Estimation of the gene pool of the CIMMYT collection winter bread wheat on presence of the Lr 34 gene

Nowadays in Russia and in the world, the problem of improving food security is becoming more and more urgent. One of the main crops grown worldwide is winter bread wheat. Varieties resistant to main leaf diseases can produce large grain yields. Thus, the study and identification of resistance genes are of great importance. The purpose of the current work was to estimate the gene pool of winter bread wheat from the CIMMYT collection (Mexico) according to the age brown rust Lr 34 resistance gene. In the study of collection samples, there have been used such methods as DNA extraction using CTAB, PCR, electrophoresis on agarose gels. As a result of the study, there has been identified a presence of a functional allele of the Lr 34 gene in 146 winter bread wheat samples out of 411 studied ones (sets 20th IWWYT-SA, 21th IWWYT-IRR, 25th FAWWON-IRR, 25th FAWWON-SA). There have been identified three samples with a heterozygous allelic state of the Lr 34 gene. There have been identified 232 samples with the non-functional Lr 34 gene allele. 30 winter bread wheat samples had no amplification of DNA fragments with the molecular marker csLV34, which means a significant microsatellite sequence variability for which the molecular marker was developed in their genotype. 121 out of 146 winter bread wheat samples with the functional brown rust Lr 34 resistance gene showed resistance in field conditions and in the infectious plots. The rest 25 samples with the Lr 34 gene belonged to the group of moderately resistant ones in the infectious plots. The identified 121 CIMMYT collection winter bread wheat varieties, with the Lr 34 gene possessing a resistant type of pathogen damage response (for example, 9919, 9921, 9928, 9809, 9811, 9812, 23, 24, 30, 262, 265, 266, etc.) have been recommended for use in leaf rust resistance pyramiding in future breeding programs.

Protection of spring wheat with biopreparations and fungicides in the forest steppe of Priobye: I. First results in extreme weather conditions

The paper presents data on a comparative test of the efficacy of chemical, fungal and bacterial fungicides in limiting the harmfulness of main diseases of spring wheat. The research was carried out on leached chernozem of the forest-steppe of Priobye of the Novosibirsk region. It was shown that Sternifag, SP reduces the development of root rot at the end of the growing season by 48 %, which is comparable to the effect of a chemical dressing agent Scarlet, ME (imazalil+tebuconazole) and is slightly inferior to the action of combined application of fungal preparation Trichocin, SP with the bacterial preparation Vitaplan, SP (55 %). Preplanting seed treatment effectively reduced the development of leaf infections: Scarlet, ME suppressed the development of Septoria blotch by 54 %, Scarlet, ME + Vitaplan, SP – of powdery mildew by 69 %, Trichotsin,SP + Vitaplan, SP – of brown rust by 74 %. Fungicide Titul 390, KKR reduced the development of these diseases by 60, 81 and 85 %, respectively. Alirin-B, W with Trichocin, SP suppressed brown rust by 64 %. Cellulolytic activity increased 1.3–1.9 times compared to the control as a result of the action of biological products and Sternifag, SP. The amount of plant residues decreased 2.4 and 1.9 times 15 and 30 days after application. The greatest increase in yield was provided by chemical fungicides – 0.7 t / ha, they were not inferior to the use of Alirin-B, W with Vitaplan, SP against the background of etching with Scarlet, ME fungicide.

Genome-Wide Association Mapping of Crown and Brown Rust Resistance in Perennial Ryegrass

