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.
