Low Temperature Tolerance of Apple Shoots Following Exposure to Warm Temperatures in Late Winter
Bibliographic record
Abstract
The goal of this research was to evaluate resistance of apple rootstocks to late winter deacclimation during a 2-day exposure to warm temperatures in Maine. We measured the cold temperature tolerance of xylem, phloem, and cambium from 0 to −40 °C in 1- and 2-year-old shoot pieces from apple rootstock cultivars and advanced selections ‘M.9 T337’ (M.9), ‘M.7 EMLA’ (M.7), ‘Budagovsky 9’ (B.9), ‘Geneva® 41’ (G.41), ‘Geneva 30’ (G.30), ‘Geneva 935’ (G.935), ‘Geneva 814’ (G.814), G.4013, G.5257, and Vineland 6 (V.6) after a 2-day exposure to warm (22 °C) or cold (2 to 4 °C) temperatures. Injury was measured on a 0 to 10 rating scale based on percentage of discolored cross-sectional xylem and phloem, and cambial length and circumference with brown discoloration, with 0 indicating no browning and 10 indicating browning in the entire tissue. Injury was also measured as intensity of browning on a scale of 0 (no browning) to 5 (dark brown to black). The weighted averages of the two ratings were used to calculate an index of browning. Genotypic variation occurred in the degree of deacclimation, which ranged from none to as much as 15 °C loss in hardiness. Two genotypes, ‘G.41’ and ‘M.9’, showed little change in hardiness in both years they were tested. Two genotypes, G.4013 and ‘G.814’, lost substantial hardiness in both years and may be vulnerable to late winter freeze-thaw events, but were among the hardiest before deacclimation. ‘G.935’ and G.5257 showed a small loss of hardiness, whereas ‘B.9’ lost hardiness in the cambium, but not the xylem, and V.6 lost hardiness after warm exposure, but showed almost no injury at temperatures as cold as −35 °C. The loss of hardiness of these four genotypes that were tested in only one year should be verified with additional testing because of the potential for yearly variation.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".