Reaction of selected Brassica vegetable crops to Canadian pathotypes of<i>Plasmodiophora brassicae</i>
Bibliographic record
Abstract
Clubroot, caused by the protist pathogen Plasmodiophora brassicae, causes substantial yield and quality losses in Brassica vegetable crops around the world. Cultivars of several vegetable and oilseed Brassica crops with resistance to clubroot have been developed recently. This study compared clubroot incidence and severity on resistant and standard (susceptible) cultivars of broccoli (Brassica oleracea var. italica), Brussels sprouts (B. oleracea var. gemmifera), Shanghai pak choy (B. rapa var. communis) and napa cabbage (B. rapa spp. pekinensis) grown at field sites naturally infested with pathotype 6 of P. brassicae (P6) in Ontario and pathotypes 3 (P3) and 5 (P5) in Alberta. In Ontario, all of the susceptible cultivars had 100% clubroot incidence and very high severity. The resistant cultivars of Shanghai pak choy and Brussels sprouts had no symptoms of clubroot, and disease severity was low in resistant broccoli. For each crop species, yield of the resistant cultivar(s) was higher than in the standard cultivar(s) under moderate to high disease pressure. In Alberta, the standard cultivars of each Brassica crop were highly susceptible to P3, except for napa cabbage ‘Bilko’. The clubroot reaction to pathotypes 2, 3, 5 and 6 of the cultivars grown in the field trials in Ontario was assessed under controlled conditions. The reaction to P6 was consistent with the field assessments, but several of the cultivars exhibited a differential reaction to pathotypes 2, 3 and 5. No symptoms were observed on Tillage Radish® (Raphanus sativus var. longipinnatus) in an infested (P5) field trial at Bassano, Alberta, but some clubroot symptoms (9%) developed on roots under controlled conditions.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".