Somaclonal Male-Sterile Mutants and Their Expressions in Indica Rice

In past five years from 1984 to 1988, 48 cases of male sterile (ms) mutants in nine varieties were found, in which 30 cases belonged to R_1 generation and 28 to R_2 generation. The frequency of ms variation in R, generation was around 1% and 2% in R_2 generatiom. According to the characters of ms-mutants and their genetic expressions,pollen grain free(nuclear sterile) and abortive pollen (cytoplasmic genetic sterile) could be classified, In 1R54, two cases of pollen grain free ms-mutants were discovered similar in different generations (R_1 and R_2 generation) and different years (1985 and 1986) . Among ms-mutants of the abortive pollen type, one (54257) was found to be the cytoplasmic genetic male sterile mutant. Zheng-Shan 97, Er-Jiu-Ai,162-5 (a stable somaclonefrom IR52) and Gui-Chao 2 could maintain male sterility when crossed to the ms line (54257) . IR24, IR36, IR54,Shuang-Er-Zhan and others could restore its fertility. This result showed that 54257 was a cytoplasmic ms-mutant.This is the first sample that the cytoplasmic ms mutant could be induced by tissue culture in the world.