Abstract: To enhance the rooting ability of Malus baccata (L .)Borkh, hairy roots were induced from cuttings of M. baccata (L .)Borkh explants co-cultured with A. rhizogenes (8196＆R1601). Shoots were regenerated from hairy roots. Different strains of A.rhizogenes, medium, time of co-cultivation and usage of acetosyringone (AS) were researched. It indicated that the highest rooting rate (88.89%)was obtained when explants were infected by the 8196 bacterium suspension with AS(100 μmol﹒L-1), co-cultured for 3 days and cultured on 1/4MS medium . Regeneration system was established by screening different plant growth regulator recombination. Adventitious shoots were regenerated from calli that were induced from hairy roots in medium with 2.0 mg﹒L-1 BA, 0.1 mg﹒L-1 IBA and 0.1 mg﹒L-1 GA3 . Regeneration frequency was 3 %. Rooting ability of regeneration shoots increased significantly. It is a very promising method for M. baccata (L .)Borkh transformation.

Key words: M. baccata (L .)Borkh, A. rhizogenes, transformation, regeneration