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Genome-wide association studies (GWAS) are among the genetic tools for the mining of genomic loci associated with useful agronomic traits. The study enabled us to find new genetic markers associated with grain yield as well as quality. The sample under study consisted of spring wheat cultivars developed in different decades of the last century. A panel of 186 accessions was evaluated at VIR's experiment station in Pushkin across a 3-year period of field trials. In total, 24 SNPs associated with six productivity characteristics were revealed. Along with detecting significant markers for each year of the field study, meta-analyses were conducted. Loci associated with useful yield-related agronomic characteristics were detected on chromosomes 4A, 5A, 6A, 6B, and 7B. In addition to previously described regions, novel loci associated with grain yield and quality were identified during the study. We presume that the utilization of contrast cultivars which originated in different breeding periods allowed us to identify new markers associated with useful agronomic characteristics. [ABSTRACT FROM AUTHOR]

Background. Improving the grain quality of modern spring bread wheat cultivars is a highly relevant task of breeding. To solve this problem, old and local wheat varieties (landraces) are of considerable interest. A rich collection of them is available among the plant genetic resources preserved at VIR. With this in view, the aim of this research was to identify sources of high protein, gluten, macro- and micronutrient content out of the landraces from the VIR collection for improvement of wheat grain quality through breeding.Materials and methods. Field and laboratory research were conducted in the experimental field of Omsk State Agrarian University under the conditions of the southern forest-steppe of Western Siberia in 2020–2021. Sowing was carried out on fallow on conventional sowing dates. Mineral composition in the grain of the studied landraces was analyzed at the Kurchatov Genomic Center, Novosibirsk, using atomic absorption spectrometry techniques.Results. The research results showed that landraces from different regions of Russia, Kazakhstan, Tajikistan, and Kyrgyzstan were characterized by high levels of protein (18.4–18.8%) and gluten (35.9–36.0%) in grain. Landraces from Kazakhstan had low Zn content (on average 38.3 mg/kg), while those from Kyrgyzstan, on the contrary, had high content of Zn (41.9 mg/kg) and Fe (55.1 mg/kg), and landraces from Tajikistan had high K content (3820 mg/kg). A positive relationship between the concentrations of Mg, Mn, Fe, and Zn was found in the grain of wheat landraces.Conclusion. Wheat landraces are of interest as genetic resources for the development of high-protein cultivars with improved nutritional value of grain for the milling and breadmaking industries.

The occurrence of two types of cultivars of spring bread wheat of Canada that differ in their necrotic genotypes was shown. The cultivars of one type had the ne1ne1Ne2Ne2 genotype, and the cultivars of the second type had the ne1ne1ne2ne2 genotype. The Ne1Ne1ne2ne2 genotype was not found. The Ne2 genes were represented by alleles of medium strength, ms, and strong alleles, s. By pedigree analysis, the donors of the Ne2 gene were identified. [ABSTRACT FROM AUTHOR]

Genome-wide association studies (GWAS) are among the genetic tools for the mining of genomic loci associated with useful agronomic traits. The study enabled us to find new genetic markers associated with grain yield as well as quality. The sample under study consisted of spring wheat cultivars developed in different decades of the last century. A panel of 186 accessions was evaluated at VIR’s experiment station in Pushkin across a 3-year period of field trials. In total, 24 SNPs associated with six productivity characteristics were revealed. Along with detecting significant markers for each year of the field study, meta-analyses were conducted. Loci associated with useful yield-related agronomic characteristics were detected on chromosomes 4A, 5A, 6A, 6B, and 7B. In addition to previously described regions, novel loci associated with grain yield and quality were identified during the study. We presume that the utilization of contrast cultivars which originated in different breeding periods allowed us to identify new markers associated with useful agronomic characteristics.

There has been presented the information on the purposeful process of developing the spring bread wheat variety ‘Arseya’, which was included in the state list of breeding achievements of the Russian Federation in the Central Region in 2020. The mean productivity of the variety plots of the Central region was 3.0 t/ha, the maximum productivity of 4.8 t/ha was obtained in the Bryansk region in 2018. The purpose of the current study was to estimate the valuable traits of the new spring bread wheat variety ‘Arseya’ with the zoned varieties of the Central region in a comparative analysis. As a result, there was found that the mean productivity of the variety ‘Arseya’ was 4.94 t/ha in the competitive variety testing for 2015–2020. Through the years of study, the lowest and highest levels of productivity exceeded the standard values of the variety ‘Agata’ on 0.30–0.49 t/ha. The comparative analysis of the varieties zoned in the Central Region showed that the new variety ‘Arseya’ exceeded them in productivity on 0.50–0.88 t/ha, or 10.1–17.8% on average. There was established that the highest level of productivity was formed under the optimal weather conditions of 2017. The largest productivity values were given by the varieties ‘Dariya’ and ‘Arseya’ with 6.28 t/ha and 5.72 t/ha, respectively. The lowest productivity range was identified in the varieties ‘Agata’ and ‘Arseya’ with 11.6% and 11.9%, respectively. The variety ‘Arseya’ under the generally accepted cultivation technology, showed the productivity potential by 86%. When calculating the stability factor (S.F.) indicators and the productivity range (d), there has been identified that the varieties ‘Agata’ and ‘Arseya’ have the lowest values of 1.33 and 1.35, i.e. 24.7% and 25.9% respectively. The spring bread wheat variety ‘Arseya’ is fully adapted to local agroclimatic conditions.

