Genetic and environmental contributions to variation and population divergence in a broad-spectrum foliar defence of 'Eucalyptus tricarpa'

Title
Genetic and environmental contributions to variation and population divergence in a broad-spectrum foliar defence of 'Eucalyptus tricarpa'
Publication Date
2010
Author(s)
Andrew, Rose
( author )
OrcID: https://orcid.org/0000-0003-0099-8336
Email: randre20@une.edu.au
UNE Id une-id:randre20
Wallis, Ian R
Harwood, Chris E
Foley, William J
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Oxford University Press
Place of publication
United Kingdom
DOI
10.1093/aob/mcq034
UNE publication id
une:15894
Abstract
'Background and Aims' Both environmental and genetic effects contribute to phenotypic variation within and among populations. Genetic differentiation of quantitative traits among populations has been shown in many species, yet it can also be accompanied by other genetic changes, such as divergence in phenotypic plasticity and in genetic variance. Sideroxylonal (a formylated phloroglucinol compound or FPC) is an important chemical defence in eucalypts. The effect of environmental variation on its production is a critical gap in our understanding of its genetics and evolution. 'Methods' The stability of genetic variation in sideroxylonal was assessed within and among populations of Eucalyptus tricarpa in three replicated provenance/progeny trials. The covariance structure of the data was also modelled to test whether genetic variances were consistent among populations and Fain's test was applied for major gene effects. 'Key Results' A significant genotype x environment interaction occurred at the level of population, and was related to temperature range and seasonality in source populations. Within-population genetic variation was not affected by genotype x environment effects or different sampling years. However, within-population genetic variance for sideroxylonal concentration differed significantly among source populations. Regression of family variance on family mean suggested that this trait is subject to major gene effects, which could explain the observed differences in genetic variances among populations. 'Conclusions' These results highlight the importance of replicated common-garden experiments for understanding the genetic basis of population differences. Genotype x environment interactions are unlikely to impede evolution or responses to artificial selection on sideroxylonal, but the lack of genetic variation in some populations may be a constraint. The results are broadly consistent with localized selection on foliar defence and illustrate that differentiation in population means, whether due to selection or to drift, can be accompanied by changes in other characteristics, such as plasticity and genetic variance.
Link
Citation
Annals of Botany, 105(5), p. 707-717
ISSN
1095-8290
0305-7364
Start page
707
End page
717

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