Canadian Journal of Plant Pathology (2002) 24, 205-210

B.D. McCallum and P. Seto-Goh (2002)
Physiologic specialization of wheat leaf rust (Puccinia triticina) in Canada in 1999
Canadian Journal of Plant Pathology 24 (2), 205-210
Abstract: There were high levels of wheat leaf rust in the eastern prairies of Canada in 1999. Late-seeded crops were subjected to heavy inoculum pressure and favorable conditions for rust infection. A total of 38 virulence phenotypes were identified from 394 Puccinia triticina isolates collected from leaf rust infected wheat plants across Canada. The most common virulence phenotypes were MBDS (42.1%), TGBJ (16.0%), and THBJ (14.5%). Many current spring wheat cultivars contain the resistance gene Lr16, which was less effective in 1999 than in previous years. In Manitoba and Saskatchewan the proportion of virulence phenotypes virulent to Lr16, such as TGBJ and THBJ, increased from 24.3% in 1998 to 38.0% in 1999. This continues an annual trend of increasing Lr16 virulence that started in 1995. Most of the virulence phenotypes virulent to Lr16 were also virulent to the adult plant resistance gene Lr13, which is found in combination with Lr16 in some current spring wheat cultivars. The virulence phenotypes identified from Alberta, and their relative proportions, were similar to those from Manitoba and Saskatchewan. Although there were only 36 isolates from Ontario, nine of the 15 virulence phenotypes identified were unique to eastern Canada. Virulence to Lr18 was also detected in Ontario but not from western Canada. The data are consistent with the hypothesis that the eastern Canadian population is distinct from the western Canadian population.

En 1999, la rouille des feuilles du blé était abondante dans l'Est des Prairies canadiennes. Les cultures semées tardivement furent sujettes à une pression d'inoculum élevée et à des conditions favorables au développement de la rouille. Un total de 38 phénotypes de virulence furent identifiés parmi 394 isolats de Puccinia triticina récoltés sur du blé infecté par la rouille des feuilles à travers le Canada. Les phénotypes de virulence les plus communs étaient MBDS (42,1%), TGBJ (16,0%) et THBJ (14,5%). Plusieurs cultivars actuels de blé de printemps possèdent le gène de résistance Lr16 qui fut moins efficace en 1999 que lors des années précédentes. Au Manitoba et en Saskatchewan, la proportion de phénotypes de virulence virulents envers le Lr16, tels que les TGBJ et THBJ, augmenta de 34,3% en 1998 à 38% en 1999. Il s'agit de la continuation de la tendance annuelle à une augmentation de la virulence envers le Lr16 amorcée en 1995. La plupart des phénotypes de virulence virulents envers le Lr16 étaient également virulents envers le gène de résistance Lr13 des plantes adultes qui est combiné au le Lr16 dans certains cultivars actuels de blé de printemps. Les phénotypes de virulence identifiés en Alberta, et leurs proportions relatives, étaient semblables à ceux du Manitoba et de la Saskatchewan. Quoique seulement 36 isolats provenaient de l'Ontario, neuf des 15 phénotypes de virulence identifiés étaient spécifiques à l'Est du Canada. La virulence envers le Lr18 fut aussi détectée en Ontario mais pas dans l'Ouest du Canada. Les données appuient l'hypothèse que la population de l'Est du Canada est distincte de celle de l'Ouest du Canada.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Brent D. McCallum

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Puccinia triticina		Canada (west)
	Puccinia triticina	Wheat (Triticum)	Canada (east)