Root Rot Caused by Species of Fusarium on Brassica carinata in South Dakota

2018 ◽  
Vol 19 (3) ◽  
pp. 188-192
Author(s):  
Paul N. Okello ◽  
Kristina Petrović ◽  
Brian Kontz ◽  
Shaukat Ali ◽  
Laura F. Marek ◽  
...  
Keyword(s):  
South Dakota ◽  
Root Rot ◽  
Rating Scale ◽  
Fusarium Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
The United States ◽  
Brassica Carinata ◽  
Oilseed Crop ◽  
Root Diseases

Brassica carinata is an emerging oilseed crop in the United States, and root diseases caused by Fusarium have the potential to cause yield losses in production. In this study, B. carinata plants were randomly sampled at vegetative and seed development plant stages from South Dakota State University experimental plots. Reddish-brown lesions were observed on roots of sampled plants from which F. acuminatum, F. oxysporum, F. solani, and F. sporotrichioides were recovered. The Fusarium species were identified based on morphology and phylogenetic analyses of the translation elongation factor 1-α gene region. Pathogenicity of the four Fusarium species was evaluated on five B. carinata accessions using a modified inoculum layer method in the greenhouse. At 21 days after inoculation, root rot severity caused by Fusarium on the B. carinata accessions was assessed on a rating scale of 0 to 4 and evaluated using relative treatment effects (RTEs). The F. oxysporum isolate caused significant differences in RTE (P = 0.01) among the B. carinata accessions. However, there were no significant differences in RTE among the B. carinata accessions in response to F. acuminatum (P = 0.82), F. solani (P = 0.76), and F. sporotrichioides (P = 0.47) isolates.

scholarly journals Eight Species of Fusarium Cause Root Rot of Corn (Zea mays) in South Dakota

2019 ◽  
Vol 20 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Paul N. Okello ◽  
Kristina Petrović ◽  
Brian Kontz ◽  
Febina M. Mathew
Keyword(s):  
Zea Mays ◽  
South Dakota ◽  
Root Rot ◽  
Rating Scale ◽  
Elongation Factor ◽  
The United States ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Layer Method ◽  
Elongation Factor 1

Fusarium root rot of corn (Zea mays L.) is yield-limiting in the United States, but there is no information available on the disease in South Dakota. In 2015, corn seedlings with discolored roots were arbitrarily sampled from 50 South Dakota fields, and 198 isolates were recovered. Eight species (F. acuminatum, F. boothii, F. equiseti-incarnatum complex, F. graminearum, F. oxysporum, F. proliferatum, F. solani, and F. subglutinans) were identified by morphology and translation elongation factor 1-α gene sequencing. F. graminearum (26.8%) was the most common fungus, and F. boothii (0.5%) was the least recovered. Fourteen isolates, representing the eight species, were evaluated for their pathogenicity on 2-week-old seedlings of inbred ‘B73’ using the inoculum layer method in the greenhouse. Fourteen days postinoculation, root rot severity was evaluated on a 1-to-5 rating scale and expressed as relative treatment effects (RTEs). F. proliferatum isolate P2 caused significantly greater RTE (based on 95% confidence intervals) on seedlings than the other isolates and the noninoculated control, except F. graminearum isolate FG23. This study indicates that the eight species of Fusarium are aggressive root rot pathogens of corn in South Dakota, and this information will help evaluate strategies for producers to manage these pathogens in their fields.

scholarly journals Characterization of Fusarium and Neocosmospora Species Associated With Crown Rot and Stem Canker of Pistachio Rootstocks in California

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1931-1939 ◽  
Author(s):  
Maria Crespo ◽  
Daniel P. Lawrence ◽  
Mohamed T. Nouri ◽  
David A. Doll ◽  
Florent P. Trouillas
Keyword(s):  
Rna Polymerase Ii ◽  
Fusarium Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Stem Canker ◽  
The United States ◽  
Fungal Species ◽  
Crown Rot ◽  
Pathogenicity Tests ◽  
Pistachio Trees

