Effects of Two Kinds of Cytokinins on Shoot Regeneration from Cotyledonary Explants of Chinese Cabbage

High efficient shoot regeneration systems were established using cotyledonary explants of two Chinese cabbage (Brassica campestrispekinensis) cultivars. Effects of two kinds of cytokinins used in this experiment on shoot regeneration were compared. The regeneration frequency of HY and LB were 92.8% and 82.4% respectively in the medium of MS+2 mg/L BA+0.5 mg/L NAA+5 mg/L AgNO₃, and the regeneration frequency of HY in medium of MS+0.25 mg/L TDZ+0.5 mg/L NAA+5 mg/L AgNO₃ was up to 98.8%. As a kind of cytokinins, TDZ was more active than BA. In the medium supplemented with TDZ, it was more efficient and rapid for shoot regeneration, there were more buds on the explants than in the media with BA. AgNO₃ was indispensable for the shoot regeneration.