EN
Assessment of reaction of some selected potato cultivars (registered in 2005–2007) to late blight and soft rot was carried out in a field experiment at Bonin in 2008–2009. At harvest time, 10 kg samples of tubers, were taken from all plots. The natural infection of tuber was recorded twice: two samples were assessed in the autumn (post harvest), and two of them in the spring (after storage period). The level of natural infection of late blight and soft rot were calculated as percent weight of tuber sample. Additionaly, reaction of potato cultivars to dry and soft rot pathogeus was tested after artificial infection under laboratory conditions. There were significant differences in the level of late blight and soft rot after artifical infection. Cultivars: Berber, Flaming, Eugenia, Miłek and Oman (very early and early) and Niagara (mid late and late) were more susceptible to late blight and soft rot than standards. Among tested genotypes significantly more resistant were varieties Carrera, Oman and Owacja (late blight) and Dali (soft rot).