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Genetic improvement through breeding is one of the key approaches to increasing biomass supply. This paper documents the breeding progress to date for four perennial biomass crops (PBCs) that have high output–input energy ratios: namely Panicum virgatum (switchgrass), species of the genera Miscanthus (miscanthus), Salix (willow) and Populus (poplar). For each crop, we report on the size of germplasm collections, the efforts to date to phenotype and genotype, the diversity available for breeding and on the scale of breeding work as indicated by number of attempted crosses. We also report on the development of faster and more precise breeding using molecular breeding techniques. Poplar is the model tree for genetic studies and is furthest ahead in terms of biological knowledge and genetic resources. Linkage maps, transgenesis and genome editing methods are now being used in commercially focused poplar breeding. These are in development in switchgrass, miscanthus and willow generating large genetic and phenotypic data sets requiring concomitant efforts in informatics to create summaries that can be accessed and used by practical breeders. Cultivars of switchgrass and miscanthus can be seed‐based synthetic populations, semihybrids or clones. Willow and poplar cultivars are commercially deployed as clones. At local and regional level, the most advanced cultivars in each crop are at technology readiness levels which could be scaled to planting rates of thousands of hectares per year in about 5 years with existing commercial developers. Investment in further development of better cultivars is subject to current market failure and the long breeding cycles. We conclude that sustained public investment in breeding plays a key role in delivering future mass‐scale deployment of PBCs. Plant breeding links the research effort with commercial mass upscaling. The authors' assessment of development status of the four species is shown (poplar having two: one for short rotation coppice (SRC) poplar and one for the more traditional short rotation forestry (SRF)). Mass scale deployment needs developments outside the breeding arenas to drive breeding activities more rapidly and extensively. [ABSTRACT FROM AUTHOR]

The suitability of miscanthus biomass for anaerobic digestion has already been confirmed by several studies. However, it is rarely used as feedstock in biogas plants, mainly due to uncertainty about the optimal harvest regime with regard to the long‐term methane hectare yield and resilience of the crop to green cutting. The recommended green‐cut date for the only commercially available genotype Miscanthus × giganteus (M×g) ranges from September to November. This timeframe is too broad for agricultural practice and needs to be both narrowed down and further specified for different genotypes. The aim of this study was to identify the most suitable harvest window for an autumn green cut of miscanthus, which delivers both a high dry matter and methane yield while securing the long‐term productivity of the crop. A further objective was to quantify the effect of genotypic differences, such as leaf to stem ratio, on the substrate‐specific biogas and methane yield. For these purposes, a field trial with four genotypes (M×g, GNT1, GNT3, Sin55) was conducted over 2 years (2016/2017) and harvested at 2‐week intervals on three dates between mid‐September to mid‐October. Methane hectare yield ranged from 3,183 m³ CH4 ha−1 a−1 (Sin55) to 5,265 m³ CH4 ha−1 a−1 (M×g), which is mainly influenced by dry matter yield. The substrate‐specific methane yield was higher for the leaf (311.0 ml CH4 (g oDM)‐1) than the stem fraction (285.1 ml CH4 (g oDM)‐1) in all genotypes due to lower lignin content of leaves. Of all genotypes, M×g showed the highest and Sin55 the lowest nutrient use efficiency. We conclude that miscanthus in Germany should be harvested in October to maximize methane yields and nutrient recycling and minimize yield reduction. Additionally, to increase methane hectare yields even further, future miscanthus breeding should focus on a higher leaf proportion. The aim of this study was to identify the most suitable harvest window for an autumn green cut of miscanthus, which delivers both a high dry matter and methane yield while securing the long‐term productivity of the crop. Additionally, we wanted to quantify the effect of genotypic differences (leaf to stem ratio) on the substrate‐specific biogas and methane yield. For these purposes, a field trial with four genotypes was conducted over 2 years and harvested on three dates between mid‐September and mid‐October. We conclude that miscanthus in Germany should be harvested in October to maximize methane yields and nutrient recycling and minimize yield reduction. [ABSTRACT FROM AUTHOR]