Background. The knowledge of genetic control of vernalization response in the ultra-early accessions can facilitate bread wheat breeding for a high adaptive capacity. Materials and methods. The study involved the ultra-early lines Rico (k-65588) and Rimax (k-67257) as the earliest maturing lines in the VIR bread wheat collection, as well as 10 Rifor lines (k-67120, k-67121, k-67250-67256) with a high rate of development before heading. A late ripening accession ‘Forlani Roberto’ (k-42641) and ‘Leningradskaya 6’ variety (k-64900), regionally adapted to Northwestern Russia, were also studied. The alleles of the Vrn and Ppd genes were identified by the PCR analysis using the allele-specific primers published in literature sources. The response to vernalization (30 days at 3°C) and a short 12-hour day were determined using a methodology accepted at VIR. Results. The ultra-early lines respond to a short 12-hour day and 30-day vernalization very poorly. The genotype of ultra-early wheat lines is mainly represented by three genes, Vrn-A1, Vrn-B1a, and Vrn-D1, which ensure insensitivity to vernalization alongside with the expression of Ppd-D1a, which controls the response to photoperiod. The ultra-early lines Rifor 4 and Rifor 5 have a recessive allele vrn-A1a, like the original ‘Forlani Roberto’ accession. The lines Rifor 4 and Rifor 5 are vernalization-insensitive under the long day and have a very weak response under the short day (3.5±0.42 days and 4.0±0.61 days, respectively). However, ‘Forlani Roberto’ with the vrn-A1a gene responds to vernalization in the same way under any photoperiod (12.3±1.58 days and 12.2±0.74 days). Conclusion The ultra-early lines of bread wheat Rifor 4 and Rifor 5 with the vrn-A1a gene can have no response to vernalization or have a low level response. This effect can be a reason for the formation of a complex of modifier genes along with the dominant gene Vrn-D1, which forms during the hybridization of F7-8 Rico × Forlani Roberto. The ultra-early lines of bread wheat Rico, Rimax and Rifor (k-67120, k-67121, k-67250-67256) can serve as effective sources of genes for earliness in common wheat breeding.

Hybridization of resistant and unstable samples is the main method of producing resistant accession of cultivated plants. At the same time, a number of additional factors are important: the direction of crosses, the morphology of plants, the year and the spe-cific place of assessment of resistance/susceptibility. A cultivar of spring bread wheat Triticum aestivum L. Novosibirskaya 61 (breeding SRIPPB), resistant to brown rust and powdery mildew, and three susceptible samples, cultivar Skala, accession Khakasskaya (CIMMYT 2167) and spelt accession к-53660 from Tajikistan were crossed. In most variant, the F1 plants were resistant, but in the variant where Khakasskaya was used as the mother form, differences were observed: out of 21 plants, 17 plants were F1 resistant, 4 plants were sus-ceptible. The analysis of segregation was carried out to F2 generation separately in progeny from resistant and susceptible plants of F1. Segregation analysis showed that resistance dominated the offspring from resistant plants of the F1. In the progeny from susceptible F1plants most plants were susceptible to both diseases. The effect of leaf pubescence from the accession Khakasskaya on the degree of damage was also evaluated. This result indicates that the accession Khakasskaya is heterogeneous in cytoplasmic determinants. Pubes-cent plants in the F2 generation more affected by powdery mildew. Resistance to brown rust was not affected by leaf pubescence. The pubescence segregation corresponded to a digenic ratio of 13:3 for dominant epistasis. There was no significant correlation between resistant to powdery mildew and resistance brown rust. Resistance to powdery mildew and brown rust in the cultivar Novosibirskaya 61 is inherited in most cases as a dominant character.

