Résumé
We are involved in the genetic analysis of two sugarcane diseases, rust and leaf scald. Regarding rust, caused by fungus Puccinia melanocephala, we have identified a major resistance gene in the cultivar R570 and we are now working on the fine mapping of this gene with financial support from ICSB. We are using two strategies, one based on synteny between sugarcane and the other grasses and one based on Bulked Segregant Analysis with AFLP markers. The closest markers at present have been used to screen the R570 BAC library. Progress on this work will be reported. Regarding leaf scald, caused by the bacterium Xantomonas albilineans, we have undertaken field trials to assess segregation of the resistance on 95 individuals from a self progeny of R570 at CIRAD in Réunion and on 200 individuals derived from the cross R570 X M695/69 at MSIRI in Mauritius. The evaluation has been done both by scoring symptoms and colonisation patterns in sugarcane stalks after inoculation. AFLP analysis of these populations is in progress and will be used to search for quantitative resistance loci. Progress on these field trials will be presented and discussed. (Texte intégral)