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Fusarium head blight resistance loci in a stratified population of wheat landraces and varieties

Tao Li;Dadong Zhang;Xiali Zhou;Guihua Bai;Lei Li;Shiliang Gu

  To determine if Chinese and Japanese wheat landraces and varieties have unique sources of Fusarium head blight(FHB) resistance,an association mapping panel of 195 wheat accessions including both commercial varieties and landraces was genotyped with 364 genome-wide simple sequence repeat(SSR) and sequence-tagged site(STS) markers,and evaluated for type Ⅱ FHB resistance in three greenhouse experiments using single floret inoculation.Population structure analysis stratified this population into five groups with Chinese landraces in four groups.Thirty-two of 51 Chinese landraces and 24 of 27 Japanese accessions were placed in one group.Association analysis using a mixed model identified 11 markers having significant associations with FHB resistance in at least two experiments.Most of these markers coincided with known quantitative trait loci(QTL) for FHB resistance with one potentially novel QTL associated with Xgdm138-5DS and Xgwm358-5DS.Xbarc19-3AS was significant in all three experiments,and the frequency of favorable alleles was more than53%.Chinese landraces and Japanese accessions had more favorable alleles at the majority of reproducible marker loci.Nine QTL combinations were identified according to the number of favorable alleles.Mean FHB severities increased with decreasing numbers of favorable alleles at reproducible loci.The resistance loci characterized here will further diversify the wheat FHB resistance gene pool,and provide breeders with additional sources of resistance for improvement of FHB resistance in wheat.……