The dissertation is devoted to establishing the specific, racial and genotypical composition of pathogens that cause the diseases of wheat of fungal aetiology and the patterns of their populations in the Steppe region of Ukraine, as well as selection of sources and donors of effective genes of resistance to the pathogens for the purpose of development of innovative wheat varieties with genetically determined resistance to a group of pathogens. It was found that the most harmful and prevailing diseases were leaf brown rust, powdery mildew, common bunt, ear and grain fusariosis and alternariosis. The root rots, yellow and stem rusts, necrotic leaf blotches of fungal nature occur locally, however they are potentially dangerous under certain conditions. The composition of and changes in the populations of pathogens of rust and smut diseases, as well as facultative pathogens of winter wheat have been established. The developed system of phytopathological evaluation of winter wheat in the course of its breeding for integrated resistance to the major diseases has been presented. The methods of creation of artificial and combined infectious backgrounds in the field infectious nurseries have been improved. The species of cereals which are sources of genes of resistance to pathogens of various diseases have been revealed. For the first time ever, highly effective dominant genes of resistance have been identified: PmAc1 and PmAc2, LrAc1 and LrAc2, SrAc1 and SrAc2, BtAc1 and BtAc2, StbAc1 and StbAc2, Fhb1, Fhb2 and Fhb3 from Aegilops cylindrica; PmAv1 and PmAv2, SrAv1, BtAv1 from Aegilops variabilis; PmTe1 and PmTe2, LrTe1 and LrTe2, SrTe1 and SrTe2, BtTe1 from Triticum erebuni; LrAd1 and LrAd2, SrAd1 and SrAd2, BtAd1 from Amphidiploid Ad4 (Triticum dicoccoides x Triticum tauschii). Pm-, Lr, Yr-, Sr-, Bt-, Ut-, Stb-, Fhb- and Sn-genes effective for wheat breeding have been revealed among the known genes. Over the ten years from 2001 to 2010 in the field infectious nurseries resistance to diseases of 78749 domestic and foreign varieties, lines and entries of wheat have been investigated. Out of them the genotypes resistant to powdery mildew, some species of rust and smut, septoriosis and fusariosis were selected and recommended for use in wheat breeding as donors of resistance to the diseases. The lines of winter bread wheat possessing integrated resistance to the major diseases have been developed. The lines proved to be a valuable initial material for wheat breeding, and using them such innovative winter wheat varieties as Kniagynia Olga, Lastivka odes'ka and Vykhovanka odes'ka have been developed. These varieties possess genetically determined resistance to at least eight diseases. As a result of the developed and improved theoretical and methodical propositions the scientific and methodical principles of developing varieties with integrated resistance to the major diseases have been formulated and publicized for the first time. The principles presuppose control over the state of pathogenic features and tendencies of their changes in time and space, a search of sources of resistance with effective genes among wheat resources of different ecological and geographical origin; development of a technique for isolation of resistance genes with different genetic background. At certain specifications these scientific and methodical propositions can be transformed to any system of a host plant-pathogen relationship.
