High frequency plant regeneration from the cotyledonary node of common bean

An efficient regeneration system for Phaseolus vulgaris was developed from mature seeds germinated on Murashige and Skoog (MS) medium supplemented with thidiazuron or N6-benzylaminopurine (BA) for 6 d. Using cotyledonary nodes, multiple buds were induced on the MS medium supplemented with 5.0 mg dm-3 BA with the induction frequency 71.9 % after 4-week culture. The buds were then transferred onto shoot formation medium containing 1.0 mg dm-3 BA, 0.1 mg dm-3 gibberellic acid and 2.0 mg dm-3 silver nitrate. The addition of AgNO3 enhanced the frequency of the shoot formation from 61.3 to 87.6 %. Root induction medium was half-strength MS medium with 0.75 mg dm-3 indolebutyric acid and 0.02 mg dm-3 BA. The average root frequency was 84.3 %. The regenerated plantlets with healthy roots grew successfully when transferred to soil. Using this system we obtained over 10 regenerated plantlets from one explant.