2022 CTRE: Genomic and Genetic approaches to improve Christmas tree health
From Bert Cregg
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From Bert Cregg
Genomic and Genetic approaches to improve Christmas tree health
Justin G. A. Whitehill - North Carolina State University (NCSU), Department of Forestry and Environmental Resources, Raleigh, NC 27695, USA
Occurred 8:00-8:30 am, June 8, 2022
Abstract:
Fir (i.e. Abies spp.) species are the premiere conifer for Christmas tree use around the world. However, firs are extremely sensitive to the global impacts of climate change. Unfortunately, increasing evidence suggests that overall global temperatures are rising at an accelerated rate which is resulting in increased maladaptation of local conifer populations. Firs are generally adapted to cool, moist environments and geographically constrained to high elevation montane ecosystems. When grown as Christmas trees, firs are planted well below their natural elevational range and associated climatic niche. This stresses trees, decreases productivity, and increases sensitivity to pests and pathogens. Traditional genetic improvement methods cannot keep pace with climate change and the associated challenges of increased damage from pests. Instead, improved tree breeding strategies that accelerate the domestication process are needed. To mitigate the future impacts of climate change, the NC State Christmas Tree Genetics (CTG) program is implementing a multi-pronged approach using several genomic strategies. Strategies include both functional and quantitative genomics approaches. Specifically, the Whitehill lab is focusing on identifying key genomic associations in Fraser fir (A. fraseri) with important Christmas tree traits such as needle retention and pest resilience. Key pests and pathogens include: (1) Phytophthora root rot and the causal agent P. cinnamomi; (2) piercing/sucking insects such as elongate hemlock scale (EHS; Fiorinia externa); and (3) grazing ungulates like the white-tailed deer (Odocoileus virginianus). Christmas trees with natural resilience to these threats are being developed through somatic embryogenesis and identified through genomic selection approaches from existing breeding programs. Genomic approaches have the potential to generate genetically elite Christmas trees in a matter of years instead of several decades. Ultimately, genetic resistance/resilience is the only viable long-term pest management solution that will ensure the continued success of conifers around the world as climate change continues to accelerate.