Lingli Li;Yingjie Bian;Yan Dong;Jie Song;Dan Liŭ;Jianxiong Zeng;Fengju Wang;Yong Zhang;Zhonghu He;Xianchun Xia;Yan Zhang;Shuanghe Ca

Institute of Crop Sciences, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences, Beijing 100081, China;Institute of Crop Sciences, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences, Beijing 100081, Chin; International Maize and Wheat Improvement Center (CIMMYT) China Office, Beijing 100081, China

Grain number per spike;KASP marker;QTL mapping;Thousand grain weight;Triticum aestivu

Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield. Here, we identified eight stable quantitative trait loci (QTL) for yield component traits, including five loci for thousand grain weight (TGW) and three for grain number per spike (GNS) in a recombinant inbred line population derived from cross Yangxiaomai/Zhongyou 9507 across four environments. Since grain size is a major determinant of grain weight, we also mapped QTL for grain length (GL) and grain width (GW). QTGW.caas-2D, QTGW.caas-3B, QTGW.caas-5A and QTGW.caas-7A.2 for TGW co-located with those for grain size. QTGW.caas-2D also had a consistent genetic position with QGNS.caas-2D, suggesting that the pleiotropic locus is a modulator of trade-off effect between TGW and GNS. Sequencing and linkage mapping showed that TaGL3-5A and WAPO-A1 were candidate genes of QTGW.caas-5A and QTGW.caas-7A.2, respectively. We developed Kompetitive allele specific PCR (KASP) markers linked with the stable QTL for yield component traits and validated their genetic effects in a diverse panel of wheat cultivars from the Huang-Huai River Valley region. KASP-based genotyping analysis further revealed that the superior alleles of all stable QTL for TGW but not GNS were subject to positive selection, indicating that yield improvement in the region largely depends on increased TGW. Comparative analyses with previous studies showed that most of the QTL could be detected in different genetic backgrounds, and QTGW.caas-7A.1 is likely a new QTL. These findings provide not only valuable genetic information for yield improvement but also useful tools for marker-assisted selection.(c) 2022 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).