Resistance Identification To Powdery Mildew And Molecular Detection Of Resistance Genes In Wheat

Powdery mildew,caused by Blumeria graminis f.sp.tritici,is a devastating fungal disease of common wheat(Triticum aestivum L.)worldwide.Although powdery mildew can be controlled through the application of fungicides,resistance breeding is a more economic,effective and environmentally friendly approach to control the disease.Due to the wide cultivation of cultivars with a simplicity of powdery mildew resistance source,new pathogen races quickly come up and become prevalent,resulting in a short duration of effectiveness of resistant cultivars in history.So,the identification of new resistance genes and their tightly linked molecular markers should enable diversification of the genetic basis of resistance,and marker-assisted selection and gene pyramiding are imporant methods to develop new cultivars with durable resistance.One hundred and ninty-eight wheat cultivars(lines)from huanghuai southern region,were inoculated with pathotypes E09 and E20 at seedling stage and adult plants stage to characterize the resistance to powdery mildew,and the detecting of resistance genes by their tightly linked molecular markers was to definite the distribution and use of these resistance genes in this wheat region;one hundred and thirty wheat genotypes with resistance to yellow rust or leaf rust or powdery mildew,were characterized to powdery mildew at seedling stage and adult plants stage,and one STS marker and four functional markers were used to detect the allelic variation at Lr34/Yr18/Pm38 locus.The results are summarized as follows:1.The resistance level of Huanghuai southern region wheat cultivars(lines)to domestic powdery mildew pathotypes was low.The seedling resistance identification result showed that six wheat genotypes were resistant to E09 and E20(3.0%);twenty-nine and twenty wheat genotypes were resistant to E09(14.6%)and E20(10.1%),respectively.And the adult plant resistance identification result showed fifty-six wheat genotypes had different levels resistance to powdery mildew;the others were suspective to pathotypes.The results of moleculat detection showed twenty-one wheat genotypes might carry Pm2,two had Pm4 a gene,only one carried Pm21,thirty-five might carry Pm30 gene,and only four wheat genotypes carried Pm38.2.One hundred and thirty Chinese and foreign wheat genotypes with resistance to yellow rust or leaf rust or powdery mildew,were identificated with powdery mildew pathotypes E09 and E20,and Lr34/Yr18/Pm38 locus was detected with molecular markers.Results found that twenty-eight wheat genotypes were resistant to both E09 and E20(21.54%);eleven wheat genotypes had resistance to E09(8.46%);only six wheat genotypes were resistant to E20(4.62%);and the other eighty-five wheat genotypes were all suspective to E09 and E20.We also found eighty-five wheat genotypes had better resistance to powdery mildew at adult stage,and the percentage of foreign wheat genotypes was higher in these adult plant resistant wheat genotypes.Twenty-five wheat genotypes had Lr34/Yr18/Pm38 locus,and the foreign genotypes were more than Chinese.In addition,we also found cssfr3 and cssfr4 were the better molecular markers to detect the Lr34/Yr18/Pm38 locus.