Assessment of the flax varieties resistance to fusarium wilt

The purpose of the work is to identify fiber flax samples resistant to Fusarium wilt, one of the most dangerous diseases of cultivated flax. To achieve this goal, an assessment was made of the resistance to Fusarium wilt of varieties and samples of fiber flax (Linum ussitatissimum L.) from the Russian Flax Collection of the Flax Research Institute (OP NIIL, Torzhok). The experiment was carried out for three years - from 2019 to 2021 in the conditions of a "vegetation house" against a provaccination-infectious background. The studied pathogen is characterized by strong virulence and long time of preservation in the soil of Fusarium (Fusarium oxysporum Schlecht. f. lini (Bolley) Snyd. etHans). The infectious background was created by introducing into the soil 30-70 g of flax straw affected by the pathogen in previous years, and 200-300 g of pure pathogen culture. For each accounting plant, the feeding area was× 2.5 cm. Protective rows were placed along the edges of the experimental plots (3 plants per row). The experiment was carried out in triplicate. The susceptibility of cultivars and lines to the pathogen was assessed for three years; the results show average data in percentages. Most of the studied samples showed an average resistance to this disease (at the level of 50-80%). However, the highest degree of resistance to Fusarium wilt (87.5-100%) was shown by the collection specimen NIIL K-3529* (89.2%) and the variety Sursky (86.9%), selected by the All-Russian Research Institute of Flax. Varieties B-100 (40.4%) and Peresvet (37.1%) showed the least resistance to the disease, their resistance indicators were lower than the susceptible variety of the AR-5 standard (45.6%), which allows them to be classified as highly susceptible.