Seedling age and inoculum density affect clubroot severity and seed yield in canola

2011 ◽  
Vol 91 (1) ◽  
pp. 183-190 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
S. E. Strelkov ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
...  
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Negative Impact ◽  
Plasmodiophora Brassicae ◽  
Inoculum Density ◽  
Infested Soil ◽  
Seedling Age ◽  
Control Seed ◽  
Resting Spores ◽  
Infested Field

Hwang, S. F., Ahmed, H. U., Strelkov, S. E., Gossen, B. D., Turnbull, G. D., Peng, G. and Howard, R. J. 2011. Seedling age and inoculum density affect clubroot severity and seed yield in canola. Can. J. Plant Sci. 91: 183–190. Clubroot, caused by Plasmodiophora brassicae, is a serious threat to canola (Brassica napus, B. rapa) production in western Canada because of its long-lived resting spores, high spore production potential, and negative impact on seed yield when inoculum pressure is high. The effect of inoculum density was studied by diluting heavily infested field soil with pathogen-free soil-less potting mix at seven increments, ranging from completely pathogen-free to 100% infested soil, and also by incorporating resting spores into the soil-less mix at concentrations of 1×105 to 1×108 spores cm−3, along with a non-inoculated control. Seed of the susceptible canola cultivar 34 SS 65 was planted in soil of each treatment, grown to maturity, and rated for plant height, seed yield, and clubroot severity (0–3 scale) at harvest. Clubroot severity increased and plant height and seed yield decreased with increasing inoculum density. To assess the effect of seedling age on reaction to clubroot, resting spores of P. brassicae were inoculated onto roots of 1-, 2-, 3- and 4-wk-old seedlings of 34 SS 65. In addition, seed (i.e., 0-wk-old seedlings) was sown into infested soil. Inoculation of young seedlings resulted in higher clubroot severity, shorter plants and lower yield than inoculation of older seedlings. These results indicate that seed treatment fungicides with a long residual period (4 wk or more) may be useful for the management of clubroot.

scholarly journals First Report of Clubroot on Canola Caused by Plasmodiophora brassicae in North Dakota

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1438-1438 ◽  
Author(s):  
K. Chittem ◽  
S. M. Mansouripour ◽  
L. E. del Río Mendoza
Keyword(s):  
United States ◽  
North Dakota ◽  
Plasmodiophora Brassicae ◽  
The United States ◽  
Soil Samples ◽  
Pcr Analysis ◽  
Infested Soil ◽  
First Report ◽  
Resting Spores ◽  
Pathogenicity Tests

