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Highlights • Multi-criteria decision making model was developed to screen miscanthus for energy breeding. • Energy-related traits of miscanthus include the two aspects of agronomy and quality. • Miscanthus lutarioriparius is most suitable for producing electricity and pyrolysis bio-oil. • Miscanthus floridulus is most suitable for producing bioethanol and biogas. Abstract Biomass is the bioenergy carrier and can be converted to solid, liquid and gaseous fuels. Miscanthus , a plant type with high biomass yield potential, is a promising feedstock source for bioenergy production. However, the current expansion of miscanthus (Miscanthus spp.) production is constrained by a shortage of commercial varieties, especially those suitable for different energy usages and cultivation under adverse environmental conditions. Therefore, breeding or selecting high-biomass-yielding, high quality and stress tolerant miscanthus varieties is essential for the extension of miscanthus for bioenergy production. To effectively select elite germplasms and breed new varieties of miscanthus, it is necessary to establish a scientific evaluation method for analysing their energy potential. In this study, a multi-criteria decision making (MCDM) model was designed to evaluate the potential of miscanthus germplasms as feedstock in four energy usages including combustion for power generation (CPG), pyrolysis for bio-oil production (PBP), fermentation for ethanol production (FEP) and fermentation for biogas production (FBP). The MCDM model was constructed based on 11 sub-criteria indices, which were grouped into agronomic-related and quality-related criteria indices. The agronomic-related criteria indices include dry matter yield, canopy height, stem diameter, tiller number and base diameter/canopy diameter ratio. The quality-related criteria indices include the leaf/stem ratio, moisture content, ash content, cellulose content, hemicellulose content and lignin content. Thirty-eight representative germplasms of miscanthus were evaluated. The MCDM analysis results showed that Miscanthus lutarioriparius (especially the XiangNanDi no. 1 variety) and Miscanthus floridulus (especially A0521) are the best species for CPG/PBP and FEP/FBP, respectively. These results are superior to those calculated by the traditional energy potential assessment method, which showed that Miscanthus floridulus was the most suitable species for CPG, FEP and FBP, especially A0521 and D0624. Moreover, the analysis also indicated that D0505 (M. floridulus) can be used as a suitable parent together with XiangNanDi no. 1 to breed new varieties for CPG and PBP; XiangNanDi no. 1 can be used as an alternative parent for breeding to improve A0521 for use in FEP and FBP. [ABSTRACT FROM AUTHOR]

Miscanthus is an important plant resource in China, which has energy plant value, bio-material value, and ecological value. However, the taxonomy of Miscanthus remains poorly defined. To clarify the phylogenetic relationships among the Miscanthus species found in China, here we describe their morphological characters, simple sequence repeats (SSRs), inter simple sequence repeats (ISSRs), and trnL-F and rpl16 gene sequences. We identified M. sacchariflorus and M. lutarioriparius as the closest relatives of M. sinensis and M. floridulus , all of which constituted a major group. At the molecular levels, M. lutarioriparius and M. sacchariflorus were always grouped to form a monophyletic group. M. floridulus appeared as a stable secondary clade of M. sinensis. M. nepalensis , M. nudipes , and M. paniculatus were separated from the major group and more closely linked to an outgroup. M. paniculatus fell into an isolated position outside of the major group. Therefore, our findings support placing M. sacchariflorus and M. lutarioriparius in Miscanthus , treating M. lutarioriparius as a variety of M. sacchariflorus , treating M. floridulus as a subspecies of M. sinensis. We do not support merging M. nepalensis and M. nudipes into Miscanthus and propose the recognition of Diandranthus as a standalone genus, which includes D. nepalensis and D. nudipes. We do not support merging M. paniculatus into Miscanthus , and we support the recognition of Rubimons as a separate genus, including R. paniculatus. These data should help with efforts to evaluate and use Miscanthus germplasms. • Phylogenetic relationships between Chinese Miscanthus species and its relatives. • Morphological characters, SSR, ISSR, and trnL-F and rpl16 gene sequences. • Better evaluation and utilization of Miscanthus germplasm resources. • Miscanthus species were distinguished by morphological and molecular indicators. [ABSTRACT FROM AUTHOR]

• Biomass yield of M. lutarioriparius was higher than that of switchgrass. • Hybrids and M. lutarioriparius were more sensitive to rainfall than switchgrass. • Ash content of M. lutarioriparius and switchgrass was not significantly different. • The highest potential ethanol production of Miscanthus genotype was 14,600 L/ha. The lignocellulosic biomass derived from Miscanthus Anderss. and switchgrass (Panicum virgatum L.) has been widely investigated; however, large−scale production is obstructed by the lack of suitable genotypes for their growth on marginal land. To breed new varieties that can adapt to specific marginal lands, a four-year (2014−2017) field experiment was conducted using switchgrass and 12 Miscanthus genotypes on marginal land in the Yellow River Delta (YRD). The performances of Miscanthus and switchgrass were evaluated and climatic factors limiting their biomass yield were identified. During each year of the trial, 13 genotypes were harvested in winter and their biometric characteristics (biomass yield, plant height, stem diameter, and tiller number) were measured. Quality parameters (cellulose, hemicellulose, lignin, and ash) were determined in the third growing season. The three-year average biomass yield of switchgrass was 5.66 Mg/ha. The three-year average biomass yield of the 12 Miscanthus genotypes ranged from 1.99 to 32.09 Mg/ha. The biomass yields of M. lutarioriparius and hybrids were significantly higher than that of switchgrass, however, these were more sensitive to rainfall than switchgrass. No significant difference was found between the ash contents of M. lutarioripariu s, M. sacchariflorus , and switchgrass. The contents of hemicellulose, cellulose, and lignin were 377.69, 526.10, and 109.33 g/kg, respectively for switchgrass, and 247.56−391.28 g/kg, 473.52−619.85 g/kg, and 83.03−132.88 g/kg, respectively, for Miscanthus. Combining biomass yield and quality, the potential ethanol productions of M. lutarioriparius and Miscanthus hybrids were higher than that of switchgrass, and the Miscanthus hybrid h1 reached 14,600 L/ha. The results of this study provide fundamental information for the development and utilization of biomass crops on marginal land in the YRD. [ABSTRACT FROM AUTHOR]