There have been presented the results of a comparative estimation of recombinants developed on the basis of two commercial varieties (‘Sibirskaya 17’ and ‘Novosibirskaya 31’) hybridized with ‘Thatcher Lr19’ and ‘Thatcher Lr24’. Recombinants were evaluated in the field conditions in 2016, 2017 and 2020. The purpose of the current study was to identify the effect of translocations from Thinopyrum elongatum on the manifestation of productivity elements in recombinants of spring bread wheat developed on the basis of two commercial varieties. The analysis of the genetic composition of the Puccinia triticina populations in Western and Eastern Siberia did not identify genes which were virulent to resistance genes Lr19, Lr24, Lr28, Lr41, Lr47, Lr45 LrSp, Lr6Agi 1 and Lr6Agi 2. The recombinants developed on the basis of the variety ‘Sibirskaya 17’ (the variety productivity was 398.3 g/m2 , grain weight per head was 1.35 g, 1000-grain weight was 37.8 g) were characterized by the severity of the main agronomically valuable traits at the level of the recipient variety, or significantly lower (productivity was 271.5–327.8 g/m2 , grain weight per head was 1.03–1.16 g, 1000-grain weight was 32.5–36.4 g). The recombinants carrying translocations (the length of the period ‘sprouts-heading’ was 44.4 and 44.5 days, grain weight per head was 1.20 and 1.24 g) developed on the basis of the variety ‘Novosibirskaya 31’ (with 42.4 days, 1.02 g) have demonstrated a significant increase in the length of the period ‘sprouts-heading’ and grain weight per head in comparison with the recombinants without translocations (41.6 and 43.6 days, 0.99 and 1.10 g). On average over 3 years, 12 recombinants hybridized from the combination ‘Novosibirskaya 31 x Thatcher Lr19’ produced higher yields (355.6–427.5 g/m2) than those of the recipient variety (301.5 g/m2), both with (6 pcs.), and without (6 pcs.) a translocation.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide causing huge yield losses every year. Development and deployment of resistant varieties is the most economical and environment friendly approach for controlling this disease. However, because of the continuous evolution of the pathogen, resistant genes are easily overcome by new virulent Pst races, which necessitates a continuous identification and introgression of resistance genes to develop resistant wheat varieties. To identify effective source of resistance, a genome-wide association study was performed using 426 elite bread wheat genotypes based on 5176 polymorphic Diversity Arrays Technology (DArT) markers. Adult-plant-resistance was evaluated under field conditions for yellow rust resistance for two consecutive years (2014 and 2015) at ICARDA Merchouch station, Morocco. Out of the 426 genotypes, 51.17% were highly resistant with 5–10% level of severity to yellow rust. Genome wide association studies (GWAS) using a mixed linear model (MLM) identified three DArT markers on chromosomes 1B, 2B and 7B which are significantly associated with stripe rust resistance at false discovery rate p ≤ 0.05. BLAST analysis confirmed that the marker 412,394 in chromosome 2B overlapped with two previously reported QTLs (QYrlu.cau-2BS1 Luke and QYrid.ui-2B.1_IDO444). However, the two other markers 542,318 (1B) and 583,038 (5B) were not mapped within any of the previously reported gene/QTL regions; therefore, these markers may represent novel resistance loci for yellow rust. The highly resistant elite genotypes and linked molecular markers are recommended for further gene introgression and pyramiding purposes in the wheat breeding programs after validation. [ABSTRACT FROM AUTHOR]

The current paper has discussed information on the characteristics and properties of the zoned spring bread wheat varieties developed in the Federal Agricultural Scientific Centre named after V.V. Dokuchaev. The purpose of the study was to develop new spring bread wheat varieties with high productivity and grain quality, resistant to unfavorable biotic and abiotic environmental factors and adapted to the conditions of the Central Blackearth Region. In the FASC named after V.V. Dokuchaev there were developed such highly productive spring bread wheat varieties as ‘Krestyanka’, ‘Kurskaya 2038’, ‘Voronezhskaya 12’, ‘Chernozemnouralskaya 2’ and ‘Voronezhskaya 18’, which are currently approved for use in production. There were analyzed the study results of productivity, grain quality and resistance to unfavorable environmental factors in different growing periods of the varieties. There was found an unambiguous productivity excess of the developed varieties over the standard ones. The endurance of the presented varieties in unfavorable conditions indicates an increase in the stability of the main traits that characterize productivity, resistance to drought, diseases, and lodging. There has been established, that in terms of grain quality the varieties ‘Krestyanka’ and ‘Chernozemnouralskaya 2’ belong to strong wheat with potential productivity of 7.20 and 6.65 t/ha, respectively. The varieties ‘Kurskaya 2038’, ‘Voronezhskaya 12’ and ‘Voronezhskaya 18’ are valuable wheat varieties with realized productivity potential of 5.31, 5.70 and 6.96 t/ha, respectively. There has been identified that the varieties ‘Chernozemnouralskaya 2’ and ‘Voronezhskaya 18’ are recommended to sow with a seeding rate of 6.0 million germinating grains per hectare for the rapid seed reproduction and obtaining high gross grain yield, since productivity, yield of conditioned seeds, germination and 1000-grain weight at this rate was the best. The sowing dates of these varieties were early.

Background. Recently, an increased interest in crop landraces has been observed among scientists working with plant genetic resources (PGR). Institutes have been organizing collecting missions to explore old varieties still cultivated locally. Attention paid to landraces is also associated with the introduction of GIS technologies into PGR studies. The N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) holds a unique collection of spring bread wheat landraces. One of the Institute’s top priorities is to develop and maintain a passport database, using a set of fields specifically fit for landraces.Analysis of the passport database. The passport database ‘Spring Bread Wheat Landraces in the VIR Collection’ is analyzed here. The database contains information on 5,925 accessions and has 36 fields. Statistical data are presented for the main fields: origin, collection site, botanical variety, year of registration in the collection, donor institute or expedition, and collector’s name.