North Dakota leads the United States in canola (Brassica napus L.) production (4). A canola field with a distinct patch of dead plants spreading over an area of approximately 0.4 ha was detected in Cavalier County, North Dakota, in early September 2013. Numerous spots within the patch had plant mortalities >80%. Dead plants pulled from the soil had roots with severe galling and clubbing. Clubbed roots were brittle and disintegrated easily when pressed between fingers. Root and soil samples collected at several locations within and outside the affected patch were pooled in separate groups. All plants collected in the patch were symptomatic but those collected outside were not. In the lab, total genomic DNA from three symptomatic and two healthy root samples was extracted using standard procedures and freehand slices were prepared for observation with a compound microscope. Also, DNA from pooled soil samples was extracted using FastDNA Spin Kit for Soil (MP Biomedicals, Solon, OH). Round resting structures ranging from 2.2 to 4.2 μm in diameter were observed by microscopic examination of symptomatic root tissues. These structures resembled those typically produced by Plasmodiophora brassicae Woronin. This initial identification was later confirmed through PCR analysis using the species specific primers TC1F/R and TC2F/R (1). PCR products of 548 bp (TC1F/R) and 519 bp (TC2F/R) were produced in the three symptomatic and two infested soil samples, confirming the presence of P. brassicae. PCR amplicons were not detected in healthy root and soil samples. Pathogenicity tests were conducted in greenhouse to fulfill Koch's postulates. Briefly, five square plastic pots (10 × 10 × 13 cm) were filled with a 10-cm layer of Sunshine Mix #1 potting mix (Fison Horticulture, Vancouver, BC, Canada) and then 1 g of ground root galls (approximately 5 × 105 resting spores) was spread evenly on its surface and covered with 2 cm of soilless mix. A similar number of pots were filled only with soilless mix and used as controls. All pots were planted with two seeds of canola cv. Westar and incubated in greenhouse conditions at 21°C and 16 h light daily. The experiment was conducted twice. Four weeks after planting, all plants in the inoculated pots had developed galls while plants in control pots were symptomless. Presence of P. brassicae resting spores in the newly developed galls was confirmed by microscopic observations and PCR. Based on the symptoms, morphology of resting spores, PCR reactions, and pathogenicity tests, we confirm the presence of P. brassicae on canola. While P. brassicae has been reported as widespread in North America (2), to our knowledge, this is the first report of clubroot on canola in North Dakota and the United States. Clubroot became the most important disease affecting canola production in central Alberta, Canada, within 5 years of its discovery in 2003 (3); since then, the disease has been detected in Saskatchewan and Manitoba (3), Canadian provinces that share borders with North Dakota. Considering the difficulties in management of clubroot, measures should be initiated to limit the spread of the disease before it could pose a threat to United States canola production. References: (1) T. Cao et al. Plant Dis. 91:80, 2007. (2) G. Dixon J. Plant Growth Regul. 28:194, 2009. (3) S. Strelkov and S. Hwang. Can. J. Plant Pathol. 36(S1):27, 2014. (4) USDA-NASS, Ag. Statistics No. 81, 2012.

Molecular Detection of Plasmodiophora brassicae, Causal Agent of Clubroot of Crucifers, in Plant and Soil

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Tiesen Cao ◽  
Jalpa Tewari ◽  
Stephen E. Strelkov
Keyword(s):  
Ribosomal Rna ◽  
Plasmodiophora Brassicae ◽  
Rrna Gene ◽  
Infested Soil ◽  
Resting Spores ◽  
One Step ◽  
Dna Fragment ◽  
Polymerase Chain ◽  
Total P ◽  
Step Polymerase Chain Reaction

Clubroot of crucifers, caused by Plasmodiophora brassicae, recently has been identified in canola (Brassica napus) fields in Alberta, Canada. An effective strategy for managing the disease is to avoid planting cruciferous crops in P. brassicae-infested soil, because the pathogen produces resting spores that can remain infectious for many years. A simple, one-step polymerase chain reaction (PCR) protocol was developed to detect the pathogen in plant and soil samples. The primers TC1F and TC1R, based on a P. brassicae partial 18S ribosomal RNA (rRNA) gene sequence from GenBank, yielded a 548-bp product in the optimized PCR. A second pair of primers, TC2F and TC2R, which amplified a fragment of the 18S and internal transcribed spacer (ITS) 1 regions of the rDNA repeat, also was tested and produced a 519-bp product. Neither set of primers amplified any DNA fragment from noninfected plant hosts, noninfested soil, or common soil fungi and bacteria tested in this study. Quantities of 100 fg or less of total P. brassicae DNA, or 1 × 103 resting spores per gram of soil, could be detected consistently using these primers and PCR protocol, corresponding to an index of disease of 11% or lower when the soil was bioassayed. The protocol also enabled detection of P. brassicae in symptomless root tissue 3 days after inoculation with the pathogen. Therefore, the PCR assay described in this study could provide a reliable diagnosis for routine detection of P. brassicae in plant and soil materials in a specific and rapid manner.

Plasmodiophora brassicae (club root).

