Rice grain size is a key determinant of both grain yield and quality. Identification of favorable alleles for use in rice breeding may help to meet the demand for increased yield. In this study, we developed a set of 210 introgression lines (ILs) by using indica variety Huanghuazhan as the donor parent and erect-panicle japonica rice variety Wuyujing3R as the recurrent parent. A total of 133 ILs were selected for high-throughput sequencing. Using specific-locus amplified fragment (SLAF) sequencing technology, 10,103 high-quality SLAF labels evenly distributed on 12 chromosomes were obtained and selected for subsequent analysis. Using a high-density map, quantitative trait locus (QTL) mapping of grain size-related traits was performed, and a total of 38 QTLs were obtained in two environments. Furthermore, qGW2, a novel QTL that controls grain width on chromosome 2, was validated and delimited to a region of 309 kb via substitution mapping. These findings provide new genetic material and a basis for future fine mapping and cloning of favorable QTLs.

水稻籽粒大小是粮食产量和品质的关键决定因素。鉴定用于水稻育种的有利等位基因可能有助于满足提高产量的需求。在本研究中，我们以籼稻品种黄花占为供体亲本，直立穗粳稻品种五玉粳3R为轮回亲本，培育了一套210个基因渗入系（IL） 。总共选择了 133 个 IL 进行高通量测序。利用特定位点扩增片段（SLAF）测序技术，获得了均匀分布在12条染色体上的10,103个高质量SLAF标签，并选择进行后续分析。利用高密度图谱对粒级相关性状进行数量性状位点（QTL）定位，在两种环境下共获得38个QTL。此外，qGW2（一种控制 2 号染色体上谷粒宽度的新型 QTL）经过验证并通过替换作图界定为 309 kb 的区域。这些发现为未来有利QTL的精细定位和克隆提供了新的遗传物质和基础。