本试验选用４个晚粳品种（系）．采用了Ｈａｙｍａｎ和Ｍａｔｈｅｒ法对其双亲本杂交（含回交）组合的抽穗期的世代平均数进行了遗传变异分析及基固效应评估。结果表明：抽穗期呈部分显性或不完全显性表型，其显性方向（早熟或迟熟）则固组合而异。抽穗期的遗传方式符合加性一显性模型；基固的加性效应极显著，而显性效应和上位性效应则皆不显著。在抽穗期的遗传变异中，虽然加性方差和显性方差都存在，但仍以加性遗传方差为主；其狭义遗传率和广义遗传率分别高达７７％和９５％。以有效因子数目估计值推断，至少有一时显性熟期基因起作用。本文就中熟抗病晚粳类型品种选育中生育期的育种选择及熟期与白叶枯病抗病反应的关联性等问题作了初步讨论。 Four japonica varieties (lines) were selected in this experiment. Hayman and Mather methods were used to carry out genetic variation analysis and base effect evaluation on average generations of the heading date of their parents (including backcrossing) combinations. The results showed that: the heading stage was partially dominant or incomplete dominant phenotype, the dominant direction (early or late) is a combination of solid and different. The hereditary pattern of heading date accorded with the additive-explicit model; the additive effect of base-setting was extremely significant, while the dominant effect and epistatic effect were not significant. Although the additive variance and dominant variance existed in the genetic variation at heading stage, the additive genetic variance was still the main one. The narrow heritability and generalized heritability were as high as 77% and 95% respectively. Inferred from the estimates of the number of effective factors, at least one dominant maturity gene plays a role. In this paper, we discussed the breeding selection of mid-maturing japonica resistant varieties and the relationship between maturity and resistance to bacterial leaf blight.