Li J Z, Huang X Q, Heinrichs F, Ganal M W, Röder M S
Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, 06466, Gatersleben, Germany.
Theor Appl Genet. 2005 Jan;110(2):356-63. doi: 10.1007/s00122-004-1847-x. Epub 2004 Nov 10.
Advanced backcross (AB)-quantitative trait locus (QTL) analysis has been successfully applied for detecting and transferring QTLs from unadapted germplasm into elite breeding lines in various plant species. Here, we describe the application of a modified AB breeding scheme to spring barley. A BC3-doubled haploid (DH) population consisting of 181 lines derived from the German spring barley cultivar 'Brenda' (Hordeum vulgare subsp. vulgare) as the recurrent parent and the wild species line 'HS213' (H. vulgare subsp. spontaneum) as the donor line was evaluated for yield and its components as well as malting quality traits. A set of 60 microsatellite markers was used to genotype the population, and phenotypic data were collected at two locations in Germany in continuous years. Altogether, 25 significant QTLs were detected by single-marker regression analysis and interval mapping. Most positive QTLs originated from the recurrent parent 'Brenda'. A QTL, Qhd2.1, on chromosome 2HS from 'Brenda' explained 18.3% and 20.7% of the phenotypic variation for yield and heading date, respectively. Due to the small percentage of donor-parent genome of 6.25%, the BC3-DH lines could be directly used for the extraction of near-isogenic lines (NILs) for Qhd2.1. Consequently, it was possible to determine the precise location of the locus hd2.1 within a region of 6.5 cM, using an F2 population consisting of 234 individuals developed from a cross between an NIL containing a defined donor segment at this locus and 'Brenda'. The location of this QTL was consistent with the presence of a major photoperiod response gene, Ppd-H1, previously reported in this region, which is associated with pleiotropic effects on yield components. In summary, the analysis of a BC3-DH population in barley provides a compromise between the analysis of QTLs by means of an AB scheme and the generation of defined substitution lines. Several lines carrying defined different donor segments for only one single chromosome or trait in the genetic background of 'Brenda' could be selected for further genetic studies.
高代回交（AB）-数量性状位点（QTL）分析已成功应用于多种植物中，用于检测QTL并将其从未适应的种质转移到优良育种系中。在此，我们描述了一种改良的AB育种方案在春大麦中的应用。对一个由181个株系组成的BC3加倍单倍体（DH）群体进行了产量及其构成因素以及麦芽品质性状的评估，该群体以德国春大麦品种‘布伦达’（Hordeum vulgare subsp. vulgare）作为轮回亲本，野生种系‘HS213’（H. vulgare subsp. spontaneum）作为供体系。使用一组60个微卫星标记对该群体进行基因分型，并连续多年在德国的两个地点收集表型数据。通过单标记回归分析和区间作图共检测到25个显著的QTL。大多数正向QTL来自轮回亲本‘布伦达’。来自‘布伦达’的位于2HS染色体上的一个QTL，Qhd2.1，分别解释了产量和抽穗期表型变异的18.3%和20.7%。由于供体亲本基因组的比例较小，仅为6.25%，BC3-DH株系可直接用于提取Qhd2.1的近等基因系（NIL）。因此，利用由一个在此位点含有特定供体片段的NIL与‘布伦达’杂交产生的包含234个个体的F2群体，有可能确定hd2.1位点在6.5 cM区域内的精确位置。该QTL的位置与先前报道的该区域存在的一个主要光周期反应基因Ppd-H1一致，该基因对产量构成因素具有多效性影响。总之，大麦中BC3-DH群体的分析在通过AB方案分析QTL和产生特定替代系之间提供了一种折衷。可以选择几个在‘布伦达’的遗传背景中仅针对一条染色体或一个性状携带特定不同供体片段的株系用于进一步的遗传研究。
