Characterizing a miscanthus germplasm collection for yield, yield components, and genotype × environment interactions

Miscanthus is among the best biomass crops for temperate environments but current production is almost entirely associated with a single sterile clone of Miscanthus × giganteus J.M.Greef, Deuter ex Hodk., Renvoize. To create additional and improved cultivars, characterization of available germplasm is needed for biomass traits and genotype × environment (G × E) interactions. Additionally, there has been little guidance on how to best allocate experimental units in Miscanthus breeding trials. The purpose of this study was to quantify genetic diversity for biomass yield in a Miscanthus germplasm collection of 98 accessions that represent publicly available materials in North America, determine the predictive value of three putative yield component traits for estimating yield, and quantify the relative importance of G × E and error variances for estimating genotypic values. We observed large and significant differences among genotypes for all traits. Indirect selection for yield based on the tested yield-component traits alone would be too inefficient to be advisable. Estimates of G × E interactions and repeatabilities indicated that selection efficiency would benefit more from increased sampling of locations rather than years and that effective selection of Miscanthus for yield could be accomplished in Year 2 rather than Year 3 for environments similar to central and southern Illinois. Minimizing the number of years per selection cycle will be critical for maximizing genetic gain per unit of time.