Sources of vertical resistance of oilseed flax to fusarium wilt

Relevance. Fusarium wilt is the most harmful disease of flax. Climate change and rapid expansion of areas under oil flax in the country pose a risk of epiphytoties of this disease. Breeding varieties with various highly effective resistance genes will provide reliable protection against the pathogen. Methods. Phytopathological assessment of resistance to fusarium wilt was performed under the conditions of a vegetation experiment and a climate chamber (air temperature 26 °C). Selective backgrounds were created using a pure culture of the causative agent Fusarium oxysporum f. lini — isolate 39 and an artificial population of the pathogen. The infection was introduced into the soil at the rate of 400 g per 50 x 85 x 20 cm box. Results. Screening of 60 collection samples of flaxseed was carried out, 35 sources of resistance to fusarium wilt were identified, which showed a high level of resistance (81.2–100%) on selective backgrounds, which indicates the presence of highly effective R-genes for this disease. An increase in the virulence of isolate 39 was established at elevated air temperature (26 °C) during the germination-herringbone period, which led to a decrease in gene expression in 37.1% of the isolated resistant samples (damage 39.0–83.4%), a high level of resistance was retained by 22 genotypes: Uralsky, Legur, Altess, Raciol, BS-12, Arny, etc. Phytopathological testing of flax samples with modified fatty acid composition AGT 422, AGT 987, Raciol (medium-linolenic), AGT 427 and AGT 1538 (low-linolenic) revealed differences in their response to infection with 13 isolates of the pathogen, which suggests that they have non-identical vertical resistance genes to the pathogen.