High Resolution Mapping of a Novel Late Blight Resistance Gene Rpi-avl1, from the Wild Bolivian Species Solanum avilesii

Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance ( R ) genes to late blight ( Phytophthora infestans) . Here, we focus on an R gene present in the diploid Bolivian species S. avilesii . The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1 , which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F 1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl1 .