Leaf tip necrosis and seedling leaf rust resistance conditioned by <i>Lr34</i> in wheat grown at low temperatures
Bibliographic record
Abstract
Wheat leaf rust, caused by Puccinia triticina Eriks., is a common and destructive disease of wheat worldwide. The durable leaf rust-resistance gene Lr34 is typically described as an adult plant resistance gene, which is not expressed at the seedling stage at normal greenhouse temperatures. However, Lr34 is expressed at the seedling stage when plants with Lr34 are grown at low temperatures, i.e. approximately 8°C. Lines and cultivars with Lr34 demonstrate a range of responses from near immunity to intermediate reactions on the primary leaf. The Thatcher-Lr34 near isogenic lines ‘RL6058ʹ (Thatcher*6/PI58548) and ‘RL6091ʹ (Tc*6/Chinese Spring) were resistant to a number of P. triticina virulence phenotypes at the seedling stage when grown under these cool conditions, but were susceptible at typical greenhouse temperatures. A double haploid population from a cross between ‘Thatcher’ and ‘RL6058ʹ, previously genotyped for Lr34, was grown at 8°C and screened for leaf rust response at the seedling stage. The population is segregated by a seedling resistance gene that corresponds to the presence of a resistance allele of Lr34. After extended incubation at cold temperatures, the seedling progeny lines with Lr34 also developed distinct leaf tip necrosis; this phenotype was absent in susceptible plants, similar to their reaction as adult plants. When uninfected plants from this population were grown to the adult plant stage at 10°C, those with the Lr34 resistance allele had extensive leaf necrosis and shrunken, sometimes sterile, spikes.
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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 | 0.001 |
| 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".