A total of 57 introgression lines and 11 cultivars of spring bread wheat developed by All-Russian Institute of Plant Protection and cultivated in the Volga Region were analyzed. The lines were obtained with the participation of CIMMYT synthetics, durum wheat cultivars, direct crossing with Agropyron elongatum (CI-7-57) and have introgressions from related species of bread wheat, namely translocations from Ag. elongatum (7DS-7DL-7Ae#1L), Aegilops speltoides (2D-2S), Ae. ventricosum (2AL-2AS-2MV#1), Secale cereale (1BL-1R#1S), 6Agi (6D) substitution from Ag. intermedium and triticale Satu. Cultivars and lines were assessed for resistance to Saratov, Lysogorsk, Derbent and Omsk stem rust pathogen populations (Puccinia graminis f. sp. tritici), and analyzed for the presence of the known Sr resistance genes using molecular markers. The analysis of the cultivars’ and lines’ resistance to the Saratov pathogen population in the field, as well as to Omsk, Derbent and Lysogorsk populations at the seedling stage, showed the loss of efficiency of the Sr25 and Sr6Agi genes. The Sr31 gene remained effective. Thirty one wheat lines out of 57 (54.4 % of samples) were resistant to all pathogen populations taken into analysis. The Sr31/Lr26, Sr25/Lr19, Sr28, Sr57/Lr34 and Sr38/Lr37 genes were identified in the introgression lines. The Sr31/Lr26 gene was identified in 19 lines (33.3 % of samples). All lines carrying the 1RS.1BL translocation (Sr31/Lr26) were resistant to all pathogen populations taken into analysis. The Sr25/Lr19 gene was identified in 49 lines (86 %). The gene combination Sr31/Lr26+ Sr25/Lr19 was identified in 15 lines (26.3 %). The gene combinations Sr38/Lr37+Sr25/Lr19, Sr57/Lr34+Sr25/Lr19 and Sr31/Lr26+Sr25/Lr19+Sr28 were identified in 3 introgression lines. These three lines were characterized by resistance to the pathogen populations studied in this work. The Sr2, Sr24, Sr26, Sr32, Sr36 and Sr39 genes were not detected in the analyzed wheat lines.

Мета. Створити сорти пшениці м’якої ярої за використання вітчизняних та іноземних сортів, носіїв пшенично-житньої транслокації (ПЖТ). Методи. Польові, лабораторні, статистичні. Результати. Перспективним напрямом селекції, що дає змогу суттєво поліпшити генофонд пшениці м’якої ярої, є створення сортів із ПЖТ 1АL.1RS. Представлено опис багаторічних селекційних досліджень, проведених у Миронівському інституті пшениці імені В. М. Ремесла НААН України (МІП), щодо одержання сортів пшениці м’якої з ПЖТ 1АL.1RS. Як вихідний селекційний матеріал використовували сорти й лінії вітчизняної та іноземної селекції, зокрема сорт ‘ТАМ 107’ (США) із ПЖТ 1АL.1RS. У процесі виконання наукової селекційної програми створено сорти пшениці м’якої озимої ‘Експромт’ (1АL.1RS), м’якої ярої ‘Струна миронівська’ (1АL.1RS) та ‘МІП Соломія’ (1АL.1RS). Сорти ‘Струна миронівська’ та ‘МІП Соломія’, згідно з результатами аналізу спектра запасних білків, містять у своїх геномах ПЖТ 1АL.1RS. ‘МІП Соломія’ успадкував її від сорту пшениці м’якої ярої ‘Струна миронівська’. Новий сорт пшениці м’якої ярої ‘МІП Соломія’ характеризується високою врожайністю, адаптивністю, стійкістю проти борошнистої роси, фузаріозу колоса, твердої сажки, високими показниками якості зерна. Висновки. Шляхом багаторічних простих парних схрещувань іноземних сортів та вітчизняного селекційного матеріалу з використанням методу педігрі створено сорти пшениці м’якої з ПЖТ 1АL.1RS. Сорт пшениці м’якої ярої ‘МІП Соломія’, переданий у 2017 р. до Державного сортовипробування, характеризується високою врожайністю, стійкістю до вилягання, низьким відсотком ураженості грибними хворобами, стійкістю проти твердої сажки, адаптивністю. Наявність пшенично-житньої транслокації в сортів ярої пшениці миронівської селекції ‘Струна миронівська’ та ‘МІП Соломія’ підтверджено за допомогою аналізу спектра запасних білків за електрофорезу в поліакріламідному гелі.

