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Climate change is leading to increased occurrence of and yield losses to wheat diseases. Managing these diseases by introducing new, effective and diverse resistance genes into cultivars represents an important component of sustainable wheat production. In 2016 and 2017 a set of primary hexaploid synthetic wheat was studied under high disease pressure: powdery mildew, leaf and stem rust in Omsk; Septoria tritici and S. nodorum in Moscow. A total of 28 synthetics (19 CIMMYT synthetics and 9 Japanese synthetics) were selected as having combined resistance to at least two diseases in both years of testing. Two synthetics (entries 13 and 18) originating from crosses between winter durum wheat Ukrainka odesskaya-1530.94 and various Aegilopes taushii accessions, and four synthetics (entries 20, 21, 23 and 24) from cross between Canadian durum wheat Langdon and Ae. taushii were resistant to all four pathogens. Pathological and molecular markers evaluation of resistance suggests presence of new genes and diverse types of resistance. The novel genetic sources of disease resistance identified in this study can be successfully utilized in wheat breeding.

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A b s t r a c tSeptoria tritici blotch (STB) or Stagonospora nodorum blotch (SNB) are among the most harmful and economically significant diseases of wheat in the grain growing regions of the world, especially in the countries with a temperate climate. In epiphytotic years the losses from the disease can reach 30-40 %. In Russia the diseases holds a dominant position in a pathogenic complex of fungus diseases of grain crops. In this paper we first determined the parameters of partial resistance in the cultivars of wheat (genus Triticum) from the collection of the Germplasm Resources Information Network (GRIN, USA) using the stable strains of Septoria tritici and Stagonospora nodorum pathogens. The aim of our study was to select wheat varieties with long-term resistance to blotch based on field and laboratory tests. A long-term study (2009)(2010)(2011)(2012)(2013)(2014)(2015) of the disease development on the wheat cultivars from GRIN Collection were conducted at artificial infection in infection nursery (Central region of Russia, Moscow Province). The samples studied belonged to various genetic groups. A total of 20 samples were diploids (2n = 14), 409 samples were tetraploids (2n = 28), 1688 samples were hexaploids (2n = 42), and also 397 lines derived from crossing of Triticum aestivum with Aegilotriticum were tested. The area under disease progress curve was determined, and the index of resistance (IR) was calculated. The cultivars, that characterized by slow development of the disease in the field, i.e. with high-and middle IR, were selected for laboratory studies. The plants were grown in artificial climate chambers till the 3 rd leaf fully unfolded. Pieces of leaves were inoculated by a drop of spore suspension of S. tritici (4 isolates) or St. nodorum (4 isolates), 10 replications per each variety-topathotype combination. The samples were grouped according to the latent period length and size of infectious spots. As a result, 191 samples of T. aestivum subsp. aestivum and a sample of T. aestivum subsp. spelta with a high index of resistance to the disease were selected among hexaploid wheat; 16 samples were found in tetraploid wheat, including 8 samples of T. turgidum subsp. durum, 2 samples of T. turgidum subsp. turgidum, 3 samples of T. turgidum subsp. dicoccon, 3 samples of T. timopheevii subsp. timopheevii; and 4 samples were selected from diploid wheat T. monococcum subsp. aegilopoides. Eleven lines derived from crossing of T. aestivum and Aegilotriticum sp. showed the sloweddown in the disease development. The selected hexaploid wheat cultivars were mostly from North American ecology-geographical group of T. aestivum subsp. aestivum, including 77 cultivars from the USA and 18 -from Canada (34.5 % in total). Selected tetraploid wheat samples of T. turgidum subsp. durum were from North and Central America, and those of T. turgidum subsp. turgidum, T. timopheevii subsp. timopheevii and T. turgidum subsp. dicoccon from Europe and Asia. The samples from Iraq and Hungary with a high index of blotch resist...

The interest in proteases secreted by mycelial fungi is due to several reasons of which one of the most important is their involvement in the initiation and development of the pathogenic process. A comparison of saprophytic and phytopathogenic mycelial fungi revealed one characteristic feature, namely, the appearance of a new trypsin-like activity in phytopathogens that is absent in saprophytes. To clear up the question of whether the degree of pathogenicity of a fungus is related to the activity of secreted trypsin-like protease, several species of Fusarium of various pathogenicity were compared. In two species, F. sporotrichioides (which causes ear fusa-riosis of rye) and F. heterosporum (the causative agent of root rot in wheat), a clear correlation between the activity and pathogenicity was revealed: the more pathogenetic F. sporotrichioides exhibited a higher extracellular trypsin-like activity than the less pathogenetic species F. heterosporum. Thus, the presence of trypsin-like activity in a saprotroph-pathogen pair may be an indicator of the pathogenicity of a fungus; in some cases, the value of this activity may indicate the degree of its pathogenicity. This suggests that trypsin-like proteases specific to phytopathogens are directly involved in the pathogenetic process, probably, through interaction with the "sentry" protein or the product of the resistance gene.