Precise Identification of the Introgressed Segments in Powdery Mildew_ resistant Introgression Lines of Triticum aestivum_T. timopheevi

On the basis of the reported location of the Pm 6 gene, 36 homoeologous group_2 specific probes were selected to detect polymorphism between wheat/Triticum timopheevi Zhuk. Pm 6 introgression lines and their recurrent parent “Prins”. Two Pm6 introgression lines IGV1_456, IGV1_458 were distinguished from the others. Nineteen long arm specific and six short arm specific probes detected the RFLPs between resistant IGV1_456, IGV1_458 and susceptible control “Prins”, indicated that the introgressed T. timopheevi 2G chromatin involve both arms spanning across the centromere between markers Xcdo405 and Xbcd135. Only 6 of the nineteen long arm specific probes and two additional probes—BCD292,CDO678 showed RFLPs between chromosome 2B of “Prins” and IGV1_463. This means that the introgressed T. timopheevi segment in IGV1_463 with breakpoints between markers Xbcd307 and Xcdo678 is smaller than those detected in IGV1_456 and IGV1_458. Two of the six long arm specific probes PSR934, BCD135 detected polymorphism between IGV1_464 and “Prins”, and only one clone BCD135 revealed RFLPs between IGV1_465 and “Prins”, which indicated that the introgressed segments in these two lines are smaller than those in others. As the introgressed segments in all the introgression lines bear the Pm6 gene, after comparison of the overlaps of the introgressed segments, it might be reasonable to map the gene Pm 6 in the region of marker Xbcd135_2BL flanked 2BL.