Regeneration of somaclones from explants of internodal stems of Mentha piperita and M. spicata

Somaclones were regenerated from explants of internodal stems of Murray Micham and Black Mitcham peppermint (Mentha piperita) and Scotch spearmint (M. spicata) on Murashige-Skoog (MS) basal medium combinated with thidiazuron, 6-benzylaminopurine, indole-3-acetic acid and indole-3-butyric acid. The combination best suited for regeneration was MS medium supplemented with 2 mg indole-3-acetic acid and 2 mg thidiazuron per liter of medium. On this regenerative medium, nearly all explants of the peppermint cultivars regenerated numerous somaclones, but less than 20% of exlplants of Scotch spearmint produced somaclones. Depending on the medium used, somaclones were regenerated from explants of Murray Mitcham peppermint within 2 to 5 weeks, from Black Mitcham peppermint within 3-5 weeks, and from Scotch spearmint in 4-10 weeks. Explants of Native spearmint (Mentha spicata) produced only roots on the medium with 2 mg/L NAA and 1 mg/L BAP.