Susceptibility of oil flax to fusarium depending the cultivation methods in conditions of the central zone of the Krasnodar region

The research on the prevalence and degree of development fusarium of genus Fusarium Link on oil flax, depending on the seeding time (I and III decades of April), variety (VNIIMK 620, Nilin, Severny and Raduga) and seeding rates (6, 8 and 10 million pieces/ha) was carried out in 2015-2017 at the experimental plot of VNIIMK, Krasnodar. It was established that variety Nilin is the most resistant to fusarium. The average prevalence of fusarium on this variety was 12.8% with a development degree of 13.3%. The variety VNIIMK 620 has an average degree of resistance; the disease prevalence on it averaged 29.3% with a development degree of 28.5%. Varieties Raduga and Severny were the least resistant to fusarium; the disease prevalence on them was 37.7 and 38.8% with a development degree of 36.1 and 36.3%, respectively. Seeding rate did not have a significant effect on the fusarium prevalence. A slightly higher percentage of affected plants was noted at an average seeding rate of 8 million pieces/ha but the difference between the studied variants was less than 3%. The second seeding time contributed to a greater affection of oil flax by fusarium; here, the number of affected plants was on average 4.0% higher and the development degree 2.3% higher. On average, over three years of research, the correlation between the fusarium prevalence and the yield of oil flax seeds was neutral (r = -0.368). However, the correlation was strong (r = -0.754) with a high fusarium prevalence in 2017 (up to 86.5%). These data confirm that the high prevalence of Fusarium spp. in oil flax sowings in favorable conditions for the pathogen development has a negative impact on the crop and significantly decreases the seed yield. Despite the different percentage of plants affection by fusarium during the years of research, there was no significant difference in the laboratory germination of seeds received from experimental plots.