Geographical and environmental gradients shape phenotypic trait variation and genetic structure in Populus trichocarpa.
• Populus trichocarpa is widespread across western North America spanning extensive variation in photoperiod, growing season and climate. We investigated trait variation in P. trichocarpa using over 2000 trees from a common garden at Vancouver, Canada, representing replicate plantings of 461 genotypes originating from 136 provenance localities. • We measured 40 traits encompassing phenological events, biomass accumulation, growth rates, and leaf, isotope and gas exchange-based ecophysiology traits. With replicated plantings and 29,354 single nucleotide polymorphisms (SNPs) from 3518 genes, we estimated both broad-sense trait heritability (H(2)) and overall population genetic structure from principal component analysis. • Populus trichocarpa had high phenotypic variation and moderate/high H(2) for many traits. H(2) ranged from 0.3 to 0.9 in phenology, 0.3 to 0.8 in biomass and 0.1 to 0.8 in ecophysiology traits. Most traits correlated strongly with latitude, maximum daylength and temperature of tree origin, but not necessarily with elevation, precipitation or heat : moisture indices. Trait H(2) values reflected trait correlation strength with geoclimate variables. The population genetic structure had one significant principal component (PC1) which correlated with daylength and showed enrichment for genes relating to circadian rhythm and photoperiod. • Robust relationships between traits, population structure and geoclimate in P. trichocarpa reflect patterns which suggest that range-wide geographical and environment gradients have shaped its genotypic and phenotypic variability.
Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
Athena D
AD
McKown
Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
Robert D
RD
Guy
Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.|Department of Dendrology and Forest Tree Breeding, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, 165 21, Czech Republic.
Jaroslav
J
Klápště
Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Armando
A
Geraldes
Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Michael
M
Friedmann
Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Quentin C B
QCB
Cronk
Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
Yousry A
YA
El-Kassaby
Department of Wood Science, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
Shawn D
SD
Mansfield
Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Carl J
CJ
Douglas
D018533:Biomass; D001955:British Columbia; D002980:Climate; D004777:Environment; D063990:Gene Ontology; D017343:Genes, Plant; D005843:Geography; D040582:Inheritance Patterns / Q000235:genetics; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D032107:Populus / Q000235:genetics*; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable
biomass; clinal variation; ecophysiology; landscape genetics; latitude; phenology; photoperiod; poplar (Populus trichocarpa)