In vitro adventitious bud regeneration from cotyledon and hypocotyl of Malus hupehensis var. pingyiensis.

To establish a highly efficient in vitro regeneration system of Malus hupehensis var.pingyiensis,the effects of types of explants,time of culture in darkness,basic medium,kind and concentration of plant growth regulator on adventitious bud regeneration from cotyledon and hypocotyl were studied.The regeneration rate of paraxial cotyledons was 3.1 times of that of abaxial cotyledons and 3.7 times of that of hypocotyls.On the SC medium supplemented with different combinations of NAA,IBA and TDZ,the regeneration rates of paraxial cotyledons of all the treatments were more than 90%.The number of regenerated buds per explant reached 12 when the medium was supplemented with TDZ 1.0 mg·L-1 and 0.2 mg·L-1 NAA.The study showed that the paraxial cotyledons of M.hupehen-sis var.pingyiensis had higher ability to regenerate adventitious bud,and TDZ supplemented in re-generation medium could increase the regeneration rate of adventitious buds.