Clubroot resistance in canola and brassica vegetable cultivars in Ontario, Canada

2021 ◽  
Author(s):  
Sarah C. Drury ◽  
Bruce D. Gossen ◽  
Mary Ruth McDonald
Keyword(s):  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Vegetable Crops ◽  
Clubroot Resistance ◽  
Resistant Cultivars ◽  
Brassica Vegetables ◽  
Susceptible Control ◽  
Shoot Weight ◽  
Obligate Pathogen ◽  
Brassica Vegetable

Clubroot, caused by the obligate pathogen <i>Plasmodiophora brassicae</i> Woronin, has been present on brassica vegetables in Ontario for decades, but was only recently identified on canola (<i>Brassica napus</i> L.). Once <i>P. brassicae</i> is present in a field, eradication is difficult, but resistant cultivars can provide effective management. Pathotype 6 has been the predominant pathotype on vegetable crops for decades, but pathotype 2 is predominant in canola fields in Ontario. Field trials were used to assess the reaction of selected canola and vegetable Brassica cultivars to pathotype 2, and controlled environment studies were conducted to evaluate the reaction of canola the same cultivars to pathotypes 2 and 6. Four canola cultivars with putative clubroot resistance were compared to two cultivars that were expected to be susceptible and three susceptible control cultivars. Several brassica vegetables were assessed: cabbage, cauliflower, broccoli, napa cabbage, rutabaga, and Shanghai pak choi (a susceptible control). The canola cultivars marketed as resistant were highly resistant in both the field and growth room trials. The canola cultivars not marketed as resistant were susceptible to pathotype 2, as expected. All of the canola cultivars were resistant to pathotype 6. The vegetable cultivars marketed as resistant or tolerant were resistant to pathotype 6 and most were resistant to pathotype 2. A putative resistant cultivar of cabbage and one of broccoli were resistant to pathotype 6 but susceptible to pathotype 2. Clubroot consistently reduced fresh shoot weight in susceptible cultivars of canola and brassica vegetables relative to resistant cultivars.

scholarly journals Reaction to Plasmodiophora brassicae Pathotype 6 in Lines of Brassica Vegetables, Wisconsin Fast Plants, and Canola

HortScience ◽  
2012 ◽  
Vol 47 (3) ◽  
pp. 374-377 ◽  
Author(s):  
Kalpana K.C. Adhikari ◽  
Mary Ruth McDonald ◽  
Bruce D. Gossen
Keyword(s):  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Research Station ◽  
Infested Soil ◽  
Vegetable Crops ◽  
Selected Lines ◽  
Future Studies ◽  
Spring Canola ◽  
Brassica Vegetables ◽  
Short Season

Field trials were conducted from 2008 to 2010 to assess the disease reaction to clubroot, caused by Plasmodiophora brassicae Woronin, in selected lines of Brassica spp., including short-season vegetable crops [Shanghai pak choy (B. rapa subsp. Chinensis var. communis)], Chinese flowering cabbage (B. rapa subsp. Chinensis var. utilis), and napa cabbage (B. rapa subsp. Pekinensis), the Rapid Cycling Brassica Collection (RCBC), also known as Wisconsin Fast Plants, and spring canola (B. napus). The trials were conducted on naturally infested soil with P. brassicae at the Muck Crops Research Station in Ontario, Canada, where pathotype 6 is predominant. Clubroot incidence and severity were higher in 2008 and 2010 compared with 2009. The lines of Shanghai pak choy and Chinese flowering cabbage were highly susceptible to clubroot, but each of the clubroot-resistant cultivars of napa cabbage, ‘Deneko’, ‘Bilko’, and ‘Yuki’, was highly resistant to pathotype 6. Among the RCBC lines, B. carinata and B. juncea were highly susceptible and could be used as susceptible models for further studies. Two RCBC lines, B. napus and R. sativus, were resistant to pathotype 6. Two of the canola cultivars, 46A76 and 46A65, were susceptible, but two others, ‘45H21’ and ‘Invigor 5020LL’, were highly resistant to pathotype 6. This difference in response can be exploited in future studies of clubroot reaction in canola.

scholarly journals Effect of Host Resistance and Fungicide Application on Clubroot Pathotype 6 in Green Cabbage and Napa Cabbage

2012 ◽  
Vol 22 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Catarina Saude ◽  
Alan McKeown ◽  
Bruce D. Gossen ◽  
Mary Ruth McDonald
Keyword(s):  
Brassica Oleracea ◽  
Brassica Rapa ◽  
Host Resistance ◽  
Plasmodiophora Brassicae ◽  
Field Trials ◽  
Organic Soils ◽  
Southern Ontario ◽  
Clubroot Resistance ◽  
Mineral Soils ◽  
Standard Cultivar

