Axillary shoots derived from shoot tips in in vitro mass propagation of Anoectochilus formosanus hayata
Axillary shoot proliferation in in vitro mass propagation of Anoectochilus formosanus was successfully established via selection of different explant types, accessions and culture media to plantlet acclimati-zation. In the initiation stage, shoot tips and Murashige and Skoog (MS) medium containing 1.5 mg l-1 N6-benzylaminopurine (BAP) and 0.25 mg l-1 α-naphthalene acetic acid (NAA) were determined as high potential explant and medium for axillary shoot regeneration of A-1 and A-2 accessions of A. formosanus compared to others. High axillary shoots up to 7.0 shoots per explant with 1.0 cm shoot height and 9.8 leaves per explant derived from shoot tip explants of A-1 accession were signify-cantly induced and proliferated in MS medium supplemented with 1.25 mg l-1 BAP and 0.25 mg l-1 NAA. Higher root formation up to 2.4 roots per shoot and 1.0 cm root length of A-1 accession was easily prepared on Hyponex medium (2 g l-1 20N:20P:20K) containing 150 ml l-1 coconut water (CW). While high survival rate of acclimatized plantlets as high as 90.4 % was successfully done by planting them in plastic boxes containing a mixture of burned rice-husk and organic manure (1:1, v/v) after 2 months. In the study, it was also revealed that in in vitro culture of A-1 accession of A. formosanus showed higher response compared to A-2 accession in all in vitro culture stages. The successful established protocol expected can be applied for preparing high-quality planting materials for commercial purposes and developing new route of in vitro mass propagation for other species of A. formosanus.