Survey of Plant-Parasitic Nematodes in Pulse Crop Fields of the Canadian Prairies
Bibliographic record
Abstract
Gouvea Pereira, Fernanda. M.Sc., University of Manitoba, December, 2018. Survey of Plant-Parasitic Nematodes in Pulse Crop Fields of the Canadian Prairies. Advisor; Dr. Mario Tenuta. The current distribution of economically important plant parasitic nematodes is relatively unknown in the Canadian Prairies for pulse crops. The majority of previous surveys were done several decades ago and may now be suspect as a result of recent molecular identification methods; as has been the case with the quarantine pest Ditylenchus dipsaci (Kühn) Filipjev. The nematode species Ditylenchus dipsaci can constrain export markets for economically important crops, such as peas. However, a more recent study has revealed that previous identifications of D. dipsaci in yellow pea (Pisum sativum L.) exports have actually been the non-quarantine species Ditylenchus weischeri Chizhov, Borisov & Subbotin. To further our understanding of these issues, a survey was conducted in three major pulse crops growing regions of Canada (Alberta, Saskatchewan and Manitoba) to determine the occurrence of plant-parasitic nematodes associated with pea, chickpea (Cicer arietinum L.) and lentil (Lens culinaris L.). A total of 465 plant and soil samples of pea, chickpeas, lentils and creeping thistle (Cirsium arvense L.), plants from 93 fields were analysed. Recovered nematodes were identified to genus by morphological features. Molecular analysis by species-specific PCR, PCR-RFLP and sequencing of the ITS (ITS1 + 5.8S + ITS2) of the rRNA gene were also used to identify recovered nematodes to species. Twenty genera of plant-parasitic nematodes were recovered from the soil and (or) the plants of pea, chickpea, lentil and creeping thistle, including Anguina, Aphelenchoides, Ditylenchus, Helicotylenchus, Hoplolaimus, Longidorus, Merlinius, Paraphelenchus, Paratylenchus, Pratylenchus, Subanguina, Paratrichodorus, Tylenchorhynchus and Xiphinema. 2 Several fields had high density of plant-parasitic nematodes belonging to the genera Ditylenchus, Pratylenchus, Paratylenchus, Helicotylenchus and Tylenchorhynchus, which could be potentially problematic for the crops studied or for crops that are grown in rotation. Molecular analysis results indicate the recovery of D. weischeri, D. dipsaci, Pratylenchus neglectus (Rensch) Filipjev & Schuurmans-Stekhoven, Xiphinema rivesi Dalmasso and Paratylenchus nanus Cobb. Ditylenchus weischeri, a parasite of thistles and not crops, was recovered from 22 fields across Alberta, Saskatchewan and Manitoba. D. dipsaci was recovered from pods of one yellow pea field in Manitoba. These results confirm the high prevalence of D. weischeri on creeping thistle in pulse fields and the near absence of D. dipsaci.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".