Winter Hardiness Of Miscanthus (I): Overwintering Ability And Yield Of New Miscanthus Xgiganteus Genotypes In Illinois And Arkansas

Miscanthus xgiganteus (Mxg) is an important bioenergy feedstock crop. However, biomass production of Miscanthus has been largely limited to one sterile triploid cultivar, Mxg 1993-1780', which we demonstrate can have insufficient overwintering ability in temperate regions with cold winters. Key objectives for Miscanthus breeding include greater biomass yield and better adaptation to different production environments than Mxg 1993-1780'. In this study, we evaluated 13 Mxg genotypes, including 1993-1780', in replicated field trials conducted for three years at Urbana, IL; Dixon Springs, IL; and Jonesboro, AR. Entries were phenotyped for first-winter overwintering ability and plant hardiness (ratio of new tillers to old), yield in years 2 and 3, and first heading date, plant height, and culm number in years 1 and 2. We observed substantial variation for overwintering ability and biomass yield among the Mxg genotypes tested and identified ones with better overwintering ability and/or higher biomass yield than 1993-1780'. Most entries at Urbana were damaged during the first winter, whereas few or no entries were damaged at Dixon Springs or Jonesboro. However, Mxg Nagara' was entirely undamaged during the first winter and produced high biomass yields at Urbana (19.7Mg/ha in year 2 and 20.9Mg/ha in year 3), whereas Mxg 1993-1780' exhibited an overwintering loss of 29%, had severely damaged survivors (hardiness score of 25%), and reduced biomass yield (8.1Mg/ha in year 2 and 16.2Mg/ha in year 3), indicating that Mxg Nagara' could be a better choice in hardiness zone 5 (average annual minimum air temperature of -23.3 to -28.9 degrees C) or lower. In Dixon Springs, where Mxg 1993-1780' was undamaged by the first winter, it yielded highest among all the entries (21.6Mg/ha in year 3), though not significantly higher than Mxg Nagara' (18.2Mg/ha in year 3).