Septoria tritici blotch (STB) of wheat, caused by the ascomycete Zymoseptoria tritici (formerly Mycosphaerella graminicola), is one of the most important foliar diseases of wheat. In Morocco, STB is a devastating disease in temperate wheat-growing regions, and the yield losses can exceed up to 50% under favorable conditions. The aims of this study were to identify sources of resistance to STB in Septoria Association Mapping Panel (SAMP), which is composed of 377 advanced breeding lines (ABLs) from spring bread wheat breeding program of ICARDA, and to identify loci associated with resistance to STB at seedling (SRT) as well as at the adult plant (APS) stages using genome-wide association mapping (GWAM). Seedling resistance was evaluated under controlled conditions with two virulent isolates of STB (SAT-2 and 71-R3) from Morocco, whereas adult plant resistance was assessed at two hot spot locations in Morocco (Sidi Allal Tazi, Marchouch) under artificial inoculation with a mixture of STB isolates. At seedling stage, 45 and 32 ABLs were found to be resistant to 71-R3 and SAT-2 isolates of STB, respectively. At adult plant stage, 50 ABLs were found to be resistant at hot spot locations in Morocco. Furthermore, 10 genotypes showed resistance in both locations during two cropping seasons. GWAM was conducted with 9,988 SNP markers using phenotypic data for seedling and the adult plant stage. MLM model was employed in TASSEL 5 (v 5.2.53) using principal component analysis and Kinship Matrix as covariates. The GWAM analysis indicated 14 quantitative trait loci (QTL) at the seedling stage (8 for isolate SAT-2 and 6 for isolate 71-R3), while 23 QTL were detected at the adult plant stage resistance (4 at MCH-17, 16 at SAT-17, and 3 at SAT-18). SRT QTL explained together 33.3% of the phenotypic variance for seedling resistance to STB isolate SAT-2 and 28.3% for 71-R3, respectively. QTL for adult plant stage resistance explained together 13.1, 68.6, and 11.9% of the phenotypic variance for MCH-17, SAT-17, and SAT-18, respectively. Identification of STB-resistant spring bread wheat germplasm in combination with QTL detected both at SRT and APS stage will serve as an important resource in STB resistance breeding efforts.

Septoria tritici blotch (STB) of wheat, caused by the ascomycete Zymoseptoria tritici (formerly Mycosphaerella graminicola), is one of the most important foliar diseases of wheat. In Morocco, STB is a devastating disease in temperate wheat-growing regions, and the yield losses can exceed up to 50% under favorable conditions. The aims of this study were to identify sources of resistance to STB in Septoria Association Mapping Panel (SAMP), which is composed of 377 advanced breeding lines (ABLs) from spring bread wheat breeding program of ICARDA, and to identify loci associated with resistance to STB at seedling (SRT) as well as at the adult plant (APS) stages using genome-wide association mapping (GWAM). Seedling resistance was evaluated under controlled conditions with two virulent isolates of STB (SAT-2 and 71-R3) from Morocco, whereas adult plant resistance was assessed at two hot spot locations in Morocco (Sidi Allal Tazi, Marchouch) under artificial inoculation with a mixture of STB isolates. At seedling stage, 45 and 32 ABLs were found to be resistant to 71-R3 and SAT-2 isolates of STB, respectively. At adult plant stage, 50 ABLs were found to be resistant at hot spot locations in Morocco. Furthermore, 10 genotypes showed resistance in both locations during two cropping seasons. GWAM was conducted with 9,988 SNP markers using phenotypic data for seedling and the adult plant stage. MLM model was employed in TASSEL 5 (v 5.2.53) using principal component analysis and Kinship Matrix as covariates. The GWAM analysis indicated 14 quantitative trait loci (QTL) at the seedling stage (8 for isolate SAT-2 and 6 for isolate 71-R3), while 23 QTL were detected at the adult plant stage resistance (4 at MCH-17, 16 at SAT-17, and 3 at SAT-18). SRT QTL explained together 33.3% of the phenotypic variance for seedling resistance to STB isolate SAT-2 and 28.3% for 71-R3, respectively. QTL for adult plant stage resistance explained together 13.1, 68.6, and 11.9% of the phenotypic variance for MCH-17, SAT-17, and SAT-18, respectively. Identification of STB-resistant spring bread wheat germplasm in combination with QTL detected both at SRT and APS stage will serve as an important resource in STB resistance breeding efforts. [ABSTRACT FROM AUTHOR]

Background. Powdery mildew caused by Blumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal. is a widespread foliar disease of common wheat in regions with cool and wet conditions. The disease infects the foliage, stem and spike of the wheat host. The most economical and environmentally safe method for controlling powdery mildew is the development of resistant bread wheat cultivars. The objective of this work was to analyze wheat (Triticum aestivum L.) cultivars for resistance to a powdery mildew population.Materials and methods. The VIR collection of plant genetic resources is a rich source of genetic materials. The study of resistance to the fungus employed 465 common wheat cultivars. The plants were inoculated at the seedlings, heading and flowering stages of plant development. The population of fungus was virulent to Pm1, Pm2, Pm3a-d, Pm4a-b, Pm5a, Pm6, Pm7, Pm8, Pm9, Pm16, Pm19 and avirulent to Pm12. For the estimation of plant damage, a scale from 0 (no damage) to 4 (abundant pustules) was used.Results and conclusions. The estimation of powdery mildew resistance was made in the field on adult plants. Out of 465 cultivars, resistant accessions amounted to 10,5%, intermediate ones to 16.8%, and susceptible ones to 72.7%. Generally, the resistant varieties originated from Europe and Russia. The group of the resistant cultivars (adult plants) was inoculated with fungus at the seedling stage and the plant damage was estimated. The cultivars 'Kandela', 'Arabeska', 'Batalj', 'Stillet' were resistant at all growth stages. The genetic control of powdery mildew resistance at different wheat growth stages was discussed.

