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The pretreatment of lignocellulosic biomass such as Miscanthus grown on marginal agricultural land is very challenging and requires severe conditions to fractionate cell wall polymers for further valorization. The current study aimed to determine organic acid-based mild conditions to pretreat contrasting lignocellulosic Miscanthus genotypes for the efficient fractionation of cell wall components, with special focus on hemicellulose extraction. In doing so, five Miscanthus genotypes were subjected to four different acid treatments (sulfuric acid, oxalic acid, malonic acid, and citric acid) in a vertical high-pressure steam sterilizer. The results demonstrated that, among the organic acids, oxalic acid was identified as the most effective pretreatment solvent for hemicellulose separation, whereas citric acid yielded the highest amount of galacturonic acid, varying from 15 to 17 mg mL−1 across genotypes. One best performing genotype was selected for the enzymatic hydrolysis. Overall, M. floridulus genotypes exhibited the optimal quality traits for efficient bioconversion with second best in terms of ethanol production potential. [ABSTRACT FROM AUTHOR]

Miscanthus spp. has been regarded as a promising industrial plant for the sustainable production of bio-based materials. To assess its potential for microcrystalline cellulose (MCC) and cellulose nanocrystals (CNCs) production, 50 representative clones of M. sinensis and M. floridulus were selected from a nationwide collection showcasing the extensive diversity of germplasm resources. Descriptive analysis indicates that the dry biomass weight of M. floridulus is advantageous whereas M. sinensis demonstrates higher MCC and CNCs yields as well as a smaller CNCs particle size. Correlation analyses indicated that MCC yield is solely influenced by the cellulose content whereas the yield of CNCs is affected by both the cellulose content and CrI. Comparative analyses of the chemical composition, physical features (degree of polymerization, crystalline index, particle size distribution and zeta potential), and scanning electron microscopy indicated that the MCC and CNCs extracted from M. sinensis and M. floridulus exhibited remarkable stability and quality. Additionally, the CNCs derived from M. sinensis and M. floridulus exhibited a distinctive ball-shaped structure. Notably, machine learning has demonstrated its efficacy and effectiveness in the high-throughput screening of large populations of Miscanthus spp. for predicting the yield of MCC and CNCs. Our results have also laid the theoretical foundation for the exploration, cultivation, and genetic breeding of M. sinensis and M. floridulus germplasm resources with the purpose of MCC and CNCs preparation. [ABSTRACT FROM AUTHOR]

Marginal land conversion to perennial energy crops can provide biomass feedstocks and climate change mitigation. However, the effect of perennial energy crop cultivation on soil organic carbon (SOC) sequestration and its underlying mechanism in marginal land still remains incomplete. Here, SOC turnover, stability, and its potential sequestration were evaluated based on 10 years of land use change from C3 grass‐dominated marginal land to C4 energy crops Miscanthus and switchgrass cultivation. The naturally occurring 13C signature down to 60 cm depth was used to determine the energy crops‐derived C. Compared to reference marginal land, Miscanthus plantation increased the SOC stock at 0–60 cm depth by 17.8% and 64.3% in bulk and root zone, respectively. Similarly, the SOC stock under switchgrass was also 16.5% and 93.0% higher in bulk and root zone than in reference marginal land, respectively. The higher SOC stock in the root zone of switchgrass relative to Miscanthus was supported by the higher contribution of C4‐derived C to SOC (44.5% vs. 32.4%). The mean residence time of old C was higher under switchgrass than Miscanthus in the bulk zone across 0–60 cm (p < 0.05) but remained the same at 0–20 cm in the root zone. Specific SOC mineralization and temperature sensitivity were lower in soils under Miscanthus and switchgrass compared to reference marginal land. The partial least squares path model revealed that perennial energy crop cultivation enhances soil C stock via increased C4‐derived C input and reduced mineralization. In conclusion, marginal land conversion to perennial energy crops is a win–win strategy for C sequestration to mitigate climate change and support the growing bioenergy sector with biomass supply. [ABSTRACT FROM AUTHOR]

Perennial energy crops (PECs) such as Miscanthus spp. and switchgrass (Panicum virgatum L.) may have particular influence on microbial communities and their functions in soil organic carbon (C) utilization and mineralization (Cm). In this study, long‐term effects of PECs on Cm and soil hydrolase activities were examined in bulk and rhizosphere soils of Miscanthus and switchgrass grown on a red soil in South China. Long‐term cultivation (10 years) of PECs led to increases in soil organic C (SOC) and the absolute Cm of bulk and rhizosphere soils. Total Cm was correlated with dissolved organic C and dissolved organic nitrogen (N) in red soils. The specific Cm in bulk soils of switchgrass and Miscanthus were decreased by 11.73% and 20.67% comparing with the control group, respectively. Cultivation of PECs led to a relatively high C/N ratio. There was a difference in priming effect on activities of β‐glucosidase (BG), leucine amin peptidase, N‐acetyl‐β‐glucosaminidase (NAG), and phosphatase between rhizosphere and bulk soils. Compared with the control without PECs, BG activity did not change significantly in bulk soils of PECs, whereas NAG activity decreased significantly. Soil microorganisms were generally limited by soil C and phosphorus (P) in the red soil. The C and P limitations were significantly linearly related with relative Cm (p < 0.05). Phosphorus limitations in microbial communities were lower with PECs than in the control, indicating that cultivation of PECs could provide an optimal nutrient environment for both plants and microorganisms. Thus, long‐term cultivation of PECs increased SOC content but decreased specific Cm rates. However, because C and P limitations remain for plants and soil microbial communities, optimum fertilization is also necessary for sustainable growth of PECs on red soils. [ABSTRACT FROM AUTHOR]

