Boron Sensitivity and Storage in Brassica Napus and Its Potential for Clubroot Management
Bibliographic record
Abstract
Abstract Clubroot [Plasmodiophora brassica] severity in canola (Brassica napus) can be suppressed by addition of boron (B), but excess B produces phytotoxicity. However, some lines of a closely related species, B. rapa, are relatively insensitive to high levels of B. Assessment of 150 accessions of B. napus and B. rapa treated with 0, 8 and 16 kg B ha-1 as disodium octaborate tetrahydrate (trade name Solubor) identified several lines that were relatively insensitive to high levels of B. In 2015, 88 lines were planted in a clubroot-infested plot in Ontario, Canada in a replicated split-plot design, where the subplot treatments were 8 kg ha-1 of B versus a non-treated control. Boron-insensitive lines generally had slightly lower clubroot severity than sensitive lines, even in the control with no added B. Application of B reduced clubroot slightly in the most sensitive lines, but produced a large and significant reduction in severity in the most insensitive lines. Assessment of five insensitive lines under controlled conditions supported the observation that application of B substantially reduced clubroot severity in insensitive lines. Comparison of two sensitive and two insensitive lines each of B. napus and B. rapa using Boron K-edge X-ray absorption near-edge structure (XANES) spectra from a synchrotron-based soft-X-ray beamline showed that some insensitive lines were able to extract B efficiently from a soil that contained very low levels of B. The spectra of sensitive and insensitive lines differed when additional B was applied, which demonstrated that the insensitive lines stored B (and other elements such as S and P) differently than the sensitive lines. Differences in the amount and type of storage likely affect the susceptibility to clubroot, and merits further study.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".