A major resistance gene providing resistance to common rust caused by fungus Puccinia melanocephala has been identified in sugarcane cultivar R570. Earlier work was based on synteny among grasses and on Bulked Segregant Analysis with AFLP. It allowed to localize this gene at the extremity of one of the cosegregation groups of homeology group VII of the R570 genetic map and to surround it with markers, the closest being located at 2.2 and 1.9 cM on each side of the gene. We are now using various BAC resources to get closer to this gene: the R570 sugarcane BAC library, the rice Nipponbare BAC contigs and the sorghum BAC contigs. Progress on this work will be reported as well as constraints related to the high ploidy level and heterozygosity of this complex crop. (Texte intégral)