Miscanthus interspecific hybrids have been proved to have better adaptability in marginal lands than their parents. Miscanthus sacchariflorus and Miscanthus lutarioriparius were used as the parents to develop hybrids. We performed the transcriptome for 110 F1 hybrids of Miscanthus sacchariflorus × Miscanthus lutarioriparius and their parents that had been established on the Loess Plateau mine area, to estimate the population's genetic expression variation, and illuminate the adaptive mechanism of the F1 population. The result speculated that the F1 population has mainly inherited the stress response metabolic pathway of its female parent (M. sacchariflorus), which may be responsible for its higher environmental adaptability and biomass yield compared with male parents. Based on PopART, we assembled a leaf reference transcriptome for M. sacchariflorus (LRTMS) and obtained 8116 high-quality transcripts. When we analyze the differential expression of genes between F1 population and parent, 39 and 56 differentially expressed genes were screened out in the female parent and male parent, respectively. The enrichment analysis showed that pathways of carbohydrate metabolism, lipid metabolism, biosynthesis of secondary metabolites and circadian rhythm-plant played a key role in resisting the harsh environment. The carbohydrate metabolism and lipid metabolism were also significantly enriched, and the synthesis of these substances facilitated the yield. The results provided an insight into breeding Miscanthus hybrids more suited to the harsh environment of the Loess Plateau. [ABSTRACT FROM AUTHOR]

In this study, polyploid Miscanthus lutarioriparius (PML) was introduced as a new sustainable and scalable source for cellulose nanocrystal (CNC). The agronomic traits of PML were significantly different from Miscanthus × giganteus (MG), but their chemical components and physical features were similar. Notably, a remarkable co-extraction of hemicellulose, lignin and ash and non-crystalline cellulose was observed during crude cellulose isolation from PML than it from MG by modified alkaline peroxide pretreatment. In addition, subjecting crude cellulose of PML and MG biomass to sulfuric acid hydrolysis provided high-quality CNC. The analysis of particle size distribution, zeta potential, crystalline index, the degree of polymerization, SEM and yield potential suggested that the CNC extracted from PML showed higher stability, processability and productivity than that from MG. Therefore, it provides a new theoretical basis for the applications of CNC prepared by PML and MG. The results also revealed potential genetic approaches for Miscanthus spp. to enhance biomass and CNC yield. [ABSTRACT FROM AUTHOR]

Miscanthus lutarioriparius has a growing area of 100,000 ha and an annual biomass production of 1 Mt around Dongting Lake. However, due to serious soil pollution, there is a concern that the M. lutarioriparius biomass could have high heavy metal (HM) concentrations. This necessitates investigation of biomass quality to find the appropriate end use. Thus, this study aims to investigate the dynamics of HM elements in the M. lutarioriparius biomass and their impact on biomass quality across different growing areas and harvest times. We analyzed the HM concentrations in soil and biomass from 11 sites under different harvesting times (April, August and December). Results showed that Cd in soil samples was 9.43-fold higher than the national standards. The heavily polluted soil caused a high HM concentration in the biomass and the accumulation increased with the delayed harvest. The fresh young shoots in April met the food limitation for Cd and Cr, whereas Pb concentration was slightly higher than the threshold limit. The mature biomass from the southern part had higher Mn, Cd and Pb, but lower Cu, Zn and Cr concentrations than that from the eastern part. These results can provide guidance for guaranteeing the consistent quality of the M. lutarioriparius biomass for bio-based industry. [ABSTRACT FROM AUTHOR]

The genus Miscanthus is a promising lignocellulosic feedstock crop for the production of bioenergy. Miscanthus is drawing attention because it can be grown on marginal land and avoid competition with food crops. Therefore, as measures of performance, biomass yield and quality of two parent species (Miscanthus sinensis and Miscanthus lutarioriparius) and 15 of their interspecific hybrids were evaluated in a saline–alkaline soil of the Yellow River delta in China. Ethanol and biogas production potentials were also estimated. A field trial with a randomised block design with five replicates of each genotype was conducted in 2014. Biomass yield, plant height, tiller number, stem diameter, and tiller mass of each parent and hybrid were measured at the end of the growing season in 2015, 2016, and 2017. Quality traits, including cellulose, hemicellulose, lignin and ash contents, were measured. There was large genotype variation in biomass yield and in most of the biometric parameters, and cellulose (range: 0.33 to 0.45 g/g), hemicellulose (0.32 to 0.43 g/g), lignin (0.07–0.13 g/g) and ash (0.02–0.06 g/g) contents were significantly different among the hybrids. The ash content of all hybrids was significantly lower than that of M. sinensis. The two‐year (2016 and 2017) average biomass yield of the 15 hybrids ranged from 9.87 to 23.11 t/ha, which was significantly higher than that of either parent (M. sinensis: 1.20 t/ha; M. lutarioriparius: 3.87 t/ha). Two hybrids, SL8 and SL15, were identified as potential genotypes suitable for the saline–alkaline soils of the Yellow River delta. These results demonstrate that interspecific hybridisation is crucial to improve Miscanthus biomass yield and quality under marginal conditions. [ABSTRACT FROM AUTHOR]

