A protocol for Agrobacterium-mediated transformation of a local 'elite' Indian variety (Queen) of pineapple [Ananus comosus (L.) Merr, family Bromeliaceae] has been established using a standard transformation vector (pCAMBIA 1304). High transformation efficiency, expressed as the mean percentage of transgenic microshoots regenerated from initial callus explants (20.6%) was achieved using a novel encapsulation-based, antibiotic selection procedure. The Agrobacterium-infected microshoots derived from callus explants survived selection in high concentration of hygromycin (60 mg l -1 and beyond) in encapsulated alginate beads. The integration of transgene in hygromycin-resistant shoots and plants was confirmed by histochemical GUS assay, PCR amplification and Southern hybridization. It is possible to eliminate false antibiotic positives in pineapple transformation program to a large extent following this procedure.

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