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Листовые болезни яровой пшеницы-бурая ржавчина (возбудитель-Puccinia triticina), желтая пятнистость (пиренофороз) (Pyrenophora tritici-repentis) и темно-бурая пятнистость (Сochliobolus sativus = Bipolaris sorokiniana)-относятся к группе распространенных и потенциально опасных болезней в западноазиатских регионах России и Северном Казахстане. Для обоснования стратегий генетической защиты пшеницы необходимы популяционные исследования фитопатогенов. Цель работыхарактеристика структуры популяций возбудителей бурой ржавчины и желтой пятнистости яровой пшеницы по признакам вирулентности и оценка распространенности возбудителя темно-бурой пятнистости в западноазиатских регионах Российской Федерации и Северном Казахстане в 2017 г. Источником инфекционного материала служили пораженные бурой ржавчиной и пятнистостями листья образцов яровой пше ницы, собранные в Челябинской и Омской областях и Северном Казахстане. Анализ вирулентности 109 изолятов P. triticina на 20 линиях-дифференциаторах показал, что все изученные монопустульные изоляты были авирулентны к ТсLr24. Изоляты, вирулентные к ТсLr19, выявлены только в челябинской популяции. Частоты вирулентных изолятов к ТсLr2a, ТсLr2b, ТсLr2c, ТсLr11, ТсLr15, ТсLr16, ТсLr20 и ТсLr26 были выше в омской и североказахстанской популяциях, а к ТсLr9-в челябинской. При использовании 20 ТсLr-ли ний определено 27 фенотипов вирулентности P.

Background. Yellow rust (Puccinia striiformis West.) is a harmful disease of cereal crops. Significant yellow rust incidence has systematically been registered on VIR's experimental fields in Derbent (Dagestan) and Pushkin (Northwestern Russia). Resistance assessment and subsequent selection of resistance sources for breeding require proper monitoring of the virulence in the pathogen's local populations. The purpose of this work was to characterize the virulence of P. striiformis on VIR's experimental fields in Derbent and Pushkin, and use molecular markers to find out whether the studied P. striiformis isolates belong to any of the most dangerous invasive groups PstS1 and PstS2. Materials and methods. In Derbent, leaves with urediniopustules were collected from bread and durum wheat accessions; in Pushkin, from bread wheat and triticale plants. The pathogen's virulence was analyzed in the laboratory using the world and European sets of differential cultivars, and isogenic Avocet Yr lines. In 2020, the resistance of differential sets was tested in the field in Derbent under a high natural infection pressure. SCAR markers were used to identify the invasive PstS1 and PstS2 isolates. Results and conclusion. A total of 18 phenotypes (races) of P. striiformis were identified (4 in Derbent, and 14 in Pushkin). The Yr5, Yr10, Yr15, Yr17, Yr24 and Yr26 genes manifested high effectiveness in both locations. In the field, immune responses were observed in the Avocet lines with the Yr5, Yr7, Yr8, Yr10, Yr15, Yr24 and YrAR genes, and in the differential cvs. 'Vilmorin 23', 'Moro', 'Reichersberg 42', 'Heines Peko', 'Nord Desprez', 'Compare', 'Carstens V', 'Spaldings Prolific' and 'Heines VII'. Moderate resistance was recorded for the line Jupateco 73R (damage up to 5%), and cvs. 'Heines Kolben' and 'Strubes Dickkopf' (5-10%). Using molecular markers, 2 isolates from the invasive group PstS2 were identified in the Pushkin collection of P. striiformis.