Phytoremediation using Miscanthus is a valuable technique for the restoration of saline‐alkaline soil, but the potential is not quantified. To assess this potential, a 5 years field experiment was conducted on saline‐alkaline soils with three genotypes of Miscanthus and an unplanted control. The bulk soil (0–20‐cm depth) physicochemical properties were measured annually from 2015 to 2018, while the bacterial and fungal community structures of the rhizosphere soil were investigated by high‐throughput sequencing after 5 years under Miscanthus (2018). The results showed that Miscanthus cultivation on saline‐alkaline soil reduced soil salinization and improved soil fertility on this site. Specifically, compared with the blank control, the five‐years Miscanthus cultivation (mean of three different genotypes pooled) decreased the soil pH by 0.33 units (8.78–8.45) and electrical conductivity by 23.4 μS/cm (226.7–203.3 μS/cm), as well as increasing soil organic matter content from 18.9 to 34.9 g/kg and total potassium content from 15.2 to 18.0 g/kg. In addition, the soil improvement was more pronounced with a longer duration of growth. Miscanthus remediates saline‐alkaline soils by altering the microbial community compositional abundance rather than its diversity. The improvement is due to enrichment of beneficial bacteria leading to soil desalinization (e.g., by Gemmatimonadaceae), litter decomposition (e.g., by Chitinophagaceae), plant growth promotion (e.g., by Micrococcaceae), and the reduction of harmful fungi (e.g., Pleosporales and Chitinophagaceae). Soil pH, electrical conductivity, organic matter, and total potassium were the main physicochemical properties affecting bacterial and fungal communities. Our results quantify the soil improvement potential of Miscanthus and clarify the underlying microbial mechanisms, laying a solid foundation for further implementation of saline‐alkaline soil phytoremediation using Miscanthus. In the future, more extensive multi‐location trials are required to assess if these improvements are seen across a wide diversity of environments. [ABSTRACT FROM AUTHOR]

Miscanthus, a perennial rhizomatous C4 grass, has emerged as a promising lignocellulosic crop. To avoid competition with food crops, marginal lands especially saline–alkaline soil are being recommended to grow Miscanthus across China. However, the challenges such as high cost and low reproduction coefficient associated with the propagation methods are impeding its large‐scale plantation in saline–alkaline soil. In this study, a "two‐steps" propagation method was designed, which was comprised of two phases: (1) seedling cultivation and (2) seedling strengthening. The parameters (substrate composition and plug size) for this method were determined. The optimal substrate composition of the seedling bed for M. sinensis, M. lutarioriparius, and their interspecific hybrids was peat and perlite at a ratio of 3:2, 3:1, and 3:3 by volume, respectively. The seedlings were transplanted into the plugs to deliver robust plantlets. The most appropriate plug size for M. sinensis, M. lutarioriparius, and their interspecific hybrids was 50 plugs (50 cm3/plug), 72 plugs (40 cm3/plug), and 72 plugs (40 cm3/plug), respectively. Three propagation methods, that is, direct sowing of seeds, rhizomes plantation, and "two‐steps" seed‐derived plugs for M. lutarioriparius were compared in saline–alkaline soil over 3 years (2014, 2015, and 2016). The establishment rate of the seeds directly planted was poor (zero). The performance (e.g., biomass yield) of the plants derived from the "two‐steps" seed‐derived plugs was better than that of the plants derived from rhizomes directly planted. Therefore, the "two‐steps" seed‐derived plugs can be regarded as an effective propagation method to upscale Miscanthus cultivation in saline–alkaline soil. [ABSTRACT FROM AUTHOR]

To understand the effects of different marginal land and environments on the growth, biomass yield, quality, and theoretical ethanol yield of different bioenergy grasses, and to compare the adaptability of different bioenergy grasses. This study was conducted in four representative marginal lands located in Chongqing, Liuyang, Nanyang, and Beijing. The agronomic traits, cell wall compositions, and theoretical alcohol yield of nine energy grasses containing 22 accessions were compared. The effects of environmental factors on biomass yield, quality, and theoretical ethanol yield of different accessions were evaluated via parametric and non-parametric statistics and AMMI analysis, and the stability and adaptability of all accessions were also compared. The results revealed that there were significant differences in biomass yield, quality, and theoretical alcohol yield among different species at the same trial site, and the same species also showed large differences between trial sites. Grasses exhibited divergent adaptability across trial sites, such as Saccharum arundinaceum and Miscanthus floridulus were sensitive to low temperatures and could not overwinter normally in Beijing. The biomass yield of Miscanthus sacchariflorus declined as the latitude decreased. Miscanthus × giganteus , Miscanthus lutarioriparius × sinensis , and Panicum virgatum exhibited greater resistance to environmental changes, indicating superior stability and environmental adaptability. [Display omitted] • Grass biomass and quality are significantly influenced by environmental factors. • Significant environmental adaptations are observed in different grass species. • Theoretical alcohol yield of grasses varies significantly between environments. • Unperturbed field trials were conducted on 4 marginal lands and climatic conditions. [ABSTRACT FROM AUTHOR]

