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Switchgrass GWAS

Switchgrass (Panicum virgatum) collaborative common garden resources

As atmospheric carbon dioxide levels continue to climb, it is imperative that energy production systems become carbon neutral. To meet this goal, the Department of Energy (DOE) has invested significantly over the last few decades in developing robust means of sustainable bioenergy production. One strong focus has been to improve the yield potential of perennial grass feedstocks, particularly switchgrass (Panicum virgatum). Switchgrass is a genetically-diverse, warm-season C4 grass native to much of North America. Our collaborative research group has sought to unlock the genetics behind priority switchgrass traits with an unprecedented study of genetic—environmental interactions across most of the species’ North American range. We have established common garden from a clonally propagated GWAS panel at 10 locations across the species range. Our experiments center on unreplicated designs (focusing on replicating alleles across space) with upland/lowland checks planted in a spaced honeycomb scheme. A local host collaborator and a field technician manage the day-to-day care of field sites and data collection. To date, we have collected data for a host of diverse phenotypes including detailed characterization of flowering, growth architecture, leaf anatomy and physiology, leaf wax, pathogen and herbivore damage, tiller composition, and microbiome communities. We have developed advanced analysis pipelines for detection, localization, and identification of candidate genes from GWAS. Extensive description and characterization of the resource, along with results from the first years of study, can be found in found in Lovell et al. 2021.

Common gardens are a unique resource for community building – we encourage their use and welcome new collaborations. Please reach out to Tom Juenger (UT Austin; tjuenger@austin.utexas.edu) if you are interested in visiting existing experiments, sampling material, or developing collaborations.

aerial view of switchgrass common garden
Image: Switchgrass common garden, courtesy of Robert Goodwin (MSU)

Map of switchgrass common garden locations
Image: Map of switchgrass common garden locations

 

Selected publications

  • Tilhou, N., et al. 2024.  Genomic prediction for biomass yield in switchgrass leveraging multi-site and -trait datasets. G3. kae159, https://doi.org/10.1093/g3journal/jkae159
     
  • Durant, P., Juenger, T., and R. Heckman. 2024.  The genetic basis of leaf tensile resistance in switchgrass (Panicum virgatum).  American Journal of Botany 111 (5): e16349.
     
  • Headrick, K., Juenger, T., and R. W. Heckman.  2023.  Genetics, structural defense, and latitude of origin contribute differently to resistance to insect herbivory in the lab and field.  American Journal of Botany 111: e16260
     
  • Edwards, J. et al.  2022.  Heritability and host genomic determinants of switchgrass root-associated microbiota in field sites spanning its natural range.  Current Biology 33: 1926-1938.
     
  • Napier et al. 2021. Polyploidy and niche divergence in switchgrass. Proceedings of the National Academy of Sciences 119: e2118879119.
     
  • Lovell et al. 2020.  Polyploidy and genomic introgressions facilitate climate adaptation and biomass yield in switchgrass.  Nature 590: 438-444.
 

This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant no DE-SC0021126 and DE-SC0014156.