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Subdivision and genetic structure of four populations of Venturia inaequalis in Switzerland

Tenzer, Isabel ; Gessler, Cesare

In: European Journal of Plant Pathology, 1997, vol. 103, no. 6, p. 565-571

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    Title
    • Subdivision and genetic structure of four populations of Venturia inaequalis in Switzerland
    Author
    • Tenzer, Isabel. Phytomedicine/Pathology, Institute of Plant Sciences, Swiss Federal Institute of Technology, Universitätstrasse 2, 8092, Zürich, Switzerland
    • Gessler, Cesare. Phytomedicine/Pathology, Institute of Plant Sciences, Swiss Federal Institute of Technology, Universitätstrasse 2, 8092, Zürich, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • European Journal of Plant Pathology, 1997, vol. 103, no. 6, p. 565-571. Kluwer Academic Publishers
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:319554
    Summary
    Analyses of four populations of Venturia inaequalis in Switzerland were performed to obtain information about migration and to predict the probable speed of the spread of new pathotypes able to overcome resistance, e.g. Vf-resistance, of new cultivars. Genetic and haplotype diversity was calculated based on allele frequencies of random amplified polymorphic DNA (RAPD) markers and the internal transcribed spacer (ITS)-region of ribosomal DNA, which are regarded to be neutral, and the β-tubulin locus which may be under selection pressure. Within-population diversity was found to be quite similar over all four populations. Normalised haplotype diversity based on RAPD and ITS data was very high with a mean of 0.95. Diversity among populations (GST) was consistent over all neutral loci with a low mean of 0.04, but reached the high value of 0.26 for the selected β-tubulin locus. Low GST based on neutral loci may suggest a high level of gene flow. Considering these results, new pathotypes would be expected soon outside their place of identification. But actual gene flow is easily overestimated because of effects of gene flow in the past. However, naturally occurring gene flow could be increased by human activity. Therefore, it is very difficult to predict durability of the Vf-resitance in Switzerland