Plant Pathology (2004) 53, 316-324

A. Lebeda and I. Petrzelová (2004)
Variation and distribution of virulence phenotypes of Bremia lactucae in natural populations of Lactuca serriola
Plant Pathology 53 (3), 316-324
Abstract: During 1997-2000 the virulence variation and distribution of virulence phenotypes of Bremia lactucae (lettuce downy mildew) in natural populations of Lactuca serriola (prickly lettuce) were studied. Altogether 139 isolates of B. lactucae originating from the Czech Republic, France and Germany were examined for the presence of 27 virulence factors (v-factors) and their combinations. In the Czech population, 37 different v-phenotypes (P1-P37) of B. lactucae were found to occur on L. serriola. Most v-phenotypes were characterized by v-factors that match resistance (Dm genes/R-factors) carried by L. serriola. A wide diversity of v-phenotypes was recorded every year, but most were rare and did not reappear in other populations of B. lactucae. The three v-phenotypes P21, P28 and P29 were most frequent and widely distributed. There was variation both between spatially isolated populations and within populations of the pathogen. Geographic differences in virulence were found for the southern parts of Moravia, where the phenotypic composition of pathogen populations was completely different from the remaining part of the area investigated. However, some populations had v-phenotypes similar to those of spatially distant populations in Moravia.
(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): Ales Lebeda

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Bremia lactucae	Lettuce (Lactuca)	Czech Republic
	Bremia lactucae	Lettuce (Lactuca)	France
	Bremia lactucae	Lettuce (Lactuca)	Germany