以细内S和中巧A两份隐性小粒不育系作母本，用二氧化碳（CO2）处理促使其开花，分别与9份不同的大粒恢复系杂交，将杂交种与大粒父本混合过筛，研究其分选效果，以期为杂交水稻混播、混收机械化制种技术提供理论依据和技术参数；此外，还分析了小粒母本/大粒父本杂交后种子（F0）的种子直感现像，以及F1代的杂种优势表现。试验结果表明，供试材料在粒形性状上不存在明显的种子直感现象；两个小粒不育系与大粒恢复系制种得到杂交种混筛后的纯度均在97.5%以上，可以满足生产上的要求；杂交种F1的分蘖数、单株实粒数、单株重均显著高于亲本，表现较强的杂种优势。

Using Xinei S and Zhongqiao A, two small grain recessive CMS lines, as female parent, promoting their flowering with CO2, cross with nine different large grain recovery respectively, and harvest hybrid seeds. Mix hybrid seeds with the seeds of large grain male parent, and separate which by a sieve of particular specification to study the efficiency of separation, aiming to provide theoretical basis and technical parameters for mixed planting and mixed income mechanized seed production techniques of hybrid rice. Meanwhile, the xenia effect of hybrid seeds （F0） and the hybrids vigor of F1 were also be analyzed and compared in this paper. The results showed that there were no obvious xenia effect in the shape of hybrid seeds. After the mixed small grain hybrid seeds and large grain male parent went through the sieve, the purities of hybrid seeds obtained were all over 97.5%, which can meet the need of production. The number of tiller per plant, and the number of filled grains per plant, and the weight per plant were all significantly higher than that of parent, that shows strong hybrids vigor.