Effect of clubroot ( <i>Plasmodiophora brassicae</i> ) on yield of canola ( <i>Brassica napus</i> )
Bibliographic record
Abstract
Clubroot, caused by Plasmodiophora brassicae, is a major disease of canola (Brassica napus). This study evaluated the effect of clubroot development on the yield of this crop under field and greenhouse conditions. Three canola cultivars, ‘45H31’ (susceptible), ‘45H29’ (1st-generation resistance) and ‘CS2000’ (2nd-generation resistance), were inoculated with different quantities of P. brassicae inoculum and monitored for yield, pods per plant and 1000-grain weight. The field experiment was conducted over 2 years in biosecure clubroot nurseries inoculated with pathotype 5X or a mix of pathotypes 5X and 3H at 5 × 104, 5 × 106 and 5 × 108 resting spores per plant. In the greenhouse experiment, plants were inoculated with pathotypes 5X, 3H or a mixture of both at 1 × 103, 1 × 104 and 1 × 106 resting spores per plant. In both the field and greenhouse, clubroot incidence and disease severity index (DSI) increased along with inoculum concentration; the highest levels of disease were observed in the susceptible cultivar, while the lowest levels were found in ‘45H29.’ Yield, pods per plant and 1000-grain weight decreased as the DSI increased in all cultivars. Yield was affected by DSI and cultivar but not pathotype. Regression analysis indicated that under greenhouse conditions, an increment of 1% in DSI resulted in a decrease of 0.49% in yield; under field conditions, this percentage was reduced to 0.26%. While the rate of yield reduction was similar among cultivars, overall yield loss was lower in the resistant hosts, as they developed less disease.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".