INFECTION OF POTATO TUBERS OF CHOSEN CULTIVARS BY Y, M, S AND POTATO LEAFROLL VIRUSES IN ECOLOGICAL CROPS IN THE NORTH OF POLAND IN YEARS 2006-2008

摘要

The threat of PVY, PVM, PVS and PLRV infection for potato cultivars including seven "old" (cultivars already removed from the Polish Central Cultivar Registry) and seven "new" cultivars (registered in the Polish Central Cultivar Registry) was estimated under field conditions in three ecological farms placed in northern Poland in 2006-2008. After three-year-long reproduction the infection rate of the most important virus - PVY for "old" cultivars was high (average 58-100% for cultivars 'Orzel' and 'Epoka', respectively). This result is in agreement with their low resistance to the virus. Therefore these "old" cultivars are not suitable for ecological farming without frequent exchange of seed material. In turn, some "new" cultivars ('Korona', 'Bartek') had high resistance to PVY and practically were not infected under the same conditions. These cultivars can be recommended for ecological farming without risk of quick degeneration of tubers. To test if there is a need of frequent seed material exchange of the "new" cultivars, one season experiment was set in 2008. The produced tubers were almost free from infection and met seed material standards, except for cv. 'Justa' (infection rate 12%). During the investigated period infection with PLRV was notobserved in any of the tested cultivars.