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Research article - Peer-reviewed, 2006

Genetic linkage between growth rate and the intersterility genes S and P in the basidiomycete Heterobasidion annosum

Olson, A


Quantitative trait loci (QTL) for mycelial growth rate were identified and positioned on a genetic linkage map of Heterobasidion annosum sensu lato (s.l.), an important root rot pathogen on conifers. The mycelial growth rate among 84 progeny isolates were analysed in two different temperature regimes, 12 and 24 degrees C on malt extract agar and found to segregate as a continuous character. The assay identified three QTL for growth rate at low temperature positioned on the linkage groups 1, 17 and 19 with peak LOD values of 3.2, 2.9 and 4.8, respectively. At the QTL for high temperature growth, peak LOD values of 1.3, 2.8 and 2.2, were identified. The three QTL for the low temperature regime explained 20.9, 18.1 and 24.0% of the variation in the mycelial growth rate, respectively. The broad-sense heritability was estimated to be 0.97 and 0.95 for growth rate at low and high temperatures, respectively. Two of the QTL for the mycelial growth rate were shown to be tightly linked to the intersterility genes S and P, which control mating within and between closely related species and intersterility groups of H. annosum Isolates with a plus allele at the intersterility loci had a higher growth rate than isolates that harboured minus alleles. (c) 2006 The British Mycological Society. Published by Elsevier Ltd. All rights reserved


Forest pathogen; genetic linkage map; MapQTL; Pathogenicity; Virulence

Published in

Mycological Research
2006, volume: 110, pages: 979-984

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Mycology and Pathology

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