| Fusarium head blight (FHB), caused mainly by Fusarium graminearum Schwabe, is a severe disease of wheat spike and greatly reduces the yield and grain quality. This disease is widely occurred in the humid and semi-humid regions of the world. Fhbl is a major quantitative trait locus (QTL) controlling resistance to fungal spread within spikes and is widely existed in many FHB resistant germplasms such as Sumai3and Wangshuibai. In our previous study, this QTL was primarily mapped using a recombinant inbred line (RIL) population derived from susceptible variety Nanda2419and resistant variety Wangshuibai. With the help of markers-assisted selection, the near-isogenic lines (NILs) for Fhb1was validated with the developed NILs.To fine map Fhb1, some new markers were developed based on the information of the reference genome sequence of Chinese Spring3B chromosome, expressed sequence tags (ESTs) located in the3BS0.78-0.87bin and sequence information derived from positive BAC clones of Wangshuibai genomic library. A high-resolution map of Fhbl interval was finally constructed using a secondary F2population derived from Fhb1NIL with Mianyang99-323background and a large RIL population derived from Nanda2419x Wangshuibai.At the same time, plants with recombination occurring within Fhbl interval were identified using flanking markers BARC147and HBE383in two NIL-derived secondary F2populations with Mianyang99-323and PH691background and the Nanda2419x Wangshuibai RIL population. The FHB resistance evaluation of these recombinants was performed in2011and2012in multiple field trials, and indicated that they had significantly different FHB resistance performance. This made it possible to classify the recombinant lines into resistant group and susceptible group. Based on the genotypic and phenotypic data of157recombinants screened from three populations, Fhb1was finally fine mapped to the0.3cM Xmag8620-Xmag8937interval. The physical distance of this interval in Wangshuibai genome was about96kb. |
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