The use of virulence and amplified fragment length polymorphism (AFLP) to study the genetic diversity of field isolates of Ustilago tritici
Bibliographic record
Abstract
Jstilago tritici (Pers.)Rostr.is the casual agent of loose smut of wheat' The pathogen is seed-bome and rarely devastating, rather causing low to moderate annual losses.ln canada the disease is normally controlled by using resistant cultivars' Armual surveys of wheat fields allow us to monitor the incidence and severity of U' tritici' virulence analysis of collected isolates provides information to assess the effectiveness.ofhost resistance genes and study genetic diversity.Traditionally, isolates of U. tritici are collected during extensive surveys of large areas by sampling one smutted head from each infested field encountered.This study was conducted to determine if an intensive sampling of a few fields (20 smutted heads per f,reld from four fields) could yield as much information on genetic diversity as the traditional extensive sampling method (81 smutted heads collected from 81 fields), using AFLP and virulence data as a measure of diversity' Six wheat differentials were used in the virulence study.Of the161 isolates of U'tritici assessed, 17 different virulence combinations were observed' AMOVA F-test showed no significant differences in variability between the extensive and intensive collections using virulence data.In the AFLP analysis, 23 polymorphic loci were common for the extensive and intensive collections, and 40 different AFLP banding patterns were observed for isolates from the intensive collection and 59 for isolates from the extensive collections.Unlike virulence data, AMOVA F-test for AFLP data showed highly significant differences in variability between the extensive and intensive collections..The intensive sampling of 20 smutted heads per field from four fields resulted in a more genetically diverse collection than the extensive sampling of 81 heads from the technical advice and friendship shared by Cheryl, Graham, Frank, Cheri, Marcy' Chris, Sung, and Colin.Assistance with figures and slides was provided by Reg, Kathy and Mike.Assistance with statistical analysis \¡/as provided by Sheila Woods.I especially want to thank my
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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 | 0.001 |
| 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 | 0.000 | 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".