Abstract: Early generation stability rice varieties(EGSRV) and conventional rice varieties(CRV) were selected as parents to analyze the genetics of early-generation stability(EGS).The EGS lines could be derived from some crosses between EGSRV and EGSRV,and EGSRV and CRV at different frequencies,but no EGS lines were developed in crosses between CRV and CRV.Genetics analysis revealed that the EGS traits just existed in some special rice,and the frequency of EGS lines was highly associated with the traits of the both parents.In addition,the EGS traits were neither qualitative traits nor quantitative traits,and they were governed neither by dominant genes nor by recessive genes.The EGS traits could be inherited to F₁single plants by crossing,and the traits in F₂ population were considered as the genetics unit,i.e.F₃and F₄ lines derived from non-segregating F₂ showed uniform agronomic traits,and those from segregating F₂ did not,indicating the EGS traits were formed in F₁ single plant.When EGS lines occurred,the Mendelian laws in segregating lines were observed in all F₂ populations of the same combination.It was suggested that the EGS lines might exist special factors regulating genes at the beginning of cell division in zygosity,which close mitosis and open somatic meiosis,resulting in the chromosomal rearrangement and forming homozygosity in F₁single plants,and some lines with the uniform agronomic traits in F₂ population appeared.

Key words: rice(Oryza sativa), early-generation stability, stable line, somatic meiosis

摘要： 利用具有早世代稳定特性的水稻(早稳）和常规品种作为主体亲本，进行了早稳×早稳、早稳×常规品种、常规品种×常规品种等三种类型的杂交。结果显示，在早稳×早稳组合和早稳×常规品种的一些组合中分别以不同频率出现早世代稳定株系，常规品种之间的杂交组合后代没有出现早世代稳定株系。水稻早世代稳定特性是早世代稳定水稻亲本所特有的,早世代稳定株系出现频率与杂交组合双亲有密切关系；早世代稳定性状既不是质量性状也不是数量性状，既不是隐性基因控制也不是显性基因控制。水稻早世代稳定特性可以通过杂交传递到F1单株，并以F2群体中的株系为传递的基本单位。稳定株系的农艺性状与相应F1单株农艺性状一致。另一方面，同一杂交组合的F2群体中，既有农艺性状整齐一致的稳定株系，又有按孟德尔分离规律的分离株系存在。初步推断水稻早世代稳定亲本中存在特有的控制因子，在杂种合子细胞分裂启动时作用于有丝分裂的开关基因，关闭有丝分裂，启动了减数分裂，体细胞减数分裂导致染色体重排，并产生纯合胚，形成了农艺性状整齐一致的F2株系。

关键词: 水稻, 早世代稳定性, 稳定株系, 体细胞减数分裂