Sarhang E. Biological peculiarities, specialization and virulence polymorphism of Puccinia recondita Rob. Et Desm. f. sp. tritici Erikss. - Pathogen of Wheat Leaf (Brown) Rust in the eastern parts of forest-steppe in Ukraine

The dissertation is devoted to studying biological peculiarities, specialization and virulence polymorphism of wheat leaf rust pathogen under conditions of the eastern part of the Forest-Steppe Zone of Ukraine. It has been determined that wheat leaf rust is a widespread disease in the eastern part of the Forest-Steppe Zone of Ukraine and it became apparent annually during the years, the level of the development of disease reaches epiphyte. The perspective varieties with the high resistance and varieties with the moderate resistance have been isolated. The genes of resistance are isolated, which are capable of ensuring the high level of the protection of plant from the action of brown rust. The dependence of harmfulness level of pathogen of disease on the damage degree of plant and on the stage of its development during the infection has been determined. The retention of infection in winter and its renewal in the spring period depends on the winter resistant variety and level of affection by fusariose.The opportunity of host- plants of pathogen among the wild cereals, which are reserves of infection in agrocenosis, has been determined. The level of the virulence of pathogen depends on immunological properties of wheat varieties. The spectrum of physiological races of brown leaf rust on the varieties and the wild cereals is identical. The varieties of soft spring wheat are defined, which have a value as resistance donors. Majority of hard spring wheat is resistant to pathogen of brown rust.