Molecular variability of a Minnesota population of <i>Phoma medicaginis</i> var. <i>medicaginis</i> , the causal agent of spring black stem and leaf spot of alfalfa
Bibliographic record
Abstract
Spring black stem and leaf spot of alfalfa (Medicago sativa) caused by Phoma medicaginis var. medicaginis is an important disease of alfalfa in temperate regions of the United States, causing yield losses and decreasing forage quality. Isolates of the fungus vary in morphological and cultural characteristics, as well as aggressiveness on alfalfa. The sequence of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (rDNA) and amplified fragment length polymorphism (AFLP) fingerprinting were used to characterize the diversity of P. medicaginis var. medicaginis isolates collected from leaves and stems of alfalfa plants from northern and southern areas of Minnesota. Sequences of the ITS1-5.8S-ITS2 regions of the rDNA repeats from 14 isolates were highly conserved. AFLP analysis of 121 isolates with eight primer pair combinations revealed a moderate amount of variation as measured by the Dice coefficient (55%) and a gene diversity index of H = 0.23. Molecular polymorphisms were not correlated with geographic locations or plant organs from which the isolates were isolated. Analysis of molecular variance tests revealed a very low level of population subdivision between northern and southern isolates (FST = 0.02) and between isolates collected from leaves and stems (FST = 0.01). AFLP fingerprinting was successful in detecting polymorphisms among P. medicaginis var. medicaginis isolates, whereas the utility of ITS region may be restricted to taxonomic or phylogenetic studies.
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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 | 0.000 |
| 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 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".