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Submitted to: Tree Physiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/1/2016 Publication Date: 7/1/2016 Citation: Ainsworth, E.A. 2016. The importance of intraspecific variation in tree responses to elevated [CO2]: breeding and management of future forests. Tree Physiology. 36:679-681. Interpretive Summary: This commentary examines the importance of understanding intraspecific variation in tree responses to elevated carbon dioxide concentrations for breeding and management of future forests. The basis for any breeding program is intraspecific variation in the traits of interest, and for forests, growth or biomass production is a key target trait. Meta-analysis of intraspecific variation in tree species responses to elevated [CO2] revealed considerable variation in the response of photosynthesis, stem biomass, stem volume and height, and discovered that the magnitude of intraspecific variation was similar to previous reports of interspecific variation in response to elevated [CO2]. This signifies potential for breeding trees for increased productivity at elevated [CO2]. Such benefits may be clear for commercial plantations that plant a more limited number of genotypes, but there may also be important benefits for natural forests which contain large within-population genetic variation. In those forests, CO2-responsive genotypes could be used in the future for assisted gene flow, the managed translocation of genotypes to new locations to facilitate adaptation to local environmental conditions. Technical Abstract: One strategy for managing forests to sustain or increase productivity under global climate change is to initiate breeding programs which maximize responses to elevated [CO2] within species. The basis for any breeding program is intraspecific variation in the traits of interest, and for forests, growth or biomass production is a key target trait. After compiling data from 25 published manuscripts of 8 tree species, Resco de Dios et al. (2016) used meta-analysis to assess intraspecific variation in tree productivity responses to elevated [CO2]. They found considerable intraspecific variation in the [CO2] response of photosynthesis, stem biomass, stem volume and height, and discovered that the magnitude of intraspecific variation was similar to previous reports of interspecific variation in response to elevated [CO2]. This, they conclude, signifies great potential for breeding trees for increased productivity at elevated [CO2]. Breeding efforts could be supported by the development of eco-evolutionary models to guide breeders in selection of key traits for holistic improvement of fitness and the identification of quantitative trait loci and candidate genes important for adaptation of trees to elevated [CO2]. Additionally, CO2-responsive genotypes could be used in the future for assisted gene flow in natural forest ecosystems. |