Heterosis plays an important role in plant breeding and has been widely used in the production of a variety of food crops. However, cross-breeding is particularly important in the breeding of new varieties of the energy crop miscanthus due to its characteristics of self-incompatibility and lack of interspecific reproductive isolation. Therefore, in the current study, 30 direct cross hybrids and 150 reciprocal cross hybrids were obtained from a cross between M. sinensis and M. lutarioriparius. These hybrids were significantly different in phenotype and were used for a detailed analysis of heterosis. The mid-parent, over-parent and over-standard heterosis of the hybrids for yield-related agronomic traits were analyzed. The results showed that the hybrids from direct and reciprocal crosses exhibited significant trait segregation and acquired dominant agronomic traits from both parents, showing mid-parent, over-parent and over-standard heterosis. Plant height, tiller number, stem node number, and stem diameter showed maternal inheritance. Principal component analysis was used to construct the linear combination relationship of yield-related agronomic traits. Excellent hybrids were screened against the commercial miscanthus variety Miscanthus × giganteus. These hybrids were superior to their two parents and M. × giganteus in terms of phenotypic yield-related agronomic traits, biomass yield, and quality. These results not only confirmed the feasibility of breeding miscanthus by remote crosses, but also provided a reference for the application, cross-breeding and breeding of new miscanthus varieties. • First systematic analysis of heterosis for yield-related traits in miscanthus. • Significant variation in yield related traits in the hybrid of interspecific crosses of miscanthus. • Confirmed the existence of maternal inheritance of some yield-related traits in miscanthus. • Provided new ideas for breeding new miscanthus varieties through heterosis. [ABSTRACT FROM AUTHOR]

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Miscanthus lutarioriparius is a native perennial Miscanthus species of China, which is currently used as raw material of papermaking and bioenergy crop. It also has been considered as a promising eco-bioindustrial plant, which can offer raw material and gene for the biomass industry. However, lack of germplasm resources and genetic diversity information of M. lutarioriparius have become the bottleneck that prevents the stable and further development of the biomass industry. In the present study, genetic diversity of 153 M. lutarioriparius individuals nine populations was studied using 27 Start Codon Targeted (SCoT) markers. High polymorphic bands (97.67%), polymorphic information content (0.26) and allele number (1.88) showed SCoT as a reliable marker system for genetic analysis in M. lutarioriparius. At the species, the percentage of polymorphic loci [PPL] was 97.2%, Nei’s gene diversity [H] was 0.36, Shannon index [I] was 0.54 and Expected Heterozygosity [He] was 0.56. Genetic variation within populations (84.91%) was higher than among populations (15.09%) based on analysis of molecular variance (AMOVA). Moderate level of genetic differentiation was found in M. lutarioriparius populations (Fst = 0.15), which is further confirmed by STRUCTURE, principal coordinates analysis (PCoA) and an unweighted pair group method with arithmetic mean (UPGMA) analysis that could reveal a clear separation between groups of the north and south of Yangtze River. The gene flow of the populations within the respective south and north of Yangtze River area was higher, but lower between the areas. There was no obvious correlation between genetic distance and geographic distance. The breeding systems, geographical isolation and fragmented habitat of M. lutarioriparius may be due to the high level of genetic diversity, moderate genetic differentiation, and the population, structure. The study further suggests some measure for conservation of genetic resources and provides the genetic basis for improving the efficiency of breeding based on the results of diversity analysis. [ABSTRACT FROM AUTHOR]

The feasibility of visible and near infrared (NIR) spectroscopy as tool to classify Miscanthus samples was explored in this study. Three types of Miscanthus plants, namely, M. sinensis, M. sacchariflorus and M. fIoridulus, were analyzed using a NIR spectrophotometer. Several classification models based on the NIR spectra data were developed using line discriminated analysis (LDA), partial least squares (PLS), least squares support vector machine regression (LSSVR), radial basis function (RBF) and neural network (NN). The principal component analysis (PCA) presented rough classification with overlapping samples, while the models of Line_LSSVR, RBF_LSSVR and RBF_NN presented almost same calibration and validation results. Due to the higher speed of Line_LSSVR than RBF_LSSVR and RBF_NN, we selected the line_LSSVR model as a representative. In our study, the model based on line_LSSVR showed higher accuracy than LDA and PLS models. The total correct classification rates of 87.79 and 96.51% were observed based on LDA and PLS model in the testing set, respectively, while the line_LSSVR showed 99.42% of total correct classification rate. Meanwhile, the lin_LSSVR model in the testing set showed correct classification rate of 100, 100 and 96.77% for M. sinensis, M. sacchariflorus and M. fIoridulus, respectively. The lin_LSSVR model assigned 99.42% of samples to the right groups, except one M. fIoridulus sample. The results demonstrated that NIR spectra combined with a preliminary morphological classification could be an effective and reliable procedure for the classification of Miscanthus species. [ABSTRACT FROM AUTHOR]

