SUMMARY
Climate changes affect the level of damage from plant diseases, because the environment has a significant impact not only on plants, but alsoon pathogens and their vectors. Therefore, studying of the viruses, crop yield and productivity, agroclimatic changes should be in the complex. Theaim of the study was to investigate the viruses affecting winter wheat and soybean plants, their yield in conditions of infection with viruses andchanges in the climatic conditions of the Poltava region. Methods: biometric; crop and its structure; DAS-ELISA, RNA extraction from plantmaterial, RT-PCR, sequencing, phylogenetic analysis, statistical methods. Results. It is established that Wheat streak mosaic virus (WSMV) is themost widespread and harmful for wheat crop and Soybean mosaic virus (SMV) – for soybean. For the first time in Ukraine, the yield of winter wheatand soybean plants under conditions of virus damage and changes of climatic conditions in the Poltava region was studied. Correlation betweenthe HTC (the hydrothermal coefficient of Selyaninov), the damage caused by viral diseases and the productivity of winter wheat and soybean plantsis revealed. It is shown that transgenic soybean Grimo is affected with SMV, which reduce grain yield twice. The molecular genetic properties of theSMV isolate GRP-17 were studied and it is determined that it has a common origin with Iranian, American, Chinese isolates and isolate fromUkraine. It has been determined that, the amino acid substitutions in CP gene of GRP-17 are unique compared to sequences of all SMV isolatestaken for the analysis. Conclusions. Analysis of the meteorological data in the agrocenosis was carried out and it was established that the yield ofwheat and soybean crops is closely related to the ratio of precipitation and air temperature (HTC). From these parameters also depended thefrequency of WSMV and SMV detection, because they have a direct impact on insects – vectors of the viruses. The changes in the moleculargenetic level in CP gene of GRP-17 can be involved in the it's harmfulness and ability to infect transgenic soybean plants.