Zymoseptoria tritici (Z. tritici) is the main threat to global food security; it is a fungal disease that presents one of the most serious threats to wheat crops, causing severe yield losses worldwide, including in Kazakhstan. The pathogen leads to crop losses reaching from 15 to 50%. The objectives of this study were to (1) evaluate a wheat collection for Z. tritici resistance during the adult plant and seedling growth stages, (2) identify the sources of resistance genes that provide resistance to Z. tritici using molecular markers linked to Stb genes, and (3) identify potentially useful resistant wheat genotypes among cultivars and advanced breeding lines. This study evaluated 60 winter and spring wheat genotypes for Z. tritici resistance. According to the field reactions, 22 entries (35.7%) showed ≤10% disease severity in both years. The resistant reaction to a mix of Z. tritici isolates in the seedling stage was associated with adult plant resistance to disease in four wheat entries. The resistance of Rosinka 3 was due to the presence of Stb8; Omskaya 18 showed an immune reaction in the field and a moderately susceptible reaction in the seedling stage, possibly provided by a combination of the Stb7 and Stb2 genes. The high resistance in both the adult and seedling stages of Omskaya 29 and KR11-03 was due to the Stb4 and Stb2 genes and, possibly, due to the presence of unknown genes. A linked marker analysis revealed the presence of several Stb genes. The proportion of wheat entries with Stb genes was quite high at twenty-seven of the genotypes tested (45.0%), including four from Kazakhstan, nine from Russia, nine from the CIMMYT-ICARDA-IWWIP program, and five from the CIMMYT-SEPTMON nursery. Among the sixty entries, ten (16.7%) carried the resistance genes Stb2 and Stb8, and the gene Stb4 was found in seven cultivars (11.6%). Marker-assisted selection can be efficiently applied to develop wheat cultivars with effective Stb gene combinations that would directly assist in developing durable resistance in Kazakhstan. Resistant genotypes could also be used as improved parents in crossing programs to develop new wheat cultivars.

Septoria is one of the harmful diseases of wheat cultivars cultivated in the Saratov region. This infectious disease of fungal etiology limits yield indicators and rapidly progresses in many regions of the Russian Federation. The aim of the research was to assess the resistance of winter and spring wheat cultivars that are referred to as promising and recommended for cultivation in the Low Volga region of the Russian Federation to pathogens of Septoria, to study the populations of Parastagonospora nodorum and P. pseudonodorum in the territory of the Saratov region in order to detect the presence of effector genes. Using molecular markers, we performed the identification of genes encoding NEs in 220 Parastagonospora spp. fungal isolates obtained from 7 cultivars of soft winter wheat, 6 taken from the winter triticale, 5 from soft spring wheat, 3 from durum spring wheat and 1 from spring oats. Among the P. nodorum isolates studied, there were both single genes Tox1, Tox3, and ToxA, and combinations of two genes in one genotype. The presence of the ToxA gene was not noted in the genotype of P. pseudonodorum isolates. During 2020–2022, a collection of winter and spring wheat cultivars was studied to detect resistance to Septoria blotch in field conditions (13 cultivars of winter wheat and 7 cultivars of spring wheat accordingly). The resistance of the cultivars was proven by laboratory evaluation. Three inoculums were used, including the isolates of Z. tritici, P. nodorum (ToxA, Tox1, Tox3), P. pseudonodorum (ToxA, Tox1, Tox3) mainly obtained from Saratov populations of 2022 (except for P. pseudonodorum with the ToxA gene). The tested cultivars were characterized using the Xfcp623 molecular marker, diagnostic for Tsn1/ tsn1 genes, which controls sensitivity to the fungal toxin of PtrToxA. Of greatest interest are 11 wheat genotypes that showed resistance to one, two and three species which served as causative agents of Septoria blotch (Zymoseptoria tritici, P. nodorum, P. pseudonodorum). These are the soft winter wheat cultivars Gostianum 237 (tsn1), Lutescens 230 (Tsn1), Guberniya (Tsn1), Podruga (Tsn1), Anastasia (Tsn1), Sosedka (Tsn1) and the soft spring wheat cultivars Favorit (tsn1), Prokhorovka (tsn1), Saratovskaya 70 (tsn1), Saratovskaya 73 (tsn1), Belyanka (tsn1). The results obtained are of interest as they might increase the efficiency of selection based on the elimination of genotypes with dominant Tsn1 alleles sensitive to PtrToxA. In addition to the economic value of the cultivars studied, it is recommended to use them in breeding for resistance to Septoria blotch.