Field trials were conducted to evaluate resistance to clubroot (Plasmodiophora brassicae, pathotype 6) in green cabbage (Brassica oleracea var. capitata) and napa cabbage (Brassica rapa ssp. pekinensis) at sites in southern Ontario in 2009 and 2010. The reaction of green cabbage cultivars Kilaton, Tekila, Kilaxy, and Kilaherb and the commercial standard cultivars, Bronco or Atlantis, were evaluated on organic (two site-years) and mineral soils (two site-years) that were naturally infested with the clubroot pathogen. In addition, fluazinam fungicide was drench applied to one treatment of the commercial standard cultivar immediately after transplanting. The napa cabbage cultivars Yuki, Deneko, Bilko, and Mirako (in 2009) and Emiko, Mirako, Yuki, and China Gold (in 2010) were evaluated only on organic soils (two site-years). At harvest, the roots of each plant were assessed for clubroot incidence and severity. Also, plant and head characteristics of the resistant green cabbage cultivars were evaluated at one site in 2010. The green cabbage cultivars Kilaton, Tekila, Kilaxy, and Kilaherb were resistant to pathotype 6 (0% to 3.8% incidence), but ‘Bronco’ was susceptible (64% to 100% incidence). Application of fluazinam reduced clubroot severity on ‘Bronco’ by 6% at one of three sites. Resistance was more effective in reducing clubroot than application of fluazinam. Plant and head characteristics of the resistant cultivars were similar to those of ‘Bronco’ treated with fluazinam. Napa cabbage cultivars Yuki, Deneko, Bilko, Emiko, and China Gold were resistant to clubroot (0% to 13% incidence), and ‘Mirako’ was highly susceptible (87% to 92% incidence). We conclude that the clubroot resistance available in several cultivars of green and napa cabbage was effective against P. brassicae pathotype 6.

scholarly journals Influence of Soil-Borne Inoculum of Plasmodiophora brassicae Measured by qPCR on Disease Severity of Clubroot-Resistant Cultivars of Winter Oilseed Rape (Brassica napus L.)

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 433
Author(s):  
Ann-Charlotte Wallenhammar ◽  
Zahra Saad Omer ◽  
Eva Edin ◽  
Anders Jonsson
Keyword(s):  
Disease Severity ◽  
Oilseed Rape ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Field Trials ◽  
Substantial Variation ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
Resistant Cultivars ◽  
Gene Copies

Use of resistant cultivars is considered the most effective tool in managing clubroot. Three clubroot-resistant commercial winter oilseed rape (OSR) cultivars and a susceptible ‘Cultivar mix’ were evaluated for disease severity index (DSI) and yield performance in field soils, selected for varying abundance of natural inoculum of Plasmodiophora brassicae. Seven field trials were carried out during 2017–2019 in winter OSR crops, and comparative bioassays were performed in a growth chamber. Substantial variation in clubroot infection between years was observed in the field trials. For Cultivar mix, a negative correlation (y = −252.3ln(x) + 58,897.6) was found between inoculum density and seed yield in five trials, whereas no correlation was found for the resistant cultivars. In bioassays, Cultivar mix exhibited a significantly high correlation between DSIb and number of gene copies g−1 soil (R2 = 0.72). For resistant cvs., Mentor and Alister, correlation was R2 = 0.45 and 0.58, respectively, indicating that resistance was under pressure. In field trials, DSIf of the resistant cultivars was lower (<27). The recommendation is thus to use clubroot-resistant cultivars of OSR as part of Integrated Pest Management in situations where abundance of P. brassicae DNA exceeds 1300 gene copies g−1 soil.

Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance

2012 ◽  
Vol 92 (3) ◽  
pp. 501-515 ◽  
Author(s):  
Muhammad Jakir Hasan ◽  
Stephen E. Strelkov ◽  
Ronald J. Howard ◽  
Habibur Rahman
Keyword(s):  
Brassica Rapa ◽  
Oilseed Rape ◽  
Specific Resistance ◽  
Plasmodiophora Brassicae ◽  
Diploid Species ◽  
The Other ◽  
Clubroot Disease ◽  
Clubroot Resistance ◽  
Resistant Cultivars ◽  
Spring Type

Hasan, M. J., Strelkov, S. E., Howard, R. J. and Rahman, H. 2012. Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance. Can. J. Plant Sci. 92: 501–515. Clubroot disease of crucifers, caused by Plasmodiophora brassicae, poses a threat to the Canadian canola industry, and the development of resistant cultivars is urgently needed. Germplasm resistant to local pathotype(s) is the prime requirement for breeding clubroot-resistant cultivars. The objective of this study was to identify Brassica germplasm possessing resistance to P. brassicae pathotypes prevalent in Alberta. Pathotype-specific resistance was identified in the diploid species Brassica rapa (AA) and B. oleracea (CC), and in the amphidiploid B. napus (AACC). Among B. rapa genotypes, turnip was the most resistant, followed by winter type and spring type oilseed rape. The rutabaga group of B. napus, on the other hand, was homogeneous for resistance to Canadian P. brassicae pathotypes. The diploid species B. nigra (BB) also showed pathotype-specific resistance. However, the two amphidiploids carrying the B. nigra genome, B. juncea (AABB) and B. carinata (BBCC) were completely susceptible to clubroot.

