Cryopreservation of dormant herbaceous peony (Paeonia lactiflora pall.) shoot-tips by desiccation

A simplified technique for the cryoprotection of dormant shoot-tips was developed for the germplasm conservation of herbaceous peony (Paeonia lactiflora Pall.). The highest post-thaw regrowth level was obtained from shoot-tips desiccated by air drying for 5 h. The post-thaw regrowth of P. lactiflora. var. 'Mikang' was the highest (74.9 percent) among the five genotypes tested. The regeneration level after cryopreservation was highest (66approximate74%; average of 70 percent) for dormant shoot-tips collected from November to February. Shoot tips which were dissected from non-dormant buds in late March, however, showed very low post-thaw regrowth. Post-thaw regrowth of shoot-tips was promoted in MS medium containing 1 mg 1(-1) of gibberellic acid (GA3) and 0.5 mg 1(-1) of N(6)-benzyladenine (BA). The elongated shoots were rooted on a 1/4 MS medium containing 0.1 mg 1(-1) of beta-naphthalene acetic acid (NAA). In addition, random amplified polymorphic DNAs (RAPDs) assays suggested that the cryostorage treatment used here preserved the genetic fidelity of the peony dormant shoot-tips. This cryopreservation method appears to be promising for the conservation of herbaceous peony germplasm.