При поддержке: The work was performed in accordance with the State Assignment by the Ministry of Education and Science of the Russian Federation Project No. 0662-2019-0004 (The N.I. Vavilov All-Russian Institute of Plant Genetic Resources, VIR). Molecular identification of PVY virus strains and PSTVd viroid was conducted in All-Russian Institute of Plant Protection (VIZR) due to support the Comprehensive Program of Scientific Research “Development of potato breeding and seed production”. We thank I.V. Shmyglya, Leading Researcher of the Bioengineering Laboratory at the A.G. Lorkh Potato Research Institute, for the provided in vitro plants of ‘Osen’ variety infected with PSTVd and used as the positive control.