QTL Mapping Of Some Important Agronomic Traits In An Recombinant Inbred Lines (RILS) Population Derived From The Cross Of Triticum Polonicumxtriticum Aestivum Line Zhong13

Poland wheat (Triticum polonicum L.2n=4x=28=AABB）is an important species ofEmmer-rei-he Triticum, it is the tetraploid bare grain of cultivation wheat, which have manyprominent agronomic traits, such as big spike, big grain, more grain number per spike andstrong tillering, it is one of the major genetic resources high yield and high quality in wheatbreeding of new varieties.Wheat and other crops have most of the important agronomic characters are generallycontroled by the quantitative trait locus, vulnerable to the influence of the environmentalconditions. Use the traditional breeding hybrid breeding a varieties need longer time, andgenetic markers greatly promoted the development of the number of the genetic traits. Thisstudy using SSR markers in99F8recombinant inbred lines (RILs)derived from the cross ofPoland wheat (Triticum polonicum L.)×Common Wheat (Triticum aestivum L.)Zhong13.construction of genetic map of molecular markers. Timely investigation statistics the headingdate, first-flowering date, flowering date, tiller before winter, maximum tiller, valid tiller,spike length, fertile spikelet number, grains per spike and peduncle length etc.10relatedproperties of datas and the lines of the parents and the various groups in2010and2011.Using the Composite Interval Mapping and the WinQTLCart software to analysis the aboveagronomic characters of QTL positioning, for further development of QTL fine mapping andmolecular marker assisted choice lay the foundation. The main results as follows:1. Construct the genetic linkage mapFirstly, detected the polymorphism in Poland wheat and zhong13these two parents, use883pairs of SSR primers in A and B genomes. We obtained335pairs of the polymorphismprimers, the polymorphism detection rate is37.94%. Use this335pairs of primers to furtherselection the RILs groups, there are173pairs of primers in this group appear polymorphism,accounting for51.64%of the polymorphism markers.A total of115SSR markers locatedfourteen genetic linkage group include A and B genomes and covering822.9cM. The averagedistance between genetic markers for7.16cM. On average, each chain group of contain8.2markers. Contains most of the markers are3B chromosome, has13markers, followed by2Achromosome, contains12markers,1A,5B and6B the markers of chromosomes contain at least, were only five markers.2. Spike related traits QTL analysis15QTLs for spike related traits were detected using the field data of spike related traitsin two environments, they are located on chromosomes2A,3A,3B,5B and7B. Including6QTLs for spike length,5for grains per spike,2for fertile spikelet number,2for pedunclelength. These four spike related traits accounted for9.21%～22.94%,9.18%～19.71%,11.48%～13.01%and11.34%～16.03%of phenotypic variance respectively. QTL have thetraits of cluster distribution, there are8QTLs in3A chromosome, in this reason, the3Achromosome may have closely related to spike traits upgrowth. A major QTL for grains perspike which was detected in the interval of Xbarc12～Xbarc310on chromosome3A both in2010and2011was stable and reliable across environments. This QTL was0.01cM awayfrom the nearest marker. So it can be used in molecular marker-assisted breeding for theimprovement of grains per spike in wheat.3. Mature period QTL analysisDetected19QTLs of mature period related traits using the field data in twoenvironments, they are located on chromosomes1A,5A,6A,7A,2B,4B,5B and6B.Detected including8QTLs for heading date,5for first-flowering date,6for flowering date,and these3Mature period related traits accounted for10.12%～31.51%,11.98%～19.75%and9.64%～20.27%of phenotypic variance respectively. Whether the heading date,first-flowering date or flowering date, all in4B chromosome have detected the related QTLs,shown that the4B chromosome with wheat adult stage have close relationship. In addition,detected2control heading date QTLs in1A chromosome, these2QTLs for heading datecould explain phenotypic variance for28.13%and31.48%respectively, it indicates1Achromosome control more effect the heading date. This study detected several QTLs of adultstage, there were0.01cM away from the nearest marker, almost were coseparation, So it canbe direct used in molecular marker-assisted breeding for the improvement of adult stage inwheat.4. Tillering ability QTL analysisAccording to the dates in2010, detected5tillering related QTLs. Including2QTLs fortiller before winter,1for maximum tiller and2for valid tiller, they are located onchromosomes2A,7A and4B.2QTLs for tiller before winter could accounted for11.80%～23.87%of phenotypic variance respectively. Especially the QTbw2A interval the Xbarc220～Xbarc311markers, it’s a main effect QTL, and stronger controled the tiller before winter. Themaximum tiller QTL could accounted for9.54%of phenotypic variance and2QTLs for validtiller could accounted for11.26%～15.43%of phenotypic variance. These works for wheat genetic breeding research provides economic effective molecularmarker, will do great help to further develop fine mapping for QTL and molecularmarker-assisted selection provide the experimental basis.