2021 ◽  
Author(s):  
Graham McGrann
Keyword(s):  
Crop Rotation ◽  
Plasmodiophora Brassicae ◽  
Brassica Species ◽  
Infested Soil ◽  
Yield Losses ◽  
Varietal Resistance ◽  
Weed Species ◽  
Clubroot Disease ◽  
Local Spread ◽  
Resting Spores

Abstract Plasmodiophora brassicae is a root-infecting protist pathogen that causes clubroot disease in brassica species. The organism is soil-borne and has long-lived resting spores that can survive in soil for more than 15 years. Local spread of motile zoospores can be facilitated by wet conditions but most dispersal of the pathogen is through the movement of infested soil. P. brassicae has a wide host range in the brassica family including numerous weed species. Control of the disease is difficult but clubroot can be managed by a combination of crop rotation, varietal resistance, improved agronomic practice such as improved drainage and the application of lime of related products to raise pH which can limit the effects of the disease. There are currently no effective fungicides for the widespread control of clubroot. Yield losses range from 10 to 15% but can exceed 50% under disease conducive environmental conditions.

scholarly journals Propidium Monoazide Improves Quantification of Resting Spores of Plasmodiophora brassicae with qPCR

Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 442-447 ◽  
Author(s):  
Fadi Al-Daoud ◽  
Bruce D. Gossen ◽  
Justin Robson ◽  
Mary Ruth McDonald
Keyword(s):  
Heat Treatment ◽  
Plasmodiophora Brassicae ◽  
Quantitative Polymerase Chain Reaction ◽  
Infested Soil ◽  
Propidium Monoazide ◽  
Spore Viability ◽  
Heat Treated ◽  
Resting Spores ◽  
Polymerase Chain ◽  
The Impact

Plasmodiophora brassicae, which causes clubroot of Brassica crops, persists in soil as long-lived resting spores. Quantitative polymerase chain reaction (qPCR) analysis is often used to quantify resting spores but does not distinguish between DNA of viable and nonviable spores. The impact of pretreating spores with propidium monoazide (PMA), which inhibits amplification of DNA from nonviable microorganisms, was assessed in several experiments. Spore suspensions from immature and mature clubs were heat treated; then, PMA-PCR analyses and bioassays were performed to assess spore viability. Prior to heat treatment, assessments comparing PMA-PCR to qPCR for mature spores were similar, indicating that most of these spores were viable. However, only a small proportion (<26%) of immature spores were amplified in PMA-PCR. Bioassays demonstrated that clubroot severity was much higher in plants inoculated with mature spores than with immature spores. Heat treatment produced little or no change in estimates of mature spores from qPCR but spore estimates from PMA-PCR and clubroot severity in bioassays were both substantially reduced. Estimates of spore concentration with PMA-PCR were less consistent for immature spores. To facilitate use of PMA-PCR on infested soil, a protocol for extracting spores from soil was developed that provided higher extraction efficiency than the standard methods.

scholarly journals Reproduction Ability and Growth Effect of Pin Nematode, Paratylenchus nanus, With Selected Field Pea Cultivars

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2520-2526
Author(s):  
Arjun Upadhaya ◽  
Guiping Yan ◽  
Julie Pasche
Keyword(s):  
Plant Height ◽  
Seed Weight ◽  
Negative Impact ◽  
Management Strategies ◽  
High Density ◽  
Field Pea ◽  
Growth Effect ◽  
Reproductive Ability ◽  
Infested Field ◽  
Shoot Weight

