Genetics and Genomics of Switchgrass and Its Relatives.

Switchgrass (Panicum virgatum) offers major promise as a biomass and biofuel energy crop, with projected 500% return on energy inputs. However, switchgrass breeding may be complicated by its large polyploid genome. Despite this difficulty, we report here progress on multiple fronts in the genetics and genomics of switchgrass. We are currently conducting genetic mapping to discover loci involved in growth rate, phenology, biomass, and drought response under field conditions in central Texas. This mapping population (Alamo x Kanlow) is being grown under a large rainout shelter so that we can precisely impose drought and other treatments. In addition, we are developing novel mapping populations through crosses between switchgrass cultivars derived from different ecoregions. These new populations will be important for understand available genetic variation in switchgrass and launching future breeding efforts. After developing genetic maps for these populations, we hope to make them publicly available for research. Finally, we report recent genome sequencing of close diploid relatives of switchgrass (P. hallii, P. filipes, P. capillare). These sequencing efforts will assist in the identification of loci and genes involved in important biofuel related traits and will be crucial to the eventual assembly of the P. virgatum genome.