Micropropagation of Mahonia ‘Soft Caress’

Abstract

Mahonia ‘Soft Caress’ is a unique new cultivar exhibiting a compact form and delicate evergreen leaves. Protocols for micropropagation of M. ‘Soft Caress’ were developed to expedite multiplication and serve as a foundation for future work with other taxa of Mahonia Nutt. Combinations of sucrose at 30 or 45 g·L−1 in conjunction with Gamborg B5 (B5), Quoirin and Lepoivre (QL), and Murashige and Skoog (MS) basal media as well as other selected growth regulator treatments were evaluated as multiplication media. Rooting of microcuttings was conducted in vitro using combinations of indole-3-butyric acid (IBA) at 0, 2, 4, 8, or 16 μM under either light or dark. Quick dip treatments with aqueous solutions of the potassium (K) salt (K-salt) of IBA at 0, 5.2, 10.4, 20.7, or 41.4 μM were tested in a second experiment for ex vitro rooting. Media containing B5 basal salts and vitamins supplemented with sucrose at 30 g·L−1, 5 μM 6-benzylaminopurine, 5 μM kinetin, 0.5 μM indole-3-acetic acid, and 2.5 μM gibberellic acid yielded 2.80 ± 0.14 microshoots with a mean length of 14.76 ± 0.63 mm over a 6-week culture period and was an optimal multiplication media. Light treatment and IBA concentration had a significant effect on rooting percentages. Microcuttings treated with 8 μM IBA and maintained in the dark resulted in the best rooting (70%) and ex vitro establishment.