A quantitative method for inoculating strawberry leaves with<i>Xanthomonas fragariae</i>, factors affecting infection, and cultivar reactions
Bibliographic record
Abstract
Abaxial surfaces of strawberry (Fragaria × ananassa) leaves were quantitatively inoculated with the causal agent of angular leaf spot, Xanthomonas fragariae, using a rigidly mounted spray gun device to examine factors affecting infection. Lesions were uniformly distributed within the inoculation sites, and their numbers increased as the distance between the spray nozzle and leaf surface decreased and the duration of the inoculation burst increased. Leaves of plants exposed to darkness before inoculation had low numbers of lesions, but numbers increased markedly after only 0.5 h of light and became maximal after 4 h, demonstrating the importance of inducing stomatal opening prior to inoculation. Exposing plants to a high or low preinoculation humidity did not affect lesion numbers, but incubating plants at a high postinoculation humidity resulted in greater numbers of lesions than those incubated at low humidity. Exposing plants to mist for 3 days following inoculation did not further increase lesion numbers. Plants exposed to frost (–1.5 ®C for up to 1.5 h) before inoculation had fewer lesions than those exposed to no frost, a result of frost-induced closure of stomata. Nineteen isolates obtained from diverse geographic regions were assessed for their aggressiveness on five strawberry cultivars, but no isolate × cultivar interaction was observed. The isolates exhibited a continuum of increasing aggressiveness, but no substantial differences were observed. Twenty-two strawberry cultivars were evaluated for their resistance to X. fragariae. A continuum of increasing resistance was observed except for the cultivar ‘Tristar’, which appeared to be substantially more resistant than the others. In a separate test, two clones, US 4808 and US 4809, which have been released for resistance breeding purposes, were more resistant than the standard cultivar ‘Honeoye’, but they were not completely resistant. The inoculation procedure described here will be useful for quantitatively assessing angular leaf spot of progeny in disease resistance breeding programs.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".