Identification of leaf rust resistance genes in the new Russian varieties of common wheat

Background. Wheat leaf rust caused by Puccinia triticina Erikss. is a significant wheat disease in all regions of the Russian Federation. The genetic diversity of the cultivated wheat varieties regarding the type of resistance and genes that control it ensures reliable protection of this crop against the pathogen. The aim of this work was to characterize the diversity of new Russian varieties of winter and spring common wheat for leaf rust resistance genes (Lr-genes).Materials and Methods. The research material was represented by 43 varieties of winter and 25 of spring wheat included in the State Register of Selection Achievements of the Russian Federation in 2018-2020.Results. Using molecular markers, 18 Lr genes were identified: Lr1, Lr3, Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, Lr25, Lr26, Lr28, Lr29, Lr34, Lr35, Lr37, Lr41 (39), Lr47 and Lr66. A phytopathological test was used to clarify the results of molecular analysis. Ninety-three percent of the studied wheat varieties were found to contain Lr genes, either separately or in combinations. These were the highly and partially effective genes Lr24, Lr9, and Lr19, adult plant resistance genes Lr34 and Lr37, and ineffective genes Lr1, Lr3, Lr10, Lr20, and Lr26. The Lr24 gene has been identified for the first time in Russian varieties. The spring variety ‘Leader 80’, harboring this gene, is recommended for cultivation in the West Siberian and East Siberian regions. An effective combination of Lr9 + Lr26 genes, individually overcome by the pathogen, was determined in the spring cultivar ‘Silach’, highly resistant to leaf rust. The Lr9 gene was found in the winter variety ‘Gerda’, which is recommended for cultivation in the North Caucasus region. Previously, the varieties with Lr9 were not grown in the North Caucasus. An increase in the number of leaf rust resistant accessions protected by the effective adult plant resistance gene Lr37 is noted among wheat varieties undergoing regional adaptation testing. Many of the identified Lr genes (Lr19, Lr24, Lr26, Lr34, Lr37) are linked with effective Sr genes (Sr25, Sr24, Sr31, Sr57, and Sr38), which additionally ensures stable genetic protection of wheat against stem rust.Conclusions. The obtained information about representation of Lr genes in wheat varieties should be used in regional breeding programs. A timely replacement of genetically protected varieties allows stabilizing the populational composition of the phytopathogen and reducing the likelihood of epiphytotics

Characterization of commercial common wheat cultivars for resistance to tan spot causative agent

Tan spot of wheat (pyrenophorosis) is a worldwide spread and economically significant disease of wheat. Growing resistant cultivars is an environmentally friendly method of disease control. The aim of the present work was to assess tan spot resistance in common wheat cultivars recommended for cultivation in the Russian Federation, and to identify the dominant Tsn1 allele using a molecular marker. The assessment involved 39 winter and 31 spring wheat cultivars included in the State Register of Selection Achievement in 2018-2020. Evaluation of wheat resistance was carried out in laboratory conditions under artificial inoculation of seedlings and leaf segments. Two isolates of Pyrenophora tritici-repentis (Died.) Drechs, producing ToxA toxin (I_ToxA) and ToxB toxin (ToxB) were used. The dominant allele of the Tsn1 gene was identified using the Xfcp623 marker. A high level of resistance (R) to both isolates (I_ToxA and I_ToxB) was shown by spring cultivars ‘Grenada’ and ‘Silach’; moderate resistance (MR) was demonstrated by winter cultivars ‘Felicia’ and ‘Akhmat’ and spring cultivars ‘Omskaya 42’, ‘Zauralskaya Zhemchuzhina’, ‘Radmira’, ‘Tarskaya 12’ and ‘Extra’. A resistant reaction (R, MR) to the isolate I_ToxA was typical for 26% of winter cultivars and 45% of spring ones. The number of cultivars resistant to the I_ToxB isolate was significantly higher (59% and 52%, respectively). The total fraction of cultivars resistant to the isolate I_ToxA (reaction R, MR) in the collection of winter wheat was 26% and 45% in the spring wheat collection; while the fractions of cultivars resistant to the I_ToxB isolate in these collections were equal to 59% and 52%, respectively. By using the Xfcp623 marker, the diagnostic product was amplified in winter cultivars ‘Bodry’, ‘Kavalerka’, ‘Timiryazevka 150’, ‘Shef’, ‘Anastasia’, ‘Barynya’, ‘Donskaya Step’, ‘Elanskaya’ and spring cultivars ‘Odeta’, ‘Stolypinskaya 2’, ‘Iren’ 2’ and ‘OMGAU 100’. All these cultivars were moderately susceptible to the isolate I_ToxA, with the exception of ‘Odeta’ and ‘Iren’ 2’, which may indicate a decrease in the expression level of the ToxA gene in genotypes of these cultivars

