MICROPROPAGATION OF SORBUS COMMIXTA HEDL.

Abstract

Nodal explants obtained from greenhouse-grown plants of Sorbus commixta were cultured on Murashige and Skoog (MS) medium supplemented with 0, 0.5, 1.0, 2.0 or 4.0 mg l(-1) N-6-benzyladenine (BA) or thidiazuron (TDZ), and 1.0 or 2.0 mg l(-1) BA in combination with 0.5 and 1.0 mg l(-1) indole-3-acetic acid (IAA) or alpha-naphthaleneacetic acid (NAA) for axillary shoot multiplication. The maximum frequency of shoot formation (78.1%) with a mean of 6.6 shoots was obtained on MS medium supplemented with 2.0 mg l(-1) BA. Addition of IAA or NAA to BA-containing medium improved further the shoot induction response. The highest frequency of shoot induction (96%) with a mean of 16.2 shoots obtained when the nodal explants were cultured on MS medium supplemented with 2.0 mg l(-1) BA and 0.5 mg l(-1) NAA. The regenerated shoots were cultured on half-strength MS medium supplemented with 0, 0.5, 1.0, 2.0 or 4.0 mg mg l(-1) IAA, indole-3-butyric acid (IBA) or NAA for root induction. Out of the three auxins studied, IBA was found to be the most effective in promoting root induction in S. commixta followed by NAA and IAA. The regenerated shoots were rooted best on half-strength MS medium supplemented with 2.0 mg mg l(-1) IBA after 30 days of culture.