Plant Pathology (2012) 61, 739-753

E. Remesal, R. Jordán-Ramírez, R.M. Jiménez-Díaz and J.A. Navas-Cortés (2012)
Mycelial compatibility groups and pathogenic diversity in Sclerotium rolfsii populations from sugar beet crops in Mediterranean-type climate regions
Plant Pathology 61 (4), 739-753
Abstract: The population structure of Sclerotium rolfsii from autumn-sown sugar beet crops in Mediterranean-type climate regions of Chile, Italy, Portugal and Spain was determined by analyses of mycelial compatibility groups (MCGs) and pathogenicity to 11 economically important plant species. Twelve MCGs (i-xii) were identified among 459 S. rolfsii isolates. MCG iii was the most prevalent group in all countries except Italy. MCG i, the most abundant group (64·7% of isolates) was identified in Portugal and Spain. The remaining MCGs were restricted to various regions within one country (ii, vi, ix) or different countries (v), or to specific localities (iv, vii, viii, x, xi, xii). MCGs iv, vii and x each comprised one isolate. Fields extensively sampled in southern Spain were infected with one to three MCGs. Plant species differed in susceptibility to MCG tester isolates with a MCG by species interaction. Cluster analyses allowed selection into five MCG groupings and grouped plant species into species-groups 1 (broccoli, chickpea, sunflower, tomato) and 2 (cotton, pepper, sugar beet, watermelon). MCG groupings 1 (i, ix), 2 (ii, iii, vi, viii) and 5 (x, xii) were moderately virulent to species-group 1 and mildly virulent to species-group 2. MCG groupings 3 (iv, v, xi) and 4 (vii) were mildly virulent to both species-groups. Across MCG groups, species were rated highly susceptible (chickpea, sunflower), susceptible (cotton, pepper, tomato, watermelon), moderately resistant (broccoli, melon, sugar beet) and resistant (corn, wheat). Establishing the MCG population structure and virulence variability among S. rolfsii isolates should help in the management of sclerotium root rot diseases.
(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): Juan A. Navas-Cortes, Rafael M. Jimenez-Diaz

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Athelia rolfsii	Beet/sugarbeet (Beta vulgaris)	Italy
	Athelia rolfsii	Beet/sugarbeet (Beta vulgaris)	Portugal (continental)
	Athelia rolfsii	Beet/sugarbeet (Beta vulgaris)	Spain (continental)
	Athelia rolfsii	Beet/sugarbeet (Beta vulgaris)	Chile (continental)