First Report of Rhizome Blight of Ginger Caused by Binucleate <i>Rhizoctonia</i> AG-R in China
Bibliographic record
Abstract
In 2004, rhizome blight of ginger (Zingiber officinale (Willd.) Roscoe) (cv. Yunnanxiaojiang) occurred in the Kunming District of China. The surface of ginger rhizome after harvest was crimpled and covered with white hyphae. Initial symptoms on ginger were wilting on the stem and the color of the rhizome turned from white to light brown with no lesion formation. After 2 weeks, the surface of ginger rhizome was covered with white hyphae and a dry rot set in under humid conditions. The yield loss in ginger almost reached 50% because of the disease. An AG-R tester isolate paired with the unknown 37 isolates of Rhizoctonia spp. from the diseased ginger rhizomes caused a C2 reaction that confirmed their identity. Isolates of AG-R (GenBank Accession Nos. DQ885780 and DQ885781) had 100% sequence similarity with 5.8S rDNA-ITS with the AG-R tester isolate (GenBank Accession No. AF354082). To produce infected soil inoculum, 10 isolates were cultured on potato dextrose agar in a 9-cm petri dish for 3 to 4 days and then covered with approximately 20 g of autoclaved soil and kept at 25°C for 3 to 4 days. Seedlings of ginger (cv, Yunanxiaojiang) were planted in natural potting soil at a density of one plant per vinyl pot (8 cm in diameter, 9 cm high) and grown in the greenhouse for 7 days. Each seedling was inoculated with 7 g of infested soil by placing it around the rhizome. Control plants were inoculated with autoclaved soil. The experiments were carried out three times, each time with three replicates in a growth chamber kept at 25 and 16°C with a 16-h light and 8-h dark photoperiod. After 14 days, the disease severity was recorded based on a scale in which - = no symptoms; + = small lesions on seedlings, no blight; ++ = seedling blight; and +++ = plant dead. All of the 10 tested AG-R isolates caused ginger seedling blight. Rhizoctonia spp. was reisolated from these plants, confirming its pathogenicity. To our knowledge, this is the first report of rhizome blight of ginger caused by Rhizoctonia spp. and binucleate Rhizoctonia AG-R in China. References: (1) B. Sneh et al. Page 135 in: Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN, 1998.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".