Construction Of Genetic Linkage Map And QTLs Mapping For Grain Traits In Hexaploid Naked Oat By SSR

Employing202F2populations from the hybrid between the578variety and the Sanfensanvariety as the mapping population, we constructed a genetic linkage map including208SSR markers,22linkage groups covering2070.5cM. Compared with other reports, this map can cover more geneticinformation from genome of oat. The minimum distance between two markers was about0.01cM, andthe maximum distance was46.1cM. The average gap between markers in the total genetic map was9.95cM, which was suitful to the QTL analysis. The biggest number of markers in a single linkagegroup was22and the smallest number of markers was only2. The largest linkage group covered about174.4cM, and the shortest was approximately44.3cM. The mean length of the linkage group was94.11cM. Meanwhile, there were36distortion markers distributing from LG5to LG22, which took up17.3%of the total markers. There were5distrotion markers linked in the LG5and LG6, and1or2in othergroups.Based on the genetic linkage map, we studied on the QTLs of the grain traits, including grainlength (GL), grain width (GW) and1000-grain weight (TGW). We detected47markers associated withthe grain traits in the single marker analysis. Among them,14markers were related to all of the grainlength, grain width and1000-grain weight simultaneously. In addition, we also found2markers wereconnection with both the grian length and1000-grain weight,7markers with both the grain width and1000-grain weight. There were other7markers associated with the grian length,10markers with thegrain width and5markers with the1000-grain weight respectively. More important, the marker namedAM1089was related to the three traits with the most LOD score, which connected closely to the graincharacters. At the same time, we also discoveried that4distortion markers were associated with thegrain traits, one of which nominated AM3683was related to both grain width and1000-grain weight.Finally, we continued to study on the QTLs for grain traits with CIM method. We detected14QTLs associated with the three grain traits, including4QTLs for grain length that were named asqGL-1、qGL-2、qGL-3and qGL-4respectively;6QTLs for grian width named as qGW-1、qGW-2、qGW-3、qGW-4、qGW-5and qGW-6respectively;4QTLs for1000-grain weight named as qTGW-1、qTGW-2、qTGW-3and qTGW-4respectively. Those QTLs explained approximately0.09%-17.84%ofthe phenotype variation of these grain traits. The qGL-3, qGL-4, qGW-1, qGW-2and qTGW-3contributed about16.89%,11.1%,11.4%,12.7%and17.84%to the phenotype variation of grain traitswhich were defined as the major effect of QTLs. It’s interesting that qGL-3, qGW-1and qTGW-3werelocated in the same position as AM1089and close to AM1512, where was considered as a significantlocation for grain trait genes. The similiar results were also found in the single marker analysis. Inaddition, we also discovered that the qGW-4and qTGW-4were located in the same space between AM3683and AM874. The output of this study paved the way for further study in fine mapping of the graintraits and the map-baed clone of the relevant genes in oat.