Abstract Detail

The impact of climate change on plant physiology in natural and agricultural systems

Roskilly, Beth [1], Aitken, Sally [2].

Range-wide patterns of local adaptation and adaptive potential to future climates in western larch.

Shifting climates are disrupting historical patterns of local adaptation in tree populations, introducing a pressing need to understand the risks posed by climate change and mitigation strategies such as assisted gene flow. Climate niche modelling projects that areas of future suitable climate for western larch (Larix occidentalis Nutt.) will stretch far north and west of its contemporary distribution in western North America, making it a desirable candidate for assisted migration trials. It was the first conifer species approved to be operationally planted outside of its native range in British Columbia, and these plantings have demonstrated its reforestation potential on many sites throughout the province. Previous common garden studies indicate weak geographic clines for adaptive phenotypic traits compared to other co-occurring evergreen species. We assessed phenotypic data on seedling growth, phenology (bud break and bud set), drought tolerance, and cold hardiness of 52 natural populations and 28 selectively-bred families in a common garden experiment at the UBC campus in Vancouver, British Columbia in 2021. We found high phenotypic variance within populations for all phenotypic traits assessed, contributing to low differentiation among populations (6-14%) and suggesting high standing genetic variation and phenotypic plasticity within populations. Annual height growth was greater in provenances with later bud set from drier, continental climates of the eastern portion of the range. Spring bud break was later in provenances with later frost-free periods but among-population differences were small in the mild climate of the common garden site. Fall cold hardiness differed weakly among populations and was not strongly correlated to provenance mean coldest month temperature or any other temperature-related variables tested. We also implemented moderate and severe drought treatments to assess phenotypic traits related to drought tolerance, population-level plasticity (GxE), and correlations of phenotypic traits among treatments. Preliminary results indicate that drought treatments reduced among and within-population variation in the annual height growth and bud set phenology. The height growth gains found between selectively-bred families and natural populations were reduced in the drought treatments, suggesting that traits related to drought tolerance may need to be considered to maintain future growth gains in breeding programs. This study assesses population-level vulnerabilities to climate change and informs strategies for matching seed sources with emerging climates.

1 - University of British Columbia, 2424 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada
2 - Forest Sciences, 3041-2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada

none specified

Presentation Type: Colloquium Presentations
Number: C1009
Abstract ID:549
Candidate for Awards:Margaret Menzel Award,Physiological Section Physiological Section Li-COR Prize,Physiological Section Best Paper Presentation

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