California produces 99.1% of pistachios grown in the United States, and diseases affecting pistachio rootstocks represent a constant challenge to the industry. Field surveys of fungi associated with pistachio rootstocks with symptoms of crown rot and stem canker in three central California counties followed by phylogenetic analyses of translation elongation factor 1-α and second largest subunit of RNA polymerase II gene fragments identified three Fusarium species (Fusarium equiseti, Fusarium oxysporum, and Fusarium proliferatum) and two Neocosmospora species (Neocosmospora falciformis and Neocosmospora solani). F. oxysporum and N. falciformis were the fungal species most frequently recovered from symptomatic pistachio trees. Inoculations of detached twigs of cultivar Kerman pistachio Pioneer Gold I and clonal University of California, Berkeley I (UCBI) rootstocks showed that all five species could colonize pistachio wood and cause vascular discolorations. Pathogenicity tests in potted pistachio trees completed Koch’s postulates and confirmed that F. oxysporum, F. proliferatum, N. falciformis, and N. solani were capable of producing rot and discoloration in stems of clonal UCBI rootstocks, the most widely planted pistachio rootstock in California. To our knowledge, this study is the first to present insights into the biodiversity and biology of Fusarium and Neocosmospora species associated with pistachio trees in California.

scholarly journals First Report of Fusarium redolens Causing Root Rot of Soybean in Minnesota

Plant Disease ◽  
2010 ◽  
Vol 94 (8) ◽  
pp. 1069-1069 ◽  
Author(s):  
J. C. Bienapfl ◽  
D. K. Malvick ◽  
J. A. Percich
Keyword(s):  
Root Rot ◽  
Fusarium Species ◽  
Apical Cell ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Aerial Mycelium ◽  
Pathogenic Fungi ◽  
The United States ◽  
First Report ◽  
Root Necrosis

Multiple Fusarium species have been found in association with soybean (Glycine max) plants exhibiting root rot in the United States (3). Soybean plants that lacked apparent foliar symptoms, but exhibited 2- to 5-mm brown, necrotic taproot lesions and lateral root necrosis were observed in Minnesota in one field each in Marshall and Otter Tail counties in July of 2007, as well as in one field in Marshall County in July of 2008. Sampling was conducted as part of a study investigating root rot in major soybean-production areas of Minnesota. Plants were arbitrarily dug up at the R3 growth stage. Root systems were washed, surface disinfested in 0.5% NaOCl for 3 min, rinsed in deionized water, and dried. Fusarium isolates were recovered from root sections with necrotic lesions embedded in modified Nash-Snyder medium (1). One resulting Fusarium colony from one plant per county was transferred to half-strength acidified potato dextrose agar (PDA) and carnation leaf agar (CLA) to examine morphological characteristics (4). Culture morphology on PDA consisted of flat mycelium with sparse white aerial mycelium. On CLA, thick-walled macroconidia with a hooked apical cell and a foot-shaped basal cell were produced in cream-colored sporodochia. Macroconidia ranged from 32.5 to 45.0 μm long. Microconidia were oval to cylindrical with 0 to 1 septa, ranged from 7.5 to 11.25 μm long, and were produced on monophialides. Chlamydospores were produced abundantly in chains that were terminal and intercalary in the hyphae of 4-week-old cultures. Morphological characteristics of the three isolates were consistent with descriptions of F. redolens (2,4). The identity of each isolate was confirmed by sequencing the translation elongation factor 1-α (TEF) locus (4). BLAST analysis of the TEF sequences from each isolate against the FUSARIUM-ID database resulted in a 100% match for 17 accessions of F. redolens (e.g., FD 01103, FD 01369). Each F. redolens isolate was tested for pathogenicity on soybean. Sterile sorghum grain was infested with each isolate and incubated for 2 weeks. Sterile sorghum was used for control plants. Soybean seeds of cv. AG2107 were planted in 11.4-cm pots ~1 cm above a 25-cm3 layer of infested sorghum or sterile sorghum. Two replicate pots containing four plants each were used per treatment and the experiment was repeated once. Root rot was assessed 28 days after planting. Each F. redolens isolate consistently caused taproot necrosis on inoculated plants, whereas control plants did not exhibit root necrosis. Isolations were made from roots of inoculated and control plants and the isolates recovered from inoculated plants were identified as F. redolens based on morphological characteristics and TEF sequences. Fusarium species were not isolated from control plants. To our knowledge, this is the first report of F. redolens causing root rot of soybean; however, it is possible F. redolens has been found previously and misidentified as F. oxysporum (2,4). Results from inoculations suggest that F. redolens may be an important root rot pathogen in Minnesota soybean fields. References: (1) J. C. Bienapfl et al. Acta Hortic. 668:123, 2004. (2) C. Booth and J. M. Waterston. No. 27 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, England, 1964. (3) G. L. Hartman et al. Compendium of Soybean Diseases. 4th ed. The American Phytopathological Society, St. Paul, MN, 1999. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006.

