DIVERSITY OF FUNGI WITHIN Fusarium solani SPECIES COMPLEX OCCURRING ON POTATOES, THEIR PATHOGENICITY AND SENSITIVITY TO FUNGICIDES

Background. Fusarium dry rot leads to yield loss of potato during storage and also reduces the quality of seed tubers. The diversity of Fusarium species caused the disease, as well as their aggressiveness and sensitivity to fungicides used for plant protection, varies significantly. Purpose is the molecular genetic identification of Fusarium fungi from F. solani species complex (FSSC) isolated from potato tubers with dry rot symptoms, and the characterization of their physiological and biochemical features. Materials and methods. The nine FSSC strains isolated from potato tubers of different geographical origin strains were included in the study. The species identification was carried out using phylogenetic analysis of tef and rpb2 loci. The growth rate of Fusarium fungi was analyzed in the temperature range of 5–35 °C. The pathogenicity of strains was assessed as a result of inoculation of potato tubers cvs. Gala and Impala. The sensitivity of the strains to active substances was determined by cultivation them on a nutrient medium with the addition of fungicides in various concentrations. Results. The strains were identified as F. mori (1 strain), F. noneumartii (4), F. stercicola (2) and F. vanettenii (2) species. The optimal temperature for the growth of F. noneumartii, F. stercicola and F. vanettenii strains was the range of 25–30 °C, and for the F. mori strain – 30 °C. All analyzed strains did not grow on a PSA at temperature of 5 °C, five strains demonstrated the ability to grow at 35 °C. The aggressiveness of strains to potato tubers of two cultivars varied significantly. The F. noneumartii strains can be characterized as consistently highly aggressive. The cv. Impala compared to cv. Gala turned out to be more resistant to infection with F. stercicola and F. vanettenii fungi and more susceptible to F. mori. The fungicide containing benomyl inhibited the growth of all strains most effectively, compared to other fungicides. The F. noneumartii strains have demonstrated the high resistance to azoxystrobin, but they were sensitive to fludioxonil. In all analyzed strains of F. mori, F. stercicola and F. vanettenii was detected the cross-resistance to azoxystrobin and fludioxonil. Conclusion. The modern pathogen-oriented system of potato protection from Fusarium dry rot includes analysis of Fusarium species composition in a particular region, as well as the sensitivity of fungi to widely applied fungicides should be used. EDN: KQYUTJ