Biochemical and molecular responses during overwintering of red clover populations recurrently selected for improved freezing tolerance
Bibliographic record
Abstract
Low freezing tolerance reduces the persistence of red clover under northern climate. The incidence of winter damages in perennial crops could increase in the future due to the adverse effects of the predicted warmer fall temperature on plant cold acclimation. To accelerate breeding progress, two cultivars of red clover Christie (C-TF0) and Endure (E-TF0) were exposed to a recurrent selection protocol for freezing tolerance performed indoor. New populations were obtained after five (C-TF5 and E-TF5), six (C-TF6 and E-TF6), and seven (C-TF7 and E-TF7) cycles of recurrent selection. These populations were overwintered under natural conditions and monitored for freezing tolerance and cold-induced molecular traits. Freezing tolerance was improved by up to 6 °C in recurrently selected populations when compared to initial cultivars confirming that further progress are achieved with advanced cycles of selection. Monthly analysis of biochemical changes shows that higher starch concentrations at the onset of the fall hardening period are contributing to the acquisition of superior freezing tolerance through its impact on sucrose accumulation. They also contribute to the vigor of spring regrowth by sustaining more pinitol and proline synthesis. Larger concentrations of these metabolites in populations with higher levels of freezing tolerance (TF7) hint at their involvement in winter survival of red clover. Among genes differentially expressed in response to both cold acclimation and recurrent selection, a concomitant cold induction of APPR9 and cold repression of 1-aminocyclopropane-carboxylate synthase suggests a link between the repression of a pathway regulated by ethylene and the improvement of freezing tolerance in red clover.
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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".