scholarly journals Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States

2015 ◽  
Vol 105 (7) ◽  
pp. 990-997 ◽  
Author(s):  
Febina M. Mathew ◽  
Kholoud M. Alananbeh ◽  
James G. Jordahl ◽  
Scott M. Meyer ◽  
Lisa A. Castlebury ◽  
...  
Keyword(s):  
United States ◽  
Helianthus Annuus ◽  
Great Plains ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Stem Canker ◽  
The United States ◽  
Northern Great Plains ◽  
Type Specimens ◽  
Internal Transcribed Spacer Region

Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P ≤ 0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease.

scholarly journals Trichothecene Genotype of Fusarium graminearum Isolates from Soybean (Glycine max) Seedling and Root Diseases in the United States

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1012-1012 ◽  
Author(s):  
M. L. Ellis ◽  
G. P. Munkvold
Keyword(s):  
United States ◽  
North America ◽  
Fusarium Graminearum ◽  
Root Rot ◽  
Elongation Factor ◽  
Host Shift ◽  
The United States ◽  
Sensu Stricto ◽  
Head Blight ◽  
The Third

Fusarium graminearum is an economically important pathogen that causes Fusarium head blight of wheat, barley, and oat, and Gibberella ear and stalk rot of maize. More recently, F. graminearum was reported as a soybean seedling and root pathogen in North America (1,5), causing seed decay, damping-off, and brown to reddish-brown root rot symptoms. Type B trichothecene mycotoxins are commonly produced by F. graminearum, which can be categorized into three trichothecene genotypes; those that produce 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), or nivalenol (NIV). The 15-ADON genotype is dominant in populations from small grains and maize in North America (4), but the 3-ADON genotype has recently been found (4). F. graminearum was known as a pathogen of wheat and maize in North America for over a century before it was reported as a soybean pathogen. Therefore, we hypothesized that recent reports on soybean could be associated with the appearance of the 3-ADON genotype. The objective of this research was to determine the trichothecene genotype of F. graminearum isolates from soybean in the United States. Thirty-eight isolates from soybean were evaluated. Twenty-seven isolates came from a 3-year survey for Fusarium root rot from 2007 to 2009 in Iowa. Other isolates (Ahmad Fakhoury, Southern Illinois University, Carbondale) were collected from soybean seedlings during a multi-state survey in 2012, and included three isolates from Illinois, three from Indiana, and five from Nebraska. Species identification and lineage of F. graminearum were confirmed by sequencing the translation elongation factor gene (EF1-α) using EF-1H and EF-2T primers. A maximum likelihood analysis of the EF1-α, including voucher strains from nine lineages of F. graminearum (2), placed all 38 isolates into lineage 7, F. graminearum sensu stricto (representative GenBank accessions KJ415349 to KJ415352). To determine the trichothecene genotype of each isolate we used three multiplex PCR assays. The first two assays targeted a portion of trichothecene biosynthesis genes Tri3 and Tri12 (4), while the third assay targeted portions of the Tri3, Tri5, and Tri7 genes (3). The PCR for the first two assays was conducted as described by Ward et al. (4) using four sets of primers: 3CON, 3NA, 3D15A, and 3D3A; and 12CON, 12NF, 12-15F, and 12-3F for the Tri3 and Tri12 genes, respectively. The PCR for the third assay was conducted as described by Quarta et al. (3) using the following primers: Tri3F971, Tri3F1325, Tri3R1679, Tri7F340, Tri7R965, 3551H, and 4056H. The amplification products were analyzed by gel electrophoresis. All 38 isolates produced amplicons consistent with the 15-ADON genotype; ~610 and 670 bp for the Tri3 and Tri12 genes, respectively (4), and two amplicons of ~708 and 525 bp for the Tri3/Tri5 genes (3). Our results indicated that the dominant trichothecene genotype among isolates of F. graminearum from soybean is 15-ADON, and the introduction of 3-ADON isolates does not explain the recent host shift of F. graminearum to soybean in North America. To our knowledge, this is the first assessment of trichothecene genotypes in F. graminearum populations from soybean from the United States. References: (1) K. E. Broders et al. Plant Dis. 91:1155, 2007. (2) K. O'Donnell et al. Fungal Gen. Biol. 41:600, 2004. (3) A. Quarta et al. FEMS Microbiol. Lett. 259:7, 2006. (4) T. D. Ward et al. Fungal Gen. Biol. 45:473, 2008. (5) A. G. Zue et al. Can. J. Plant Pathol. 29:35, 2007.

