利用普通六倍体小麦和西藏半野生小麦杂交衍生的重组自交系定位小麦芒长QTL

Mapping QTLs for Awn Length in Recombinant Inbred Line Population Derived from the Cross between Common Wheat and Tibetan Semi-wild Wheat

芒长是普通小麦的重要农艺性状,受多个基因控制。本研究利用长芒的普通小麦郑麦9023与无芒的西藏半野生小麦Q1028构建一个重组自交系群体(186个株系);采用SSR和DAr T分子标记,构建覆盖小麦全基因组的遗传图谱(2597 cM)。基于重组自交系群体两年芒长表型数据,采用ICIM作图法对小麦芒长性状进行QTL定位分析。共检测到2个与芒长相关的QTL,即Qwa.sau-4AS和Qwa.sau-5AL。它们分别位于4AS和5AL染色体上,可分别解释7.4%和27.3%的表型变异。这2个QTL效应可能分别来源于钩芒基因Hd与抑芒基因B1。利用连锁标记进行基因型分析,表明Qwa.sau-4AS与Qwa.sau-5AL对芒长的抑制效果具有累加效应,且Qwa.sau-5AL效应强于Qwa.sau-4AS。本研究将为精细定位及克隆这2个QTL奠定基础。

Awn length is an important agronomic trait in hexaploid wheat and controlled by multiple genes. A recombinant inbred line（RIL） population containing 186 lines were developed by crossing Tibetan semi-wild wheat accession Q1028（female） and common wheat variety Zhengmai 9023, and a genome-wide genetic map（2597 cM） was constructed using SSR and DAr T markers. QTLs controlling awn length were identified with two-year phenotypic data and the genetic map by using the Inclusive Composite Interval Mapping（ICIM） method. Two QTLs associated with awn length, designated Qwa.sau-4AS and Qwa.sau-5AL, were detected on chromosomes 4A and 5A, which explained 7.4% and 27.3% of phenotypic variations, respectively. According to genetic locations, effects of the two QTLs might be from Hd and B1 genes that could reduce awn length, respectively. Genetic analysis showed that Qwa.sau-4AS and Qwa.sau-5AL had cumulative effects, with stronger inhibiting effect in Qwa.sau-5AL than in Qwa.sau-4AS. These results are valuable for fine mapping and cloning target genes controlling awn length in the future.