基于DArTseq标记的人工合成小麦农艺性状QTL定位

QTL Mapping of Agronomic Traits in Synthetic Hexaploid Wheat Based on DArTseq Marker

人工合成小麦拥有丰富的有利遗传变异,可用于普通小麦的遗改良。本研究选用两个人工合成小麦改良品系构建了由284个单株组成的F2群体,基于1 671具有染色体位置信息的多态性DAr Tseq标记构建遗传图谱,并结合该群体农艺性状(株高,穗长,穗颈节长,小穗数,穗粒数,单株有效穗数,千粒重,单株重)的表现型,利用QTL作图软件ICIMapping 4.1进行了QTL定位。结果表明,共检测到20个QTL,其中4个为株高QTL,分布于2A、3B、5B染色体上,可解释表型变异的5.4%~10.8%;4个为穗长QTL,分布于2D、3B、5B染色体上,可解释表型变异的1.4%-8.8%;3个为穗颈节长QTL,分布于1A和5A染色体上,可解释表型变异的4.6%~12.2%;2个为穗粒数QTL,分布于3D和5A染色体上,可解释表型变异的18.9%~29.8%;1个为单株有效穗数QTL,分布于2A染色体上,可解释表型变异10.2%;5个为千粒重QTL,分布于1B、5A、5B、5D和7B染色体上,可解释表型变异的8.9%~10.9%;1个为位于7B染色体上的单株重QTL,可解释表型变异的6.1%。同时,在5B和7B染色体上存在控制多个性状的同一QTL位点。利用生物信息学的方法,筛选到1个千粒重相关的候选基因。以上结果可为人工合成小麦农艺性状QTL精细定位、分子标记辅助选择育种和基因克隆奠定基础。

Synthetic hexaploid wheat （SHW） harbors abundant favorable genetic diversity, which can be utilized to common wheat improvement. In this study, two lines derived from synthetic hexaploid wheat were used to form F2 population, which contained 284 single plants. The genetic map was constructed based on 1 671 polymorphic DArTseq markers with chromosomal location information. Combined with the phenotype of agronomic traits （plant height （PHT）, spike length （SL）, uppermost internode length （UIL）, spikelets （SPI）, grain number per spike （GNS）, panicle number per plant （PNP）, thousand-grain weight （TGW）, grain weight per plant （GWP）） of this population, the QTL positioning was carried out by using QTL mapping software ICIMapping 4.1. The results showed that 20 QTLs were detected, including four QTLs for PHT, which were distributed on chromosomes 2D, 3B, 5B; four QTLs associated with SL on the chromosomes 2D, 3B, 5B; three QTLs controlling UIL on chromosomes 1A and 5A; two QTLs for GNS on chromosomes 3D and 5A; one QTL for PNP on chromosome 2A; five QTLs for TGW on chromosomes 1B, 5A and 713; one QTL for GWP on chromosomes 713. These QTLs could explain 5.4%-10.8%, 1.4%-8.8%, 4.6%-12.2%, 18.9%o-29.8%, 10.2%, 8.9%-10.9%, 6.1% of the phenotypic variations, respectively. In addition, one QTL locus that controlled multiple traits existed on 5B and 7B chromosomes. One candidate gene closely related with TGW was gotten by using bioinformatics method. These results could lay a foundation for fine-mapping of agronomic traits, molecular marker assisted selection breeding and gene cloning in synthetic hexaploid wheat.