scholarly journals Screening Brassica Cultivars for Resistance to Western Oregon Clubroot Pathotypes

2017 ◽  
Vol 27 (4) ◽  
pp. 510-516
Author(s):  
Aaron Heinrich ◽  
Shinji Kawai ◽  
Jim Myers
Keyword(s):  
Plasmodiophora Brassicae ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Crop Loss ◽  
Soilborne Pathogen ◽  
Host Reaction ◽  
Brussels Sprouts ◽  
Pak Choi ◽  
Susceptible Control ◽  
Brassicaceae Family

Growing resistant cultivars from the Brassicaceae family (brassicas) is an effective strategy to minimize crop loss caused by the soilborne pathogen Plasmodiophora brassicae (clubroot). However, there are many clubroot pathotypes, and genetic resistance to clubroot may be pathotype-specific. To determine which pathotypes are present in western Oregon, diseased roots were collected from five farms and identified by the European clubroot differential (ECD) set. To assess resistance to the identified pathotypes, 21 vegetable cultivars from nine crops with purported resistance to clubroot were evaluated for disease incidence and severity in field and greenhouse studies. The crops evaluated included broccoli (Brassica oleracea var. italica), cauliflower (B. oleracea var. botrytis), brussels sprouts (B. oleracea var. gemmifera), cabbage (B. oleracea var. capitata), napa cabbage (Brassica rapa var. pekinensis), pak choi (B. rapa var. chinensis), kohlrabi (B. oleracea var. gongylodes), turnip (B. rapa var. rapa), and rutabaga (Brassica napus var. napobrassica). ECD host reaction showed similar virulence among clubroot collections, and all field isolates had the same ECD pathotype designation, 16/02/30. Compared with a crop-specific susceptible control, 17 of 21 cultivars had some resistance to clubroot, and of those, 15 were highly resistant (≤15% incidence with low disease severity). This research demonstrated that western Oregon farmers have several commercially available cultivars with resistance to the dominant pathotyope in the region. However, each farmer must evaluate the suitability of these cultivars to meet consumer and industry requirements.

scholarly journals Influence of soil pH, rainfall, dosage, and application timing of herbicide Merlin 750 WG (isoxaflutole) on phytotoxicity level in maize (Zea mays L.)

2011 ◽  
Vol 50 (No. 2) ◽  
pp. 88-94 ◽  
Author(s):  
J. Soukup ◽  
M. Jursík ◽  
P. Hamouz ◽  
J. Holec ◽  
J. Krupka
Keyword(s):  
Soil Ph ◽  
Weight Reduction ◽  
Zea Mays L ◽  
Field Studies ◽  
Field Trials ◽  
Early Growth ◽  
Application Timing ◽  
Pot Trials ◽  
Phytotoxic Effect ◽  
Shoot Weight

Pot trials and field studies were carried out to describe the influence of soil pH and rainfall on the phytotoxic effect of the herbicide Merlin 750 WG (isoxaflutole) in maize. Symptoms as bleaching, and root and shoot weight reduction in early growth of maize were found. In pot trials, a statistically significant crop injury in early growth of maize was found only at the herbicide dose of 100 and 130 g/ha followed by 30 mm precipitation directly after herbicide application in soils with pH 6.5 and 7.2. Bleaching and significant weight reduction of maize up to growth stage BBCH 13 were observed in field trials at treatments with early post-emergence application of Merlin and 20 mm precipitations. Bleaching symptoms recovered up to BBCH 19. Significant differences were found in maize shoot weight and cob yield between treatments with and without watering (20 mm irrigation), and between pre- and post-emergence application of Merlin under field conditions. No significant differences were found between herbicide doses tested.

scholarly journals Genetics of Clubroot and Fusarium Wilt Disease Resistance in Brassica Vegetables: The Application of Marker Assisted Breeding for Disease Resistance

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 726 ◽  
Author(s):  
Hasan Mehraj ◽  
Ayasha Akter ◽  
Naomi Miyaji ◽  
Junji Miyazaki ◽  
Daniel J. Shea ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Fusarium Wilt ◽  
Interleukin 1 ◽  
Wilt Disease ◽  
R Genes ◽  
Vegetable Crops ◽  
Marker Assisted Breeding ◽  
Resistant Genes ◽  
Brassica Vegetables ◽  
Lrr Protein

