Abstract: This paper reports the studies on in vitro culture of shoot-tip of illered-onion , including callus induction and differentiation , plantlet root development and transplantation. Results showed : (1) MS basal medium supplemented with 2 ,4-D 2. 0 mg·L^-1 and KT 0. 5 mg·L^-1 was advantageous to callus induction. The frequency of callus induction was 100 %. (2) The combination of NAA 0. 1 mg·L^-1 and BA 0. 4 mg·L^-1 was the best for callus differentiation with the ratio of 88. 3 %. Most of callus was aggrandized again and induced green bud spots then formed multiplying clumpy buds , the mean number of plantlets per callus was 10. 2 . (3) 100 % of the regenerated plantlets treated with NAA 0. 01 mg·L^-1 and IBA 1. 5 mg·L^-1 and PP₃₃₃ 0. 1 mg·L^-1 could develop their roots , grew robustly and robust green leaves , after the regenerated plantlets were transplanted to soil. The survival ratio of transplanting reached 100 %.

Key words: Tillered-onion, Shoot-tip, Callus, Plant regeneration, Transplant