Predictive Models for Biomass Yield of Switchgrass Based On Morphological Traits.

The development of biofuels and biofuel sources has been set as a national goal in the United States. To reach these goals, major improvements to biofuel feedstocks will be necessary. Although switchgrass has many valuable characteristics, further improvements must be made to improve both biomass yield and to consequently increase ethanol production. Direct selection for biomass yield in switchgrass has proven difficult due to the many factors influencing biomass yield. The identification of morphological traits associated with biomass yield could increase the efficiency of breeding efforts if these traits can be used as indirect selection criteria. The objective of this research was to identify morphological traits in parent plants that are predictive of biomass yield within progeny plants. Trait measurements from 144 parent plants and biomass yield measurements from progeny were used to develop predictive models for biomass yield. Significant traits identified included: plant height, flowering date, internode length, number of nodes, leaf width, stem diameter and single plant biomass, but effects varied by year and environment. Models were subsequently cross-validated across three years and two locations. By allowing increased screening and selection for biomass yield within spaced-plant nurseries and thereby greater intensity of selection these results may impact how phenotypic selection is used for switchgrass cultivar development. Further work will be necessary to validate selection efficiency using these models within a switchgrass breeding program.