Characterization of Rhizoctonia solani in Ontario and genetic analysis of host resistance in soybean
Bibliographic record
Abstract
Rhizoctonia root and hypocotyl rot, caused by 'Rhizoctonia solani' Ku?hn (teleomorph 'Thanatephorus cucumeris' (Frank) Donk), is an important disease of soybean ('Glycine max' (L.) Merr.). To facilitate management of this disease, four studies were conducted to achieve four major objectives: (i) identifying predominant anastomosis groups (AGs) of 'R. solani' associated with soybean Rhizoctonia root and hypocotyl rot in Ontario; (ii) determining the resistance of PI 442031 to different AGs; (iii) investigating the genetic basis of resistance in PI 442031 to Rhizoctonia root and hypocotyl rot incited by AG-4 isolates; and (iv) detecting simple sequence repeat (SSR) markers linked to host resistance. Using anastomosis grouping and polymerase chain reaction (PCR) with an AG-2-2 specific primer, 'R. solani' isolates collected from diseased soybean plants across Ontario were classified into AG-2-2, AG-4 and AG-5 with AG-2-2 as the predominant group. The AG-2-2 isolates were further identified as the ecological type AG-2-2 IIIB. When inoculated with isolates of different AGs, PI 442031 was moderately resistant to AG-4, AG-5 and some AG-2-2 IIIB isolates, but highly susceptible to most AG-2-2 IIIB isolates. Classical and molecular genetic studies indicated both major and minor genes with additive gene effects conditioning resistance in PI 442031 to Rhizoctonia root and hypocotyl rot caused by AG-4. Minor resistance genes with additive gene effects were also found in moderately susceptible soybean cultivars. Three SSR markers Satt281, Satt177 and Satt245 were associated with resistance to Rhizoctonia root and hypocotyl rot in both F2 and F4:5 populations derived from the cross of PI 442031 x Sterling. The association between Satt281 and resistance was verified in a second F4:5 population of RCAT Staples x PI 442031. These studies indicated that (i) AG-2-2 IIIB is an important causal agent of soybean root and hypocotyl rot in Ontario; (ii) cultivars resistant to Rhizoctonia root and hypocotyl rot incited by AG-4 isolates could be developed through selection from the populations derived from crosses with PI 442031 as a parent, or from crosses between moderately susceptible commercial cultivars; and (iii) Satt281 may be used as a molecular marker to facilitate selection for cultivars resistant to Rhizoctonia root and hypocotyl rot in soybean breeding programs.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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".