Miscanthus is a leading bioenergy candidate for biofuels, and it thus becomes essential to characterize the desire natural Miscanthus germplasm accessions with high biomass saccharification. In this study, total 171 natural Miscanthus accessions were geographically mapped using public database. According to the equation [P(H/L| East) = P(H/L∩East)/P(East)], the probability (P) parameters were calculated on relationships between geographical distributions of Miscanthus accessions in the East of China, and related factors with high(H) or low(L) values including biomass saccahrification under 1% NaOH and 1% H2SO4 pretreatments, lignocellulose features and climate conditions. Based on the maximum P value, a golden cutting line was generated from 42°25’ N, 108°22’ E to 22°58’ N, 116°28’ E on the original locations of Miscanthus accessions with high P(H|East) values (0.800–0.813), indicating that more than 90% Miscanthus accessions were originally located in the East with high biomass saccharification. Furthermore, the averaged insolation showed high P (H|East) and P(East|H) values at 0.782 and 0.754, whereas other climate factors had low P(East|H) values, suggesting that the averaged insolation is unique factor on Miscanthus distributions for biomass saccharification. In terms of cell wall compositions and wall polymer features, both hemicelluloses level and cellulose crystallinity (CrI) of Miscanthus accessions exhibited relative high P values, suggesting that they should be the major factors accounting for geographic distributions of Miscanthus accessions with high biomass digestibility. [ABSTRACT FROM AUTHOR]

Key message: MLNAC5 functions as a stress-responsive NAC transcription factor gene and enhances drought and cold stress tolerance in transgenic Arabidopsis via the ABA-dependent signaling pathway. Abstract: NAC transcription factors (TFs) play crucial roles in plant responses to abiotic stress. Miscanthus lutarioriparius is one of Miscanthus species native to East Asia. It has attracted much attention as a bioenergy crop because of its superior biomass productivity as well as wide adaptability to different environments. However, the functions of stress-related NAC TFs remain to be elucidated in M. lutarioriparius. In this study, a detailed functional characterization of MlNAC5 was carried out. MlNAC5 was a member of ATAF subfamily and it showed the highest sequence identity to ATAF1. Subcellular localization of MlNAC5-YFP fusion protein in tobacco leaves indicated that MlNAC5 is a nuclear protein. Transactivation assay in yeast cells demonstrated that MlNAC5 functions as a transcription activator and its activation domain is located in the C-terminus. Overexpression of MlNAC5 in Arabidopsis had impacts on plant development including dwarfism, leaf senescence, leaf morphology, and late flowering under normal growth conditions. Furthermore, MlNAC5 overexpression lines in Arabidopsis exhibited hypersensitivity to abscisic acid (ABA) and NaCl. Moreover, overexpression of MlNAC5 in Arabidopsis significantly enhanced drought and cold tolerance by transcriptionally regulating some stress-responsive marker genes. Collectively, our results indicated that MlNAC5 functions as an important regulator during the process of plant development and responses to salinity, drought and cold stresses. [ABSTRACT FROM AUTHOR]

Key message: The 13 MlNAC genes could respond to various abiotic stresses, suggesting their crucial roles in stress response. Overexpression of MlNAC2 in Arabidopsis led to improved drought tolerance. Abstract: NAC (NAM, ATAF1/2 and CUC2) proteins are plant-specific transcription factors that play crucial roles in plant development, growth and stress responses. In this study, 13 stress-responsive NAC genes were identified from Miscanthus lutarioriparius. Full-length cDNA sequences were obtained for 11 MlNAC genes, which were phylogenetically classified into six subfamilies. Sequence alignment revealed the highly conserved NAC domain in the N-terminus of these MlNACs, while the C-terminus was highly divergent. We performed quantitative real-time RT-PCR to examine the expression profiles of MlNAC genes in different tissues including root, rhizome, mature stem, young stem, leaf and sheath. The 13 MlNAC genes displayed distinct tissue-specific patterns in six tissues examined. To gain further insight into their roles in response to abiotic stresses, expressions of MlNAC genes were analyzed under different stresses and hormone treatments including salt, drought, cold, wounding, abscisic acid, Methyl jasmonate and salicylic acid. The 13 MlNAC genes could respond to at least five stress treatments, and over 100-fold variations in transcript levels of MlNAC1, MlNAC2, MlNAC4, and MlNAC12 were observed in salt, drought and MeJA treatments, which indicated that MlNACs play crucial roles in stress response. Crosstalk among various abiotic stress and hormone responses was also discussed based on the expression of MlNAC genes. Overexpression of MlNAC2 in Arabidopsis (Col-0) led to improved drought tolerance. The water loss rate was significantly lower, and the recovery rate after a 60-min dehydration stress treatment was significantly higher in the MlNAC2 overexpression lines than the control. [ABSTRACT FROM AUTHOR]

Core collections can act as a genetic germplasm resource for biologists and breeders. Thirty-seven phenotypic traits from 471 Miscanthus accessions in China were used to design 203 sampling schemes to screen the genetic variations in different sampling strategies. The sampling was analyzed using the unweighted pair group method with arithmetic mean (UPGMA) and the Euclidean distance (Euclid). Several parameters including the variance of phenotypic value (VPV), Shannon–Weaver diversity index (H), coefficient of variation (CV), variance of phenotypic frequency (VPF), ratio of phenotype retained (RPR), the mean difference percentage (MD%) and the variance difference percentage of traits (VD%), the range coincidence rate (CR%) and the variable rate of quantitative traits (VR%) were used to evaluate the level of representation of the primary core collections developed by the different sampling schemes. Based on the optimal sampling strategies of prior selecting accessions, a primary core collection was constructed that maintained > 99.5% of the VPV and a CR% of 100%. This study indicates that the optimal sampling scheme consisted of prior and deviation sampling methods (PD) combined with a logarithmic proportional sampling strategy (LG) of 37.4% of the actual sampling ratio. Sampling before clustering can improve several parameters including the H, CV, RPR, VPF, and CR%. Sampling strategies including the genetic diversity index (G), logarithmic proportional (LG) and the square root proportional strategy (SG) can improve the H, whilst the constant strategy (C) can improve the RPR and VPF when the sampling scale was >30%. Furthermore, the proportional strategy (P) can improve the VPV. [ABSTRACT FROM AUTHOR]

