Molecular Mapping of a Recessive Powdery Mildew Resistance Gene in Wheat Cultivar Tian Xuan 45 Using Bulked Segregant Analysis with Polymorphic Single Nucleotide Polymorphism Relative Ratio Distribution.

Powdery mildew is a destructive foliar disease of wheat worldwide. Wheat cultivar Tian Xuan 45 exhibits resistance to the highly virulent isolate HY5. Genetic analysis of the F and F populations of a cultivar Ming Xian 169/Tian Xuan 45 cross revealed that the resistance to HY5 was controlled by a single recessive gene, temporarily designated as . A Manhattan plot with the relative frequency distribution of single nucleotide polymorphisms (SNPs) was used to rapidly narrow down the possible chromosomal regions of the associated genes. This microarray-based bulked segregant analysis (BSA) largely improved traditional analytical methods. was located in chromosomal bin 4BL5-0.86-1.00 and was flanked by SNP marker and intron length polymorphism (ILP) marker with genetic distances of 3.0 and 2.6 cM, respectively. Molecular detection in a panel of wheat cultivars using the markers linked to showed that the presence of in commercial wheat cultivars was rare. Resistance spectrum and chromosomal position analyses indicated that may be a novel recessive gene with moderate powdery mildew resistance. This new microarray-based BSA method is feasible and effective and has the potential application for mapping genes in wheat in marker-assisted breeding.