Identification of resistance genes to barley covered smut and mapping of the<i>Ruh1</i>gene using<i>Ustilago hordei</i>strains with defined avirulence genes
Bibliographic record
Abstract
Covered smut of barley (Hordeum vulgare), caused by Ustilago hordei, is a seed-borne disease. To identify and map disease resistance genes, current Canadian barley cultivars, parents of six barley mapping populations, and four differentials namely ‘Hannchen’ (Ruh1), ‘Excelsior’ (Ruh2), ‘Plush’ (Ruh6), and ‘Odessa’ (universal susceptible), were evaluated. Six mated combinations of U. hordei sporidial lines harbouring known alleles of virulence (avr) and avirulence (Avr) genes were used in the evaluation. Most of the barley cultivars carried the Ruhl resistance gene, but some also had Ruh2 or Ruh6. Many cultivars showed resistance to a U. hordei sporidial mating of genotype (avr1/avr1 avr2/avr2 avr6/avr6), virulent on ‘Hannchen’, ‘Excelsior’, and ‘Plush’. The resistance indicated the presence of novel avirulence gene(s) corresponding to a postulated resistance gene(s) in these cultivars. Fifty-six doubled-haploid lines from the mapping population ‘Harrington’/TR306 were inoculated with a sporidial mating of genotype SMI (Avr1/Avr1 avr2/avr2 avr6/avr6), avirulent on ‘Hannchen’ (Ruhl) but virulent on ‘Excelsior’ (Ruh2) and ‘Plush’ (Ruh6). ‘Harrington’ (ruh1) was susceptible to this fungal genotype possessing Avrl and TR306 (Ruhl) was resistant. Based on field and greenhouse tests, barley lines segregated 27 resistant to 29 susceptible, which was not significantly different from a I: I ratio (X 2 = 0.07, P = 0.79); this indicated the presence of the single major resistance gene Ruhl in TR306. Ruhl mapped to the short arm of chromosome I (7H) between markers iPgd1A and BCD 129 on the ‘Harrington’/TR306 map.
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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 | 0.000 | 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".