Abstract: Direct sowing of Miscanthus seed could lower crop establishment costs, and increase the rate of grower uptake and biomass supply for the emerging bio‐economy. A replicated field trial was conducted at two contrasting UK sites: Aberystwyth (ABR) in mid‐Wales and Blankney (BLK) in Lincolnshire. These sites encompass the west–east meteorological gradient in the United Kingdom where the growing season at ABR is cooler and wetter while BLK is warmer and drier. Primed and unprimed Miscanthus sinensis seeds were sown directly onto the soil surface with and without a clear biodegradable mulch film, at nine dates interspersed from May to October. Average daily mean soil surface temperatures measured over the first 2 months after sowing under the mulch film were higher than control plots (2.7°C ABR and 4.2°C BLK). At both sites, the film covering also affected soil volumetric moisture relative to uncovered control plots (−3% ABR and 8% BLK), demonstrating the negative impact of mulch film when sowing on dry soil. Over nine sowings, seed germination at ABR under film varied between −28% and +18% of germination under control conditions. Seedlings from the first three sowings at both sites under film had sufficient physiological maturity to survive the first winter period. At BLK, mulch film significantly increased tiller count and height in both the first and second years after sowing. At ABR, where temperatures were lower, film covering significantly increased tiller height but not count. Water priming had no significant effect on seed viability or germination in the field tests. Base temperatures for germination of primed and unprimed seeds on a thermal gradient plate were 7.0°C and 5.7°C, respectively, with a ± 1.7°C confidence interval. Based on our results for M. sinensis in the United Kingdom, we recommend the sowing of unprimed seed in May under film and only when the soil is moist. [ABSTRACT FROM AUTHOR]

Conversion of large areas of agricultural grassland is inevitable if European and UK domestic production of biomass is to play a significant role in meeting demand. Understanding the impact of these land-use changes on soil carbon cycling and stocks depends on accurate predictions from well-parameterized models. Key considerations are cultivation disturbance and the effect of autotrophic root input stimulation on soil carbon decomposition under novel biomass crops. This study presents partitioned parameters from the conversion of semi-improved grassland to Miscanthus bioenergy production and compares the contribution of autotrophic and heterotrophic respiration to overall ecosystem respiration of CO2 in the first and second years of establishment. Repeated measures of respiration from within and without root exclusion collars were used to produce time-series model integrations separating live root inputs from decomposition of grass residues ploughed in with cultivation of the new crop. These parameters were then compared to total ecosystem respiration derived from eddy covariance sensors. Average soil surface respiration was 13.4% higher in the second growing season, increasing from 2.9 to 3.29 g CO2-C m−2 day−1. Total ecosystem respiration followed a similar trend, increasing from 4.07 to 5.4 g CO2-C m−2 day−1. Heterotrophic respiration from the root exclusion collars was 32.2% lower in the second growing season at 1.20 g CO2-C m−2 day−1 compared to the previous year at 1.77 g CO2-C m−2 day−1. Of the total respiration flux over the two-year time period, aboveground autotrophic respiration plus litter decomposition contributed 38.46% to total ecosystem respiration while belowground autotrophic respiration and stimulation by live root inputs contributed 46.44% to soil surface respiration. This figure is notably higher than mean figures for nonforest soils derived from the literature and demonstrates the importance of crop-specific parameterization of respiration models. [ABSTRACT FROM AUTHOR]

Field trials in Europe with Miscanthus over the past 25 years have demonstrated that interspecies hybrids such as M. × giganteus ( M × g) combine both high yield potentials and low inputs in a wide range of soils and climates. Miscanthus hybrids are expected to play a major role in the provision of perennial lignocellulosic biomass across much of Europe as part of a lower carbon economy. However, even with favourable policies in some European countries, uptake has been slow. M × g, as a sterile clone, can only be propagated vegetatively, which leads to high establishment costs and low multiplication rates. Consequently, a decade ago, a strategic decision to develop rapidly multiplied seeded hybrids was taken. To make progress on this goal, we have (1) harnessed the genetic diversity in Miscanthus by crossing and progeny testing thousands of parental combinations to select several candidate seed-based hybrids adapted to European environments, (2) established field scale seed production methods with annual multiplication factors >1500×, (3) developed the agronomy for establishing large stands from seed sown plug plants to reduce establishment times by a year compared to M × g, (4) trialled a range of harvest techniques to improve compositional quality and logistics on a large scale, (5) performed spatial analyses of yield potential and land availability to identify regional opportunities across Europe and doubled the area within the bio-climatic envelope, (6) considered on-farm economic, practical and environmental benefits that can be attractive to growers. The technical barriers to adoption have now been overcome sufficiently such that Miscanthus is ready to use as a low-carbon feedstock in the European bio-economy. [ABSTRACT FROM AUTHOR]

