Powdery mildew resistance of Nordic spring bread wheat accessions from the collection of the Vavilov Institute (VIR)

Background. Powdery mildew is one of the harmful and destructive foliar diseases of cereal crops, caused by the fungus Вlumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal. Annual harvest losses may reach 10–15%, and up to 30% in an epidemic year. The VIR collection contains rich diversity of wheat, a valuable source of original material for wheat resistance breeding programs.The aim of this study was to generalize the results of long-term field and laboratory investigations on powdery mildew resistance in spring bread wheat of Nordic origin from the VIR collection and search for accessions resistant in all development phases.Materials and methods. Powdery mildew resistance was analyzed in 279 accessions originated from Sweden, Finland, Norway and Denmark. The tests were performed from 1961 to 2019 against a natural population of the fungus in VIR’s experimental field (Pushkin, St. Petersburg). Field and laboratory studies were carried out in accordance with the guidelines developed by VIR.Results. The analysis of the field data on powdery mildew resistance in spring bread wheat accessions against the Pushkin population of the fungus showed that many Nordic accessions were resistant from 1970 till 1990. These data were retested in 2012–2013. One hundred and five accessions of old landraces and modern cultivars of Nordic origin were studied under field and laboratory conditions for their response to a natural population of the fungus. Accessions resistant in all phases of plant development were identified.Conclusion. Swedish cultivars ‘Sunnan’ (k-58177), ‘Canon’ (k-60992), ‘Sober’ (k-61080) ‘Dragon’ (k-61515) and ‘Dacke’ (k-63479) preserved their resistance to the powdery mildew population beginning from 1993. Spring bread wheat cultivars ‘SW Vals’ (k-64436), ‘SW Milljet’ (k-64434), ‘SW Estrad’ (k-64435), ‘SW Vinjet’ (k-64436), ‘Zebra’ (k-64707), ‘SW Kungsjet’ (k-66036), ‘SW Kronjet’ (k-66097) and ‘Boett’ (k66353) demonstrated adult and seedling resistance in the period from 2005 to 2019

Ranking of spring bread wheat genotypes according to the heading date and growing season duration in different ecogeographic environments

Background. Adaptation of spring bread wheat cultivars to climate change requires a study of the factors affecting the length of their growing season in various environments. An attempt is made to analyze regularities in the effect of ecogeographic conditions on the correlations shown by the duration of the growing season and interphase periods in spring bread wheat genotypes.Materials and methods. Correlation coefficients were studied for the impact of the environment and temperature on the duration of the interphase periods from sprouting to heading (SH) and from heading to yellow ripeness (HR) versus the period from sprouting to yellow ripeness (SR) in VIR’s wheat collection across 18 sites located in Russia and Uzbekistan from 41 to 60°N and from 30 to 135°E. The effect of the genotype and year on SH and HR was studied, and agrometeorological regression models of SH and HR were constructed, based on the data obtained during the studies of the collection in St. Petersburg in 1945–2021.Results. For the sites below 52–54°N, the SR/SH correlation coefficient was generally higher than SR/HR, and in the upper latitudes it was vice versa. The change in the ratio of coefficients occurred due to an increase in the interannual variability of HR at lower temperatures. The effect of HR on SR became greater than that of SH at temperatures below 18°С during HR. The data of a long-term study in St. Petersburg demonstrated that the effect of the genotype on SH was 18.9%, with 68.9% of the year, and the effect of the factors on HR was 4.1 and 71.3%, respectively. Regression models showed that HR was determined by temperature for at least 81%, while SH had a lower coefficient of determination by weather (56%).Conclusion. Ranking of wheat genotypes according to their heading time reflected their differentiation in earliness. A significant contribution of HR was conspicuous under temperatures below 18°C after heading at latitudes above 52–54°N

Prospects of employing modern European cultivars of spring bread wheat in the breeding for powdery mildew resistance in the Northwestern region of Russia

Background. Powdery mildew of bread wheat caused by the fungus Blumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal is a widespread foliar disease of wheat in regions with cool and wet climate. It infects the foliage, stem and spike of the wheat host and causes yield reduction. Breeding for resistance is the economical way to control this disease. The object of this work was to analyze spring cultivars of wheat (Triticum aestivum L.) for powdery mildew resistance and some productivity indicators.Materials and methods. The study involved 150 European spring bread wheat cultivars whose resistance to the fungus was assessed at the seedling, heading and flowering phases of plant development. The population of the fungus manifested virulence to Pm1, Pm2, Pm3a-d, Pm4a-b, Pm5a, Pm6, Pm7, Pm8, Pm9, Pm16 and Pm19, and avirulence to Pm12. The damage to seedlings was evaluated using the scale from 0 (no damage) to 4 (abundant pustules). Resistance of the adult plants was analyzed according to the scale from 9 (no damage) to 1 (abundant pustules).Results and conclusions. Of the 150 cultivars, resistance at the seedling stage was shown by 12,7%, and at the adult stage by 20,1%. The cultivars ‘Dacke’, ‘SW Estrad’, ‘Sparrow’ and ‘Aranka’ were resistant in all phases of plant growth. ‘Naxos’ was characterized by a short period from seedlings to heading. The cultivars ‘Aranka’, ‘Zuzana’, ‘Septima’, ‘Tercia’ and ‘Sparrow’ had short stems, while ‘Torka’, ‘Sparrow’ and ‘Pasteur’ – large grains

