Location of Pm3g, a powdery mildew resistance allele in wheat, by using a monosomic analysis and by identifying associated molecular markers

A segregating population of doubled-haploid lines issued from the cross bet ween the wheat ( Triticum aestivum L. em. Thell) cultivars Courtot, resista nt to several isolates of powdery mildew ( Blumeria graminis DC. f. sp. tri tici Em. Marchal), and Chinese Spring (susceptible) was used to map Mlar, a gene carried by Courtot and conferring resistance to this pathogen. The as signation of Mlar using monosomic lines of Courtot was confirmed by the map ping analysis. Mlar was located on the short arm of the chromosome 1A, in t he vicinity of the locus XGli-A5 coding for storage proteins. This result w as in accordance with those demonstrating that Mlar was an allele of the Pm 3 locus (Pm3g), a gene also involved in the resistance to powdery mildew.