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Short- and long-term growth response to multiple drought episodes: evidence of genetic adaptation in a conifer species
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  • Jaime Azcona,
  • Eduardo Cappa,
  • Latitia Da Ros,
  • Blaise Ratcliffe,
  • Charles Chen,
  • Xiaojing Wei,
  • Yang Liu,
  • Shawn Mansfield,
  • Andreas Hamann,
  • Yousry El-kassaby,
  • Barb Thomas
Jaime Azcona
CSIC
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Eduardo Cappa
INTA
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Latitia Da Ros
Agriculture and Agri-Food Canada
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Blaise Ratcliffe
UBC
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Charles Chen
Oklahoma State University
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Xiaojing Wei
University of Alberta
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Yang Liu
The University of Queensland
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Shawn Mansfield
UBC
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Andreas Hamann
University of Alberta
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Yousry El-kassaby
University of British Columbia
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Barb Thomas
University of Alberta Faculty of Agricultural Life and Environmental Sciences

Corresponding Author:bthomas@ualberta.ca

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Abstract

Drought tolerance of tree species is a concern in the context of climate change, and tree ring analyses can be used to assess past growth response(s) to drought events. In this study we applied this approach to 1,281 individuals with known pedigree in long-term genetic test plantations of lodgepole pine in western Canada. We assessed resistance, resilience and recovery metrics, and analyzed their causal relationships with long-term growth and susceptibility to disease through structural equation modeling. We found that trees with low short-term resilience to drought events also experienced severe reductions in long-term growth. Narrow-sense heritability of drought tolerance metrics was low for short-term responses at specific sites, but a new long-term decline index for families showed moderate genetic heritability (h ̵̂^2 of 0.15 to 0.30 ± 0.03). We also detected evidence of local adaptation, with trees from lower elevation showing better drought adaptation. We conclude that selection of genotypes for drought tolerance is possible, and that other species or populations could be screened using this method. We also note that the new long-term decline index developed in this study shows a higher degree of genetic control than other metrices, and may therefore be of broader interest in dendrochronological research.
30 Jul 2024Submitted to Ecology and Evolution
31 Jul 2024Submission Checks Completed
31 Jul 2024Assigned to Editor
14 Aug 2024Reviewer(s) Assigned
23 Sep 2024Review(s) Completed, Editorial Evaluation Pending
27 Sep 2024Editorial Decision: Revise Minor