Background. Loose smut caused by Ustilago tritici (Pers.) Rostr. is one of the major diseases of wheat widespread in all areas of its cultivation. Breeding centers in Russia constantly need new sources of resistance to this disease. Screening of spring wheat accessions for resistance to loose smut has been carried out since 2016 in the Genetics Department of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in collaboration with the Wheat Genetic Resources Department.Materials and methods. In the 2016-2018 growing seasons, new 139 accessions of spring bread wheat were screened for resistance to loose smut against a severe infection background according to the well-known method (Krivchenko, 1984). During wheat's flowering phase, from 7 to 10 ears of each accession were inoculated with a fungal infection collected on VIR's experimental field. The severity of the infection was determined by the disease symptoms on the susceptible reference cultivars: 'Reward', 'Diamant' and 'Scala'. Assessment of the infection lesions was carried out in the next year after inoculation by counting the diseased and healthy ears in each accession.Results and conclusion. The ears of eleven accessions were resistant to loose smut during two years of evaluation. During three years of evaluation the disease symptoms were not detected on the plants of eight accessions: 'Salavat Yulaev' (k-65560, Bashkortostan), 'Fori 4' (k-65592, Leningrad Province); 'Diablon' (k- 65444, Germany), 'Ke Feng 10' (k-65472, China), k-65479 (Algeria), k- 65482 (Turkey), 'Alikat' (k-65586, Canada) and 'Selection 1403' (k- 65828, USA). Three years of evaluation showed that 10 varieties were moderately resistant (no more than 5% affected ears): 4 from Russia, 2 from Canada, and single accessions from Spain, China, Pakistan and Tajikistan. The mentioned accessions are of interest for the development of spring bread wheat cultivars with resistance to loose smut for cultivation in the North-Western region of Russia.

Background. VIR's Department of Wheat holds the collections of viable accessions and its originals. The process of reproduction and restoration of germination ability in wheat collections requires monitoring of varietal purity and integrity. For this purpose, botanical varieties that describe sets of morphological characteristics of the spike and grain are used. However, sometimes it is necessary to check the conformity of a variety with its original accession. In this case, the gliadin electrophoretic banding patterns are reliable markers in identifying cultivars and biotypes of wheat.Materials and methods. The study included 7 accessions of spring bread wheat: 3 for the cultivar 'Rubin' and 4 for the cultivar 'Novinka'. Identification of accessions by electrophoresis of gliadin storage protein was carried out according to the generally accepted method.Results and conclusions. Comparison of gliadin electrophoretic banding patterns of the varieties from the VIR collection of plant genetic resources with analogous accessions from other genebanks of the world resulted in the recovery of the lost varieties 'Rubin' (Sweden) and 'Novinka' (Russia).

The introgression lines of spring bread wheat L679 and L299, which are resistant to the leaf rust pathogen, were analyzed. These lines were obtained as a result of interspecific hybridization of the spring bread wheat cultivar Dobrynya and the durum wheat cultivar Zolotaya volna. The effectiveness of the resistances of L679 and L299 were evaluated against the Saratov population of the pathogen in the field as well as for three test clones with virulence to the Lr9, Lr19, and Lr26-resistance genes. High resistance was determined both in the stage of seedlings and in the stage of adult plants. The study into the presence of known Lr-resistance genes using seventeen DNA markers revealed the presence of the Lr19 gene and an unidentified gene. The hybridological analysis confirmed the presence of a complementary interaction of the two genes. The prebreeding studies of lines L679 and L299 were conducted during 2015–2019. The experimental material was randomly sown in 7 m2 plots in four replicates. The productivity and quality of grain—assessed based on the crude gluten content, indicators of the IDK-1, and the physical properties of the dough, evaluated using a Chopin alveograph—were studied. The obtained data were subjected to ANOVA analysis. The prebreeding studies have shown that the agronomic traits in L679 and L299 based on grain productivity and the quality of bread flour did not deteriorate, either in years with epiphytotic pathogens or during severe droughts. [ABSTRACT FROM AUTHOR]

