Characterization of Argentinian wild <i>Helianthus annuus</i> populations in their responses to <i>Plasmopara halstedii</i> infection
Bibliographic record
Abstract
The pathogen Plasmopara halstedii, causing downy mildew (DM), is a widespread sunflower disease which can be controlled by single dominant genes. Wild Helianthus annuus have been a valuable source of vertical resistance to control P. halstedii, but such resistance may eventually be overcome by new races of the pathogen. Alternatively, quantitative, or partial resistance, is more stable and may be combined with vertical resistance to prevent DM outbreaks. We assessed the responses of six populations of wild H. annuus naturalized in Argentina to race 710 of P. halstedii. We examined: 1) the aerial phenotype (including seedling death) using two damage scales and three disease indices, 2) the growth of the pathogen along the hypocotyls, and 3) the presence of the pathogen in the root system. We found that the evaluated sunflower wild populations had lower disease levels than the susceptible cultivated controls. A histologic analysis showed that the wild H. annuus seedlings showed cellular reactions (e.g. necrosis and the deposit of materials on the walls of invaded cells) to restrict the pathogen’s growth, allowing the identification of two possible types of resistance: type I, when the growth of the pathogen was limited to the base of the hypocotyls, and type II, when the pathogen managed to invade the entire length of the hypocotyls. The wild sunflower populations also showed differential responses to root infections. A quantitative or partial genetic resistance, rather than resistance based on major genes, seems to be operating in the sampled populations. The individuals found to be resistant in each population represent promising germplasm for sunflower breeding.
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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 | 0.001 |
| 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".