Efficient Micropropagation of Japanese photinia [Photinia glabra (Thunb.) Maxim.]Retaining Genetic and Epigenetic Stability

We established a tissue culture system for efficient micropropagation of Japanese photinia\[Photinia glabra(Thunb.)Maxim.\] by enhanced branching of axillary buds taken from branches of a single donor tree.The culture system consists of choosing the suitable explant coupled with sequential use of three media,namely,the bud-induction medium(MS medium supplemented with 1.2 mg·L-1 BAP,0.2 mg·L-1 NAA),subculture medium(WPM medium added with 0.75 mg·L-1 BAP,0.15 mg·L-1 NAA)and root-induction medium(half-strength MS medium fortified with 2.5 mg·L-1 IAA and 0.3 mg ·L-1 IBA).In addition,by using AFLP and MSAP markers we investigated the genetic and DNA methylation pattern stability of samples of 36 and 24 morphologically normal plants respectively,which were randomly taken from a population of more than 100 000 micropropagated plants established in the field.We found that of the 615 and 392 reproducible bands scored respectively for AFLP and MSAP,no evidence for occurrence of genetic or epigenetic instability.This,together with phenotypic uniformity of the micropropagated population,suggests that micropropagation through enhanced axillary bud branching ensured genetic and epigenetic fidelity of the donor plant in Japanese Photinia.Therefore,the protocol reported here can be readily employed for large-scale commercial propagation of this ornamental plant species.