One of the important tasks of agricultural production is an opportunity to predict changes in the pathogenic complex of grain crops. It is important not only to identify presence of certain pests, but also to estimate a degree of pathogen development, a role of the host varieties, their immunological potential. The species S. tritici occupies a leading position among the pathogenic complex of septorious spots. Most commonly the species S. tritici was identified on the winter varieties “Moskovskaya 39” and “Severodonetskaya Yubileynaya” with a frequency of occurrence of 90%. The same situation was identified among spring wheat varieties. The species S. nodorum occupies the second position in the distribution of septorious spots in the pathogenic complex. The species S. avenae was significantly inferior to the first two. For each variety being tested, the degree of damage made by a separate type of septoria was calculated according to the frequency of occurrence of each type of pathogen (a species composition) and the plant incidence of septoria. Among the spring soft wheat varieties, there can be identified “L 503”, “Favorit”, “Tulaykovskaya 10”. The septoria incidence degree of these varieties was 27.9%, 23.6%, and 29.3% respectively. Since the S. tritici occurrence in these varieties was more often compared to others (84%, 78%, and 83%, respectively), these varieties can be classified as poorly susceptible to the pathogen. The spring durum wheat varieties are more resistant to Septoriosis. The variety “Orenburgskaya 10” is found the best in this trait with only 17.1% incidence degree. The variety “Krasnokutka 10” showed the largest incidence degree (37.9%). Using the F-test (Fisher test) and the multiple comparisons (Bonferroni-Holm method), there has been shown a significant effect of the agroclimatic year conditions, a life form and the species on the formation of the species composition of Septoria spots. At the same time, the ratio of the species S. tritici, S. nodorum, S. avena throughout all years of study remains stable.

Background. Leaf and stem diseases of cereal crops are among the most harmful in the agrocenoses of Tambov Province, significantly reducing grain yield and rapidly progressing in many regions of Russia. The aim of the study was to identify spring bread wheat lines and cultivars developed at the Middle-Russian Branch of the I.V. Michurin Federal Science Center that show resistance to leaf and stem diseases.Materials and methods. The target material was represented by 3 cultivars and 23 breeding lines of spring bread wheat. Disease resistance in seedlings was assessed in the laboratory, while for adult plants the process was carried out in the field in 2020–2022. The presence of the Tsn1 allele controlling susceptibility to the PtrToxA fungal toxin was detected using the Xfcp623 molecular marker.Results and conclusions. Accessions with high levels of resistance to Zymoseptoria tritici were identified: L-8252, L-82/60, L-8107, L-8078(23), L-43-9, L-43-1, L-4, Stb-8/15, Stb-7/15, and Stb-92. Accessions Stb-97, Stb-89, Stb-89(a), Stb-90, Stb-34, and Rl-6-22 were resistant to Parastagonospora nodorum; L-8134, L-8114, L-82/60, L-8107, Stb-10/15, Stb-9/15, Stb-8/15, Stb-7/15, Stb-97, Stb-89, Stb-89(a), Stb-90, Stb-34, and Rl-6-22 to P. pseudonodorum; L-8252, L-8107, L-43-9, L-43-1, L-4, Stb10/15, Stb-9/15, Stb-97, Stb-92, Stb-92(a), Stb-89, Stb-89(a), and Stb-34 to Pyrenophora tritici-repentis; and L-8114, L-82/60, L-43-9, L-43-1, L-4, Stb-90, Stb-34, and Rl-6-22 to Bipolaris sorokiniana. The cultivars and breeding lines showed group resistance to two, three or four pathogens. It was Lines L-8252, L-8134, L-82/60, L-8107, L-8078 (23), L-43-9, L-43-1, L-4, Stb-89, Stb-90, Stb-34, and L-33809-7-3 were observed to carry the recessive allele of the tsn1 gene.