Sources for the breeding of soft spring wheat in the conditions of Novosibirsk region

The sources were identified among collection samples characterized by highly pronounced economic and valuable features, which allows new geographically remote source material to be taken to the regional breeding practices. This research aims to assess the agronomic traits (duration of the growing period, lodging resistance and plant height, 1000-grain weight, grain weight and yield) in soft spring wheat varieties of different ecological and geographical origin. Estimation was carried out by a 9-point system of expression of the trait during the study, which allows identifying samples with the greatest expression of the trait in the years of study with respect to the average experience. 5439 samples have been studied over 28 years, with 1106 of them, over two years or more. The study was carried out according to the methods of VIR on plots of 2 m2. It was shown that the samples mainly had no correlation between the yield and the duration of the growing period, while the average dependence (г = 0.6) was revealed between the yield and the height of the plants. Varieties forming the intermediate (4.5-5 points) and above average (6-7) yield in a short growing period (69-85 days) were identified (Lutescens 675, Irkut-skaya 49, Simbirca, Hybrid F3 S-141, Hybrid F4, Hybrid F3 S-289 and Hybrid F4 S-2300 and Pamyati Vavenko-va). A high average score (8.6-9) at 1000 grains weight was shown for 16 varieties with variation from 37 g (N43 and IAO-9) to 56 g (Hofed 1). A high average score (8-9) in the evaluation of grain weight was shown for Pamyati Leont'eva, Ekada 70, Simbirtsit, Don Jose, Yong-Liang 4 and Long-Mai 11, which formed ears with an average weight from 0.96 to 2.30 g. A consistently high score (9) reflecting the yield was in the varieties Condestavel, PF 843025, Prilenskaya 19, Pamyati Leont'eva, Omskaya Krasa

Results of analyzing the passport database ‘Spring bread wheat landraces in the VIR collection’

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

Effective sources of powdery mildew resistance among spring bread wheat for the northwest of the Russian Federation

Background. Bread wheat (Triticum aestivum L.) is one of the world’s main food crops. In Russia, its gross harvest in recent years has reached 21.079 million tons. Blumeria graminis is one of the most harmful diseases of bread wheat. Annual harvest losses can reach 10–30%. In Leningrad Province, powdery mildew appears almost every year on cereals. Development of cultivars resistant to powdery mildew is the most important trend in spring bread wheat breeding. Its progress is determined by new sources of effective resistance genes and their incorporation into promising spring bread wheat cultivars. The purpose of this work was to retest the seedling and adult resistance to powdery mildew in spring bread wheat accessions selected over a period of more than twenty years and redefine the effectiveness of disease resistance sources at the present time.Materials and methods. Since 2000, VIR has conducted a search for powdery mildew resistance among 1283 spring bread wheat accessions. The identified 36 sources of adult and seedling powdery mildew resistance were reevaluated in 2022. Field and laboratory studies into the resistance to the pathogen were performed according to VIR’s guidelines.Results and discussion. In 2022, field and laboratory studies of spring bread wheat cultivars revealed accessions with resistance to the pathogen in all phases of plant development. Six sources remained resistant to powdery mildew for 13–22 years, another six showed resistance for 7–12 years, and 8 cultivars were immune for 6 years. Resistance of 9 accessions identified for this trait in 2020 was confirmed.Conclusion. Field and laboratory research into the resistance of spring bread wheat accessions to the pathogen identified sources retaining seedling and adult resistance to the Leningrad population of powdery mildew for 7 years or more. These accessions are recommended for use in wheat breeding programs

Earliness of spring bread wheat accessions under the conditions of the Middle Volga Region

Background. Development of early-ripening high-yielding cultivars of spring bread wheat is a complicated and difficult process. Striving for higher yields has triggered a trend to prolong the growing season pf the cultivars released by the Tatar Research Institute of Agriculture (TatRIA). Our breeding efforts to produce early cultivars, based on using an early-ripening sample as one of the parents, were unsuccessful. This paper presents a search for solutions to the said problem.Materials and methods. We studied spring bread wheat accessions from the collections of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) and Baicheng Academy of Agricultural Sciences (China) as well as promising lines developed by TatRIA. The study of the material was based on conventional spring bread wheat breeding methods. Phenological phases of wheat development were identified using the Zadoks scale.Results. An ambiguous role played by the vernalization response (Vrn) and photoperiod sensitivity (Ppd) genes in wheat earliness was shown, which is consistent with the data repeatedly presented in other publications. We identified accessions with the shortest period from sprouting to heading. Under our climate conditions, the earliest cultivars were those from Novosibirsk Province, Russia, and the North-Eastern China, where wheat development from sprouting to heading lasted 36–46 days

Evaluation of spring bread wheat accessions from the VIR collection for resistance to loose smut

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

The expression of powdery mildew resistance in spring bread wheat cultivars from the VIR collection of plant genetic resources

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