Plant lignin is one of the major wall components that greatly contribute to biomass recalcitrance for biofuel production. In this study, total 79 representative Miscanthus germplasms were determined with wide biomass digestibility and diverse monolignol composition. Integrative analyses indicated that three major monolignols (S, G, H) and S/G ratio could account for lignin negative influence on biomass digestibility upon NaOH and H2SO4 pretreatments. Notably, the biomass enzymatic digestions were predominately affected by the non-KOH-extractable lignin and interlinked-phenolics, other than the KOH-extractable ones that cover 80% of total lignin. Furthermore, a positive correlation was found between the monolignols and phenolics at p<0.05 level in the non-KOH-extractable only, suggesting their tight association to form the minor wall-networks against cellulases accessibility. The results indicated that the non-KOH-extractable lignin-complex should be the target either for cost-effective biomass pretreatments or for relatively simply genetic modification of plant cell walls in Miscanthus. [ABSTRACT FROM AUTHOR]

The hybrid origin of Miscanthus purpurascens has previously been proposed, primarily because of its intermediate morphology. In this study, phylogenies based on the DNA sequences from the internal transcribed spacer region of nuclear ribosomal DNA (nrDNA ITS), on the DNA sequences of the trnL intron and trnL-F intergenic spacer of chloroplast DNA, and on amplified fragment length polymorphism (AFLP) fingerprinting confirm that M. purpurascens originated through homoploid hybridization between M. sinensis and M. sacchariflorus. Two different types of ITS sequences were identified from almost all plants of M. purpurascens. One type was found to be closely related to M. sinensis and the other to M. sacchariflorus. Miscanthus purpurascens was found to possess many M. sinensis- and M. sacchariflorus-specific AFLP bands but no band specific to itself. Clustering with the Unweighted Pair Group Method with Arithmetic Mean and principal coordinate analysis based on the AFLP data also demonstrated that M. purpurascens is an approximate intermediate of the two species. In addition, M. purpurascens has the plastid genome of M. sinensis or M. sacchariflorus, suggesting that either species could be its maternal parent. All specimens of M. purpurascens and its coexisting parental species are identified as diploids (2 n = 2 x = 38). Possible mechanisms of natural hybridization, hybrid status, chloroplast DNA recombination, and evolutionary implications of this hybridization are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: In this study, total 80 typical Miscanthus accessions were examined with diverse lignocellulose features, including cellulose crystallinity (CrI), degree of polymerization (DP), and mole number (MN). Correlation analysis revealed that the crude cellulose CrI and MN, as well as crystalline cellulose DP, displayed significantly negative influence on biomass enzymatic digestibility under pretreatments with NaOH or H2SO4 at three concentrations. By contrast, the comparative analysis of two Miscanthus samples with similar cellulose contents showed that crude cellulose DP and crystalline cellulose MN were positive factors on biomass saccharification, indicating cross effects among the cellulose levels and the three cellulose features. The results can provide insights into mechanism of the lignocellulose enzymatic digestion, and also suggest potential approaches for genetic engineering of bioenergy crops. [Copyright &y& Elsevier]

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]

The composition, cellulose degradability and biochemical methane potential (BMP) of M. sinensis , M. floridulus , Miscanthus × giganteus and M. lutarioriparius were investigated concomitantly at different growth/harvest times during their growing season. For all the four species, there was only a slight change in the compositional content. Meanwhile there was a huge change in the BMP values. At the growth time of 60 days the BMPs ranged from 247.1 to 266.5 ml g −1 VS. As growth time was prolonged, the BMPs decreased by 11–35%. For each species, the BMP was positively correlated to the cellulose degradability with the correlation coefficients (R 2 ) ranging from 0.8055 to 0.9925. This suggests that besides the biomass yield, it is justifiable to consider cellulose degradability when selecting the suitable harvest time for biofuels production from Miscanthus , especially in tropical and subtropical regions where Miscanthus can be harvested twice or more within a year. [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]

