Race distribution of <i>Pyrenophora tritici-repentis</i> in relation to ploidy level and susceptibility of durum and winter bread wheat
Bibliographic record
Abstract
Tan spot is a destructive disease of wheat caused by the fungus Pyrenophora tritici-repentis (Ptr), with most fungal isolates in Canada known to produce the necrotrophic effector (NE) ToxA. In this study, 144 Ptr isolates collected from durum, winter bread wheat, and grasses in western Canada were evaluated for race classification on a host differential set. The susceptibility of 114 durum and winter bread wheat genotypes to Ptr races 2 (R2), 3 (R3), and 5 (R5), producing the NEs ToxA, ToxB, and ToxC, respectively, was evaluated in bioassays. The host genotypes were tested for the presence of Tsn1, the ToxA-sensitivity gene, by PCR analysis. Race composition varied based on the host type and ploidy level from which the isolates were recovered. R1 (ToxA and ToxC-producer) and R2 were predominant on wheat and occurred in equal frequency on durum, while R1 occurred twice as frequently as R2 on winter bread wheat. R3 was recovered only from durum wheat, and the non-pathogenic R4 was the only race recovered from grasses. Susceptibility to R2 and R3 was more common in Canadian than in European wheat, while susceptibility to R5 was more common in durum and European wheat. Tsn1 amplified at a higher percentage in Canadian (51.2% in winter bread, 59.0% in durum) vs. European (20.5%) wheat genotypes. The presence of Tsn1, however, did not result in susceptibility to ToxA-producing isolates in 35.9% of durum genotypes, indicating that other factors are involved in the Ptr-durum interaction and that ToxA-Tsn1 may not play a significant role in tetraploid wheat.
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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 | 0.001 | 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) | 0.001 | 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".