| Wheat is one of the most important food crops in China and even in the world, Enjoying the title of "world food". Due to global warming, fusarium head blight(FHB) have occurred in almost producting wheat areas, causing the yeild declining and D(?) toxin accumulated, which have Seriously damaged food security and have been a threat to human and animal’s health. Now, there are few anti-source materials and resistance genes to be found and applied.,Hance,exploring new resistance sources and genes and breeding new varieties of wheat with good resistance to FHB is the best way to solve this problem. L693 is a self-breeding and new FHB resistance wheat material,with a susceptible sister L661. In this study, we will use them as parent materials to create the F2 populations and F2:3 families. The way to identify their resistance is single-flower infusion inoculation. Through several years and areas’ identification, we have collected sick spike rate, the incidence of disease stage, disease index, grain test species and other datas. Using the F2 population of L693/L661, the genetic linkage map has been constructed and their genetic mechanisms of resistance have been studied, combined with the identification data, the relevant chains of molecular markers are found to conduct chromosomal location of FHB resistance QTLs, grain weight and disease kernel rate related QTLs. This study lays some foundation for further study, such as, cloning wheat FHB resistance gene and implementing molecular marker-assisted breeding.The main results obtained are as follows:1 L693, a new wheat material, has high resistance to both infection and expansion, provided with fusarium head blight, Which also has stripe rust and powdery mildew resistance. Concequently it is a new good and important resistance source to wheat.2 The populations separation ratio of the FHB resistance and susceptibility in the L693/L661 F2 populations is 7:9, in line with classical genetics two pairs of complementary genes (9:7), showing that the FHB resistance trait of L693 is controlled by two genes, recessive genes controlling FHB resistance traits, which is dominant genes controlling susceptible traits. The FHB of wheat is quantitative trait, in line with the two major genes and many other genes model, suggesting that there are two major QTLs and some other minor QTLs on the chromosome of L693.3 In this paper,229 L693/L661 F2 populations is used to construct 2B,3B, 1B,3A four chromosomal linkage map containing 51 markers, which locates the 22 marker loci on linkage group 2B, covering 2B chromosome 135.151 cM, the average genetic distance among markers is 6.15 cM. There are 20 marker loci located on 3B linkage groups, covering 3B chromosome 113.690 cM, the average genetic distance among markers is 5.69 cM. In addition, there are 5 marker loci on chromosome 1B and 4 marker loci on chromosome 3A. It provides the available and reliable genetic linkage map for the chromosomal location of related QTLs.4 It is discovered that four new FHB resistance QTLs are separately located on the 35.27 cM of Xbarc55-2B-Xbarc1155-2B region, the 19.28 cM of Xwmc54-3B-Xwmc615-3B region,10.29 cM of Xgwm566-3B-Xgpw1146a-3B region and 18.04cM of Xgpw1146α-3B-Xwmc471-3B region, and their maximum contribution rates of FHB resistance are respectively 11.4%,26%,14.1% and 12.7%. The differences of genetic locus between our QTLs on chromosome 3B and Fhb1 are significant and there is not published or named FHB resistance QTL on 2B chromosome, which proves that the four FHB resistance QTLs on chromosome 2B and 3B are new. The three QTLs on 3B are close proximity, and we can guess that the three QTLs are closely linked together, which could be seen as a main effect QTL on chromosome 3B, the contribution rate of which is 26%. additionally, the Xbarc55-2B-Xbarc1155-2B on the 2B chromosome may be a main effect QTL, whose contribution rate is 11.4%. Maybe, the chance of FHB resistance QTL on chromosome 1B is bigger than others. Localization results is in good agreement with two major genes plus multiple genes model.5 It is discovered that two disease kernel rate-related QTLs on chromosome 2B locate on Xgpw2039-2B-Xwmc243-2B and Xbarc55-2B-Xcnl6-2B region. What’s more, there are four relevant QTLs located on chromosome 3B, and one new QTL detected on Xwmc54-3B-Xwmc615-3B region,associated with the grain weight and diseased kernel rate,is different from Fhb1. Two disease kernel rate-related new QTLs which is different from Fhb1 respectively located on Xwmc544-3B-Xgpw1146a-3B and Xwmc777-3B-Xwmc471-3B region; and also found a new QTL with the same lacation of Fhb1 associated with diseased kernel rate. |
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