Molecular Markers And Chromosomal Location Of Powdery Mildew Resistance Gene In Bread Wheat Line N0324(Triticum Aestivum L.)

Powdery mildew, caused by Blumeria graminis (DC.) E.O speer f. sp. tritici is one of themajor wheat diseases around the world. It is very frequent in cool and humid climates.Cultivation of wheat varieties resistant to powdery mildew is the primary viable option tocontrol the disease effects. Breeding researches explore wheat relatives and landraces withpurpose to identify powdery mildew resistance genes (Pm genes) to be used in wheat breedingto control the disease. Identified Pm genes are then characterized by molecular markers whichfacilitate the detection in offspring generations of plants carrying these genes during the crosswhen a line is involved as powdery mildew resistant parent. Common wheat line N0324,derived from Triticum dicoccoides is resistant to powdery mildew race ‘Guanzhong4’. Theobjective of the present study was to molecularly characterize the powdery mildew resistantgene in common wheat line N0324. F2population derived from the cross between N0324andShaanyou225, a highly susceptible common wheat cultivar to powdery mildew was used asplant materials. The segregation of two hundred and five F2plants both phenotypically andgenotypically was accorded to a Mendelian’s expected3:1ratio and fit the model of a singlerecessive gene conferring resistance in N0324.Four hundred and thirty microsatellites also termed simple sequence repeats (SSRs) werescreened by bulk segregant analysis (BSA) method. Four SSR markers were link to theresistance gene in common wheat line N0324. These markers were Xwmc441, Xbarc7,Xbarc13, and Xbarc55linked to the gene with genetic distances of10.6,23,23and23.9cM,respectively. All four markers were assigned to chromosome2B using Chinese Springhomoeologous group2nullisomic-tetrasomics and ditelosomics lines. The gene wastemporarily designed Pm5055and was mapped on chromosome2B,10.6cM away from itsclose linked marker Xwmc441. The relationship of Pm5055with known Pm genes onchromosome2B was not clearly elucidated in this study due to the long distance betweenPm5055and its linked primers.