Miscanthus, a genus of perennial C4 grasses from Eastern Asia, has strong biomass potential, combining high diy matter yields, perennial growth, efficient use of nitrogen and water and good disease resistance, making it one of the leading energy crops. We recount the history of Miscanthus research in Europe, starting with the introduction of 'giganteus' in 1935 to Denmark. In 1989 Mike Jones, of Trinity College Dublin, initiated Miscanthus research in Ireland and coordinated field trials in Europe in some of the earliest eco-physiological experiments that led to a better understanding of the exceptional performance of this C4 plant in temperate climates. These included the first Miscanthus field trial in Ireland, planted in 1990 in Cashel, County Tipperary, the output of which was used to parameterise the growth model MISCANMOD with the clone M. x giganteus. This model was developed later into a powerful and flexible Fortran version (MiscanFor) that is now used to predict Miscanthus crop perfonnance in different soils under current and future climate conditions. A brief discussion of the recent changes in the socio-economic-environment drivers for bio-energy crops is also included. The long term research programmes for improving the breeding and agronomy of Miscanthus as a renewable energy source are now reaching commercial maturity and will hopefully aid in our attempts to de-carbonise energy producing systems and to mitigate the impacts of climate change. [ABSTRACT FROM AUTHOR]

To date, most Miscanthus trials and commercial fields have been planted on arable land. Energy crops will need to be grown more on lower grade lands unsuitable for arable crops. Grasslands represent a major land resource for energy crops. In grasslands, where soil organic carbon ( SOC) levels can be high, there have been concerns that the carbon mitigation benefits of bioenergy from Miscanthus could be offset by losses in SOC associated with land use change. At a site in Wales (UK), we quantified the relatively short-term impacts (6 years) of four novel Miscanthus hybrids and Miscanthus × giganteus on SOC in improved grassland. After 6 years, using stable carbon isotope ratios (13C/12C), the amount of Miscanthus derived C (C4) in total SOC was considerable (ca. 12%) and positively correlated to belowground biomass of different hybrids. Nevertheless, significant changes in SOC stocks (0-30 cm) were not detected as C4 Miscanthus carbon replaced the initial C3 grassland carbon; however, initial SOC decreased more in the presence of higher belowground biomass. We ascribed this apparently contradictory result to the rhizosphere priming effect triggered by easily available C sources. Observed changes in SOC partitioning were modelled using the RothC soil carbon turnover model and projected for 20 years showing that there is no significant change in SOC throughout the anticipated life of a Miscanthus crop. We interpret our observations to mean that the new labile C from Miscanthus has replaced the labile C from the grassland and, therefore, planting Miscanthus causes an insignificant change in soil organic carbon. The overall C mitigation benefit is therefore not decreased by depletion of soil C and is due to substitution of fossil fuel by the aboveground biomass, in this instance 73-108 Mg C ha−1 for the lowest and highest yielding hybrids, respectively, after 6 years. [ABSTRACT FROM AUTHOR]

To accelerate domestication of Miscanthus, an important energy crop, 244 replicated genotypes, including two different species and their hybrids, were analysed for morphological traits and biomass yield over three growing seasons following an establishment phase of 2 years in the largest Miscanthus diversity trial described to date. Stem and leaf traits were selected that contributed both directly and indirectly to total harvested biomass yield, and there was variation in all traits measured. Morphological diversity within the population was correlated with dry matter yield (DMY) both as individual traits and in combination, in order to determine the respective contributions of the traits to biomass accumulation and to identify breeding targets for yield improvement. Predictive morphometric analysis was possible at year 3 within Miscanthus sinensis genotypes but not between M. sinensis, Miscanthus sacchariflorus, and interspecific hybrids. Yield is a complex trait, and no single simple trait explained more than 33% of DMY, which varied from 1 to 5297g among genotypes within this trial. Associating simple traits increased the power of the morphological data to predict yield to 60%. Trait variety, in combination, enabled multiple ideotypes, thereby increasing the potential diversity of the crop for multiple growth locations and end uses. Both triploids and interspecific hybrids produced the highest mature yields, indicating that there is significant heterosis to be exploited within Miscanthus that might be overlooked in early selection screens within years 1–3. The potential for optimizing biomass yield by selecting on the basis of morphology is discussed. [ABSTRACT FROM AUTHOR]