Fructans (fructo-oligosaccharides) is one of the most important carbohydrates in wheat vegetative tissues and plays a vital role in wheat grain development. One hundred and forty 'Avocet'× 'Chilero' wheat (Triticum aestivum L.) recombinant inbred lines (RILs) were phenotyped for grain fructans at Luoyang and Langzhou field sites in the 2015-2016 and 2016-2017 growing seasons and 2090 Diversity Arrays Technology (DArT) molecular marker data were used to determine genomic regions controlling fructan content. Eleven significant quantitative trait loci (QTL) for wheat fructan content were identified on chromosomes 1B, 2A, 2B, 2D, 3D, 4B, 6B, 6D, 7A, and 7B using the inclusive composite interval mapping (ICIM) method, explaining 4.08% to 27.40% of the phenotypic variance, with seven exceeding 10%. The single environment analysis identified QF.haust-6D.1 and QF.haust-7B in Luoyang, QF.haust-1B, QF.haust-2D, QF.haust-3D, and QF.haust-7B in Lanzhou, and QF.haust-1B, QF.haust-7A, and QF.haust-7B in average phenotypic performance. The multi-environment analysis identified QF.haust-2B and QF.haust-7B, which explained 21.01% and 17.39% of the phenotypic variance, respectively. The positive allele of QF.haust-2B and QF.haust-7B were all originated from Chilero. QF.haust-2B was flanked by the 3957031 and SNP1203021 markers; candidate genes for QF.haust-2B were identified by anchoring marker sequences in the IGWSC wheat genome sequence, involving a variety of biological processes, such as the regulation of ribosomes metabolism in wheat. We also constructed the physical map for wheat grain fructan QF.haust-2B and QF.haust-7B, QF.haust-7B with a physical length of 11.47 Mb between marker SNP3026392 and 3954877 and 103 genes within the segment, in which ten were related to glucose metabolism. This study provides a theoretical basis and technical support for wheat grain fructan content-related genes and molecular marker-assisted breeding. [ABSTRACT FROM AUTHOR]

The genetic polymorphism of 62 genotypes of spring bread wheat ( Triticum aestivum L.) of different ecological and geographical origin has been studied for 13 microsatellite loci using SSR-markers. A cluster analysis has revealed samples for use in hybridization that are most genetically distant from the varieties of selection in Primorsky krai. Lines 161 and 168, which combine the resistance to spike and grain fusarium with a high productivity, were developed with the involvement of the selected varieties, Long 98-4081 (China) and Primorskaya 39 (Russia, Primorsky krai). [ABSTRACT FROM AUTHOR]

Evaluation of bread wheat varieties carrying the wheat-rye translocation has been performed for the natural resistance of plants to leaf rust and powdery mildew. It has been revealed that such bread wheat varieties as Omskaya 37 and Omskaya 38 show a high field resistance to leaf rust and, in a varying degree, to powdery mildew. The breeding material has been evaluated for the resistance to Ug99 in Kenya. The resistant lines have been isolated and recommended for further selection. Based on the introgressive material, a number of commercial varieties (Pamyati Maystrenko and Omskaya 41) with the complex resistance to leaf pathogens and high adaptability to unfavorable abiotic factors of the environment have been created. Varieties with alien genetic materials have been involved in the hybridization for development of new promising lines. [ABSTRACT FROM AUTHOR]

Anthocyanins have health-promoting properties and are used to treat many diseases. Purple, blue and black wheat variety contain large quantities of anthocyanins in the outer kernel layers. Anthocyanins in wheat grains accumulate either in the pericarp, under the control of Pp genes, or in the aleurone layer (Ba genes). In black-grained (or deep purple) wheat, anthocyanins can be found in both the pericarp and the aleurone layer. Two lines of Saratovskaya 29 (S29) variety with a black grain color have been created to combine Pp and Ba genes controlling anthocyanins accumulation in one genotype. The lines have been obtained as a result of crossing near isogenic line i:S29 Pp1Pp3 PF and i:S29 Pp1Pp3 P with a blue-grain substituted line s:S294E(4B), and subsequent visual selection of plants with black grain coloring in the progeny F 4-5. The presence of both pigments in the pericarp and aleurone layer was assessed using light microscopy. The total anthocyanin content in the bran fraction of the new obtained black-grained lines ranged from 145.5 to 241.3 μg/g compared to 135 μg/g of the blue-grain line s:S294E(4B), and 79.4 μg/g – i:S29 Pp1Pp P and 81.5 μg/g – i:S29 Pp1Pp PF . The developed lines may be of interest in breeding programs to increase anthocyanins in commercial varieties. [Display omitted] • Pyramiding of Pp and Ba1 genes in the spring bread wheat of Saratovskaya 29 background. • The hybrid wheat grains could have higher anthocyanin contents than their parents. • Development of two lines of the variety Saratovskaya 29 with high content of anthocyanins. [ABSTRACT FROM AUTHOR]

