Background. The article deals with the problems faced while studying and maintaining a collection of plant genetic resources against a strong virus infection background.Materials and methods. The data obtained during 8 years of monitoring over 1000 potato accessions for the incidence of virus diseases are presented. The work was carried out at Pushkin and Pavlovsk Laboratories of VIR and at the Polar Experiment Station of VIR (Khibiny, Arctic Circle). Visual control of the symptoms of the infection was combined with an enzyme-linked immunosorbent assay (ELISA) for potato mosaic viruses Х, S, M and Y.Results and conclusions. For many years, the global collection of VIR has been studied and maintained under a threat of strong virus infections. Among the viruses that have the widest distribution and cause significant damage to potato, there are viruses M and Y in Pushkin, and Х in Khibiny. Among the infected plant material, accessions with a latent virus infection, manifesting tolerance to the pathogens, have constantly been observed. The conventional point-based principle of scoring field resistance of potato cultivars and hybrids to viruses requires a significant revision. A new alternative approach is proposed for virus resistance assessment, when the clonal reproduction type of the tested accessions is taken into account.

Background. Information is provided about the results obtained by screening the VIR collection of improved potato varieties for main commercial traits: earliness, high yield, high starch content, and resistance to late blight (Phytophthora infestans (Mont.) de Bary), viruses, and pests, such as cyst nematode (Globodera rostochiensis Woll. (Ro1)), and Colorado beetle (Leptinotarsa decemlineata Say).Materials and methods. Potato accessions representing domestic and foreign varieties from the VIR collection served as the material for this research. The screening was performed according to the techniques developed at the Potato Genetic Resources Department of VIR.Results and conclusion. Potato varieties with valuable commercial traits were identified as breeding sources promising for earliness: ‘Bashkirskiy’ (k-25338), ‘Charoit’ (k-25221), ‘Colleen’ (k-25224), ‘Lagun’ (k-25294), etc.; for high yield: ‘Ametist’ (k-25336), ‘Banba’ (k-25222), ‘Bastion’ (k-25198), ‘Nur-Alem’ (k-25253), ‘Senim’ (k-25306), etc.; for high starch content: ‘Charaўnik’ (k-25139), ‘Darnitsa’ (k-25179), ‘Lad’ (k-25180), ‘Maksimum’ (k-25136), etc.; for resistance to late blight: local variety (Georgia) (k-25298, k-25326), ‘Sunkar’ (k-25258), ‘Udovitskiy’ (k-25260), ‘Vektor’ (k-25200), ‘Zvezdochka’ (k-25209); for resistance to viruses: ‘Azart’ (k-25196), Gala (k-25270), ‘Nadezhda’ (k-25213), Utro (k-25219), ‘Volat’ (k-25263), etc. Varieties combining resistance to gold potato cyst nematode with other valuable commercial traits were selected. Varieties with relative resistance to Colorado potato beetle were isolated under favorable conditions for the pest’s development. As a result of the research, new source material was identified, with a potential to improve major commercial traits of potato: earliness, high yield, high starch content, resistance to late blight, viruses, and pests (cyst nematode and Colorado beetle).

В результате ботанических экспедиций в Америку, организованных в 1925–1929 гг. Н.И. Вавиловым, и его личных поездок туда в 1930 и 1932 гг. начался новый этап в селекции картофеля, основанный на открытии богатого исходного видового материала и вовлечении его в межвидовую гибридизацию с культурным Solanum tuberosum L. Почти все отечественные и мировые сорта картофеля являются ныне межвидовыми гибридами. Это значительно обогатило их генетическую природу и увеличило способность противостоять различным экстремальным биотическим и абиотическим факторам среды.

Отсутствие универсального общепринятого определения биологического вида в значительной степени является причиной разных подходов к таксономии растений, включая клубненосные виды картофеля (род Solanum). В статье сделана попытка рассмотреть различные концепции, критерии и признаки вида применительно к культурным видам картофеля. Приведены основания считать, что наиболее подробно разработанной, структурированной и отвечающей номенклатурным и практическим нуждам картофелеводов является система С.М. Букасова.