The Chemotypes 3ADON, 15ADON, NIV, and NX-2 of Fusarium graminearum Vary in Aggressiveness on Wheat

Non-Peer ReviewedThe aggressiveness of Fusarium graminearum chemotypes was assessed in a greenhouse experiment on spring wheat genotypes that varied in resistance to Fusarium head blight (FHB). Fifteen isolates (five 3ADON, five 15ADON, three NIV, and two NX-2) of F. graminearum isolated from Saskatchewan wheat fields were evaluated using point inoculation (Type II resistance assay). Evaluation was on three wheat genotypes assessed as resistant, moderately resistant, and susceptible to FHB and near-isogenic lines (NILs) in the CDC Go (moderately susceptible) background, carrying Fhb quantitative trait locus (QTL) in four combinations: Fhb1, Fhb2, Fhb5, and Fhb1+Fhb2+Fhb5. All four F. graminearum chemotypes were pathogenic on wheat and varied in aggressiveness. Disease severity (FHB) of 3ADON, 15ADON, NIV, and NX-2 isolates differed, with 3ADON (29.7 ± 3.6) and 15ADON (22.4 ± 2.9) isolates more aggressive than NIV (16.7 ± 2.8) , and NX-2 (16.2 ± 3.1) isolates. Significant differences were observed for mycotoxin accumulation among chemotypes, which was highest for 3ADON (14.1 ± 2.26 ppm). There was no interaction between chemotype and wheat line for disease severity or mycotoxin accumulation. Link to Video Presentation: https://youtu.be/KW7imkOeU5

Multi-locus genome-wide association studies reveal the genetic architecture of Fusarium head blight resistance in durum wheat

Durum wheat is more susceptible to Fusarium head blight (FHB) than other types or classes of wheat. The disease is one of the most devastating in wheat; it reduces yield and end-use quality and contaminates the grain with fungal mycotoxins such as deoxynivalenol (DON). A panel of 265 Canadian and European durum wheat cultivars, as well as breeding and experimental lines, were tested in artificially inoculated field environments (2019–2022, inclusive) and two greenhouse trials (2019 and 2020). The trials were assessed for FHB severity and incidence, visual rating index, Fusarium-damaged kernels, DON accumulation, anthesis or heading date, maturity date, and plant height. In addition, yellow pigment and protein content were analyzed for the 2020 field season. To capture loci underlying FHB resistance and related traits, GWAS was performed using single-locus and several multi-locus models, employing 13,504 SNPs. Thirty-one QTL significantly associated with one or more FHB-related traits were identified, of which nine were consistent across environments and associated with multiple FHB-related traits. Although many of the QTL were identified in regions previously reported to affect FHB, the QTL QFhb-3B.2, associated with FHB severity, incidence, and DON accumulation, appears to be novel. We developed KASP markers for six FHB-associated QTL that were consistently detected across multiple environments and validated them on the Global Durum Panel (GDP). Analysis of allelic diversity and the frequencies of these revealed that the lines in the GDP harbor between zero and six resistance alleles. This study provides a comprehensive assessment of the genetic basis of FHB resistance and DON accumulation in durum wheat. Accessions with multiple favorable alleles were identified and will be useful genetic resources to improve FHB resistance in durum breeding programs through marker-assisted recurrent selection and gene stacking

CDC Rowland oilseed flax

CDC Rowland, a late maturing oilseed flax (Linum usitatissimum L.), was registered in 2018 by the Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan. This cultivar had a significant yield advantage (12% higher) comparable to CDC Bethune in all soil zones of the Northern Prairies. The yield of CDC Rowland was 117, 116, and 105% of CDC Bethune in the Black, Brown, Black and Grey soil zones of Western Canada, respectively. This cultivar has medium (44.6%) oil content, superior oil quality (iodine value (IV) 194.5; alpha linolenic acid (ALA) content 59.3%), and large seed size (thousand seed weight (TSW) 6.8 g) coupled with resistance to lodging. It is immune to North American rust (race 371) caused by Melampsora lini and moderately resistant to wilt caused by Fusarium oxysporum f. sp. lini and powdery mildew caused by Oidium lini.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

CDC Plava oilseed flax

CDC Plava oilseed flax (Linum usitatissimum L.), registered in 2015 by the Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan, is targeted to the shorter growing season, Dark Brown, Black, Grey, and Dark Grey soil zones of the Northern Prairies. This cultivar has a high seed yield (106%) compared with cultivar (cv.) CDC Bethune and a medium maturity rating equal to cv. Prairie Thunder. It has medium oil content (47.0%), alpha-linolenic acid content (57.8%), seed size (6.1 g thousand seed weight, TSW), and good lodging resistance. It is resistant to North American races of rust caused by Melampsora lini, and moderately resistant to wilt caused by Fusarium oxysporum f. sp. lini.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

CDC Melyn yellow seed coat oilseed flax

CDC Melyn is a yellow seed coat oilseed flax (Linum usitatissimum L.), registered in 2016 by the Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan. This cultivar has yield (106%) comparable to cultivar AC Nugget (the yield standard for yellow seed coat oilseed flax) and maturity rating equal to Flanders. It has a medium (46.6%) oil content, iodine value (199.4), alpha-linolenic acid content (61%) and a thousand seed weight of 5.0 g. It is immune to flax rust caused by Melampsora lini and moderately resistant to wilt and powdery mildew caused by Fusarium oxysporum f. sp. lini and Oidium lini, respectively.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