The genus Brassica contains important vegetable crops, which serve as a source of oil seed, condiments, and forages. However, their production is hampered by various diseases such as clubroot and Fusarium wilt, especially in Brassica vegetables. Soil-borne diseases are difficult to manage by traditional methods. Host resistance is an important tool for minimizing disease and many types of resistance (R) genes have been identified. More than 20 major clubroot (CR) disease-related loci have been identified in Brassica vegetables and several CR-resistant genes have been isolated by map-based cloning. Fusarium wilt resistant genes in Brassica vegetables have also been isolated. These isolated R genes encode the toll-interleukin-1 receptor/nucleotide-binding site/leucine-rice-repeat (TIR-NBS-LRR) protein. DNA markers that are linked with disease resistance allele have been successfully applied to improve disease resistance through marker-assisted selection (MAS). In this review, we focused on the recent status of identifying clubroot and Fusarium wilt R genes and the feasibility of using MAS for developing disease resistance cultivars in Brassica vegetables.

scholarly journals Virulence Spectrum of Single-Spore and Field Isolates of Plasmodiophora brassicae Able to Overcome Resistance in Canola (Brassica napus)

Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Homa Askarian ◽  
Alireza Akhavan ◽  
Victor P. Manolii ◽  
Tiesen Cao ◽  
Sheau-Fang Hwang ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Confidence Interval ◽  
Plasmodiophora Brassicae ◽  
Large Collection ◽  
Single Spore ◽  
Brassica Napus L ◽  
Clubroot Resistance ◽  
Field Isolates ◽  
Virulence Spectrum ◽  
Important Disease

Clubroot, caused by Plasmodiophora brassicae Woronin, is an important disease of canola (Brassica napus L.) that is managed mainly by planting clubroot-resistant (CR) cultivars. Field isolates of P. brassicae can be heterogeneous mixtures of various pathotypes, making assessments of the genetics of host–pathogen interactions challenging. Thirty-four single-spore isolates were obtained from nine field isolates of the pathogen collected from CR canola cultivars. The virulence patterns of the single-spore and field isolates were assessed on the 13 host genotypes of the Canadian Clubroot Differential (CCD) set, which includes the differentials of Williams and Somé et al. Indices of disease (IDs) severity of 25, 33, and 50% (±95% confidence interval) were compared as potential thresholds to distinguish between resistant and susceptible reactions, with an ID of 50% giving the most consistent responses for pathotype classification purposes. With this threshold, 13 pathotypes could be distinguished based on the CCD system, 7 on the differentials of Williams, and 3 on the hosts of Somé et al. The highest correlations were observed among virulence matrices generated using the three threshold IDs on the CCD set. Genetically homogeneous single-spore isolates gave a clearer profile of the P. brassicae pathotype structure. Novel pathotypes, not reported in Canada previously, were identified among the isolates. This large collection of single-spore isolates can serve as a reference in screening and breeding for clubroot resistance.

scholarly journals Stability of Slow-Rusting Resistance to Puccinia asparagi and Managing Rust in Asparagus

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 997-1000 ◽  
Author(s):  
Dennis A. Johnson
Keyword(s):  
Irrigation Management ◽  
Field Trials ◽  
Disease Progress Curve ◽  
Resistant Cultivars ◽  
Disease Progress ◽  
Slow Rusting ◽  
South Central ◽  
Progress Curve ◽  
The Stability

The stability of slow-rusting resistance to Puccinia asparagi in several asparagus cultivars was evaluated in two replicated field trials. Rust epidemics were monitored in each trial for 8 years spanning a period of 13 years (1983–1990 and 1987–1995). Inoculum of P. asparagi, an autoecious macrocyclic rust, originated each year as teliospores. In the first trial, the cultivars Jersey Titan, Jersey Centennial, Jersey Giant, Delmonte-361, and UC-157 had consistently lower area under the disease progress curve (AUDPC) values than Wash T2 and WSU-1. Cultivar Mary Washington was intermediate between the two groups of resistant and susceptible cultivars in 6 of 8 years. Jersey Titan consistently ranked number 1 for resistance with the lowest AUDPC values all 8 years. In the second trial, Jersey Giant, Delmonte-361, and UC-157 had consistently lower AUDPC values than Larac, Gynlim, Cito, Largo 17-3, and Franklim in each of 8 years. Jersey Giant, Delmonte-361, and UC-157 always ranked low (1, 2, or 3) for AUDPC. A shift from rust-susceptible to rust-resistant asparagus cultivars began in central Washington around 1996. In 2011, resistant cultivars made up nearly 96% of the asparagus plantings. From 1996 to 2011, rust was not considered a problem in commercial fields with slow-rusting resistant cultivars. Use of durable, slow-rusting cultivars, along with sanitation practices that reduced levels of aecia in nonharvested nurseries and on volunteer asparagus plants and judicious irrigation management, has effectively managed asparagus rust in commercial fields for at least 29 years in south-central Washington.

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