Bio-energy production from lignocelluloses biomass has gained a lot of interest in recent years. Miscanthus sp. are high lignocelluloses biomass yielding with relatively high carbohydrate content cultivable on different soils and under climatic conditions. However, the lignocellulosic nature means that cellulose and hemicellulose are cover by lignin network that might limit hydrolysis. In this study, physical pretreatments (size reduction), physiochemical (steam expulsion) and chemical pre-treatments (mild acid and alkaline) were investigated in a view to improve the anaerobic biodegradability of Miscanthus lutarioriparius for biogas production. Prior to the pretreatment and methane potential test, the compositional analyses of M . lutarioriparius was performed in order unveil the carbohydrate (cellulose and hemicelluloses), protein and lignin contents. From these analyses, the maximum theoretical methane potential was estimated. All pretreatments led to solubilisation of organic matter as was evidenced by increase dissolve COD and ammonium nitrogen. There was a positive correlation between dissolved COD and methane yields meanwhile a negative correlation was observed for reducing sugar and methane yields. The achieved methane yields ranged from 121 to 238 ml CH 4 /g VS. Steam explosion, 0.3 M NaOH treatment and 0.5 mm size reduction led to the highest increases in methane yields, which was in the order of 57% with regard to the untreated samples. These improvements resulted in 71% of theoretical methane yield of M. lutarioriparius. Alkaline pretreatment in particular also improve the rate of methane production as was evidenced by the fact that as high 15% of the final methane yield that was achieve on the first day as compared to only 3% for the untreated sample. Indeed, the time to reach 90% of the ultimate methane yield was reduced by 13 days following 0.3 M NaOH treatment. M. lutarioriparius may therefore represent an interesting candidate as a lignocellulosic feedstock for biogas production after suitable pretreatment. [ABSTRACT FROM AUTHOR]

Miscanthus is characterized by high biomass production potential and low input requirements and therefore considered a leading candidate for second-generation energy crops. Because China has limited agricultural land resources, development of its miscanthus-based bioenergy industry must rely on the use of marginal land. This study focuses on the assessment of the production potential of miscanthus on China’s marginal land, which in this context is defined as land presently not used for agricultural production, residential purposes and other social uses. Geographic Information System (GIS) techniques and model simulation are adopted to identify the productive marginal areas for miscanthus and to estimate their biomass and bioenergy production potential. The results show that although a large marginal area of 17,163.54×10 4 ha is available for producing miscanthus, due to the limitation of low winter temperatures and low precipitation levels in some areas, the total suitable marginal area is only 769.37×10 4 ha. The Monteith radiation yield model was used to determine the potential miscanthus yield in Chinese climatic conditions. The simulation gave actual harvestable yield levels on arable land of 18.1–44.2 t ha −1 yr −1 . Taking the environmental stresses of marginal conditions into account then gave an achievable miscanthus yield potential on marginal land of 2.1–32.4 t ha −1 yr −1 (average for the different marginal lands). Based on these achievable yield levels, the total biomass production potential on the entire marginal area is 13,521.7×10 4 t yr −1 ; the bio-electricity generation and total greenhouse gas saving potential from these biomasses are 183.9 TW h yr −1 and 21,242.4×10 4 t CO 2 eq. yr −1 , respectively. The spatial distribution of the suitable marginal areas shows that they are mainly concentrated in the central part of Northeast China and the Loess Plateau. Both regions are recommended as priority development zones for the Chinese miscanthus-based bioenergy industry. [ABSTRACT FROM AUTHOR]

Severe environmental and ecological problems have resulted due to the unharvested Miscanthus lutarioriparius biomass in Dongting Lake, the largest miscanthus production hub in the world. Pyrolyzing the miscanthus biomass to produce biochar is a win–win strategy for abandoned miscanthus biomass utilization and Cd-polluted paddy restoration in Hunan. However, the sorption efficiency of biochar requires improvement by modification. It is theoretically possible that biological modification by fungi and bacteria as well as a modification technique using Fe will increase the Cd sorption capacity. Thus, the current study used two biomass biomodification techniques, FB (fungal decomposition) and BB (bacterial digestion), and one biochar Fe-modification technique (by NH 3 ·H 2 O–FeCl 3), and determined their ability to improve biochar quality. The results showed that the biomass modification by FB and BB increased the Cd sorption capacity of the derived biochar. The Cd sorption capacity of FB-derived biochar (36.4 mg g−1) was significantly greater as compared to BB-derived biochar (30.2 mg g−1) and the unmodified control (14.8 mg g−1). This improvement can be further optimized by Fe-modification, with an average potential of 22.2% (13.5–32.3%). The increased Cd sorption capacity is attributed to (in descending order of importance) the increased amount of ash, specific surface area, amount of alkaline functional groups and phenolic hydroxyl groups, and the pH of the biochar after modification. The Fe-FB-derived biochar pyrolyzed under 650 °C was tested and exhibited the highest Cd sorption capacity, at 64.9 mg g−1. Biomodification of M. lutarioriparius biomass and its subsequent pyrolysis to produce biochar will simultaneously provide economic and ecological benefits. This approach provides a model for the integrated production of food and energy from biomass. [Display omitted] • Biomass modification strongly increases the Cd sorption capacity of biochar. • Fungal decomposition and bacterial digestion are effective modification techniques. • The Cd sorption capacity of biochar can be further optimized by Fe modification. [ABSTRACT FROM AUTHOR]

Plant lignin is one of the major wall components that greatly contribute to biomass recalcitrance for biofuel production. In this study, total 79 representative Miscanthus germplasms were determined with wide biomass digestibility and diverse monolignol composition. Integrative analyses indicated that three major monolignols (S, G, H) and S/G ratio could account for lignin negative influence on biomass digestibility upon NaOH and H2SO4 pretreatments. Notably, the biomass enzymatic digestions were predominately affected by the non-KOH-extractable lignin and interlinked-phenolics, other than the KOH-extractable ones that cover 80% of total lignin. Furthermore, a positive correlation was found between the monolignols and phenolics at p<0.05 level in the non-KOH-extractable only, suggesting their tight association to form the minor wall-networks against cellulases accessibility. The results indicated that the non-KOH-extractable lignin-complex should be the target either for cost-effective biomass pretreatments or for relatively simply genetic modification of plant cell walls in Miscanthus. [ABSTRACT FROM AUTHOR]

