Unravelling the genetic control of flowering time in the bioenergy grass Miscanthus

The perennial C4 rhizomatous grass Miscanthus has been identified as a leading candidate for low input bioenergy production in Europe and elsewhere. Miscanthus has an extensive geographical range and produces high yields of lignocellulosic material. Existing commercial Miscanthus biomass cropping relies on a single genotype: M. x giganteus, a hybrid of M. sinensis and M. sacchariflorus. The Institute of Biology, Environment and Rural Sciences (IBERS) has established a breeding programme to broaden the genetic base of commercial lines and improve biomass yield and conversion efficiency. Optimisation of flowering time has been identified as key to improving both the yield and quality of biomass. Flowering triggers the end of growth for the season, thereby reducing yield if flowering occurs too early. However, flowering is also a trigger for senescence and is therefore associated with there mobilisation of nutrients to the underground rhizome. Genotypes exhibiting late flowering are therefore best for a sustainable, carbon-neutral crop. An F1 mapping population, based on a cross between early and late flowering genotypes of M. sinensis, has been generated as part of the IBERS Miscanthus breeding programme and is being used to identify QTL associated with flowering time. Further data will be provided through association mapping studies carried out on a Miscanthus synthetic population. Sequence information from genes controlling flowering time in other species will be exploited to identify homologues in Miscanthus. These candidate genes will then be used to correlate single nucleotide polymorphisms with flowering phenotype.