POPULATION GENETICS STUDY OF THE WHEAT LEAF RUST AGENT PUCCINIA TRITICINA IN DAGESTAN

Background. Leaf rust (causative agent Puccinia triticina Erikss.) is a harmful disease of wheat, Aegilops and triticale in Dagestan.  Germplasm collections of bread wheat and other Triticum and  Aegilops species are studied every year in the experimental field at  the Dagestan Experimental Station of VIR (DES VIR), and evaluated  for leaf rust resistance. Monitoring of the pathogen's virulence makes it possible to assess the dynamics of the fungus's  variability and correct the results of phytopathological scores  performed in different years. The study of the Derbent population  has a long history, and has been conducted since 1970. The aim of  this work is to analyze the virulence of the P. triticina population in 2008-2017.Materials and methods. Infectious material was represented by  leaves of bread wheat with uredopustules collected in the experimental field of DES VIR in 2008, 2009, 2011, 2014, 2016, and 2017. Populations were cloned to obtain monopustule isolates. For  this and for virulence analysis, the laboratory technique of detached  leaves preserved in the benzimidazole solution was used. In total,  144 isolates were employed in virulence studies: 32 in 2008, 37 in  2009, 14 in 2011, 14 in 2014, 26 in 2016, and 21 in 2017.Results and discussion. The genes Lr9, Lr19, Lr24, Lr28, Lr29, Lr41, Lr42, Lr45, Lr47, Lr50, Lr51, Lr53, and Lr65 were  characterized by high efficiency. This means that wheat samples  protected by these genes will demonstrate high-level resistance in  the fields of southern Dagestan. Variations in virulence frequencies  were recorded in Thatcher lines (Tc) with the genes Lr1, Lr2a, Lr2b,  Lг2с , Lr3a, Lr3bg, Lr15, Lr16, Lr20 and Lr26. Using 20 almost  isogenic Thatcher lines (TcLr), 20 phenotypes (races) of the  pathogen were identified. Indexes of genetic distances (Nei and Fst)  indicated at the changes in the structure of the Derbent population in 2014-2017, when compared with 2008-2011. The long- term dynamics analysis (1970-2017) of P. triticina virulence using 10  TcLr lines revealed certain stability in the Derbent population  structure in 1970-2011 and its changes in the subsequent period

Intraspecific variability of Puccinia triticina on hexaploid Triticum species and Aegilops trivialis

The analysis of pathogen intraspecific differentiation is a necessary stage for the development of a strategy of wheat leaf rust resistance breeding. To characterize the structure of the populations, virulence to Thatcher lines with leaf rust resistance genes (TcLr) and microsatellite markers may be used. The purpose of the present research is to study the intraspecific variability of the fungus Puccinia triticina Erikss. on Triticum L. hexaploid species and Aegilops trivialis (Zhuk.) Migusch. et Chak. using SSR-markers. Leaves of Triticum aestivum L., T. compactum Host., T. macha Dekapr. et Menabde, T. petropavlovskyi Udacz. et Migusch., T. spelta L., T. sphaerococcum Perc., T. vavilovii Jakubz. and Ae. trivialis with uredinia were collected on the experimental field of the Dagestan experiment station of VIR (Derbent) in 2014. For SSR-analysis 109, monopustule isolates previously characterized for virulence to 20 TcLr-lines were used. As a result of 18 microsatellite loci polymorphism analysis, 16 genotypes were identified. Genetic similarity between collections of isolates from the hexaploid types of wheat was significantly higher based on microsatellite markers than based on virulence. Microsatellite analysis confirmed a high similarity between Derbent isolates of P. triticina coming from the hexaploid Triticum species (including isolates from common wheat) and Aegilops trivialis

