Occurrence and Distribution of Physiological Races of <i>Exserohilum turcicum</i> in Ontario, Canada
Notice bibliographique
Résumé
Northern corn leaf blight (NCLB) caused by Exserohilum turcicum is the most common and economically significant fungal leaf disease of corn in Ontario, Canada. During the past 10 years in Ontario, severity and incidence of NCLB have increased, possibly owing to the appearance of new races. Several races have been identified in various parts of the world; however, information on occurrence and distribution of races in Ontario is lacking. In the current study, 677 single conidial isolates of E. turcicum were isolated from 687 symptomatic leaf samples collected between 2012 and 2016. These isolates were evaluated for pathogenicity on six corn differential inbreds (A619, A619Ht1, A619Ht2, A619Ht3, A632Htn1, and H102Htm1) under controlled environmental conditions and then grouped into 17 physiological races (0, 1, 2, 3, M, N, 12, 1M, 1N, 3M, 13M, 12N, 13N, 1MN, 12MN, 13MN, 123MN) based on the reaction of the inbreds to infection (resistant or susceptible). Four races (0, 1M, 1N, and 1MN) were most frequent, with an isolation frequency of 13, 10, 12, and 41%, respectively. Seventy-six percent of the isolates were virulent on more than one Ht resistance gene, with 2.4% (16 isolates) virulent on all five Ht resistance genes used in this study. Further analysis of the distribution of races in four regions over the years revealed that the occurrence and distribution of the races changed with time in Ontario. Overall, the frequency of virulence of the 677 isolates screened on the differentials with resistance genes Ht1, Ht2, Ht3, Htm1, and Htn1 varied from 6 to 81% (Ht1 81%, Ht2 6%, Ht3 12%, Htm1 64%, and Htn1 64%). Virulent isolates produced fewer lesions on the Htm1 differential, and smaller lesions that were slower and having less sporulation on the Htn1 differential, compared with infection of the differentials with Ht1, Ht2, and Ht3 resistance genes. Virulence frequency also changed within the four geographical regions of Ontario, with fewer isolates virulent on all resistance genes in eastern Ontario compared with southern and western Ontario. Isolates from southern Ontario had greater virulence frequency against Ht1 and Htm1, whereas isolates from western Ontario were more frequently virulent on Ht1 and Htn1. The information generated in this study on the distribution of E. turcicum races in Ontario corn will help growers to select appropriate hybrids with required resistance genes and will assist seed companies in deploying resistance genes in corn hybrids across the province or within a particular region.
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 ».