. The rooting rate ex vitro was higher than in vitro, although cultivar and species differences were seen. There was a rooting rate of 48% or more in Natsuhaze (Vaccinium oldhamii Miq.) after one month of acclimatization, and a very high rooting rate of 72% was shown in shoots 3 cm in length. Ex vitro rooting using mist irrigation in a glasshouse was attempted with the aim of practical implementation. The survival rate after two months of acclimatization was 95.8, 75.0 and 91.7% in Natsuhaze, 'Berkeley', and 'Redpearl', and the rooting rate was 80.6, 63.9 and 83.3%, respectively. Within 12 months, these plants were 20 to 30 cm tall and suitable for field planting.