Genetic Linkage Map Construction And QTL Mapping For Main Agronomic And Quality Traits In A Recombinant Inbred Population Derived From Nuomai1×Gaocheng8901

Wheat is an important kind of resources that human relies to survive as the largest acreage andhighest output crop. But the genetics research of wheat has lagged behind that of the rice and maize.With the development of molecular genetics and genomics research, build molecular genetics mapof wheat and use it to map QTL for agronomic traits and quality traits, and then make clear theirpositions and effects on the chromosomes in order to fine mapping further. It not only preparesgenetic resources for molecular marker-assisted selection and molecular marker breeding, but aslohas great value in improvement of wheat yield and quality traits. In the present study, we reported anew genetic linkage map developed from a recombinant lines population of256lines, which wasgenerated from the cross between two Chinese common wheat varieties Nuomai1and Gaocheng8901. QTL analyses were performed using the software of Icimapping version3.0. QTLs for11traits including plant height, heading stage, spike length, compactness, spikelets per spike, fertilespikelets, grains per spike, flour protein content, flour whiteness, dough mixing characteristics andstarch pasting property were analyzed. The results were as the following:1. Nuomai1is an early-maturing waxy wheat variety (null at three Wx alleles); Gaocheng8901is a famous strong gluten wheat variety. Nuomai1(female parent)×Gaocheng8901(maleparent), and used for the construction of the genetic map and QTL mapping. We tested thepolymorphism of912DArT markers213SSR markers among the two parents and the lines. Ofthese,479DArT markers and14pairs of SSR primers could be used for genetic map construction.2. A genetic linkage map containing498markers, including479DArT markers,14SSRmarkers,2HMW-GS markers and3Wx protein markers mapping on21chromosomes usingMAPMAKER/Exp version3.0software, was finally developed. The map covered4229.7cM withan average distance of9.77cM, which resulted in24linkage groups comprising3to42loci with amean of176.2cM per linkage group. The chi-square test showed that a total of168markers werethe genetics distortion segregation (P<0.05) markers, accounting for33.7%.62DArT markers andone SSR marker deviated toward female parent Nuomai1,104DArT markers and one Wx markertoward male parent Gaocheng8901. They were mainly distributed on chromosomes2A,2B,4D,5B. Besides, the map positioned of55DArT markers were determined. They were distributed onthe chromosomes except2A,2B,3A,4B and5B. 3. QTLs for11traits including agronomic traits and quality traits were analyzed in3differentenvironments. A total of172additive QTLs were detected (65for agronomic traits and107forquality traits). Of those65QTL for agronomic traits,11QTL were identified in two or threedifferent environments,5of which accounted for no less than10%of the phenotypic variation,being major stable QTL. They were located on chromosomes1B and6B; Of those107QTL forquality traits,32QTL were identified in two or three different environments,11of which weremajor stable QTL explaining more than10%of the phenotypic variation. They were located onchromosomes1D,2D,4A and7D.4. QTLs showed pleiotropic effects and were co-located on chromosomal regions of1A、1B、1D、2A、3B、4A、6A、6B、7A and7D. On the wPt-9757－Glu-A1interval of1A, the wPt-3563－wPt-8226interval,thewPt-6442－wPt-3824intervalof1B,thecfd-183－wPt-729773interval,Glu-D1－wPt-3743interval of1D, the wPt-664948－Wx-B1interval, the Wx-B1－wPt-0105interval of4A, the wPt-729920－wPt-664792interval of6A, the wPt-730273－wPt-6329intervalof6B, the wPt-731311－Wx-A1interval of7A and the Wx-D1－wPt-664368interval of7D, weredetected34stable QTLs regions. It contained the traits of plant height, heading stage, compactness,flour protein content, flour whiteness, dough mixing characteristics and starch pasting property.5. Most loci of controlling mixing characteristics were located need by the HMW-GS markers,and the additive effects value of the QTL which closely linked to Glu-D1was higher than the QTLlinked to Glu-A1.It testified futher the importance of Glu-1loci, especially Glu-D1on doughmixing characteristics.6A was another important chromosome for mixing characteristics.6. QTLs controlled flour protein content, mixograph peak value (MPV), mixograph peakwidth (MPW) and RVA parameters were closely linked to Wx prontein markers. It showed that theWaxy protein not expressed at Wx alleles not only had a directly influence on starch pastingproperty, but also was relevant to flour protein content, thus contributed to the dough mixingcharacteristics. There was a new major stable QTL for breakdown on the wPt-6687—wPt-731336interval of2D.