Species and hybrids of Miscanthus are a promising energy crop, but their outcrossing mating systems and perennial life cycles are serious challenges for breeding programs. One approach to accelerating the domestication of Miscanthus is to harness the tremendous genetic variation that is present within this genus using phenotypic data from extensive field trials, high-density genotyping and sequencing technologies, and rapidly developing statistical methods of relating phenotype to genotype. The success of this approach, however, hinges on detailed knowledge about the population genetic structure of the germplasm used in the breeding program. We therefore used data for 120 single-nucleotide polymorphism and 52 simple sequence repeat markers to depict patterns of putatively neutral population structure among 244 Miscanthus genotypes grown in a field trial near Aberystwyth ( UK) and delineate a population of 145 M . sinensis genotypes that will be used for association mapping and genomic selection. Comparative multivariate analyses of molecular marker and phenotypic data for 17 traits related to phenology, morphology/biomass, and cell wall composition revealed significant geographic patterns in this population. A longitudinal cline accounted for a substantial proportion of molecular marker variation ( R 2 = 0.60, P = 3.4 × 10−15). In contrast, genetic variation for phenotypic traits tended to follow latitudinal and altitudinal gradients, with several traits appearing to have been affected by divergent selection (i.e., QST >> FST). These contrasting geographic trends are unusual relative to other plants and provide opportunities for powerful studies of phenotype-genotype associations and the evolutionary history of M. sinensis. [ABSTRACT FROM AUTHOR]

Background and Aims The bioenergy grass Miscanthus is native to eastern Asia. As Miscanthus uses C4 photosynthesis, the cooler temperatures experienced in much of northern Europe are expected to limit productivity. Identification of genetic diversity in chilling tolerance will enable breeders to generate more productive varieties for these cooler regions. Characterizing the temporal relationships between photosynthesis, carbohydrate and molecular expression of relevant genes is key to understanding genotypic differences in tolerance or sensitivity. Methods To characterize chilling responses in four Miscanthus genotypes, plants were exposed to a sudden reduction in temperature. The genotypes studied comprised of two M. sinensis, one M. sacchariflorus and one inter-species hybrid, M. × giganteus. Changes in photosynthesis (Asat), carbohydrate composition and the expression of target transcripts were observed following chilling-shock. After 4 d the decline in leaf elongation rate (LER) in the different genotypes was measured. Results Following chilling-shock the greatest decline in Asat was observed in M. sacchariflorus and one M. sinensis genotype. Carbohydrate concentrations increased in all genotypes following chilling but to a lesser extent in M. sacchariflorus. Two stress inducible genes were most highly expressed in the genotypes that experienced the greatest declines in Asat and LER. Miscanthus × giganteus retained the highest Asat and was unique in exhibiting no decline in LER following transfer to 12 °C. Conclusions Miscanthus × giganteus exhibits a superior tolerance to chilling shock than other genotypes of Miscanthus. The absence of sucrose accumulation in M. sacchariflorus during chilling-shock suggests an impairment in enzyme function. A candidate transcription factor, MsCBF3, is most highly expressed in the most sensitive genotypes and may be a suitable molecular marker for predicting chilling sensitivity. [ABSTRACT FROM PUBLISHER]

Miscanthus sacchariflorus is a fast-growing C4 perennial grass that can naturally hybridize with M. sinensis to produce interspecific hybrids, such as the sterile triploid M.× giganteus. The creation of such hybrids is essential for the rapid domestication of this novel bioenergy crop. However, progress has been hindered by poor understanding of the environmental cues promoting floral transition in M. sacchariflorus, which flowers less readily than M. sinensis. The purpose of this work was to identify the flowering requirements of M. sacchariflorus genotypes in order to expedite the introduction of new germplasm optimized to different environments. Six M. sacchariflorus accessions collected from a range of latitudes were grown under controlled photoperiod and temperature conditions, and flowering, biomass, and morphological phenotypic data were captured. Results indicated that M. sacchariflorus, irrespective of origin, is a quantitative short-day plant. Flowering under static long days (15.3h daylength), compared with shorter photoperiods, was delayed by an average 61 d, with an average associated increase of 52% of above-ground biomass (DM plant–1). Timing of floral initiation occurred between photoperiods of 14.2h and 12.1h, and accumulated temperatures of 553–1157 °C above a base temperature of 10 °C. Miscanthus sacchariflorus flowering phenology closely resembles that of Sorghum and Saccharum, indicating potentially similar floral pathways and suggesting that determination of the underlying genetic mechanisms will be facilitated by the syntenic relationships existing between these important C4 grasses. [ABSTRACT FROM AUTHOR]

