Development of New Types of Cytoplasmic Male Sterile and Restorer Lines from Rice Somaclones

Young panicles from 11 rice materials were cultured on different media to induce calli and subsequent plant regeneration, followed by the examination of pollen fertility of regenerants to determine their characteristics of sterility and fertility. 79 cases of male sterile variants in seven rice materials were found, in which 72 cases belonged to R₁ generation (regenerated plants from rice somaclones), and seven to R₂ generation (plants from first self-pollination). 10 673 regenerated plants were obtained in R₁ generation; and the frequency of male sterile variation was about 1%. Male sterile variants were found in Zhenshan 97B and Taiyin 1 in R₂ generation, and the average male sterile variation frequency in both Zhenshan 97B and Taiyin 1 was about 2%. The phenomenon that type of pollen abortion could change from one to another through tissue culture was found in rice somaclones in R₁ generation. A new excellent cytoplasmic type of cytoplasmic male sterile (CMS) line (S10-2A) has been developed from Minghui 63, and One exceptional restorer line was obtained form the fertile revertants of Baoyuan A and Hongyuan A by means of genealogical method, respectively. Factors influencing male sterile variation frequency were also discussed.