QTL mapping of soybean node numbers on the main stem and meta-analysis for mining candidate genes

The soybean (Glycine max) node number on the main stem (NNMS) is closely related to seed yield of soybean. The aim of this study was to identify important loci affecting soybean NNMS using meta-analysis based on a reference physical map. Twenty-nine NNMS-related QTLs were mapped across 8 years with a recombination inbred line (RIL) population. Fifty-four QTLs related to NNMS of soybean identified from the database and our research were collected and each QTL was projected onto the soybean physical map. Through meta-analysis, 11 consensus soybean NNMS QTLs were obtained and located on LG D1b, LG C2, LG B1, LG F, LG L, and LG I. The map distance was from 0.02 to 4.22 Mb, the variation of original QTLs was from 2 to 4, and the mean R2 values ranged from 6.90% to 27.40%. Furthermore, 488 candidate genes were located in these consensus QTLs, 6 of which had a relationship with NNMS. These results may help lay a foundation for fine mapping of QTLs/genes related to NNMS that can be used to help breed high-yield soybean cultivars.大豆（Glycine max）主茎节数（node number on the main stem, NNMS）与大豆籽粒产量密切相关。本研究旨在基于参考物理图谱开展元分析，以筛选影响大豆主茎节数的关键位点。研究团队利用重组自交系（recombination inbred line, RIL）群体，历经8年试验，共定位得到29个与大豆主茎节数相关的数量性状位点（quantitative trait locus, QTL）。研究人员从公开数据库及本团队的研究成果中，共收集到54个大豆主茎节数相关QTL，并将所有QTL逐一映射至大豆参考物理图谱。通过元分析，最终获得11个大豆主茎节数一致性QTL，分别定位于LG D1b、LG C2、LG B1、LG F、LG L及LG I连锁群。上述一致性QTL的图谱区间长度介于0.02至4.22 Mb之间，整合的原始QTL数量为2至4个，平均表型解释率（R²值）范围为6.90%至27.40%。此外，在上述一致性QTL的区间内共定位到488个候选基因，其中6个基因与大豆主茎节数存在关联。本研究结果可为大豆主茎节数相关QTL/基因的精细定位奠定理论基础，进而助力高产大豆品种的选育工作。