Abstract: Jinnong 1A is a new type of cytoplasm male sterile (CMS) line in three-line hybrid rice (Oryza sativa L.). It is completely different from the sterile line of CMS-WA and CMS-HL types, and designated as CMS-FA type. In this study, Jinnong 1A, as the female parent, was crossed with 220 rice varieties originated from 10 countries and 13 provinces of China. The fertility of the F₁ generation was evaluated with F₁ pollen dye ability rate, bagged seed-setting rate, and natural seed-setting rate. The male parent was classified into maintainer or restorer lines when all the three fertility indices were ≤10% or ≥80% in the F₁ generation. Otherwise, it was regarded as non-parental variety for CMS-FA hybrid rice. In the total 220 varieties, 122 were identified as maintainer lines of Jinnong 1A, which accounted for 55.5%, but no varieties could be used as restorer lines. The other 98 varieties (accounting for 45.5%) were non-parent for CMS-FA hybrid rice. With regard to CMS-WA sterile line, Zhenshan 97A taken as the control in the study, the maintainer and restorer lines were 44 (20.0%) and 42 (19.1%), respectively. Compared with CMS-WA hybrid system, the CMS-FA system had a higher parent utilization rate by 16.4 percentile, especially the maintainer line utilization was higher by 35.5 percentile (up to 1.8 folds). Generally, the fertility abilities of domestic varieties were higher that those of in-troduced varieties in the F₁ generation.

Key words: CMS-FA, Maintainer line, Utilization rate of parental resources of hybrid rice, Pollen dyeability percentage, Bagged seed-setting percentage, Self-setting percentage