Diaporthe seed decay of soybean [Glycine max (L.) Merr.] is endemic in the United States, but new fungi are involved

Plant Disease ◽  
2020 ◽  
Author(s):  
Kristina Petrovic ◽  
Demetra Skaltsas ◽  
Lisa Castlebury ◽  
Brian Kontz ◽  
Tom Allen ◽  
...  
Keyword(s):  
United States ◽  
Glycine Max ◽  
Seed Quality ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
The United States ◽  
Post Inoculation ◽  
Seed Decay ◽  
Comprehensive Survey ◽  
Glycine Max L

Diaporthe seed decay can compromise seed quality in soybean [Glycine max (L.) Merr.] in the warm and humid production areas of the United States during crop maturation. In the current study, 45 isolates of Diaporthe were recovered from seed sampled from soybean fields affected by Diaporthe-associated diseases in eight U.S. states in 2017. The isolates obtained belonged to 10 species of Diaporthe based on morphology and phylogenetic analyses of the internal transcribed spacer, the partial translation elongation factor 1-alpha, and beta-tubulin gene sequences. The associated species included D. aspalathi, D. caulivora, D. kongii, D. longicolla, D. sojae, D. ueckerae, D. unshiuensis and three novel fungi, D. bacilloides, D. flavescens and D. insulistroma. One isolate each of the 10 species was examined for pathogenicity on seed of cv. ‘Sava’ under controlled conditions. Seven days post-inoculation, significant differences in the percentages of decayed seeds and seedling necrosis were observed among the isolates and the non-inoculated control (p<0.0001). While the isolates of D. bacilloides, D. longicolla, and D. ueckerae caused significantly greater percentage of decayed seeds (p<0.0001), the isolate of D. aspalathi caused the greatest seedling necrosis (p<0.0001) when compared to the non-inoculated control. The observation of new fungi causing Diaporthe seed decay suggests the need for a more comprehensive survey in the U.S. soybean producing areas since members of the genus Diaporthe appear to form a complex that causes seed decay.

