National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan) and National Center of Crop Molecular Breeding, Huazhong Agricultural University , Wuhan 430070 , China.
College of Life Science, Heilongjiang University , Haerbin 150080 , China.
Breed Sci. 2014 Sep;64(3):231-9. doi: 10.1270/jsbbs.64.231. Epub 2014 Sep 1.
Rice grain shape and yield are usually controlled by multiple quantitative trait loci (QTL). This study used a set of F9-10 recombinant inbred lines (RILs) derived from a cross of Huahui 3 (Bt/Xa21) and Zhongguoxiangdao, and detected 27 QTLs on ten rice chromosomes. Among them, twelve QTLs responsive for grain shape/ or yield were mostly reproducibly detected and had not yet been reported before. Interestingly, the two known genes involved in the materials, with one insect-resistant Bt gene, and the other disease-resistant Xa21 gene, were found to closely link the QTLs responsive for grain shape and weight. The Bt fragment insertion was firstly mapped on the chromosome 10 in Huahui 3 and may disrupt grain-related QTLs resulting in weaker yield performance in transgenic plants. The introgression of Xa21 gene by backcrossing from donor material into receptor Minghui 63 may also contain a donor linkage drag which included minor-effect QTL alleles positively affecting grain shape and yield. The QTL analysis on rice grain appearance quality exemplified the typical events of transgenic or backcrossing breeding. The QTL findings in this study will in the future facilitate the gene isolation and breeding application for improvement of rice grain shape and yield.
稻米的粒形和产量通常由多个数量性状位点（QTL）控制。本研究利用华恢 3（Bt/Xa21）与中香 1 号杂交的 F9-10 重组自交系（RILs）群体，在水稻的 10 条染色体上共检测到 27 个 QTL。其中，12 个控制粒形/或产量的 QTL 被多次稳定检测到，且之前尚未有报道。有趣的是，两个与材料有关的已知基因，一个是抗虫的 Bt 基因，另一个是抗病的 Xa21 基因，被发现与控制粒形和粒重的 QTL 紧密连锁。Bt 片段的插入首先被定位在华恢 3 号的第 10 号染色体上，可能破坏了与粒型相关的 QTL，导致转基因植株的产量表现较弱。来自供体材料的 Xa21 基因的回交也可能包含一个供体连锁拖曳，其中包括对粒形和产量有正向影响的微效 QTL 等位基因。对稻米外观品质的 QTL 分析说明了转基因或回交育种的典型事件。本研究中的 QTL 发现将有助于未来对控制水稻粒形和产量的基因进行分离和应用。