Septoria tritici blotch is one of the harmful diseases of wheat cultivars cultivated in the Russian Federation and the Republic of Kazakhstan. The purpose of the research was to study a sample of Zymoseptoria tritici isolates obtained from the Saratov and Tambov (Russian Federation) and Almaty (Republic of Kazakhstan) regions according to the degree of the azoxystrobin sensitivity, as well as to evaluate these isolates for the presence of the G143A mutation using PCR-RFLP analysis. The azoxystrobin sensitivity of Z. tritici isolates was evaluated by studying the growth restriction of cultures on a nutrient medium (concentrations of active drug in the medium were 100, 10, 1, 0.1, 0.01 mg/l.). In the control, on the 21st day of cultivation, the diameter of the colonies of Z. tritici strains varied from 14.24±1.43 mm to 19.53±0.66 mm. Azoxystrobin had a significant inhibitory effect on the growth of fungal isolates from the Tambov region: EC50 is 1.72 μg/l, from the Almaty region EC50 is 2.36 μg/l, from the Saratov region EC50 is 2.63 μg/l. The results of biotesting made it possible to identify isolates of Z. tritici resistant to azoxystrobin: 277-22-5, 277-22-13 (from Kazakhstan); 104-23-9, 104-23-10 (from the Saratov region); 19-23-5, 19-23-8 (from the Tambov region). PCR-RFLP method made it possible to identify mitochondrial mutations G143A in selected fungal isolates, which are associated with the development of resistance to fungicides in the causative agent of septoria. This work is the beginning of a more in-depth study of the sensitivity of the economically significant phytopathogen Z. tritici to fungicides in the territories of Russia and the Republic of Kazakhstan.

Triticum aestivum L. (bread wheat) is the most important cereal crop in world grain production, including in the territory of the Russian Federation. One of the most important factors influencing the yield and quality of wheat grain is the affection of plants with leaf rust (Puccinia triticina Erikss.). To broaden the set of sources for effective rust resistance, spring bread wheat samples from N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) were monitored for adult resistance to the disease under natural infections for many decades at three distant locations of the Russian Federation: the Dagestan Experimental Station (DES) of VIR (10,549 accessions), Yekaterinino Experimental Station (YES) (4384 accessions), and Pushkin Experimental Field (PEF) (7704 accessions). Information on the disease development at these three stations is presented at least for 51 last years. As a result of disease development evaluation under natural epiphytotic conditions for not less than 3 years, 293 (15 landraces, 127 breeding lines, and 151 commercial varieties), 118 (1 landrace, 38 breeding lines, and 79 commercial varieties), and 127 (10 landraces, 48 breeding lines, and 69 commercial varieties) samples were classified as resistant to leaf rust at DES, YES, and PEF, respectively. Among samples from the State Register of Breeding Achievements in Russia, 15, 13, and 8 spring wheat varieties were resistant to leaf rust at DES, YES, and PEF, respectively. Juvenile resistance was estimated under laboratory conditions after seedling inoculation with a complex population of P. triticina: 73 highly resistant varieties and breeding lines were identified; all landraces, including those classified as resistant in the fields, were susceptible to disease at the seedling stage. A total of 26 wheat accessions were identified to be resistant to leaf rust at two to three locations; 14 of them possess adult resistance, and 12 samples have seedling resistance. According to results of PCR amplification with primers specific to markers of effective genes for leaf rust resistance, 6 accessions have gene Lr9, 1 sample is protected by Lr19, and 1 sample possesses gene Lr24. Wheat samples identified as possessing effective seedling or adult resistance could be of interest for breeding in some regions of the Russian Federation and other countries.