以5个北方常规粳稻品种和4个杂交粳稻品种为材料，对两种类型粳稻的苗期根系性状差异和产量之间的关系进行了分析研究，期望通过研究两种不同类型品种苗期根系特征来解答北方杂交粳稻杂种优势不突出的原因，为品种选育提供理论支撑。结果表明，北方杂交粳稻苗期根系的平均直径比常规粳稻粗19%左右，而在根长、投影面积、表面积、根体积、根尖数上均比常规粳稻小；与常规粳稻相比，杂交粳稻苗期根系属于“短粗胖”类型。相关性分析表明，苗期根系平均直径和根体积与产量呈正相关，因此，选育苗期根系粗壮且根体积较大的品种对产量有更大的提升作用。

The relationship between root traits and yield of conventional japonica rice and hybrid japonica rice at seedling stage were analyzed in this study, using five conventional japonica rice and four hybrid japonica rice as materials. It is hoped that the root characteristics of two types of japonica rice at seedling stage could be used to answer the non-prominent heterosis of japonica hybrid rice in the northern China and to provide some theoretical support for breeding. The results showed that the average root diameter of hybrid japonica rice was about 19% higher than that of conventional japonica rice at seedling stage, while the root length, the area of projection, the surface area, the root volume and the number of root tips were less than those of conventional japonica rice. Northern hybrid japonica rice seedling root system is “short fat” type. Correlation analysis showed that root diameter and root volume at seedling stage were positively correlated with yield, therefore, the varieties with stronger root and larger root volume at seedling stage had more yield.