Genetic diversity of potato varieties bred in Russia and its neighboring countries based on the polymorphism of SSR-loci and markers associated with resistance R -genes

The genetic diversity of potato varieties from the collection of Vavilov Institute of Plant Genetic Resources (VIR) was analyzed based on microsatellite analysis. These varieties have been bred in Russia and its neighboring countries since 1931. Application of 14 highly polymorphic nuclear microsatellites (SSRs) has enabled 113 varieties to be fully distinguished. Additionally, we have studied these varieties for the distribution of 8 DNA markers associated with three R-genes involved in controlling resistance to two quarantine objects: potato wart Synchytrium endobioticum and golden potato cyst nematode Globodera rostochiensis, occurring locally in some regions of the Russian Federation. All the analyzed varieties with resistance to the S. endobioticum pathotype 1 revealed the diagnostic marker Nl251400 of the Sen1 gene, while a few susceptible cultivars lost this diagnostic fragment. The tested markers of the H1 and Gro1-4 genes, which confer resistance to the G. rostochiensis pathotype Ro1 revealed different predictability. In the molecular screening of potato varieties, it is better to use several markers of these genes. The results of molecular screening using six markers of H1 and Gro1-4 genes allowed us to detect six haplotypes in the tested subset. Five haplotypes include varieties with different combinations of the markers tested; the majority (87.9%) of these varieties were highly resistant or moderately resistant to G. rostochiensis. The most numerous haplotype H1/0 included 76 varieties, which did not possess any marker of H1 and Gro1-4 genes; 96.1% of these varieties were susceptible to G. rostochiensis. Predictive associations between the haplotype content, wart and nematode resistance, pedigree, and the variety in their age are discussed.