CDC Dorado yellow seed coat oilseed flax

CDC Dorado is a yellow seed coat oilseed flax (Linum usitatissimum L.), registered in 2017 by the Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan. This cultivar has 7% higher yield than AC Nugget in the Black soil zone of the Prairies coupled with a maturity earlier than Flanders across ten site years in Western Canada. It has a medium (45.2%) oil content, high iodine value (IV 204.2) and alpha-linolenic acid (ALA) content (64%), and a thousand seed weight (TSW) of 6.0 g. It has disease ratings of immune to flax rust caused by Melampsora lini and is moderately resistant to wilt and powdery mildew caused by Fusarium oxysporum f. sp. lini and Oidium lini, respectively.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

CDC Buryu oilseed flax

CDC Buryu, a late maturing oilseed flax (Linum usitatissimum L.), was registered in 2016 by the Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan. This cultivar had yield (106%) comparable to CDC Bethune and a maturity rating equal to Flanders in all soil zones of the Northern Prairies. The yield advantage over CDC Bethune was greater (>8%) in the Brown soil and Black soil zones of the Northern Prairies. It had medium oil content, oil quality, and seed size and good lodging resistance. It is immune to North American rust (race 371) caused by Melampsora lini and moderately resistant to wilt caused by Fusarium oxysporum f. sp. Lini and powdery mildew caused by Oidium lini.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

A High-Throughput Fast Chromatography-Tandem Mass Spectrometry-Based Method for Deoxynivalenol Quantification in Wheat Grain

Fusarium head blight (FHB), caused by Fusarium spp., is a destructive disease of cereal grains. Apart from grain yield loss, a major quality concern is contamination with Fusarium-produced mycotoxins, specifically deoxynivalenol (DON). Mycotoxins accumulate in the grain, making it unfit for consumption by humans and animals. Breeding cultivars with high disease resistance and low mycotoxin contamination is a priority for wheat breeders. However, DON measurement in breeding programs is expensive and time consuming due to the lack of efficient quantification methods. In this study, we established a simple fast chromatography-tandem mass spectrometry method, which employed a one-step acetonitrile extraction protocol with a short guard column to reduce complexity, cost, and analysis time. To ensure robustness and reproducibility, the method was validated according to the U.S. Food and Drug Administration Guidance for Bioanalytical Method Validation. Furthermore, the method was applied for determination of DON in 102 wheat grain samples. Obtained results highly correlated with the conventional immunological method for all tested samples. With its ease of use, rapid sample analysis, and high sensitivity and accuracy, the method could be integrated into current FHB breeding programs to increase breeding efficiency and accelerate screening progress to identify germplasm with increased resistance to DON accumulation. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license

Race characterization of <i>Pyrenophora tritici-repentis</i> and sensitivity to propiconazole and pyraclostrobin fungicides

<p>Tan spot, caused by <i>Pyrenophora tritici-repentis</i> (<i>Ptr</i>), is one of the most destructive leaf spot diseases of wheat in Canada. Several races of the fungus are known to occur. Wheat growers have adopted fungicides to manage tan spot; however, intensive spraying may lead to development of reduced sensitivity to fungicides in the pathogen. In this study, 62 <i>Ptr</i> isolates were collected from across Saskatchewan and Alberta and characterized to race on a wheat differential set, with confirmation of race designations by polymerase chain reaction. This same set of isolates, and 27 isolates from an earlier study, were also evaluated for sensitivity to propiconazole and pyraclostrobin fungicides by determining the effective concentration of each needed to inhibit radial growth and conidiospore germination by 50%. Races 1 and 2 were predominant in western Canada, with 57% of isolates classified as race 1 and 40% as race 2. In Alberta, race 1 was most common (76%), while in Saskatchewan, it was race 2 (57%). Two of 26 isolates were classified as race 3, which was detected only in Saskatchewan in 2013. There was no evidence of reduced sensitivity of either fungicide in the <i>Ptr</i> isolates examined. This study provides a baseline for <i>Ptr</i> sensitivity to propiconazole and pyraclostrobin to which future collections of the pathogen may be compared.</p

Genetic analysis of resistance to stripe rust in durum wheat (Triticum turgidum L. var. durum).

Stripe rust, caused by the fungal pathogen Puccinia striiformis Westend. f. sp. tritici Eriks, is an important disease of bread wheat (Triticum aestivum L.) worldwide and there is an indication that it may also become a serious disease of durum wheat (T. turgidum L. var. durum). Therefore, we investigated the genetic architecture underlying resistance to stripe rust in adapted durum wheat germplasm. Wheat infection assays were conducted under controlled conditions in Canada and under field conditions in Mexico. Disease assessments were performed on a population of 155 doubled haploid (DH) lines derived from the cross of Kofa (susceptible) and W9262-260D3 (moderately resistant) and on a breeding panel that consisted of 92 diverse cultivars and breeding lines. Both populations were genotyped using the 90K single-nucleotide polymorphism (SNP) iSelect assay. In the DH population, QTL for stripe rust resistance were identified on chromosome 7B (LOD 6.87-11.47) and chromosome 5B (LOD 3.88-9.17). The QTL for stripe rust resistance on chromosome 7B was supported in the breeding panel. Both QTL were anchored to the genome sequence of wild emmer wheat, which identified gene candidates involved in disease resistance. Exome capture sequencing identified variation in the candidate genes between Kofa and W9262-260D3. These genetic insights will be useful in durum breeding to enhance resistance to stripe rust