Genome-wide association studies (GWAS) were undertaken to identify SNP markers associated with yield and yield-related traits in 123 Pakistani historical wheat cultivars evaluated during 2011-2014 seasons under rainfed field conditions. The population was genotyped by using high-density Illumina iSelect 90K single nucleotide polymorphism (SNP) assay, and finally 14,960 high quality SNPs were used in GWAS. Population structure examined using 1000 unlinked markers identified seven subpopulations (K = 7) that were representative of different breeding programs in Pakistan, in addition to local landraces. Forty four stable marker-trait associations (MTAs) with -log p > 4 were identified for nine yield-related traits. Nine multi-trait MTAs were found on chromosomes 1AL, 1BS, 2AL, 2BS, 2BL, 4BL, 5BL, 6AL, and 6BL, and those on 5BL and 6AL were stable across two seasons. Gene annotation and syntey identified that 14 trait-associated SNPs were linked to genes having significant importance in plant development. Favorable alleles for days to heading (DH), plant height (PH), thousand grain weight (TGW), and grain yield (GY) showed minor additive effects and their frequencies were slightly higher in cultivars released after 2000. However, no selection pressure on any favorable allele was identified. These genomic regions identified have historically contributed to achieve yield gains from 2.63 million tons in 1947 to 25.7 million tons in 2015. Future breeding strategies can be devised to initiate marker assisted breeding to accumulate these favorable alleles of SNPs associated with yield-related traits to increase grain yield. Additionally, in silico identification of 454-contigs corresponding to MTAs will facilitate fine mapping and subsequent cloning of candidate genes and functional marker development. [ABSTRACT FROM AUTHOR]

For the first time, the authors assessed and mapped the chromosome QTLs (Quantitative Trait Loci) for the manifestation of morpho-physiological and agronomic indices of plant water status and related quantitative traits, such as plant height, weight, and dry matter content in spring bread wheat ( Triticum aestivum L.). Following the study of ten agronomic traits, 13 QTLs were mapped on linkage groups 1A, 1B, 2B, 2D, 4A, 5A, 5B, 5D, 6A, and 6D. Some of the identified QTLs concurrently determined several traits. The physiological components of water status were shown to correlate with quantitative traits in wheat plants, such as plant height, weight, and dry matter content, and the correlation coefficients were calculated for all traits under study. Water retention capacity after 3 h correlated with water retention capacity after 24 h ( r = 0.47). The correlations were also established between water retention capacity after 3 h and plant height at booting stage ( r = 0.29) and between water retention capacity after 3 h and plant dry weight ( r = 0.33). Statistical calculations supported generally observed negative correlation (up to −1) between leaf water and dry matter contents, as well as between the root indices of variance in the mapping population of wheat lines. The results obtained in the present study will promote future efforts to fine-map the genes residing within the identified QTLs, to eventually clone these genes in order to establish the physiological mechanisms for maintaining water homeostasis in higher plant cells and to accomplish the practical implementation of marker-assisted assessment of water status in wheat plants studied on the basis of morpho-physiological and economical indices. [ABSTRACT FROM AUTHOR]

Genotype-environment interaction (GxE) has a great impact on wheat physiology, morphology and grain yield (GY). We evaluated an association mapping panel of spring wheat advanced lines for chlorophyll content, canopy temperature (CT), and yield-related traits under three different watering regimes in two consecutive growing seasons. Genome-wide association mapping identified 457 SNPs, with significant effects that varied with the watering regimes and growing seasons, of which 199 and 69 SNPs showed pleiotropic and conditionally neutral effects, respectively, on the measured traits. We mapped 61 SNPs with effects higher than 10% on all traits, showing antagonistic pleiotropic effects on CT, corresponding to 46 genes; some of these genes represent good candidates to control wheat response to water availability. Surprisingly, no significant SNPs were mapped in the semi-dwarfing genes, Rht-B1b or Rht-D1b. However, haplotype analysis of the SNPs located at the positions of both genes revealed significant interactions of GY with the watering regimes for Rht-B1b and with the growing season for Rht-D1b. We selected genotypes that outperformed two local check cultivars; some of them overlapped across the three watering regimes and could be used to create a multi-parent population to further unravel the genetic factors underlying yield component traits across drought stress. Our results demonstrate the importance of incorporating GxE in mapping models to better understand wheat response to different watering regimes and to select stable markers for selection. • Three genotypes outperformed two local check cultivars under all treatments, whereas the remaining genotypes showed GxE. • Out of the 457 significant SNPs, 199 and 69 SNPs showed pleiotropic and conditionally neutral effects, respectively. • 61 main-effect SNPs can assist significantly in marker-assisted breeding programs. • Two favorable QTLs on 5D and 7D increased GY, and as an adaptive strategy to cope with drought, lowered CT. [ABSTRACT FROM AUTHOR]

Under conditions of a natural stem rust epiphytotic caused by Puccinia graminis f. sp. tritici race Ug99 + Sr24 (TTKST), a set of introgressive spring bread wheat lines developed at the Southeast Agricultural Research Institute was evaluated at KARI's international stem rust screening nursery (Kenya). New sources of resistance to the pathogen and effective resistance genes have been revealed. [ABSTRACT FROM AUTHOR]