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Studies of the persistence of red clover cultivars in Sweden

with particular reference to Sclerotinia trifoliorum

Öhberg, Helena (2008). Studies of the persistence of red clover cultivars in Sweden. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2008:8
ISBN 978-91-85913-41-1
[Doctoral thesis]

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Abstract

Clover rot (caused by Sclerotinia trifoliorum) and its influence on the persistence of red clover (Trifolium pratense) was studied in this thesis. Twenty-one red clover cultivars, of various types, were examined in both field and controlled environment experiments. Field experiments were performed at six sites in different climatic regions. The prevalence of root rot, caused by a broad soil-inhabiting group of secondary invading fungi, including Fusarium spp, was also studied. Both diseases were found to be prevalent throughout the country and disease severity was unaffected by latitude. The late flowering clover cultivars grown in southern Sweden exhibited lower levels of mortality due to clover rot than the earlier heading cultivars. In addition, lower root rot disease indices were recorded for the late flowering cultivars. Tetraploid cultivars grown in northern Sweden exhibited lower levels of mortality due to clover rot than diploid ones. This pattern was not found in southern Sweden or in the controlled environment experiments, where conditions were optimised for clover rot infection. In contrast, tetraploid ones had greater root rot disease indices than diploid cultivars in most cases. Studies of more than 250 Sclerotinia trifoliorum isolates revealed a high level of genetic variation. In laboratory tests, twenty of the isolates exhibited different capacities to cause disease. Fungal strains from northern Sweden generally caused more plant death, but aggressive strains were also found in southern Sweden. The fungus Coniothyrium minitans was shown to control clover rot infection in cultivar SW Torun at a northern site with heavy natural soil infestation.

Authors/Creators:Öhberg, Helena
Title:Studies of the persistence of red clover cultivars in Sweden
Subtitle:with particular reference to Sclerotinia trifoliorum
Year of publishing :2008
Volume:2008:8
Number of Pages:46
Papers/manuscripts:
NumberReferences
ALLI. Öhberg, H., Ruth, P. & Bång, U. 2008. Differential responses of red clover cultivars to Sclerotinia trifoliorum under diverse natural climatic conditions. (Plant Pathology, Doi: 10.1111/j.1365-3059.2007.01822.x) II. Öhberg, H., Ruth, P. & Bång, U. 2005. Effect of ploidy and flowering type of red clover cultivars and of isolate origin on severity of clover rot, Sclerotinia trifoliorum. Journal of Phytopathology 153, 505-511 III. Öhberg, H. & Bång, U. 2008. Biological control of clover rot on red clover by Coniothyrium minitans under natural and controlled climatic conditions. Submitted IV. Öhberg, H. & Bång, U. 2008. Occurrence of Fusarium root rot complex in various red clover cultivars under different natural climatic conditions. (Manuscript)
Place of Publication:Umeå
ISBN for printed version:978-91-85913-41-1
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:trifolium pratense, sclerotinia trifoliorum, root rots, fusarium, fungal diseases, coniothyrium, disease resistance, varieties, climatic factors, sweden
Keywords:Trifolium pratense, clover rot, Fusarium root rot, disease incidence and severity, cultivar resistance, Coniothyrium minitans.
URN:NBN:urn:nbn:se:slu:epsilon-2190
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-2190
ID Code:1741
Department:(NL, NJ) > Dept. of Agricultural Research for Northern Sweden
(VH) > Dept. of Agricultural Research for Northern Sweden
Deposited By: Helena Öhberg
Deposited On:21 Apr 2008 00:00
Metadata Last Modified:02 Dec 2014 10:13

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