Abstract: Near infrared spectroscopy (NIRS) has been broadly applied as a quick assay for biological component and property analysis. However, NIRS remains unavailable for in-depth analysis of biomass digestibility in plants. In this study, NIRS was used to determine biomass enzymatic digestibility using 199 Miscanthus samples, which represents a rich germplasm resource and provides for a stable calibration model. The intensive evaluation indicates that the calibration and validation sets are comparable. Using the modified partial least squares method, seven optimal equations were generated with high determination coefficient on calibration (R 2) at 0.75–0.89, cross-validation (R 2 cv) at 0.69–0.87, and the ratio performance deviation (RPD) at 1.80–2.74, which provide multiple options for NIRS prediction of biomass digestibility under different pretreatments. As biomass digestibility is a crucial parameter for biofuel processing, NIRS is a powerful tool for the high-throughput screening of biomass samples in plants. [Copyright &y& Elsevier]

Miscanthus lutarioriparius is an endemic species in China and has been widely accepted as a promising eco-bioindustrial plant. Currently, predominantly used germplasms have narrow genetic diversity, which causes a gene resource utilization plateau. Therefore, this study was designed to map the geographic and genetic distribution of M. lutarioriparius. Grid search tuning technique was applied to combine occurrence sites, which was followed by the genetic diversity analysis using the Simple Sequence Repeat markers. The results have revealed that the natural distribution of M. lutarioriparius is in the area with altitude less than 300 m and enclosed by the eastern line of East China Sea, western boundary along the longitude line of 111° E, northern boundary of the Qinling-Huai River line, and the southern line of the 27–28° N in Hunan and Jiangxi, and the 30° N line in Zhejiang. The further analysis has demonstrated that the northern line is mainly determined by the climatic factors, whereas the other three boundaries by the dispersal barriers of the sea and high mountains. The genetic diversity of M. lutarioriparius across its distribution range is high with a total Nei's genetic diversity of 0.2462. Populations from the downstream of the Yangtze River generally have a higher genetic diversity than the relative upstream areas. The centeres of genetic diversity for the M. lutarioriparius across China are located in the central and the southern Jiangsu. Outcomes of this study will help expanding the M. lutarioriparius cultivation through improving breeding and subsequently accelerate the development of biobased industry. • Exact distribution range of M. lutarioriparius across China was firstly mapped. • Spatial distribution of M. lutarioriparius genetic variation was mapped. • M. lutarioriparius has a high genetic diversity than that of other monocots. • Key for the development of future biobased industry. • Central and southern Jiangsu are centers of M. lutarioriparius genetic variation. [ABSTRACT FROM AUTHOR]

Miscanthus has been used to breed a variety of energy crops suitable for cultivation in various adverse environments. The collection, conservation, characterization and maintenance of Miscanthus genetic resources are the basic premises for improving Miscanthus crop varieties and their utilization. Large datasets will be generated at the same time. A system designed to manage and analyse those large datasets of Miscanthus germplasms in a coherent and systematic manner is urgently needed. In the present study, the Miscanthus Germplasm Database (MGDB) is constructed to rationalize the storage, update, query and analysis of Miscanthus germplasm data for a multiuser environment. A multi-criteria decision-making model has been introduced into the MGDB to help evaluate Miscanthus and screen elite germplasm. Four hundred eighty-five representative materials of Miscanthus were evaluated and the results are described below. 1. Assessment of the energy potential: Miscanthus lutarioriparius (particularly accession A0118) and Miscanthus floridulus (particularly accession C0540) are the best species to use for combustion for power generation (CPG)/pyrolysis for bio-oil production (PBP) and fermentation for ethanol production (FEP)/fermentation for biogas production (FBP), respectively. 2. Assessment of the breeding potential: The optimal crossing combination is M. lutarioriparius and M. floridulus because of the parental advantages and complementarity. The C0602/C0540 accessions (M. floridulus) represent a suitable parent together with A0118 to breed new varieties for CPG and PBP; A0118 represents as an alternative parent for breeding to improve C0540 for use in FEP and FBP. 3. Prediction of the species distribution: The elite germplasm resources of M. floridulus are mainly distributed in ten floristic regions: IIID9a, IIID9b, IIID9c, IIID9d, IIID10c, IIID11a, IIID11b, IIID11c, IIID11d and IIID12a. The elite germplasm resources of M. lutarioriparius are mainly distributed in four floristic regions: IIID9a, IIID9b, IIID9d and IIID10c. • A Miscanthus Germplasm Database is constructed to rationalize the storage, update, query and analysis of data. • The Miscanthus Germplasm Database can be used to screen elite germplasms. • The occurrence rate of elite germplasms in the floristic regions can be predicted using the Miscanthus Germplasm Database. • Parental materials for breeding different varieties can be selected using the Miscanthus Germplasm Database. [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]