The high yield potential of winter wheats cannot be realized due to disease pressure under field conditions. One of the most harmful of such diseases is stem rust, hence the constant search for sources of resistance and the development of new varieties resistant to stem rust is of great relevance. This study deals with the identification of stem rust resistance genes in a collection of winter wheats grown in Southern Russia. This genepool has not been studied yet. A total of 620 samples of winter soft wheat from various ecological and geographical zones were tested under field conditions. To identify the specific genes or alleles responsible for resistance, all samples were genotyped using PCR. As a result, the groups of resistant samples, carrying the Sr2, Sr31, Sr38 and Sr44 genes in various combinations, were identified. Most of the stem rust resistance was provided by the presence of the effective Sr44 gene. This information can be used in the future breeding work for stem rust resistance.

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.

Systematic work on the development of winter wheat varieties possessing resistance to a complex of the most harmful diseases has been carried out in the Agricultural Research Center “Donskoy” since the early 1970s. During this period, there has been created a large number of varieties that possess resistance to 3–4 diseases in conditions of infectious backgrounds of pathogens. Due to the analysis of varieties, there was identified a small number of varieties resistant to powdery mildew. Powdery mildew, caused by the fungus Blumeria graminis (DC) Speer, annually occurs on wheat, affecting all aboveground plant organs. Earlier the FSBSI “ARC “Donskoy” developed and widely cultivated the medium-resistant varieties ‘Tanais’ (2006), ‘Nakhodka’ (2015), ‘Etyud’, ‘Shef’, ‘Lilit’ (2016), ‘Volnitsa’ (2017), ‘Polina’, Yubiley Dona’ , ‘Podarok Krymu’ (2018), ‘Niva Dona’ (2019). In recent years, breeders have developed such varieties with high resistance to the pathogen as ‘Donskaya Step’ (2016), ‘Premiera’, ‘Univer’ (2018), ‘Priazovye’, ‘Zolotoy Kolos’ (2020). But the breeding process of varieties for resistance to powdery mildew is difficult, since it is explained by the small number of effective resistance genes and their sources. Therefore, the purpose of the current study was to identify new sources of resistance to the pathogen. Under the conditions of artificial infection, during last 10 years there was conducted a testing of 302 varieties and samples of winter wheat of domestic and foreign breeding. There have not been identified immune varieties. There was identified a small percentage (15.2) of varieties that were resistant to the pathogen. Among the Russian varieties they were ‘L 3191 k-5-8’, ‘Akhmat’, ‘Alievich’, ‘Barier’, ‘Ulyasha’, ‘Knyaginya Olga’, which were not attacked by the disease over the years of testing. Among foreign varieties, the varieties ‘Bombus’, ‘Sailor’ (France), ‘Etana’, ‘Rotax’, ‘KVS-Emil’ (Germany), ‘Fidelius’ (Austria), ‘MV 09-04’ (Hungary) were identified as the best ones in their resistance to powdery mildew. All identified sources of resistance have been recommended in breeding programs for immunity.

В статье представлены результаты совместных многолетних иммунологических исследований сортов и селекционных линий озимой пшеницы селекции ФГБНУ «АНЦ «Донской» к северокавказской популяции возбудителя желтой ржавчины, проведенные при искусственном заражении в различных агроэкологических условиях (г. Зерноград, Ростовская область-ФГБНУ «АНЦ «Донской» и г. Краснодар-ФГБНУ «ВНИИБЗР»). Желтая ржавчина (возбудитель Puccinia striiformis f. sp. tritici West.) является опасным заболеванием пшеницы во всех регионах мира, возделывающих зерно, в том числе и на юге России. В годы с благоприятными условиями потери урожая пшеницы от данного патогена могут достигать 70-100%. Одним из наиболее эффективных методов защиты пшеницы является выращивание устойчивых к патогену сортов. Для их создания необходим регулярный скрининг источников устойчивости среди сортов и линий пшеницы различной селекции. В условиях полевых стационаров ФГБНУ «АНЦ «Донской» (2014-2016 гг.) и ФГБНУ «ВНИИБЗР» (2017-2019 гг.) на искусственных инфекционных фонах P. striiformis прошли испытание селекционные и коллекционные сорта и сортообразцы пшеницы, созданные в отделе селекции и семеноводства озимой пшеницы ФГБНУ «Аграрный научный центр «Донской». На протяжении 40 последних лет донские селекционеры, привлекая различные источники и доноры устойчивости, создавали сорта пшеницы с высокой устойчивостью к основным болезням, в том числе и к желтой ржавчине. Это сорта Донская безостая, Дон 85, Донщина, Колос Дона, Зерноградка 8, Дон 93, Дон 95, Донской маяк и др. В результате проведенных исследований в различных агроклиматических зонах среди изученного материала установлена высокая доля (от 52,0 до 87,3%) устойчивых к желтой ржавчине сортов и сортообразцов. Высокую устойчивость, по многолетним данным, проявляют сорта озимой мягкой пшени

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