Genetic diversity of resistance to Phytophthora infestans derived from Solanum venturii.

As the cultivated potatoes are not resistant to late blight caused by Phytophthora infestans, wild Solanum species are considered to be great resources for achieving durable resistance. This study reports newly identified resistance loci derived from Solanum venturii. Two mapping populations from the same accession, but different genotypes were used. Three specific loci segregated in the first population based on the isolates used for the resistance assay. One has already been mapped on the same region of chromosome 9, whereas the other two were localized below the first locus. In the second population, two specific resistance loci segregated and their genetic positions were also expected to be on the south from other genes clustered on chromosome 9. The resistance loci identified in this study could be different and isolate-specific. These results, together with markers developed using sequences of previously cloned resistance genes and integrated genetic maps of different late blight resistance loci, indicate that there are two resistance gene clusters on the long arm of chromosome 9. [ABSTRACT FROM AUTHOR]