Agronomic and physiological performances of different species of Miscanthus, a major energy crop. A review

The European Union recommends the use of lignocellulosic biomass to produce biofuels in order to reduce greenhouse gas emissions. Miscanthus x giganteus, aC(4) perennial and rhizomatous plant, has been identified as a good candidate for biomass production because of its high potential yield, of up to 49 t DM.ha(-1) for autumn harvest and 26 t DM.ha(-1) for winter harvest, under low input levels. Here, we review current knowledge on the biomass production in Europe of M x giganteus and its two parental species, M. sinensis and M. sacchariflorus, under different stress conditions. This review identifies two key areas where M. giganteus crops could be improved: (i) tolerance to frost during winter or early spring is essential, mainly in Northern Europe, in order to ensure overwintering and protect young shoots following early emergence. Susceptibility to winter frost at temperatures below -3.5 degrees C for rhizomes and -8 degrees C for young shoots of M. x giganteus can lead to significant plant losses and lower yields, and (ii) a good water supply is necessary to ensure good establishment rates and satisfactory biomass production. Reductions of up to 84% in above-ground dry matter production because of a lack of water for the autumn harvest, and up to 26% for the winter harvest have been observed. M. sinensis, which displays greater genetic variability than M. giganteus, will provide the necessary genetic resources for frost and water stress tolerance. It is also necessary to either identify genotypes among M. sinensis species that are able to produce an above-ground biomass yield close to the biomass production of M. giganteus under limited water supplies and/or low temperatures, or to generate new interspecific hybrids of M. giganteus with greater tolerance. Particular attention should be paid to nitrogen response; although no response to nitrogen supply has been observed in M. giganteus, M. sinensis produces higher levels of biomass with nitrogen inputs.