具野稻细胞质的胞质型雄性不育系的体细胞克隆变异 I.IR66707A及IR69700A体细胞克隆变异的类型

Somaclonal Variation of Cytoplasmic Male Sterile Lines with Wild Rice Cytoplasm I. The Types of Somaclonal Variation from IR66707A & IR69700A

摘要:

水稻雄性不育系IR66707A及IR69700A来自国际水稻所（IRRI）,它们的不育性只能被保持而不能被恢复,属于胞质型雄性不育。以这两个不育系以及它们与正常品种的杂种F₁为供体,经离体培养,共获得了136个体细胞克隆。在R₁代中发现了三个类型的突变或变异,即:可育突变、雄性不育和雌雄性均不育的变异。第一类型的可育突变有两例,其R₂的可育与不可育（出现分离）之比为3:1,证实为显性单基因突变。第二类型的雄性不育又可分为两种:第一种是不育性可被恢复的,与供体不育系完全不同,其中一部分克隆的不育性不能被保持但可因环境的改变而转换为可育,另一部分克隆的不育性不受环境因素的影响（不具转换能力）,但其不育性既可恢复又可不完全保持（即F₁的育性尚有分离）。第二种是不育性不能被恢复,与供体相似。育性不具转换能力的突变可望培育成为核质互作型雄性不育系,而育性可转换的突变则可望培育成为两系杂交稻中的两用核不育系。

Abstract:

Male sterile rice varieties IR66707A and IR69700A from IRRI contain cytoplasm of Oryza perennis and O. glumaepatula, respectively. Their sterility can only be maintained but cannot be restored, so they are cytoplasmic male sterile. Among the total 136 somaclones, three types of mutants were obtained by somatic cell culturing from the two male sterile lines, and their F1 progenies derived from crossing with normal cultivars. They were fertile mutants (type Ⅰ), various male sterile mutants (type Ⅱ ), and female sterile mutants(type III)．In type I，among 18 clones (R₁) from the donors of hybrid F₁，two were fertile．The fertility in the R₂ generation was segregated and the ratio of fertility to sterility was 3：1， showing that the mutants were controlled by a single dominant gene． In Type II， the sterility of some clones could be restored which were quite different from the donors of male sterile lines． Among these clones a part of the sterility could not be maintained but could be converted to be fertile as the environment changed，another part was inconvertible，but restorable and incompletely maintainable，although some segregation appeared．Also in type Ⅱ，the sterility of some clones could not be restored， and were similar to the donors． It is suggested that the convertible mutants could serve as dual-purpose genic male-sterile lines in rice breeding．Type Ⅲ was completely sterile，both for male and female．