We have created a high-resolution linkage map of Miscanthus sinensis, using genotyping-by-sequencing (GBS), identifying all 19 linkage groups for the first time. The result is technically significant since Miscanthus has a very large and highly heterozygous genome, but has no or limited genomics information to date. The composite linkage map containing markers from both parental linkage maps is composed of 3,745 SNP markers spanning 2,396 cM on 19 linkage groups with a 0.64 cM average resolution. Comparative genomics analyses of the M. sinensis composite linkage map to the genomes of sorghum, maize, rice, and Brachypodium distachyon indicate that sorghum has the closest syntenic relationship to Miscanthus compared to other species. The comparative results revealed that each pair of the 19 M. sinensis linkages aligned to one sorghum chromosome, except for LG8, which mapped to two sorghum chromosomes (4 and 7), presumably due to a chromosome fusion event after genome duplication. The data also revealed several other chromosome rearrangements relative to sorghum, including two telomere-centromere inversions of the sorghum syntenic chromosome 7 in LG8 of M. sinensis and two paracentric inversions of sorghum syntenic chromosome 4 in LG7 and LG8 of M. sinensis. The results clearly demonstrate, for the first time, that the diploid M. sinensis is tetraploid origin consisting of two sub-genomes. This complete and high resolution composite linkage map will not only serve as a useful resource for novel QTL discoveries, but also enable informed deployment of the wealth of existing genomics resources of other species to the improvement of Miscanthus as a high biomass energy crop. In addition, it has utility as a reference for genome sequence assembly for the forthcoming whole genome sequencing of the Miscanthus genus. [ABSTRACT FROM AUTHOR]

Senescence impacts the harvestable biomass yield and quality in Miscanthus. Very early autumn senescence shortens the canopy duration reducing yield potential. When senescence is too late or slow, the crop does not ripen sufficiently before harvest, resulting in high moisture and nutrient offtakes that reduce biomass quality. In this study, variation in senescence was monitored over 3 years in a trial of 244 Miscanthus genotypes planted in four replicate blocks. The experiment comprised 199 genotypes of Miscanthus sinensis, 36 genotypes of Miscanthus sacchariflorus, and 9 genotypes of Miscanthus × giganteus. On average, M. sinensis genotypes remained greener for longer than M. sacchariflorus genotypes. There was a strong correlation between senescence and moisture content at harvest in 2007 and 2008 ( R = 0.59, R = 0.57, respectively; n = 244). The senescence rate of M. × giganteus, an interspecific hybrid between M. sinensis and M. sacchariflorus, was found to lie between the two parental species groups. Environmental signals likely to be involved in the timing and rate of senescence, such as variation in photoperiod and thermal time that occurred through the growing season were investigated. Interactions between individual environmental signals and senescence were difficult to separate. The majority of plants senesced consistently between replicate blocks, and rank order was mostly consistent across all years suggesting strong genotypic control of senescence. This study provides valuable information for the future optimisation of Miscanthus, and potentially other energy grasses, where new varieties are needed to maximise net energy yields and crop quality for different end uses in different global regions. [ABSTRACT FROM AUTHOR]

This review addresses the main issues concerning anticipated demands for the use of land for food and for bioenergy. It should be possible to meet increasing demands for food using existing and new technologies although this may not be easily or cheaply accomplished. The alleviation of hunger depends on food accessibility as well as food availability. Modern civilizations also require energy. This article presents the vision for bioenergy in terms of four major gains for society: a reduction in C emissions from the substitution of fossil fuels with appropriate energy crops; a significant contribution to energy security by reductions in fossil fuel dependence, for example, to meet government targets; new options that stimulate rural and urban economic development, and reduced dependence of global agriculture on fossil fuels. This vision is likely to be best fulfilled by the use of dedicated perennial bioenergy crops. We outline a number of factors that need to be taken into account in estimating the land area available for bioenergy. In terms of provisioning services, the value of biofuels is estimated at $54.7-$330 bn per year at a crude oil price of $100 per barrel. In terms of regulatory services, the value of carbon emissions saved is estimated at $56-$218 bn at a carbon price of $40 per tonne. Although global government subsidies for biofuels have been estimated at $20 bn (IEA, 2010b), these are dwarfed by subsidies for fossil fuel consumption ($312 bn; IEA, 2010b) and by total agricultural support for food and commodity crops ($383.7 bn in 2009; OECD, 2010). [ABSTRACT FROM AUTHOR]