Greenhouse experiments were conducted to determine the reproductive ability and effect of the pin nematode Paratylenchus nanus from North Dakota on field pea cultivars. Reproduction of P. nanus was determined on seven field pea cultivars using naturally infested field soils at low (1,500/kg of soil) and high (4,500/kg soil) initial pin nematode densities. Nematode effect on plant growth and seed yield was evaluated at 4,500 P. nanus per 1 kg of soil by artificially inoculating P. nanus on six field pea cultivars. Reproductive factor (RF) of P. nanus was observed to be greater at the low density than the high density of the nematode. At the low population density, RF values ranged from 1.10 to 11.20, whereas at the high density, RF ranged from 1.20 to 2.50. In experiments evaluating P. nanus effects on cultivar growth, the nematode (4,500 P. nanus per 1 kg soil) caused reduction (P < 0.05) of plant height in most cultivars tested, and it also significantly impacted dry shoot weight and dry seed weight in some experiments. Plant height and shoot weight reductions were the highest in the cultivar Arcadia (up to 37 and 53%, respectively), with a dry seed weight reduction up to 32%. This research demonstrated for the first time the negative impact of P. nanus on field peas in controlled greenhouse conditions, which is an important step toward developing effective management strategies to improve the productivity of this leguminous crop.

Effects of fungicide, seeding date and seedling age on clubroot severity, seedling emergence and yield of canola

2012 ◽  
Vol 92 (6) ◽  
pp. 1175-1186 ◽  
Author(s):  
S. F. Hwang ◽  
T. Cao ◽  
Q. Xiao ◽  
H. U. Ahmed ◽  
V. P. Manolii ◽  
...  
Keyword(s):  
Plant Height ◽  
Disease Severity ◽  
Sustainable Management ◽  
Plasmodiophora Brassicae ◽  
Seedling Emergence ◽  
Field Trials ◽  
Susceptible Cultivar ◽  
Clubroot Disease ◽  
Seedling Age ◽  
Seeding Date

Hwang, S. F., Cao, T., Xiao, Q., Ahmed, H. U., Manolii, V. P., Turnbull, G. D., Gossen, B. D., Peng, G. and Strelkov, S. E. 2012. Effects of fungicide, seeding date and seedling age on clubroot severity, seedling emergence and yield of canola. Can. J. Plant Sci. 92: 1175–1186. The infestation of seeds by Plasmodiophora brassicae can result in the transmission of clubroot disease in canola. Five fungicides, including Dynasty 100 FS (azoxystrobin), Helix Xtra (thiamethoxam+difenoconazole+metataxyl+fludioxonil), NebijinTM 5SC (flusulfamide), Prosper FX (clothianidin+carbathiin+trifloxystrobin+metalaxyl), and Vitavax RS (carbathiin+thiram), were evaluated under greenhouse conditions using artificially infested canola seeds for their efficacy in eliminating seed-borne inoculum. All of the fungicides significantly reduced clubroot relative to the non-treated control, but NebijinTM 5SC and Dynasty 100 FS were the most effective. However, in field trials with Cruiser 5 FS (thiamethoxam), Helix Xtra, Dynasty, Prosper and Sedaxane (pyrazole anilide) applied alone or as a mixture, none of the treatments reduced clubroot severity or improved seedling emergence or yield compared with the insecticidal control (Cruiser 5 FS) in the susceptible cultivar. Clubroot severity was lower in early-seeded canola compared with the late-seeded crops in 2 site-years. The younger seedlings had greater disease severity and reduced plant height and yield than did older seedlings in both resistant and susceptible canola cultivars. We conclude that a combination of approaches including seed treatments and manipulation of seeding dates in conjunction with deployment of resistant cultivars is necessary for the sustainable management of clubroot in canola.

scholarly journals Wybrane zagadnienia z biologii grzyba Plasmodiophora brassicae Wor. [Some problems in the life-cycle of fungus Plasmodiophora brassicae, Wor.]

2015 ◽  
Vol 26 (1) ◽  
pp. 147-160 ◽  
Author(s):  
B. Nowicki
Keyword(s):  
Life Cycle ◽  
Soil Ph ◽  
Plasmodiophora Brassicae ◽  
Acid Soil ◽  
Infested Soil ◽  
Alkaline Soils ◽  
Resting Spores ◽  
Ph Range

The quickest loss of infectivity of <i>Plasmodiophora brassicae</i> Wor. resting spores was observed in acid soil. Jnlectivity was ratained longer in neutral and alkaline soils. The infection of cabbage seedlings took place in a broad pH range from 3.3 to 8.1, the optimum soil pH for infection being at 5.3 - 5.7. When the number of spores in the soil increased the infection took place in the infection took place in the broader pH range. The plants which were planted as seedlings in infested soil were infected in a broader pH range than plants which were grown from seeds in infested soil.

