Abstract: 2. 475×10^-10 C/ kg ray was used to radiate the callus of Magnolia denudata induced from the growing􀀁point in the medium MS+ Sodium naphenate 0. 1 mg/ L+ 6-BA 1. 5 mg/ L+ 2, 4􀀁D 1 mg/ L+ sugar 45 g/L. In the medium MS + ZT 2 mg/ L+ 2, 4-D 1 mg/ L, adventit ious seedlings with variation properties can be differentiated from some treated t issues. Those good seedlings were transplanted into soil and among them a chimaera with one part growing well and the other part basically same as the original parent was selected. A sexual reproduction was carried out on the mutation part with good variat ion characters. As a result, new breed bearing qualities such as growing fast and luxuriantly having strong resistance, blooming twice a year etc. was obtained.

Key words: Magnolia denudata, Callus, Radiation􀀁, induced mutation, Selective breeding, New breed