Germplasm Screening And QTLs Analysis For FHB Resistance In Common Wheat (Triticum AestivumL.)

Fusarium graminearum has posed a serious threat to wheat production in the world,not only causing yield and grain quality losses, but the fungus also produces a mycotoxin, deoxynivalenol. Breeding wheat resistant to FHB is the method of choice to minimize crop and grain quality losses caused by the disease. Germplasm screening is the first step in a breeding program for the integration of FHB resistance into commercial wheat cultivars.Dissect the genetic base underlying the agronomy traits and broaden the genetic resource,improve the ability of wheat to various stress to improve the yield and the resistance to FHB is a long period task.In the Near isogenic introgrsssion line (NIIL) of an artificial synthesized hexaploid wheat Am3by crossing Triticum carthlicum with Aegilops tauschii, introgression lines containing different dornor parent chromsome fragment were selected by molecular markers to prepare for the QTL location of resistance to FHB. At same time330wheat varieties and mapping population of199recombinant inbred lines derived from the cross of Neixiang188/Yanzhan1were evaluated for their resistance to FHB. The results obtained were listed as blow:1. In the year of2005-2006,330wheat varieties resistance to FHB were evaluated.Forty-six wheat varieties FHB severity were better Mianyang26and their resistance were evaluated again in the year of2006～2007. Disease index was analyzed by tree diagram of cluster analysis, and6cluster group s for49varieties were classified,2,5,10,14,15and13varieties were classified into group I～VI. Except Jimai32which FHB average severity was bigger than Yangmai5,other varieties disease spike rate、average sevrhy、 disease index of group I, group II, group III were lower than Yangmai5.2. A mapping population of199recombinant inbred lines derived from the cross of Neixiang188/Yanzhan1were evaluated for their resistance to FHB from2005-2008.Ten QTLs were detected on chromosome2A、2D、4B、4D、5A、5B、5D.Four QTLs(QFhb-CAAS-4D2、 QFhb-CAAS-5B、QFhb-CAAS-5D.1、 QFhb-CAAS-5D.2) were detected in two years.Perhaps their resistance type to FHB was type I.In ten QTLs7from Neixiang188and3from Yanzhan1.3. In the BC4F3and BC4F5progenies of Laizhou953crossing with Am3,258lines resistance to FHB were evaluated. In146BC4F3lines,6lines resistance to FHB were MR. Thirty-seven lines resistance to FHB were better than Am3.The rate of disease spike and disease index were significantly correlated with plant height.In112BC4F5lines,6lines resistance to FHB were MR. The rate of disease spike and disease index were significantly correlated with Spikelet density.4. In the BC4F5progenies of Laizhou953crossing with Am3.15lines were selected to detect the intogressed dornor fragment by SSR marker.Among678pairs primers137pairs of them can detect polymorphism.The distance between markers was12.12cM and6.52marker were detected on every chromosome.The number of polymorphic marker on chromosome5D and5A were more than other chromosomes.There were92introgression fragment were detected in15lines.17of introgressin fragment were detected in lines-819.In21wheat chromosome groups,1A,6D,7A were not detected introgression fragment. The number of the introgression fragment on chromosome3D and5B were most. According to the Somers wheat consensus SSR map, size of introgression fragment were estimated.The length of introgression fragment was8.77cM. Three QTLs were detected in15lines and Qdi-caas-5A was located near Bare40.Perhaps this QTL was related with type III resistance.