Diversity and Sources of Multiple Disease Resistance in <i>Hordeum spontaneum</i>
Bibliographic record
Abstract
Hordeum spontaneum, the progenitor of cultivated barley, is known to be a rich source of disease resistance genes. The objective of this study was to assess the diversity of H. spontaneum accessions from Israel and Jordan for their reaction to six fungal pathogens of importance to cultivated barley in the United States and Canada. Overall, a high level of macro-scale (across collection sites) and micro-scale (within a collection site) diversity for disease reaction was found in the 116 accessions of H. spontaneum evaluated at the seedling stage. Additionally, genetic heterozygosity for resistance loci was common in H. spontaneum. The frequency of resistance in accessions from Jordan and Israel was high for Septoria speckled leaf blotch (77 and 98%, respectively), leaf rust (70 and 90%), net blotch (72 and 68%), and powdery mildew (58 and 70%); intermediate for spot blotch (53 and 46%); and low for stem rust (2 and 26%). The level of disease resistance in H. spontaneum was not strongly correlated with any of the weather variables (temperature, precipitation, and humidity) monitored near the collection sites. However, in general, resistance was more often found in germ plasm from mesic (e.g., Mediterranean coast) than in xeric (e.g., Negev Desert) areas. Two H. spontaneum accessions (Shechem 12-32 and Damon 11-11) were resistant to all six pathogens and may be useful parents in programs breeding barley for multiple disease resistance. The high level of diversity and heterozygosity for disease reaction found in this study indicates that H. spontaneum is an extraordinarily rich and largely untapped source of unique disease resistance alleles for cultivated barley improvement.
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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 | 0.001 |
| 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) | 0.001 | 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".