Background. The relevance of the research is due to the fact that, despite the breeding achievements in releasing cultivars with high potential yield and resistance to the most common stressors in the regions, it is almost impossible to foresee and accurately predict the reaction of cultivars under production conditions. Besides, extreme weather events, including heat waves, droughts and downpours, will increasingly manifest themselves under global climate warming. To reduce the risk of a significant decrease in gross grain harvests in dry years and achieve high results under favorable conditions, the goal was to develop a comprehensive indicator for assessing the agroecological adaptability of genotypes to some consequences of global climate warming.Materials and methods. The results of a competitive test of 5 cultivars and 9 promising lines of spring wheat for their yield across six years contrasting in moisture availability by calculating the indicators of responsiveness to favorable conditions, grain yield depression under unfavorable conditions and the relative yield index were used to develop a complex indicator proposed to assess the agroecological adaptability of a genotype to contrasting environmental conditions.Results. The proposed method makes it possible to perform a comprehensive assessment that takes into account the responsiveness of an accession to improved agroclimatic conditions and the degree of its reaction to adverse environmental factors, taking into account the yield index in the studied set. The method is recommended for evaluating the source material and identifying the diversity of its responses to changes in agroclimatic conditions as well as for the stage of competitive variety testing in plant breeding for adaptability.

Relevance. It is important to evaluate the effectiveness of modern fungicides and their effect on the development of leaf infections of grain sorghum in order to optimize plant protection against diseases.   Methods. The studies were carried out in the fields of the Volga Scientific Research Institute of Selection and Seed-Growing named after P.N. Konstantinov on grain sorghum variety Premiere in 2014–2016. Leaf diseases were estimated by eye in the field during the phases of flowering, milky, waxy, and full grain ripeness. The average lesion of each plant was evaluated, and the prevalence and intensity of disease development was established. Seeds were treated immediately before sowing. Biological effectiveness of the studied fungicides was determined by prevalence and intensity of disease development.   Results. Analysis of leaves showed that quite a wide complex of pathogens belonging to the kingdom of fungi caused blotches on sorghum leaves. Mycelium and spores of fungi Alternaria sp., Fusarium sp., Helminthosporium sp. and others were detected on the affected leaves in the stain area. The obtained results allow us to conclude that the development of the fungal leaf blotches in sorghum in the conditions of forest-steppe of the Samara region considerably depends on hydrothermal conditions of the year: the more arid are conditions of May and June, the higher amount of precipitation and thelower temperature is in July, the higher is leaf blotch infestation of sorghum. Seed pretreatment with fungicides suppressed fungal leaf blotch development in the Premiere variety by 13.6–47.0 % in 2014, 6.9–62.2 % – in 2015, and 3.5–53.7 % – in 2016. At the same time, the highest biological efficacy showed treatment of seeds with fungicides of contact-system action “Fundazol” and “Vitaros”; was 25.0–75.0 % in prevalence and 26.2–62.2 % in the intensity of leaf blotch development.

akes it possible to determine the infestation of plants and seeds with pathogens, as well as to save a high yield and improve the quality of grain, among other things. The aim of our research was to identify pathogenic microflora on sorghum seeds and determine the degree of their distribution. Place of research: Samara region. According to the phytopathological expertise of 2018-2020, it was found that the mold of grain sorghum seeds is caused by many types of mold fungi, but the most common were Cladosporium sp., Trichothecium roseum, Mucor sp., Penicillium sp. To a lesser extent, fungi of the genus Aspergillus were found. Pathogenic fungi from the genus Alternaria were observed on the surface of 2.0% of sorghum seeds, Fusarium sp. - 2.0 %. Among the two varieties of grain sorghum, the most susceptible to infection with pathogens was a sample with a yellowish-white color of seeds compared to orange-red, respectively, 49.3 % and 33.5 % of seeds infected with pathogens. In our opinion, this difference in seed damage may be due to the absence of tannins in the yellowish-white grain and its presence in the orange-red grain, which corresponds to the data of many authors. The number of healthy seeds in the sample with yellowish-white grain color was 50.7% and 66.5% with orange-red. The variety with a yellowish-white seed color was more strongly affected by mold fungi from the genus Cladosporium sp., Trichothecium roseum, Mucor sp., Penicillium sp. - on average, about 40.3 %. The interaction of pathogens in the community of mycobiota of grain undoubtedly affects their vital activity, which ultimately affects the relationship with the host plant. The results obtained will make a significant contribution to local technologies, to the environmentally reasonable integrated protection of sorghum from pathogens.

Wheat seeds are a favorable environment for pathogenic mycoflora, which in turn causes a decrease in seed viability and the release of various mycotoxins that significantly affect the growth and development of plants. The study of the phytosanitary condition of spring soft wheat seed material of competitive variety testing for the seed borne pathogen was carried out. As a result of research, a high degree of infection of seeds with pathogens of root rot and mold on a natural infectious background was revealed. The studied seed samples were dominated by fungi: Alternaria sp. (with a percentage frequency from 3 to 23% in favorable years and 36-53% in unfavorable years, and a relative abundance of 7.9-54.8% and 48-69. 2%, respectively), Fusarium sp. (with a percentage frequency from 8 to 26% in favorable years and 1-19% in unfavorable years, and a relative abundance of 17.9-61.9% and 8-33. 3%, respectively) and a group of fungi that cause seed mold. Differences in precipitation and relative humidity may be a possible reason for differences in the frequency of occurrence and in the form of fungi found on wheat seeds in different years.

No abstract