In order to reduce the cost of asexually propagated plantlet production and variation occurring in clones, propagation of B. napus genetic male sterile line (GMS) 156A was studied in vitro. Axillary buds ~1.5 cm from plants derived from in vitro culture were used as explants, after treatment with IBA or NAA. Such a procedure gave a propagation coefficient of 8-10 plantlets/month, much higher than that of proliferation in test tubes. Treatment with 100 mg IBA or 100 mg NAA/litre for 4-5 h before transplanting was favourable for rooting in the soil in October or November under the climatic conditions around Chengdu. Regenerated plants arising from the axillary buds of generations 1 to 3 flowered directly without vernalization, whereas plants derived from 4 or more subcultures failed to blossom without it. Plants derived from calluses had to undergo vernalization in order to flower. No substantial differences were observed in the main agronomic characters between axillary bud-derived plants and seed-propagated offsprings of the donor plants, although callus-derived plants showed considerable differences in plant uniformity and other main agronomic characters.