Fusarium spp. associated with root rot of pulse crops and their cross pathogenicity to cereal crops in Montana

Plant Disease ◽  
2020 ◽  
Author(s):  
Swarnalatha Moparthi ◽  
Mary Eileen Burrows ◽  
Josephine Mgbechi-Ezeri ◽  
Bright Agindotan
Keyword(s):  
Root Rot ◽  
Fusarium Species ◽  
Elongation Factor ◽  
Abundant Species ◽  
Cereal Crops ◽  
Fusarium Spp ◽  
Internal Transcribed Spacer Region ◽  
Translation Elongation ◽  
Pulse Crops ◽  
Disease Management Strategy

Root rot caused by Fusarium species is a major problem in the pulse growing regions of Montana. Fusarium isolates (n=112) were obtained from seeds and/or roots of chickpea, dry pea, and lentil. Isolates were identified by comparing the sequences of the internal transcribed spacer region and the translation elongation factor 1-α in Fusarium-ID database. Fusarium avenaceum was the most abundant species (28%), followed by F. acuminatum (21%), F. poae (13%), F. oxysporum (8%), F. culmorum (6%), F. redolens (6%), F. sporotrichioides (6%), F. solani (4%), F. graminearum (2%), F. torulosum (2%) and F. tricinctum (0.9%). The aggressiveness of a subset of 50 isolates that represent various sources of isolation was tested on three pulse crops and two cereal crops. Nonparametric analysis of variance conducted on ranks of disease severity indicated that F. avenaceum and F. solani isolates were highly aggressive on pea and chickpea. In lentil, F. avenaceum and F. culmorum were highly aggressive. In barley, F. avenaceum, F. solani, F. culmorum, and F. graminearum were highly aggressive. In wheat, F. avenaceum, F. graminearum, and F. culmorum were highly aggressive. Two F. avenaceum isolates were highly aggressive across all the crops tested and found to be cross pathogenic. One isolate of F. culmorum and an isolate of F. graminearum obtained from chickpea and lentil seed were highly aggressive on barley and wheat. The results indicate that multiple Fusarium spp. from seeds and roots can cause root rot on both pulse and cereal crops. Rotating these crops may still lead to an increase in inoculum levels, making crop rotation limited in efficacy as a disease management strategy.

scholarly journals Maize/Soybean Relay Strip Intercropping Reduces the Occurrence of Fusarium Root Rot and Changes the Diversity of the Pathogenic Fusarium Species

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 211
Author(s):  
Xiaoli Chang ◽  
Li Yan ◽  
Muhammd Naeem ◽  
Muhammad Ibrahim Khaskheli ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Root Rot ◽  
Species Complex ◽  
Crop Yields ◽  
Fusarium Species ◽  
Elongation Factor ◽  
Translation Elongation ◽  
Soybean Root ◽  
Continuous Maize ◽  
Strip Intercropping

Fusarium species are the most detrimental pathogens of soybean root rot worldwide, causing large loss in soybean production. Maize/soybean relay strip intercropping has significant advantages on the increase of crop yields and efficient use of agricultural resources, but its effects on the occurrence and pathogen population of soybean root rot are rarely known. In this study, root rot was investigated in the fields of the continuous maize/soybean strip relay intercropping and soybean monoculture. Fusarium species were isolated from diseased soybean roots and identified based on sequence analysis of translation elongation factor 1α (EF-1α) and RNA polymerase II second largest subunit (RPB2), and the diversity and pathogenicity of these species were also analyzed. Our results showed that intercropping significantly decreased soybean root rot over monoculture. A more diverse Fusarium population including Fusarium solani species complex (FSSC), F. incarnatum-equiseti species complex (FIESC), F. oxysporum, F. fujikuroi, F. proliferatum and F. verticillioides, F. graminearum and F. asiaticum was identified from intercropping while FSSC, FIESC, F. oxysporum, F. commune, F. asiaticum and F. meridionale were found from monoculture. All Fusarium species caused soybean root infection but exhibited distinct aggressiveness. The most aggressive F. oxysporum was more frequently isolated in monoculture than intercropping. FSSC and FIESC were the dominant species complex and differed in their aggressiveness. Additionally, F. fujikuroi, F. proliferatum and F. verticillioides were specifically identified from intercropping with weak or middle aggressiveness. Except for F. graminearum, F. meridionale and F. asiaticum were firstly reported to cause soybean root rot in China. This study indicates maize/soybean relay strip intercropping can reduce soybean root rot, change the diversity and aggressiveness of Fusarium species, which provides an important reference for effective management of this disease.