Resistance of synthetic hexaploid wheat to the leaf rust pathogen

Background. One of the promising sources for enrichment of the common wheat (Triticum aestivum L.) gene pool with new alleles is synthetic hexaploid wheat (SHW), or allopolyploids from crossing tetraploid wheats (2n = 4x = 28, BBAA) with accessions of Aegilops tauschii Coss. (2n = 2x = 14, DD), and subsequent doubling of the chromosome number in the hybrids. Objectives of the study were to evaluate the SHW accessions from the VIR collection for resistance to Puccinia triticina Erikss. populations collected in Russia; genotype the accessions; and summarize information from the published sources concerning the resistance of the studied accessions to other harmful diseases and pests.Materials and methods. Resistance of 36 SHW accessions from the VIR collection to the populations of P. triticina was assessed in the laboratory and in the field, under artificial infection pressure, using the techniques developed by the Institute of Plant Protection. A phytopathological test and PCR markers were used to identify the Lr genes.Results and conclusion. The SHW accessions were characterized according to their resistance to the Russian populations of the wheat leaf rust pathogen. The sources of resistance in the phase of emergence and in adult plants were identified. The phytopathological test isolated three accessions with Lr23; the PCR marker of Lr21=Lr40 was found in 11 accessions, Lr39=Lr41 in 19, and Lr22a in 3. At the same time, k-65496, k-65515 and k-65517 had si multaneously Lr21=Lr40 and Lr39=Lr41, while k-65497, k-65503 and k-65508 had Lr22a and Lr39=Lr41. The analysis of published data showed that many of the studied SHW accessions were also resistant to other harmful diseases and insect pests, so they are of interest for further studying and possible use in domestic breeding

Characteristics of virulence of Puccinia triticina populations and the potential of the Lr24, Lr25, LrSp genes for spring common wheat breeding in the Southern Ural

Monitoring of pathogen populations is important for successful genetic wheat protection against leaf rust and identification of pathotypes with virulence to the resistance genes used. The aim of this work was analysis of Puccinia triticina populations in the Chelyabinsk region for virulence and studying the effectiveness of Lr-genes at the field for improving and stabilization of genetic protection from wheat leaf rust in the Southern Urals. Infection materials were collected in the experimental field of the Сhelyabinsk Research Institute of Agriculture from breeding lines, commercial and perspective wheat varieties in 2014–2016. In total, 383 single pustule isolates were studied: 180 in 2014, 131 in 2015, and 72 in 2016. The Lr24 gene was characterized as highly effective. The single isolate virulent to ТсLr19 line was revealed only in 2014. Isolates virulent to the Lr9 gene occurred annually both on the varieties carrying this gene and those without it, and all of them were characterized by avirulence to the Lr26 gene. According to the Nei index (N), no significant differences in virulence were revealed between Chelyabinsk populations in 2014–2016. 27 virulence phenotypes were determined using 20 TcLr-lines. The phenotypes TQTTR and TGTTR avirulent to lines ТсLr19, ТсLr24, ТсLr26 and ТсLr9, ТсLr19, ТсLr24, ТсLr26, respectively, were common in 2014–2016. The results on the effectiveness of Lr-genes at the seedling stage correlated with estimates for Thatcher Lr-lines, breeding materials and varieties with known Lr-genes grown at the field on the breeding nursery of the Сhelyabinsk Research Institute of Agriculture. The highly effective genes Lr24, Lr25, Lr28, Lr29, Lr37 and some others were found to have promise for use in wheat breeding in the Ural. The use of these genes and combination of these genes with non-effective ones will allow the genetic diversity of new wheat varieties to be increased and the fungus populations to be stabilized. By now, at the field conditions in the Ural region, the effective combinations of Lr-genes revealed are Lr9+Lr19, Lr9+Lr26, Lr9+Lr37, Lr9+Lr10+Lr26, and Lr9+Lr26+Lr37

The effect of the 7DL-7Ae#1L·7Ae#1S translocation on the productivity and quality of spring bread wheat grain

