Molecular identification of powdery mildew resistance genes in common wheat (Triticum aestivum L.)

RFLP markers for the wheat powdery mildew resistance genes Pm1 and Pm2 were tagged by means of near-isogenic lines. The probe Whs178 is located 3 cM from the Pm1 gene. For the powdery mildew resistance gene Pm2, two markers were identified. The linkage between the Pm2 resistance locus and one of these two probes was estimated to be 3 cM with a F2 population. Both markers can be used to detect the presence of the corresponding resistance gene in commercial cultivars. "Bulked segregant analysis" was applied to identify linkage disequillibrium between the resistance gene Pm18 and the abovementioned marker, which was linked to this locus at a distance of 4 cM. Furthermore, the RAPD marker OPH-111900 (5'-CTTCCGCAGT-3') was selected with pools created from a population segregating for the resistance of 'Trigo BR 34'. The RAPD marker was mapped about 13 cM from this resistance locus.