The present work aimed the establishment of a regeneration protocol for annatto (Bixa orellana L.) from different juvenile explants. In order to promote shoot induction, different concentrations and/or combinations of IAA and the cytokinins BAP and ZEA were assessed. Better regeneration responses were achieved when segmented hypocotyl, cotiledonary nodes and inverted hypocotyl were cultured onto MS-based medium supplemented with ZEA (2.28 µM) and IAA (0.30 µM), ZEA (4.56 µM) or ZEA (4.56 µM), respectively. Rooting of elongated shoots displayed higher frequencies when half-strength MS medium with IBA (5 µM) was used. No genetic variation was detected among regenerants as revealed by cytological analysis based on metaphasic chromosome countings (2n = 14).
micropropagation; organogenesis; annatto; tissue culture