scholarly journals Cross Pathogenicity Studies Show South Dakota Isolates of Fusarium acuminatum, F. equiseti, F. graminearum, F. oxysporum, F. proliferatum, F. solani, and F. subglutinans from Either Soybean or Corn are Pathogenic to Both Crops

2019 ◽  
Vol 20 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Paul N. Okello ◽  
Febina M. Mathew
Keyword(s):  
Zea Mays ◽  
South Dakota ◽  
Root Rot ◽  
Rating Scale ◽  
Zea Mays L ◽  
The Other ◽  
Management Options ◽  
Inoculum Sources ◽  
Fusarium Acuminatum ◽  
Glycine Max L

In South Dakota, despite that integrated pest management options are available, Fusarium root rot is an emerging disease on soybean (Glycine max L.) and corn (Zea mays L.). Surveys were conducted across South Dakota on soybean and corn fields in 2014 and 2015, respectively, to assess the prevalence of species of Fusarium causing root rot. Fusarium acuminatum, F. equiseti, F. graminearum, F. oxysporum, F. proliferatum, F. solani, and F. subglutinans were identified common to soybean and corn. A total of 21 isolates, representing these seven species, were evaluated for their pathogenicity on soybean (‘Williams 82’) and corn (‘B73’) using the inoculum layer inoculation method in the greenhouse. At 14 days postinoculation, the seedlings were evaluated for root rot severity (1-to-5 rating scale), and relative treatment effects (RTEs) were estimated. A significant effect of the treatments was observed on RTE for soybean (P = 1.1 × 10−7) and corn (P = 3.0 × 10−14). Two F. proliferatum isolates and one F. graminearum isolate from corn caused significantly greater RTE than the other treatments (including the noninoculated control) on soybean and corn. Results indicate that soybean and corn can serve as inoculum sources of the seven species of Fusarium that are pathogenic to both crops.

Response of soybean cultivars to root rot caused by Fusarium species

2010 ◽  
Vol 90 (5) ◽  
pp. 767-776 ◽  
Author(s):  
J X Zhang ◽  
A G Xue ◽  
H J Zhang ◽  
A E Nagasawa ◽  
J T Tambong
Keyword(s):  
United States ◽  
Root Rot ◽  
Fusarium Species ◽  
Seedling Emergence ◽  
Dry Weight ◽  
The United States ◽  
Pathogenic Species ◽  
Fusarium Root Rot ◽  
Soybean Cultivars ◽  
Soybean Roots

Fusarium root rot complex is a major soybean disease in Canada and the United States. Since 2006, four Fusarium species, F. oxysporum Schlechtendahl emend. Snyder & Hansen, F. graminearum Schwabe, F. avenaceum (Corda: Fr.) Sacc., and F. tricinctum (Corda) Sacc., have frequently been isolated from soybean roots in eastern Ontario, Canada. The objective of the current study was to screen 57 soybean cultivars that are commercially available in Canada for resistance to these four Fusarium root rot pathogens under greenhouse conditions. Based on root rot severity and reductions in seedling emergence, plant height and root dry weight, F. avenaceum was the most pathogenic species, followed by F. graminearum. The pathogenicity of F. oxysporum on soybean cultivars was not significantly different from that of F. tricinctum, but was significantly lower than that of F. graminearum. In replicated experiments, six, nine, eleven and seven cultivars were consistently rated as the most resistant to F. avenaceum, F. graminearum, F. oxysporum and F. tricinctum, respectively. Cultivar Maple Amber was resistant to all four Fusarium species based on root rot severity, while cultivar Altona was resistant to F. avenaceum, F. oxysporum and F. tricinctum. Four cultivars, 9004, AC Harmony, Lanark and Maple Arrow, each showed resistance to two different Fusarium species.Key words: Soybean, Glycine max, Fusarium root rot, Fusarium oxysporum, F. graminearum, F. avenaceum, F. tricinctum

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