The 7DL-7Ae#1L·7Ae#1S translocation with the Lr29 gene attracts the attention of bread wheat breeders by its effectiveness against Puccinia triticina. However, its impact on useful agronomic traits has been little studied. In this report, the prebreeding value of 7DL-7Ae#1L·7Ae#1S was studied in analogue lines (ALs) of spring bread wheat cultivars Saratovskaya 68 and Saratovskaya 70 during 2019–2021. The presence of the Lr29 gene was conf irmed by using molecular marker Lr29F24. The ALs with the Lr29 gene were highly resistant to P. triticina against a natural epiphytotics background and in laboratory conditions. 7DL-7Ae#1L·7Ae#1S in Saratovskaya 68 ALs reduced grain productivity in all years of research. On average, the decrease was 35 and 42 %, or in absolute f igures 1163 and 1039 against 1802 kg/ha in the cultivar-recipient. In Saratovskaya 70 ALs, there was a decrease in grain yield in 2019 and 2020, and there were no differences in 2021. On average, the decrease was 18 and 32 %, or in absolute f igures 1101 and 912 against 1342 kg/ha in the cultivar-recipient. The analogues of both cultivars showed a signif icant decrease in the weight of 1000 grains, which ranged from 14 to 20 % for Saratovskaya 68 and 17–18 % for Saratovskaya 70. An increase in the period of germination-earing was noted only in Saratovskaya 68 lines, which averaged 1.3 days. ALs of Saratovskaya 70 had no differences in this trait. 7DL-7Ae#1L·7Ae#1S did not affect plant height and lodging resistance in all ALs. Studies of the bread-making quality in lines with 7DL-7Ae#1L·7Ae#1S revealed a signif icant increase in grain protein and gluten content. As for the effect on the alveograph indicators, there were differences between ALs of both cultivars. While Saratovskaya 68 ALs had a decrease in elasticity and in the ratio of dough tenacity to the extensibility, Saratovskaya 70 lines had an increase in these indicators. All lines increased the f lour strength and the loaves volume, but while Saratovskaya 68 ALs had an increased porosity rating, Saratovskaya 70 ALs had the same rating as the recipient

Population genetics studies of <i>Puccinia striiformis</i> f. sp. <i>tritici</i> in Dagestan and Northwestern Russia

Background. Yellow rust (Puccinia striiformis West.) is a harmful disease of cereal crops. Significant yellow rust in cidence has systematically been registered on VIR’s experimental fields in Derbent (Dagestan) and Pushkin (North western 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 uredinio pustules 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 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

Virulence diversity of the yellow rust pathogen population in Dagestan

Background. Yellow rust incidence on Triticum L. has been observed to surge up in Dagestan in recent years, facilitating selection of highly resistant genotypes. Information on the effectiveness of Yr genes and the pathogen’s virulence and racial composition is needed to interpret field assessment data correctly. The objective of this study was to describe the virulence of the Dagestan population of Puccinia striiformis West. at the seedling stage, evaluate the resistance of differentiators to yellow rust in the field, and identify invasive PstS1 and PstS2 races.Materials and methods. Leaves with urediniopustules were collected from bread wheat accessions at Dagestan Experiment Station of VIR (DЕS VIR) in 2020–2022. Virulence was analyzed in the laboratory using 14 AvYr lines (Avocet NIL) and 15 differential wheat cultivars. Age-specific resistance of virulence testers under high natural infection pressure was studied in the field of DES VIR. A set of SCAR markers (SCP19M24a1, SCP19M24a2, SCP19M26a1, and SCP19M26a2) were used to identify invasive races.Results and discussion. Avocet lines with Yr5, Yr10, Yr15, Yr24, and Yr26, and cv. ‘Moro’ (Yr10, YrMor) manifested resistance to all isolates. Virulence to Yr17 was detected only in the isolates from cvs. ‘Graf’ and ‘Svarog’ carrying this gene, and ‘Siete Ceros’. The Dagestan collection demonstrated high genetic diversity. Common phenotypes were identified on cv. ‘Graf’ in 2021 and 2020. There was no temporal differentiation between pathogen collections in the years of testing. High field resistance to yellow rust was recorded in lines with Yr5, Yr8, Yr10, Yr15 and Yr24, and in cvs. ‘Moro’, ‘Compair’, ‘Carstens’ and ‘Spaldings Prolific’. Cvs. ‘Reichersberg 42’ and ‘Heines Peko Vilmorin 23’ were resistant in 2020 and 2022, and moderately affected (up to 10%) in 2021. Molecular analysis identified all three isolates belonging to the invasive PstS2 group on cv. ‘Siete Cerros’ and L 650 in 2021, and cv. ‘Vassa’ in 2022

Assessment of age passport and biological

В статье, по таблице В. Сухова, представлена оценка паспортного и биологического возраста студентов, занимающихся в отделении оздоровительной физической культуры и отнесенных по состоянию здоровья к специальной медицинской или подготовительной группе.Assessment of passport and biological age of the students who are engaged in office of the improving physical culture and carried for health reasons to special medical or preparatory group is presented in article, according to V. Sukhov's table