A population of 239 perennial ryegrass (Lolium perenne L.) genotypes was analyzed to identify marker-trait associations for crown rust (Puccinia coronata f. sp. lolii) and brown rust (Puccinia graminis f. sp. loliina) resistance. Phenotypic data from field trials showed a low correlation (r = 0.17) between the two traits. Genotypes were resequenced, and a total of 14,538,978 SNPs were used to analyze population structure, linkage disequilibrium (LD), and for genome-wide association study. The SNP heritability (h2SNP) was 0.4 and 0.8 for crown and brown rust resistance, respectively. The high-density SNP dataset allowed us to estimate LD decay with the highest possible precision to date for perennial ryegrass. Results showed a low LD extension with a rapid decay of r2 value below 0.2 after 520 bp on average. Additionally, QTL regions for both traits were detected, as well as candidate genes by applying Genome Complex Trait Analysis and Multi-marker Analysis of GenoMic Annotation. Moreover, two significant genes, LpPc6 and LpPl6, were identified for crown and brown rust resistance, respectively, when SNPs were aggregated to the gene level. The two candidate genes encode proteins with phosphatase activity, which putatively can be induced by the host to perceive, amplify and transfer signals to downstream components, thus activating a plant defense response.

Resistance of modern spring barley cultivars to harmful organisms

Background. Diseases and pests cause great damage to barley stands and harvests. Harvest losses from harmful organisms reach 25–30%.Materials and methods. During 2017–2020, 46 spring barley cultivars from the VIR collection, listed in the State Register for Selection Achievements, were studied for their resistance to fritfly, net and spot blotches, brown rust, and powdery mildew. The tests were carried out in the field with provocative colonization by fritfly and under natural infection pressure of leaf pathogens.Results and conclusions. In 2017, net blotch predominated over other diseases. In 2018, there was an epyphytotic outburst of spot blotch, and cultivars with weak development of this disease were identified. In 2019 and 2020, the incidence of brown rust and powdery mildew was significant, and the virulence of fritfly increased greatly in the same years. Field tests resulted in identification of 3 barley accessions resistant to fritfly: ‘Odon’ (k-31118, Buryatia), ‘Miar’ (k-31203, Orenburg Province), and ‘Omsky 99’ (k-31230, Omsk Province). Cv. ‘Posada’ (k-31245, Germany) was weakly affected by fritfly, brown rust and powdery mildew. Cultivars were selected for their low susceptibility to powdery mildew (up to 5%): ‘Chiraz’ (k-31131, Denmark), ‘Cheerio’ (k-31297, Denmark), and ‘Odyssey’ (k-31333, England), and brown rust: ‘Chiraz’ (k-31131, Denmark), ‘Eifel’ (k-31249, France), ‘Ursa’ (k-31339), and ‘Sunshine’ (k-31129, Germany). Such long-term assessment results can be used in breeding programs to develop cultivars with group or complex resistance to harmful organisms.

Variabilitatea genotipurilor de colecţie de grâu (Triticum aestivum L.) în baza sensibilităţii la unele maladii fungice

The common wheat genotypes under study showed a differentiated variability in terms of suscep-tibility to septoria, brown rust, spike fusariosis, which made it possible to differentiate them into clusters and identify those with higher resistance to these diseases. Based on the assessments from 2020-2021, the varieties Trubion, Numitor, Urbanus, Python, Miranda, Centurion, Amor, Aneta, Neven, Messino, Nasnaga, Tika-Taka, Judița, Avenue, Speranța, Dacia, Transilvania, Selania, Avânt which have shown resistance to extreme drought, fungal diseases and high indices of the spike productivity elements can be recommended as the initial material for the breeding programs.

Search for immunologically valuable winter rye genotypes using separate parameters of non-specific resistance

