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Potato cyst nematodes (PCN) collected in six localities in the Leningrad region of North West Russia were identified as Globodera rostochiensis pathotype Ro1 and were used for subsequent resistance tests. Seventynine accessions of cultivated and closely related wild potato species from the VIR collection in Russia were screened on resistance to G. rostochiensis pathotype Ro1 and on the presence of molecular markers for H1 and Gro1-4 resistance genes. No associations were detected between the resistance level of diploid and tetraploid Andean and tetraploid Chilean potato landraces (indigenous cultivars) and their related wild species and their geographical distribution or presence of PCR-based markers that are associated with the H1 and Gro1-4 genes. At the same time, all susceptible genotypes lacked such markers. New sources of resistance were found and could be used in breeding.

The germplasm collections of the Vavilov Institute of Plant Industry, Russia represent the first germplasm collection made for potatoes, now numbering 8,680 accessions. It has tremendous historical and practical importance and a rich history, having been used to document a polyploid series in the cultivated species, to formulate initial taxonomic hypotheses in potato, for studies of interspecific hybridization, and serving as the germplasm base for Russian breeding efforts. Despite its importance and size, there has never been a study of its molecular diversity, and there were many gaps in its passport data. The purpose of the present study is to obtain morphological, ploidy, and microsatellite (SSR) data needed to set up a useful subset of the collection of cultivated potatoes and closely related wild species, Electronic supplementary material The online version of this article (and to use this collection to study cultivated potato taxonomy and phylogeny. Through assessments of viability, passport data, and chromosome counts, we selected a subset of 238 cultivated and 54 wild accessions. A morphological and nuclear SSR study of these collections distinguished only three cultivated species: Solanum curtilobum, S. juzepczukii and S. tuberosum, not the many more cultivated potato species of prior taxonomic treatments. The SSR study supports the ideas of S. acaule as one of the parental species for S. curtilobum and S. juzepczukii. The morphological and SSR results are very similar to other recent studies of cultivated species, and show the need to reclassify the collection of cultivated potatoes by modern taxonomic criteria.

With 7 figures and 1 table Abstract The causal agent of potato wart (Synchytrium endobioticum) is an obligate parasitic chytrid fungus. It is included as a quarantine pathogen in 55 countries, with losses in susceptible cultivars reaching 50–100%. The aim of our study was to characterize the resistance to S. endobioticum pathotype 1 in cultivated potatoes from a well‐characterized subset of the Vavilov Institute of Plant Industry collection and to determine whether this resistance is associated with cultivated potato species taxonomy, with ploidy, with geographic distance or with a molecular marker Nl25‐1400 proposed for molecular screening for resistance to pathotype 1 of S. endobioticum. Within the diversity of 52 landrace genotypes, our work shows a lack of such predictive associations with wart resistance. High intraspecific variation of wart diseases resistance allows the selection of extremely resistant and susceptible genotypes available for future genetic and breeding studies.

One of the prospective ways to safely preserve the genetic resources of red and black currant for breeding needs is the cryopreservation of cuttings with dormant buds. Vegetative cuttings of 12 varieties of red and 11 varieties of black currant were harvested in various regions of Russia: North, Northwest, and Central. Their viability after cryopreservation in nitrogen vapors (about −184 °C) under field conditions was studied. For red currant samples, it ranged from 61.2 ± 1.2% to 72.3 ± 3.0%, black currant—from 58.9 ± 1.1% to 73.5 ± 1.9%. In the group of red currant varieties, there were no significant differences in viability between varieties after cryopreservation. In the group of black currant varieties, “Chereshneva” and “Georgiy” had lower viability after storage in liquid nitrogen vapors than the others, 61.1% and 58.9%, respectively. On red currant, dry growing conditions of the experiment year significantly decreased the viability after cryopreservation. Neither black nor red currants revealed the influence of the place of harvesting on the survival of cuttings after cryopreservation. These results indicate the possibility of using cryopreservation to preserve cuttings of red and black currant with dormant buds collected in regions with different climatic environments.