Persistence of Glyphosate‐Resistant Canola in Western Canadian Cropping Systems
Bibliographic record
Abstract
Canola ( Brassica napus L.) is the most important oilseed crop in western Canada. Its prevalence across the Canadian Prairies influences the occurrence and impact of canola volunteers as weeds. Here we determined the persistence of canola seed in cropping systems so effective volunteer management strategies can be developed. In mid‐ to late‐October of 2000, approximately 770 seeds m −2 of glyphosate [ N ‐(phosphonomethyl)glycine]–resistant (GR) canola were scattered on plot areas at seven western Canadian sites. From 2001 to 2003 the plots were seeded to a wheat ( Triticum aestivum L.)–field pea ( Pisum sativum L.)–barley ( Hordeum vulgare L.) rotation or a fallow–field pea–fallow rotation in five different seeding systems involving seeding dates and soil disturbance levels, and monitored four times each year for canola plant density. Crop seeding date did not consistently influence volunteer canola density. With some exceptions, higher levels of soil disturbance led to higher volunteer canola densities. The vast majority of canola seedlings were recruited in the year following seed dispersal (2001). Across all locations, rotations, and seeding systems, and averaged over preplanting (PREP) and in‐crop prespray (PRES) intervals, canola densities were 6.2, 0.7, and 0.0 plants m −2 in 2001, 2002, and 2003, respectively. Canola volunteers were usually most abundant at PREP and PRES intervals; total recruitment at those intervals averaged across all seeding systems in the continuous cropping rotation was 3% (25 plants m −2 ). Preventing seed production in new canola volunteers in 2001 reduced canola densities in subsequent years (2002 and 2003) below those required to mitigate weed–crop competition influences in most crops.
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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".