First Report of Damping-Off of Canola Caused by <i>Rhizoctonia solani</i> AG 2-1 in Washington State
Notice bibliographique
Résumé
In early September 2003, winter canola (Brassica napus L) cv. Inca was direct seeded into plots previously cropped with spring barley at the Washington State University Dryland Research Station at Lind, WA. Before planting, the plots received 80 mm of water by sprinkler irrigation, and 2 weeks later, volunteer barley was killed with Paraquat contact herbicide. In late September, 3 weeks after planting, canola seedlings exhibited postemergence damping-off and lesions on the hypocotyls, resulting in significant stand reductions. Rhizoctonia solani was isolated from infected hypocotyls using water agar amended with chloramphenicol (100 μg/ml). Cultures on potato dextrose agar produced dark brown colonies with dark brown microsclerotia. Three isolates were grown on autoclaved oat seed for 3 weeks in 1-liter Erlenmeyer flasks at 22°C, and colonized seed was air dried in a laminar flow hood, ground in a coffee grinder, and added to a Thatuna silt loam at 1% (w/w). The infested soil was placed into 4- × 20.5-cm plastic tubes and planted with five canola seeds per tube, five tubes per isolate. In the control treatment, soil was not infested. Plants were grown in a temperature-controlled room in a greenhouse at 16°C, 12-h light/dark. Isolates caused pre- and postemergence damping-off after 1 week, and the surviving seedlings had significantly less plant height and dry weight. Isolates were identified as AG 2-1 by pairing cultures with AG 8, 2-1, and 10 on agar-coated slides (1). Selected isolates were also identified as AG 2-1 by sequencing of the ITS 1 and 2 regions of the rDNA and matching them to sequences in GenBank. On a farm north of Pullman, WA in 2004, R. solani was isolated from soil in spring and winter wheat fields using a toothpick baiting method (2). R. solani was found primarily from sites previously cropped with winter and spring canola. These isolates were identified as AG 2-1 and five isolates were tested in the greenhouse, as described above, on canola (cv. Inca), lentil (Lens culinaris Medik. cv. Merrit), wheat (Triticum aestivum L. cv. Madsen), barley (Hordeum vulgare L. cv. Baronesse), pea (Pisum sativum L. cv. Stirling), and chickpea (Cicer arietinum L. cv. Sierra). Three of five isolates significantly reduced emergence of canola, and all isolates significantly reduced dry weight of canola seedlings and caused lesions on hypocotyls. None of the isolates reduced emergence of the other crops. All isolates reduced the dry weight of pea and three isolates reduced plant height. None of the isolates reduced the dry weight of lentil, chickpea, wheat, or barley. One of the isolates was also tested on Arabidopsis thaliana and found to be pathogenic. R. solani AG 2-1 has been reported as an important pathogen on canola in Canada and Australia, but has not been reported from the Pacific Northwest of the United States. R. solani AG 2-1 is also pathogenic on rapeseed, mustard, and subterranean clover and has been isolated from wheat, sugar beets, and potato (3). Canola is a minor rotation crop in cereal-based cropping systems in eastern Washington (1,600 ha in 2005), but there is increasing interest in this oilseed crop for biodiesel production. However, R. solani AG 2-1 may reduce stands and yield of canola. References: (1) W. C. Kronland and M. E. Stanghellini. Phytopathology 78:820, 1988. (2) T. C. Paulitz and K. L. Schroeder. Plant Dis.89:767, 2005. (3) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society. St. Paul, MN, 1991.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».