The identification of optimum condition for direct regeneration in black raspberry

Adventitious buds appeared within 2 weeks on the base of the petiole explants and increased for two months. A maximum of regeneration (15.6%) was obtained on the medium containing $1.5\;{\mu}M$ TDZ in combination with $1\;{\mu}M$ IBA. To know which explants are the best for the induction of regeneration, three explants such as leaf, petiole and leaf-petiole were used. Among the explant types, the leaf-petiole explant was significantly more effective than leaf and petiole for promoting adventitious shoots, with leaf-petiole inducing at the highest regeneration frequency (33.7%). The regeneration frequency of adventitious shoots in the leaf-petiole explants was significantly affected by leaf size and the position of explants. The leaf-petiole smaller than 5 mm leaf in width was induced at the highest regeneration frequency (68.9%). The smaller leaf sizes, the greater regeneration frequency. Also when the leaves are nearer to the shoot tip, the regeneration frequency is higher. When the rooted micro-shoots were transferred to the soil after growing for 6 weeks in the media, the survival rate was 90%.