The complete chloroplast (cp) genomes of two Miscanthus species, M. sinensis and M. sacchariflorus, were sequenced and investigated for genes, genome size variation, and polymorphisms. There are 154 genes in both cp genomes, consisting of 122 coding genes, 40 tRNA genes, and 8 rRNA genes. The cp genome contains two inverted repeat (IR) regions, separated by large single copy (LSC) region and small single copy (SSC) region. 112bp indels in M. sinensis and 152bp in M. sacchariflorus were found mainly in LSC and SSC, which are responsible for 40 bp-difference in cp genome size in two species. Likewise, out of 94bp of SNPs, 88bp were found in LSC and SSC regions. Although gene number and sequence structure were quite well conserved, indel distribution and size were different in these two Miscanthus species.

More than 300 Miscanthus accessions as a potential bioenergy crop were collected in Korea and their morphological traits were investigated at various growth stages. Among morphological traits, stem growth habit, the presence of awn in spikelet, and autumn new shoot are the most important key traits enabling to cluster Miscanthus accessions into M. sinensis and M. sacchariflorus groups. Miscanthus sinensis has bunch stem growth habit and awn in spikelet, and produces autumn new shoot, while M. sacchariflorus has scattering stem growth habit with no awn in spikelet and does not produce autumn new shoot. Interestingly, we found several Miscanthus accessions showing intermediate morphological traits. 7 M. sinensis accessions showed morphological traits similar to M. sacchariflorus and 17 M. sacchariflorus accessions showed morphological traits similar to M. sinensis. Flow cytometry and chromosome counting finally revealed 5 Miscanthus hybrids, suggesting that they are resulted from natural hybridization between M. sinensis and M. sacchariflorus. Therefore, these Miscanthus hybrids can be used to understand genetic recombination between these two Miscanthus species and our understanding may support future efforts for breeding new Miscanthus variety with high biomass productivity and environmental adaptability.

Miscanthus, a perennial rhizomatous C4 grass, is a potential biomass crop, mainly because of its high yield potential and low demand for inputs. But, overwintering is the biggest problem for establishment of Miscanthus in the first year after planting rhizomes, particularly in East Nothern Asia, where winter is very cold. In this study, overwintering and freezing tests with Miscanthus rhizomes were conducted in the field (Experimental Farm Station of Seoul National University, Suwon, Korea) and the freezer maintained at -18℃, respectively. For overwintering test, rhizomes of Miscanthus sinensis, M. sacchariflorus and M. x giganteus were buried at 1, 3, 6, and 9 cm soil depths in the field in December 2009 and transplanted in a plastic pot containing sandy loam soil in March 2010. The pot was then placed in the incubation room maintained at 35/25℃ for assessing seedling establishment and early growth. For freezing test, Miscanthus rhizomes planted at 3 cm soil depth in a plastic pot containing sandy loam soil were kept in the freezer for different durations and then transfer to the incubation room for assessing seedling establishment and early growth. Rhizomes buried at 1 cm showed the least seedling establishment, while those buried at 6 cm showed the best seedling establishment, suggesting that rhizomes need to be planted at 6 cm for their successful overwintering. When rhizomes were exposed to freezing temperature down to -18℃, their survival decreased with increasing the duration of freezing exposure. From 12 hours of exposure their survival rate decreased significantly and finally reached to zero at longer than 24 hours of exposure. Further studies will be conducted to screen cold tolerant genotypes.

Miscanthus, a perennial rhizomatous C4 grass, is a potential biomass crop. Its propagation can be made by seed, rhizome and cultured tissue. Propagation by rhizomes or cultured tissues is expensive, while seed propagation is rather simple and cheaper. However, little effort has been made to investigate seed germination, particularly in relation with exogeneous chemicals including plant growth regulators to improve germination. This study was conducted to improve the seed germination of Miscanthus with GA3, NaClO, KNO3 and procloraz. iscanthus sacchariflorus and Miscanthus sinesis seeds were treated with the above chemicals at different concentrations. Decoated seeds were soaked in GA3, NaClO, KNO3, and procloraz solutions. Pretreated 20 Miscanthus seeds were then sown in each petri dish covered with a single layer of Watman filter paper and maintained in the incubation chamber at 33℃/25℃ (day/night). Seed germination were measured every 8 hours. As a result, the best germination was obtained at 250 mg/L GA3, 0.3% NaClO, 1 mM KNO3 and 1 mL/L procloraz solutions.

Miscanthus is a rhizomatous perennial C4 grass and has been studied as a lignocellulosic biomass energy crop in Europe and USA. Although Korea has many native Miscanthus species, however, Miscanthus has never been considered as a potential bioenergy crop and not much studied. Therefore, we collected Miscanthus spp (M. sinensis and M. sacchariflorus) in Korea and overseas and conducted a field experiment during 2008-2010 to investigate their agronomic characteristics related to biomass yield and thus to select genotypes with a high biomass yield potential. The agronomic characteristics assessed are plant height, leaf area, stem thickness, stem density, flowering time, dry weight and so on. Some Korean genotypes particularly collected in Jeju and Gyeonggi showed very high biomass yield, suggesting that they can be used for breeding a new Miscanthus cultivar for biomass production. Correlation analyses showed that plant height, stem thickness and density are closely related with biomass yield. Flowering times vary with genotypes and their collection sites. Phenotypic information of Korean Miscanthus we present herein may be useful for further studies on Miscanthus as a bioenergy crop.