More than 100 Russian varieties and collection samples of winter rye were studied under the conditions of the Kirov region against the natural infectious background of the development of mycoses (2019-2020). The degree of damage by powdery mildew during the years of research reached 86.3 %, septoria – 63.3 %, brown rust – 40.5 %, stem rust – 60.0 %, rhynchosporiosis – 29.3 %. During plant ontogenesis (from phases 31 to 85 Zadoks scale), the growth of fungal infection in varietal biocenoses was analyzed. When accounting for diseases, well-known methods were used. The nature of plant-microbial interactions and the parameters of resistance were assessed by indicators of ADDC (area under the curve of disease development), IR (resistance index) and LP (latency period). A close relationship was established between the duration of LP and the degree of septoria infection (r = -0.98), brown rust (r = -0.95), powdery mildew (r = -0.92), stem rust (r = -0.80), rhynchosporiosis (r = -0.67). The regression equations are linear (R2 = 0.84 ... 0.96) and indicate a daily increase in diseases (from 0.52 to 0.88 %). In the course of immunological management, there have been identified about 20 varieties of Russian selection distinguished by nonspecific resistance to two or more diseases, slow (slow rusting) growth of infection in varietal biocenoses and a long latent period of pathogenesis. Among them are the varieties of the Federal Agricultural Research Center of the North-East named N.V. Rudnitsky (Falyonskaya 4, Vyatka 2, Rushnik, Kirovskaya 89, Snezhana, Flora, Rumba), other scientific institutions of the Russian Federation (Alisa, Pamyati Bambysheva, P-01/14, GP-901 and others) and new samples from the VIR collection (Trinodis 4 Minvak – 139/09 NP, Estet NP 42/14 and others). They can be used in breeding as sources, and indicators of ADDC, IR, LP – as immunologically significant parameters of nonspecific resistance.

ADAPTABILITY OF WINTER WHEAT FROM THE INSTITUTE OF PLANT INDUSTRY (VIR) COLLECTION IN THE CIS-MIDDLE URALS

The purpose of the research is to identify sources of economically valuable properties for creating a genetic collection of winter wheat in the Cis-middle Urals. The material for research was 30 varieties of winter wheat from the VIR collection for adaptability. The study was carried out in 2016-2019 at the experimental field of the UdmFIC Ural Branch of the Russian Academy of Sciences (Pervomaysky village, Zavyalovsky district of Udmurtia). The soil of the experimental site is well cultivated sod-podzolic medium loamy. According to method of L.A. Zhivotkova, Z.N. Morozova, L.I. Sekatueva (1994) 15 varieties were more adapted to local conditions. These varieties, on average for 3 years of research, formed higher yields (by 2-107 %) than the average for all varieties. The indicator of the level of stability of the variety (ILSV), calculated by the method of E.D. Nettevich (1985) identified only three of the most valuable varieties - Sarlota (ILSV 283 %), Venistar (ILSV 238 %) and Alauda (ILSV 124 %). Overwintering of varieties on average for 2017-2019 was 32 ... 68 %, for the standard-60 %. The best winter hardiness was obtained in the samples Sarlota (68 %) and Vanda (63 %). The sources of high grain content of the spike (33.6...50.8 pcs.) were identified – variety samples Markola, Sarlota, Veldana, Venistar. Large grain (mass of 1000 grains 42.6...52.3 g) formed varieties Charodijka Bilotserkivsʹka, Gonoveva, Stanislava, Sarlota, Vanda. Warm and humid weather in the summer of 2019 led to the massive development of powdery mildew. The varieties Charodijka BilotserkivskaKa, KhmelnNychanka, Zluka, Komertsijna, Markola, Gonoveva were highly stable (7...9 points) for this disease. The increased air temperature and the presence of a drip liquid were the reasons for the intensive development of brown rust in 2017. High stability (7...9 points) this year the varieties Gordovyta, Lasurna, Zluka, Gonoveva, Sarlota, Veldana and Venistar showed signs of illness

Ferrous materials degradation: characterisation of rust by colour – an overview

An overview of the characterisation of rust by colour is presented. Each distinct rust colour is caused by atmospheric impurities, high or low moisture content and high or low oxygen environment over time. Yellow rust is mainly due to the high moisture environment over a period of time, which drips. Brown rust is dry, crusty and due to water and oxygen contact with localised patches on component surfaces. Black rust, the most stable form, occurs in low moisture and low oxygen environment. The rust residue shows where the reaction started, especially in contact with chlorides. The causative factors of red rust are atmospheric and similar to black rust in a chloride-containing environment. The effect of packaging, manufacturing and environmental factors on rust colour is briefly discussed. Visual characterization of rust could pre-empt root causes and analytical tools for validation. The limitations of these concepts are mentioned and directions for future research highlighted.