ASSESSMENT OF RESISTANCE OF SOYBEAN VARIETIES TO MYCOSES USING ORGANIC CULTIVATION TECHNOLOGIES

Abstract

The article considers issues related to the production of environmentally safe soybean products using elements of organic farming. The purpose of the research was to study the resistance of organic soybean varieties to fusarium root rot, ascochyta, and downy mildew in the conditions of central Polissya of Ukraine. The research was conducted during 2023–2024 in the production crops of LLC “Agrovest-Group”. The microflora of soybean seeds was determined according to DSTU 4138-2002. To determine the assessment of resistance in the phase of the beginning of seed formation to ascochyta, downy mildew, a visual method was used according to the symptoms of the disease. In the process of implementing the tasks, 6 varieties of soybean of organic origin of foreign selection were studied, which were included in the State Register of Plant Varieties Suitable for Distribution in Ukraine. It was established that the largest number of soybean seeds was populated by Alternaria sp. fungi, and amounted to 3.8 to 15.3 %, depending on the variety. The varieties susceptible to these fungi were Atacama, the degree of damage was 15.3 %, Achillea – 14.6 %. The spread of fungi of the genera Fusarium sp. was observed at the level of 0.2–1.5 %, Peronospora sp. – 1.0–10.8 %. The varieties Sphynx – 1.5 % and Achillea – 1.2 % of infected seeds were susceptible to fusarium infection. The varieties unstable to the pathogens Peronospora sp. were Achillea – 10.8 % and Atacama – 8.1 %. Relatively resistant to ascochyta blight were the varieties Strive, the development of the disease was 11.0 %, Commander – 12.3 %, and Achillea – 13.6 %. The varieties Viola, Sphinx, Atacama are not resistant to ascophytosis, the development of the disease is within 14.4–19.0 %, the spread – 39.7–43.3 %. Relative resistance to peronosporosis was found in the soybean varieties Commander (development of the disease – 6.0 %, the spread of the disease – 15.6 %), Achillea (8.3 %, 21.4 %), Strive (8.8 %, 24.0 %). All studied soybean varieties are biologically not resistant to diseases of fungal etiology. Relatively resistant to ascochyta blight were the varieties Strive, the development of the disease was 11.0 %, Commander – 12.3 %, and Achillea – 13.6 %. Relative resistance to downy mildew was found in soybean varieties – Commander (development of the disease – 6.0 %, spread of the disease – 15.6 %), Achillea (8.3 %, 21.4 %), Strive (8.8 %, 24.0 %). Resistance to fusarium root rot was found in the varieties Strive, Commander, Achillea. Depending on the variety, the yield varied on average over the years of research from 2.02 to 3.05 t/ha. The greatest increase in soybean grain yield was obtained when growing the varieties Achillea and Strive, where the increase was 0.83 and 0.45 t/ha, respectively, which is 37.4 and 20.3 % more compared to the standard variety Viola.