Flowering time diversity in Miscanthus: A tool for the optimisation of biomass

The C4 tropical grass, Miscanthus, is a leading candidate for the provision of carbon neutral energy. Increasing pressures on land for food and fuel necessitate the optimisation of all crops for yield and quality. IBERS hosts one of the largest collections of Miscanthus germplasm and is the site of diverse and coordinated studies aimed at identifying and breeding top-performing Miscanthus varieties. Plants grown for biomass require the longest possible season of vegetative growth as the switch to reproductive growth slows or stops biomass accumulation. Floral transition can also mark the initiation of senescence, when nutrients are remobilised to the underground rhizome for over-wintering. This remobilisation is critical for carbon neutrality, as well as improving combustion efficiency through the removal of harmful elements. Phenological data accumulated over three years suggest a wide range of photoperiodic and thermal time requirements for flowering within the IBERS germplasm collection. This collection is the basis from which additional resources have been developed and are being used for association studies. A candidate gene approach has been adopted using sequences known to regulate floral transition in model species such as Arabidopsis and rice. A genetic map is under construction and quantitative trait loci will be identified using this and an F1 mapping family exhibiting diverse flowering times. In addition, transverse sections of plants grown in a controlled environment provide preliminary data concerning the photoperiodic and thermal time requirements of a number of genotypes, as well as days to heading following floral initiation.