Rice kernel shape affects kernel quality (appearance) and yield (1000-kernel weight) and therefore is an important agronomic trait, but its inheritance is complicated. We identified a long-kernel rice chromosome segment substitution line (CSSL), Z741, derived from Nipponbare as a recipient and Xihui 18 as a donor parent. Z741 has six substitution segments distributed on rice chromosomes 3, 6, 7, 8 and 12 with an average replacement length of 5.82 Mb. Analysis of a secondary F₂ population from a cross between Nipponbare and Z741 identified 20 QTLs for important agronomic traits. The kernel length of Z741 is controlled by a major QTL (qKL3) and a minor QTL (qKL7). Candidate gene prediction and sequencing indicated that qKL3 may be an allele of OsPPKL1, which encodes a protein phosphatase implicated in brassinosteroid signaling, and qKL7 is an unreported QTL. Finally, we validated eight QTLs (qKL3, qKL7, qRLW3-1, qRLW7, qPH3-1, qKWT3, qKWT7 and qNPB6) using three selected single- segment substitution lines (SSSLs), S1, S2 and S3. Also, we detected five QTLs (qKL6, qKW3, qKW7, qKW6 and qRLW6) in S1, S2 and S3, which were not found in the Nipponbare/Z741 F₂ population. However, qNPB3, qNPB7 and qPL3 QTLs were not validated by the three SSSLs in 2019, suggesting that minor QTLs are susceptible to environmental factors. These results lay the foundation for studying the biodiversity of kernal length and molecular breeding of different kernel types.

水稻籽粒的形状会影响籽粒的品质（外观）和产量（1000粒重），因此是重要的农艺性状，但其遗传却很复杂。我们确定了长核稻染色体片段替代品系（CSSL）Z741，其来自日本晴（Nipponbare）作为受体，而喜回18（Xihui 18）作为供体亲本。Z741在水稻3号，6号，7号，8号和12号染色体上分布有六个替换片段，平均替换长度为5.82 Mb。通过Nipponbare和Z741之间的杂交对次要的F ₂种群进行分析，确定了20个重要农艺性状的QTL。Z741的内核长度由主要QTL（qKL3）和次要QTL（qKL7）控制。候选基因预测和测序表明qKL3可能是OsPPKL1的等位基因，其编码与油菜素类固醇信号传导有关的蛋白质磷酸酶，而qKL7是未报告的QTL。最后，我们使用三个选定的单段替换行（SSSL），S1，S2和S3验证了八个QTL（qKL3，qKL7，qRLW3-1，qRLW7，qPH3-1，qKWT3，qKWT7和qNPB6）。此外，我们在S1，S2和S3中检测到五个QTL（qKL6，qKW3，qKW7，qKW6和qRLW6），在Nipponbare / Z741 F _2中找不到这些QTL。人口。但是，qNPB3，qNPB7和qPL3 QTL在2019年未被这三个SSSL验证，这表明较小的QTL易受环境因素的影响。这些结果为研究核长度的生物多样性和不同种仁类型的分子育种奠定了基础。