Evaluation of foreign potato varieties for resistance to the potato tuber nematode <i>Ditylenchus destructor</i>

The purpose of the research is to assess foreign potato varieties for resistance to potato tuber nematode by different methods: in laboratory setting, greenhouse experiment, and field experiment. Materials and methods. A potato tuber nematode suspension was added to each tuber with 100 and 40 specimens in the laboratory and greenhouse experiments, respectively. At 3 months of storage in a refrigerator at 6–7 ºC in the greenhouse experiment, at 70 days of potato plant growing, nematodes were isolated from tubers using the phytohelminthological method. Twelve potato varieties were planted with 15 tubers of each variety in the field experiment. During planting, halves of tubers affected by Ditylenchus infection were placed in each hole. After growing and harvesting, tubers of 10 plants of each variety were placed in bags and stored at 10–15 ºC for 60 days. The infection rate of each sample was determined by the ratio of potato tubers infected and uninfected by the potato tuber nematode, as well as by the percentage of Ditylenchus-infected tubers. Results and discussion. In evaluating foreign potato varieties for susceptibility to the potato tuber nematode by three methods, it was found that all tested potato varieties were infected with Ditylenchus destructor nematodes to a greater or lesser extent. In terms of susceptibility to the potato tuber nematode, the varieties were classified as highly susceptible (Riviera, Excellence, Bellarosa, Roco), moderately susceptible (Arizona, Evolution, Impala, Picasso, Arrow) and weakly susceptible (Vineta, Collette) potato varieties. No potato tuber nematode-resistant varieties were identified. All three tested evaluation methods of potato varieties for susceptibility to potato tuber nematode showed that they could be used in the testing of variety resistance to the potato tuber nematode. When the first two methods were conducted in the controlled environment, the field evaluation method depended on agrometeorological growing conditions of the tested potato varieties. In storage, the disease developed in D. destructor-infected tubers, and the Ditylenchus infection signs increased, and the nematode reproduced. This technique should be used in evaluating potato varieties for resistance to the potato tuber nematode D. destructor.