| 1.Blumeria graminis f.sp.tritici(Bgt)is an important wheat disease,which poses a certain threat to the safe production of wheat.In 2019,the cumulative incidence of powdery mildew in Wheat of China was nearly 8.7 million hm2,which seriously affected the safe production of wheat in China.However,the proportion of disease-resistant wheat varieties in actual production was relatively low,and effective disease-resistant genes were lacking.As one of the main wheat producing provinces in China,it is of great significance for normal wheat production to understand powdery mildew resistance in Hebei province.In this study,371 wheat accessions(including 256 commercial varieties from 1956 to 2018 and 115 high-generation lines)from Hebei province were tested for resistance to powdery mildew in seedling stage with isolates of E09 and E20 respectively,and molecular markers associated were used to detect eight mapped Pm genes.The results showed that among the accessions tested,6.2%and 11.9%were resistant to E09 and E20 alone,respectively,and 4.9%were resistant to both isolates.Some accessions were identified to contain resistance genes such as Pm1c,Pm2,Pm4b,Pm21,Pm24 and Pm35 respectively,and no accessions were identified possessing gene Pm12.Pm8 was detected in almost half of the accessions.It was shown that ratio of resistant authorized varieties in the tested accessions is much higher than that of high-generation lines,indicating that genetic germplasm improvement enhancement for powdery mildew resistance is an urgent task at present and should be paid more attention.When using linkage or co-segregation markers for Pm gene detection,by means of the method that the number of materials that the resistant reaction type consistent with result of the marker detection occupies the total number of materials detected by the linkage marker of the gene,finding markers linked to Pm12,Pm21 and Pm35 is highly effective,and because the marker of these genes is use convenient to use,these markers can be used preferentially to detect target genes.In general,there is a shortage of powdery mildew resistant germplasm resources and effective resistance genes in wheat in Hebei province.Of course,this study also detected some wheat germplasm that may contain new disease-resistant genes,which can be used as future research objects.2.Pubingzi 017-1,a high generation strain of wheat,showed strong disease resistance at seedling stage.Based on the genetic analysis of resistance using F1,F2 and F2:3 populations derived from the cross Pubingzi 017-1×Jingshuang 16,found that the resistance of Pubingzi 017-1 was controlled by a pair of dominant genes and tentatively designated PmPBZ017 when detected using the Bgt isolate E09.The gene was located on chromosome 2BL by combining 55K gene chip and F2 population linkage marker genetic analysis.In the PmPB2017 linkage map constructed with 8 SSR markers,the closest linkage marker was Xicscl795 with a genetic distance of 12.5cM.The preliminary localization of the powdery mildew resistance gene of this strain not only clarified the gene of Pubingzi 017-1,but also provided the basis for the fine localization of this gene. |
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