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Adaptation and exogenous selection in a P icea glauca × P icea engelmannii hybrid zone: implications for forest management under climate change
Author(s) -
De La Torre Amanda R.,
Wang Tongli,
Jaquish Barry,
Aitken Sally N.
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12540
Subject(s) - picea engelmannii , biology , introgression , hybrid , local adaptation , adaptation (eye) , selection (genetic algorithm) , hardiness (plants) , hybrid zone , phenology , ecology , botany , genetic variation , genetics , gene , population , cultivar , gene flow , montane ecology , demography , artificial intelligence , neuroscience , sociology , computer science
Summary The nature of selection responsible for the maintenance of the economically and ecologically important P icea glauca × P icea engelmannii hybrid zone was investigated. Genomic, phenotypic and climatic data were used to test assumptions of hybrid zone maintenance and to model future scenarios under climate change. Genome‐wide estimates of admixture based on a panel of 86 candidate gene single nucleotide polymorphisms were combined with long‐term quantitative data on growth and survival (over 20 yr), as well as one‐time assessments of bud burst and bud set phenology, and cold hardiness traits. A total of 15 498 individuals were phenotyped for growth and survival. Our results suggest that the P . glauca × P . engelmannii hybrid zone is maintained by local adaptation to growing season length and snowpack (exogenous selection). Hybrids appeared to be fitter than pure species in intermediate environments, which fits expectations of the bounded hybrid superiority model of hybrid zone maintenance. Adaptive introgression from parental species has probably contributed to increased hybrid fitness in intermediate habitats. While P . engelmannii ancestry is higher than P . glauca ancestry in hybrid populations, on average, selective breeding in managed hybrid populations is shifting genomic composition towards P . glauca , potentially pre‐adapting managed populations to warmer climates.