STUDY OF EFFECT OF EMS, MMS AND GR ON YIELD CONTRIBUTING TRAITS IN URDBEAN, VIGNA MUNGO

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
A. B. SAGADE
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Seed Weight ◽  
Inhibitory Effect ◽  
Individual Plant ◽  
Mean Values ◽  
Methane Sulphonate ◽  
Pod Length ◽  
100 Seed Weight ◽  
Number Of Seeds

The study of the effect of three well known mutagens, ethyl methane sulphonate (EMS), methyl methane sulphonate (MMS) and gamma rays (GR) on the yield contributing traits of the urdbean variety TPU-4 were carried out in the M3 generation. Effect of selected mutagenic treatments/doses of EMS (0.02, 0.03 and 0.04 M), MMS (0.0025, 0.05 and 0.01 M) and (GR) (30, 40 and 50 KR) on different yield contributing traits like plant height, plant spread, number of pods per plant, pod length, number of seeds per pod, seed yield per plant and 100 seed weight were analyzed in the M3 populations of the variety TPU-4. Seeds of M2 plants and control were harvested separately and sown to raise M3 population.. Genetic variabilty in the mutagen administered M3 progeny of the urdbean variety TPU-4 was analyzed by employing statistical methods. Data on mean values and shift in the mean of seven quantitative traits was evaluated on individual plant basis. The experimental findings revealed that concentrations / dose of the all these mutagens showed inhibitory effect on plant height, number of pods per plant, pod length and number of seeds per pod. Lower concentrations of mutagens exerted a promotory effect on plant spread, 100 seed weight and seed yield per plant while higher concentrations of these mutagens inhibited them to different extent.

Study onGenetic Variability, Heritability and Genetic Advance for Seed Yield and Component Traits in Rice

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
PUNIT KUMAR ◽  
VICHITRA KUMAR ARYA ◽  
PRADEEP KUMAR ◽  
LOKENDRA KUMAR ◽  
JOGENDRA SINGH
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Seed Yield ◽  
Flag Leaf ◽  
Grain Weight ◽  
Major Influence ◽  
Genetic Advance ◽  
Component Traits ◽  
Biological Yield ◽  
1000 Grain Weight

A study on genetic variability, heritability and genetic advance for seed yield and component traits was made in 40 genotypes of riceduring kharif 2011-2012 at SHIATS, Allahabad. The analysis of variance showed highly significant differences among the treatments for all the 13 traits under study.The genotypes namely CN 1446-5-8-17-1-MLD4 and CR 2706 recorded highest mean performance for panicles per hill and grain yield. The highest genotypic and phenotypic variances (VG and VP) were recorded for spikelets per panicle (3595.78 and 3642.41) followed by biological yield (355.72 and 360.62) and plant height (231.48 and 234.35).High heritability (broad sense) coupled with high genetic advance was observed for plant height, flag leaf length, panicles per hill, tillers per hill, days to maturity, spikelet’s per panicle, biological yield, harvest index, 1000 grain weight and grain yield, indicating that selection will be effective based on these traits because they were under the influence of additive and additive x additive type of gene action. Highest coefficient of variation (PCV and GCV) was recorded for tillers per hill (18.42% and 17.23%), panicle per hill (19.76 % and 18.68%), spikelet’s per panicle (34.30 and34.07 %), biological yield (28.31 % and 28.12 %), 1000 grain weight (15.57 % and 15 31 %) and grain yield (46.66% and 23.54 %), indicating that these traits are under the major influence of genetic control, therefore the above mentioned traits contributed maximum to higher grain yield compared to other traits, indicating grain yield improvement through the associated traits.

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