利用SNP基因芯片技术进行小麦遗传图谱构建及重要农艺性状QTL分析

Construction of wheat genetic map and QTL analysis of main agronomic traits using SNP genotyping chips technology

小麦遗传图谱是进行小麦染色体分析和表型研究的遗传基础.构建高密度遗传图谱,针对小麦重要农艺性状进行初级定位,确定相关性状主效数量性状位点(Quantitative Trait Loci,QTL),有助于开发辅助选择的实用性标记,并为利用次级群体进行精细定位和基因挖掘奠定基础.本研究以H461×CN16的重组自交系(Recombinant Inbred Line,RIL)为作图群体,利用90k小麦SNP基因芯片技术,对包含188个家系的RIL群体(F7)进行多态性分析,构建高密度遗传图谱,并利用Map QTL5.0的多QTL模型(MQM),对旗叶长、穗粒数等8个重要农艺性状进行QTL定位分析.构建了包括43个连锁群的分子遗传图谱,成功连锁到除2D、5D、6D外的18条染色体.该图谱共含有6 573个多态性SNP标记,覆盖的遗传距离长2 647.02 c M,标记间平均距离仅为0.4 c M.A、B、D三个染色体组分别含有标记2 696、3 094和684个;覆盖染色长度分别为1 130.92 c M、1 164.82 c M和330.44 c M;分别建立19、18和5个连锁群.对8种重要田间农艺性状进行QTL分析,共检测到66个重要农艺性状QTL,其中包括26个主效QTL,包含未见报道的新位点7个.全部QTL分布于2A、4A、6A、2B、4B、5B、2D、4D、7D 9条染色体上,单个QTL可解释表型变异率7.4%-19.5%,其中62个QTL加性效应来自母本H461,其余来自父本CN16.以上结果为小麦重要农艺性状QTL精细定位打下了基础,也为分子标记辅助育种提供了参考.

Wheat genetic map is a basic method for genome analysis and understanding of the genetic basis of phenotypic variation.This study aimed to construct high density genetic maps in order to perform QTL analysis for agronomic and quality traits of wheat to provide reference for molecular marker assisted selection breeding,fine mapping and excavation of relevant genes.An RIL（recombinant inbred lines） population including 188 lines from H461 CN16 was analyzed using wheat 90 k SNP genotyping chips technology.Subsequently,a high density genetic map was constructed.QTL for agronomic and quality traits were analyzed using MapQTL5.0 by multi-QTL model（MQM）.The traits studied contained 9 agronomic traits including effective tillers,flag leaf length and kernel number.Aa a result,a genetic map of wheat consisting of 43 linkage groups was constructed with 6 573 polymorphism SNP markers,located in 18 chromosomes of the wheat genome except for 2D,5D,6D,covering 2 647.02 cM with an average interval distance of 0.4 cM.Among them 2 696 SNP markers（41%） were from Genome A,covering 1 130.92 cM,with an average interval distance of 0.42 cM,establishing 19 linkage groups;3 094 SNP markers（47.1%）were from Genome B,covering 1 164.82 cM,with an average interval distance of 0.38 cM,establishing 18 linkage groups;Genome D contained 684 SNP markers（10.4%）,covering 330.44 cM,with an average interval distance 0.48 cM,establishing 5linkage groups;Moreover,99 SNP makers were located simultaneously in 2A/2B/2D chromosomes,constructing one linkage group.We detected a total of 8 agronomic traits associated with 66 QTLs,including 26 main-effective QTL,among which 7（located in 2A,4A,6A,2B,4B,5B,2D,4D,7D） were detected for the first time.Single QTL explained phenotypic variance of 7.4%-19.5%,with 62 QTL additive effects from H461,and the rest from CN16.The results lay a foundation for further finemapping of relevant QTL,and provide help in molecular marker assisted selection breeding.