Abstract:

After identifying the new male sterile cytoplasm (CMS-FA) from wild rice, a series of good quality CMS-FA male sterile lines and restorer lines as well as CMS-FA hybrid rice combinations with good quality and strong heterosis were developed, based on which the genetic studies of male sterility restorer gene for CMS-FA hybrid rice was conducted. The cross of CMS-FA male sterile line Jinnong 1A × CMS-FA male sterile restorer line Jinhui 3 was made to get F₁ seeds. F₁ generation plants were planted and let them self-cross to get F₂ seeds. In the meantime, backcrosses of male sterile line × F₁ and F₁ × maintainer line were carried out to get two test cross populations (male sterile line // male sterile line / restorer line and male sterile line / restorer line // maintainer line). Then the populations of P₁, P₂, F₁, F₂, B₁F₁, and B₂F₁ were planted at the same time to evaluate the three fertility indexes of stained pollen rate, bagged seed-setting percent and natural seed-setting percent, and to conduct chi-square test for the genetic segregation ratio of each population. The results showed that the F₁ of CMS-FA male sterile line × CMS-FA male sterile restorer line was normal in fertility, indicating the male restorer gene (male fertile gene) is dominant genetically. F₂ population had a segregation ratio of 3 fertile plants:1 sterile plant, proving that the fertility restoration of CMS-FA male sterility was controlled by a pair of dominant genes. The two populations of test cross B₁F₁ and B₂F₁ had a segregation ratio of 1 fertile plant:1 sterile plant, which proved the single gene genetic model of F₂ male restorer gene (male fertile gene). The genotypes of CMS-FA three lines were temporarily determined as S(SS)for male sterile line, F(SS) for maintainer line and S(FF) for restorer line.

Key words: Hybrid rice, New cytoplasmic resource CMS-FA, Male sterility, Restorer gene, Inheritance