Establishment of Callus Induction and Differentiation System from Mature Embryos of Japonica Rice

In order to promote the new high-yielding rice warieties in disease resistance research,mature embryo of japonica rice is taken as the explants and the effects of the optimal induction medium on inducing rate and regeneration frequency of rice callus,and other factors such as subculture conditions,the course of callus differentiation culture,light intensity and sucrose concentration are studied.Then efficient tissue culture system for Yujing 6 and Xindao 18 are established.The experiment results indicate that selecting suitable medium is the basis to improve the induction rate and the quality of embryogenic callus from mature embryos.Callus induction medium used to culture mature embryos of Xindao 18 and Yujing 6 are MB1(MSB5+2,4-D 2 mg/L+6-BA 1 mg/L+KT 1 mg/L+ABA 1 mg/L),MB2(MSB5+2,4-D 3 mg/L+6-BA 1 mg/L+KT 1 mg/L+ABA 0.5 mg/L) respectively,and the callus ratio of Xindao 18 and Yujing 6 are 95.24%,91.07% respectively.The best medium of proliferation is MB3 (MSB5+2,4-D 3.5 mg/L+6-BA 1.5 mg /L).It is effective that using three-step differentiation method MSD0/N6B5D0 →N6B5D2 →MSD0.The optimum temperature is 33 ℃ and the appropriate light intensity is 43.75 μmol·m-2·s-1.The highest frequency of plant regeneration of callus induced from Xindao 18's mature embryos is 99.3%,and for Yujing 6 the frequency is 83.33%.