Overview of the Bioenergy Sorghum Breeding Program At the University of Florida: Challenges and Opportunities in the Sunshine State.

Due to its sunny and warm climate, the State of Florida has the potential to become a leader in bioenergy production. Sweet sorghum is an attractive bioenergy crop in the state because of its short establishment time, high biomass potential of soluble sugars and biomass, limited need for irrigation and fertilizer, tolerance to harsh environments, and compatibility with sugarcane processing. However, current varieties and hybrids of sorghum are poorly adapted to the challenges presented by the sandy soils and the pervasive fungal pathogens of the area. The bioenergy sorghum breeding program at the University of Florida is working towards the improvement of sorghum as a bioenergy crop by exploiting the genetic diversity of the species, including sweet and grain sorghums and high biomass sorghums with altered lignin composition. We are investigating the physiological and anatomical traits that confer enhanced drought tolerance to some genotypes, including root architecture, photosynthetic resilience and osmoprotectant solute concentration. Genomic and genetic approaches are being used to study of the basis of sugar accumulation and its relationship with grain and biomass production. Marker development to facilitate the introgression of anthracnose resistance genes present in a UF-developed set of sorghum lines is underway. The combination of QTL, gene expression and physiological studies will ultimately allow us to identify genes underlying traits for successful bioenergy production. This knowledge will facilitate the creation of lines and hybrids with high yield and good bioprocessing characteristics, adapted to the stresses their area of production.