CEREALS ASSESSMENT TOWARDS CONTAMINATION OF PHYTOPATHOGENIC FUNGI IN FOREST-STEPPE AREA OF UKRAINE

Abstract

The usage of high-quality seed, not affected by pathogens and fungi promote the high and stable yields. The condition of seeds determines their germination, seedling damage and adult plants, which ultimately affects the yield and on their quality. The significant risk of seed infection was registered in years with high humidity in the pre-harvest and harvest period. Therefore, along with the traditional seed control it is necessary to conduct phytopahtology expertise, allowing to identify the species composition of the microflora of seeds and the degree of infection with different pathogens. Smut disease - a solid and loose smut of wheat, hard and loose smut of barley - cause crop losses are clear - in the form of the destruction of the ear, and hidden - in the form of a reduction in seed germination, reduce winter hardiness, plant growth inhibition. Pathogens root rot causing blight, Fusarium and Helminthosporium that insignificantly demand on environmental conditions and extremely plastic. They have large set of enzymes that can exist on a variety of substrates, and therefore are widely distributed in nature and cause considerable damage to crops. Especially significant losses occur if the humidity during the ripening grain observed for several seasons, which leads to accumulation of the infection naturally. The aim of research was to assess the contamination of grain of spring wheat and barley phytopathogenic fungi in one of the main grain regions of Ukraine - the southern forest. The research conducted during the summer 2014 and compared with the results of previous years. Samples were taken from different plots. Seed contamination of samples by various phytopathogenic fungi was determined by the number of infected kernels per 100 seed sample. Frequency of registered species was recorded. For every studied sample we set the percentage of species. Analysis of the grain on the fungal infection and avdelenie in pure culture was performed according to the procedures used a method of washing and centrifugation, seeds, embryos analysis method, biological method based on the stimulation of development and growth of pathogens in the infected seeds during seed germination in nutrient media. We analyzed 200 samples of wheat and barley grain with 8 games on the definition of the infestation and root rot spores solid and smut. In all the samples studied was dominated latent form of infection grains (outwardly healthy, germinating, well executed seeds had normal luster, patina fungus was absent); but sometimes observed apparent lesion (plaque formation, a different degree of deformation of grains). When the microscope isolated fungi was established dominance of species such as fungi of the genera Alternaria, Helmintosporium, Fusarium, smut fungi. The research of cereal seeds showed that all the tested party for the harvest in 2014 were infected with different pathogens in different degrees. On the basis of literature data and our own observations, comparing infection rates average cereal seeds complex fungal diseases, it may be noted that in 2014 the percentage of infestation was higher than in previous years, there is a trend of growth in incidence. The results showed that the overall percentage of infected root rots seeds of spring wheat in 2014 was 55.5 %, the infestation of spring barley was 64.7 %. Compared to previous years the trend increase in the prevalence of fungal diseases on cereals: wheat infestation grew by 12.8 %, barley - 2.13 %. Smut infected - 11.2 % wheat, barley - 37.4 %. Infection bunt was 4.6 %, including 3.3 % of wheat; Barley 17.6 %. The growth and development of root rot during the growing season depended on the presence of soil infection. Infection of grain crops by smut diseases depend on the quality of seed sown. Reducing the prevalence of smut disease is possible at early winter and late spring sowing to prevent the spore germination at low temperature. Keywords: seeds, disease, infection, agents of fungal diseases, spores.