7对早籼不育系、保持系按完全双列杂交方式配制的不育杂种在田间进行天然异交试验。双列联合分析了天然异交率和14个花器性状。其中柱头宽、子房长和柱头角度的基因型差异不显著。与常规稻比较,不育系花器构造无显著改良,但开花习性有利于异交。花器构造诸性状与异交率呈遗传负相关,开花习性诸性状则相反。柱头单边和总外露率与异交率的关系最密切。遗传决定异交的最佳性状组合为高柱头外露、大柱头和小颖花。通径分析了各性状对异交的加性、非加性、表型和环境效应。讨论了现有不育系种质利用的途径和通过4个花器性状的改良提高不育系异交率的育种策略。 Seven pairs of early indica CMS lines were maintained in line with complete double crosses of male sterile hybrids in the field of natural outcrossing experiments. Dual alignment analysis of natural outcrossing rate and 14 floral traits. There was no significant difference in stigma width, ovary length and stigma angle. Compared with conventional rice, there was no significant improvement in floral structure of CMS lines, but flowering habits were favorable for outcrossing. The floral traits and the rate of outcrossing were negatively correlated, and the flowering traits were opposite. The stigma unilateral and total exsertion rates are most closely related to outcrossing rates. The best combination of genetic determinants of outcrossing is high stigma exsertion, large stigma and small spezifolia. Path analysis of the additive traits, non-additive, phenotypic and environmental effects of different traits. The ways of utilizing the germplasm of existing sterile lines and the breeding strategy of improving the outcrossing rate of the sterile lines through the improvement of four floral traits were discussed.