[Objective] This study was to understand the genetic dynamics of three-line hybrid rice,and explore the respective effect of sterile line and restoring line on grain characters of hybrid rice.[Method] Four three-line sterile lines and 27 restoring lines(cultivars) commonly cultivated in Central China region were regarded as experimental materials to conduct 4×27NCⅡ cross design,and the grain characters of three-line hybrid rice were analyzed at genetic and correlation levels.[Result] Four characters of grain length,grain width,1 000-grain weight and length-width ratio play the leading role in additive gene effect;these four characters were simultaneously influenced by male parent and female parent,but the effect from male parent was relatively larger.The grain length,grain width,1 000-grain weight and length-width ratio all have high broad heritabilities(respectively 99.65%,98.31%,95.27% and 98.81%).Correlation analysis showed that grain length was positively correlated with 1 000-grain weight and length-width ratio at extremely significant level;1 000-grain weight was positively correlated with grain length and length-width ratio at extremely significant level,and was insignificantly correlated with grain width;grain width was negatively correlated with grain length and length-width ratio at extremely significant level.Path analysis showed that the direct path coefficients of grain length,grain width and 1 000-grain weight to length-width ratio were 0.624 6,-0.555 9 and-0.015 8,respectively.[Conclusion] This study systematically analyzed the effects of sterile line and restoring line on grain characters of hybrid rice,which provided theoretical basis for breeding high quality and yield hybrid rice.