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Brown rust is the main disease of wheat soft varieties in the Rostov region. The majority of wheat varieties (more than 87%) developed in the FSBSI “Agricultural Research Center “Donskoy” show resistance to this causative agent. In order to obtain a complete immunological characteristics of the developed varieties, there were carried out the researches to identify the resis­tance genes (Lr) in the early and adult stages of plant growing in cooperation with the Mycology and Phytopathology Laboratory of the FSBSI ARIZR. There were studied 37 varieties of winter soft wheat on the infectious fields of the south and northwest of Russia, as well as by the methods of a phytopathological test (to three isolates of the fungus with virulence to TcLr9, TcLr19, TcLr26 and the Zernograd pathogen population) and by the PCR analysis using 10 molecular markers Lr1, Lr3, Lr9, Lr10, Lr19, Lr20, Lr24, Lr26, Lr34 and Lr37. DNA was isolated by a micro-method according to K. Edwards, the PCR was carried out in a C-1000 amplifier (Bio Rad, US). The study established that there were no universal varieties among the studied ones which were resistant to all three clones and the Zergograd population. The varieties “Polina”, “Volnitsa” and “Zernogradka 11” showed resistance to the three clones, but in the phase of sprouting they show susceptibility to the pathogen population. According to the results of PCR analysis, the resistance genes Lr9, Lr19, Lr24, Lr26 were also not found in the varieties. 29 out of 37 studied varieties contained the adult resistance gene Lr34, and 20 varieties had the inefficient gene Lr3, which neither apart nor together could protect the plants from brown rust in the field. This indicates that the tolerant varieties carry additional non-identified Lr-genes. In a number of varieties there have been established 2 resistance genes. The variety “Kipchak” susceptible in the field contained the Lr1 gene, which lost its effectiveness. The differences in the damage degree of some varieties in the conditions of the Rostov region and St. Peters­burg indicate a difference in the North Caucasian and northwestern populations by virulence to the causative agent of brown rust.

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Leaf and stem diseases (rusts and blotches) are harmful to spring wheat in all areas of its cultivation. The use of resistant varieties is an environmentally safe way of protection. The objective of the present study was to comprehensively evaluate leaf and stem disease resistance in 44 promising cultivars of soft spring wheat, as well as to identify Lr‑ and Sr‑genes in them. The accessions were obtained from the Kazakhstan‑Siberian Spring Wheat Improvement Network (KASIB) in 2017 and 2018. Wheat resistance to leaf and stem rust, to septoriosis and to tan spot was evaluated in field conditions in Southern Kazakhstan (infection plot at the Research Institute for Biological Safety Problems). Wheat seedlings resistance to septoriosis, leaf and stem rust was evaluated under laboratory conditions. The Lr and Sr genes were identified using a phytopathological test and molecular markers. Field studies resulted in selection of two lines, Lut. KS 14/09‑2 and SPCHS 69, with highly effective group resistance to rusts and blotches. By using molecular markers, the gene cluster Lr34/Sr57/Yr18/Pm38, Lr1 gene, and wheat‑rye translocation 1BL.1RS carrying genes Lr26/Sr31/Yr9/Pm8 were detected in Lut. KS 14/09‑2. A translocation from wheatgrass with highly effective genes of resistance to stem (Sr24) and leaf (Lr24) rusts, as well as 1AL.1RS translocation from rye with a complex of effective genes of resistance to fungous diseases and pests were detected in the line SPCHS 69. Eight wheat lines (Lut. 393/05, Lut. 2028, Lut. 261, Lut. 1103, Lut. 22‑17, Lut. 37‑17, line 4‑10‑16, Stepnaya 245) appeared to be resistant to Stagonospora nodorum blotch and tan spot; and four varieties (OmGAU‑100, Element 22, Stolypinskaya 2, and Silach) demonstrated resistance to leaf and stem rust. The molecular marker analysis showed moderate genetic diversity of the studied collection in terms of resistance genes. The genes Lr1, Lr9, Lr10, Lr19/Sr25, Lr24/Sr24, Lr26/Sr31/Yr9/Pm8, Lr34/Sr57/Yr18/Pm38, Lr37/Sr38/Yr17, both separately and in different combinations, were detected in the tested accessions. The evaluated material may be recommended for the use in wheat breeding for disease resistance in Russia and in Kazakhstan.

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