Characterization of flowering time diversity in Miscanthus species

Miscanthus sinensis, M. sacchariflorus and their hybrids have been identified as leading
candidates for the provision of bioenergy production across several continents. Flowering
time is an important trait affecting biomass yield as well as certain quality attributes, such
as moisture content at harvest. The aim of this study was to ascertain the level of diversity
available to breeders and potential for hybridisation of different accessions in a large
collection of Miscanthus.We also sought to determine trends in flowering time within and
between species with respect to environment and origin of collection data (where known),
whether flowering order was maintained across years, and the extent of uniformity of
flowering in different genotypes. Flowering time was observed weekly in 244 genotypes
of two Miscanthus species (M. sinensis, M. sacchariflorus) and inter-specific hybrids
including M. x giganteus over 3 years and using 4 clonal replicates of each genotype on
a trial planted near Aberystwyth (Wales, UK). Differences in flowering time across the
entire collection ranged from 160 to 334 days (June to November) and photoperiods
between 7.8 and 16.6 h, with associated accumulated temperatures of 161 to 865oCd. More
than two thirds of the collection flowered by the end of each growing season. M. sinensis
individuals were the earliest genotypes to flower and showed the greatest diversity with
respect to the onset of flowering. Flowering times in genotypes of known origin in Asia
could be partially explained by growing season rain fall, degree days and mean
temperature. Uniform flowering was identified in some genotypes. This will be important
for the development of genetically diverse seed-based crops. Rank order of flowering was
shown to be consistent across Western Europe, thereby justifying single site trials as the
basis of germplasm characterisation for wider geographical deployment.