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Research article - Peer-reviewed, 2001

Genetic diversity in relation to sexual and asexual reproduction in populations of Melampsora larici-epitea

Samils, Berit; Stepien, Valérie; Lagercrantz, Ulf; Lascoux, Martin; Gullberg, Urban


Genetic diversity of Melampsora larici-epitea leaf rust from three cultivated stands of the willow Salix viminalis was studied using AFLP polymorphisms at 60 loci. One population was located in Northern Ireland and two in Sweden. Analysis of molecular variance (AMOVA) showed that most of the genetic variation was distributed on a fine scale within the field in all populations. Both Swedish populations displayed a very high genotypic diversity (normalized Shannon's indices of 0.95 and 1.00) and random association among loci. These results suggested that sexual reproduction had an important influence on the Swedish populations. The occurence of the alternate host (larch) adjacent to one of the Swedish rust populations did not affect the genetic diversity. However, severe rust attacks started earlier in the season in this population. The M. larici-epitea population in Northern Ireland was characterized by a low genotypic diversity (normalized Shannon's index = 0.54) and non-random association among loci was indicated by test of multilocus association and by pairwise tests among loci. These results suggested that asexual reproduction had a major effect on the genetic structure of this population, probably because of the overwintering of asexual spores and/or a population bottleneck associated with the annual sexual phase.


AFLP; AMOVA; genetic structure; leaf rust; linkage disequilibrium; Salix viminalis

Published in

European Journal of Plant Pathology
2001, volume: 107, number: 9, pages: 871-881

Authors' information

SLU - Swedish University of Agricultural Sciences
Stepien, Valérie
University of Liège
Lagercrantz, Ulf
SLU - Swedish University of Agricultural Sciences
Lascoux, Martin
Uppsala University
Gullberg, Urban
SLU - Swedish University of Agricultural Sciences

UKÄ Subject classification

Agricultural Science
Forest Science

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