Miscanthus - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 55

stresses can guarantee good biomass production. Cold stress tolerance is important
for the cultivation in cooler regions. No reports of yield reduction by disease and pests
have been cited at the present time. However, disease and pest problems may happen
if the cultivation areas increase in the future. One of the targets for improving
Miscanthus is to change the content and optimize the ratio of lignin, cellulose, and
hemicelluloses in cell walls [ 98 ]. This is one of the most popular approaches for
improvement of saccharification which is important for a bioenergy crop because
high saccharification benefits fermentation of sugars into ethanol [ 98 , 99 ].

Breeding Strategies and Integration of New Biotechnologies

Germplasm Collection and Characterization

The most important factor for breeding programs is a thorough knowledge of the
genotypic and phenotypic variation available in the genetic resources of Miscanthus
spp. There are wide ranges of phenotypic variation resulting from environmental
pressures (e.g., cold temperature, acid soil, salinity) and from genetic isolation
leading to specific ecotypes. Genetic resources from Japan [ 36 , 47 , 100 ], China [ 75 ,
101 , 102 ], and Taiwan [ 24 , 103 ] are available for breeding of Miscanthus spp. With
an increase of interest in Miscanthus as a sustainable renewable energy crop,
germplasm collection of Miscanthus spp. has been intensively carried out in native
vegetation areas of Asia [ 17 ]. In our group, a total of 1,000 accessions of
Miscanthus spp. have been collected throughout Japan recently. Germplasm can
be collected in the form of seeds or rhizomes, but seeds may be preferable over
rhizomes because they can be stored for longer periods of time. The Institute of
Biological, Environmental and Rural Sciences (IBERS), Aberystwyth, UK, and the
University of Illinois have collected many germplasm of Miscanthus spp. from the
countries growing Miscanthus (Clifton-Brown, Sacks personal communication).
Flowering time is one of the several factors to be considered in selecting high
biomass Miscanthus [ 25 ]. Miscanthus plants that are late flowering or nonflowering
tend to yield higher than those that are early flowering [ 25 ]. Jensen et al. [ 91 ]
observed the flowering time of various M. sinensis for 3 years at Aberystwyth,
UK. The plants were collected from Japan, China, Korea, and Russia (latitude range
32.2-43.6 N). The onset of flowering time varied from mid-June to late November.
Accessions from more northern areas and higher altitudes tended to flower earlier
than accessions from southern areas or lower altitudes. Our evaluation of
M. sinensis collected throughout Japan also revealed that accessions from northern
areas, such as Hokkaido, generally showed an earlier flowering time and ripening
than those from southern areas. M. sinensis accessions from high-altitude regions of
central Main and Shikoku Islands show that

late flowering was tolerant to

Hokkaido's cold environment and showed high biomass potential [ 104 ].
M. giganteus is a promising biomass crop in temperate and cool regions, since

the yield is still high at low temperature compared to C 3 plants or C 4 plants such as