Variation in Cell Wall Composition and Saccharification Potential of Seed-Based Miscanthus Hybrids Grown on Marginal Lands Across Six European Trial Locations

Miscanthus breeding programs have focused on developing intraspecific (M. sinensis × M. sinensis) and interspecific (M. sinensis × M. sacchariflorus) seed-based hybrids with distinct cell wall characteristics for different biomass value chains. Here, we evaluated the performance of 13 novel hybrids (including seed-based intraspecific, seed-based interspecific, and one clonally propagated interspecific hybrid) relative to Miscanthus × giganteus (M × g). We compared the cell wall composition, saccharification efficiency, and yield after spring harvests in 2021 and 2022 across six European locations. Cell wall content and composition varied significantly among hybrids and were influenced by environmental conditions, yet differences due to parental background were largely consistent across locations. On average, seed-based interspecific hybrids (80.6%–84.0% neutral detergent fiber) had a lower total cell wall content than the other hybrids evaluated in this study (88.3%–90.8%). In contrast, cellulose was ~5.5% higher in hybrids with an M. sinensis × M. sacchariflorus background relative to the intraspecific hybrids, while hemicellulose averaged above 34% for intraspecific hybrids, 29.4% to 31.8% in the interspecific hybrids, and below 27% for M × g. Lignin content was highest in M × g (~13.8%), intermediate in the interspecific hybrids (11.0%–12.2%), and lowest in the intraspecific hybrids (~10%). These compositional traits translated into saccharification efficiencies that were 32.9% higher for the intraspecific hybrids and 9.8%–13.1% higher for the interspecific hybrids (seed-based and clonally propagated) compared to M × g. Accounting for biomass yield, either several seed-based hybrids or the novel clonally propagated hybrid exceeded the theoretical ethanol potential of M × g at all trial locations, indicating strong potential for their use in lignocellulosic biofuel production.