The high establishment costs of Miscanthus by clonal propagation are a barrier to widespread deployment. Direct sowing is the cheapest method, but limited field trials have given generally poor results. Miscanthus, a perennial grass with C4 photosynthesis has tropical origins, but is found growing both at high latitudes (>40°) and altitudes (>1000 m) in Asia. In this paper, we investigate if significant variation in the thermal requirements for germination exist in 10 Miscanthus sinensis half-sib families and compare these with Panicum virgatum (Switchgrass - Trailblazer), Phalaris arundinaceae (Reed canary grass - P10) and Lolium perenne (perennial ryegrass cv AberDart) and maize ( Zea mays cv Aviso). The comparisons were made on a thermal gradient bar with a controlled temperature oscillating ± 5 °C on a 12 h cycle and germination was monitored daily for 35 days at mean temperatures ranging from 5.3 to 26.5 °C. Base temperatures were calculated below which germination of at least 50% of viable seeds ceased. Base temperatures were lowest for L. perenne and Zea mays at 3.4 and 4.5 °C respectively; for different Miscanthus half-sib families base temperatures ranged between 9.7 and 11.6 °C and these were higher than maize and switchgrass which share C4 photosynthesis with Miscanthus. Parameters derived from germination and temperature were used to predict germination patterns in Europe based on historical climate data. We predict that seed establishment of Miscanthus in spring time is unlikely to be viable in Northern Europe under present climatic conditions without crop management practices aimed at raising soil temperature, and that useful variation in thermal requirement for germination in Miscanthus is available which should facilitate seed germination in other regions. [ABSTRACT FROM AUTHOR]

Using bio-fuels, such as bio-ethanol or bio-diesel in transportation, or biomass in power generation reduces CO2 emissions as the carbon is fixed by the plants from the atmosphere and saves the equivalent fossil fuel. The perennial rhizomatous C4 grass Miscanthus has one of the highest energy intensities per hectare of land in Europe. Here we model the future potential of Europe to produce Miscanthus with four different future land use and climate change scenarios and conclude that up to 17% of Europe's current primary energy consumption could be provided by this bio-energy crop by the year 2080 but that inter-annual variation of crop yield can be more than 20%. We conclude that that the highest greenhouse gas mitigation from bio-energy can be achieved by growing a Miscanthus crop on existing fertile and degraded arable land and not on land with a currently undisturbed ecosystem. [ABSTRACT FROM AUTHOR]

Reliable estimates of feedstock resources are a prerequisite to the establishment of a biomass based-industry for energy and non food products. Field trials in the European Union (EU) show that Miscanthus spp. can produce high yields. Here we use a model (MISCANMOD) coupled with a GIS environment to estimate the contribution that Miscanthus could make to projected national electricity consumption. We describe the integration of different data sets, transformation procedures, and spatial analyses using GIS to produce energy statistics for the EU-25. Overall, Miscanthus grown on the 10% of arable land which is currently in set-aside could generate 282 TWh yr−1 electricity. This would meet 39% of the EU-25 target of 723 TWh yr−1 of electricity from renewable energy sources (RES) by 2010. As RES targets rise, land available for energy crops is also expected to increase. We consider three additional scenarios where Miscanthus could be grown on 10%, 20% and 35% of all agricultural land and we estimate it could generate respectively 345, 691 and 1209 TWh yr−1 of electrical energy. At a national scale France, Poland and Germany have the highest potentials for Miscanthus production based on agricultural land area (respectively 83, 52, 49 TWh yr−1 when 10% agricultural land is used). Finally, we reduced the scale to the EU NUTS2 (Nomenclature of Territorial Units for Statistics) regions to examine regional generation capacities. Key regions have been identified where national RES targets are exceeded. These regions could become net exporters of renewable energy. [ABSTRACT FROM AUTHOR]

When considering renewable energy from plants, corn ethanol and reforestation have been widely promoted. Herbaceous perennials, which produce an annual crop of above ground shoots, may have some important advantages over both of these systems. Herbaceous perennials require far fewer energy and financial inputs than annual arable crops. They can be higher yielding than forestry crops and utilize existing farm equipment. Perennial energy crops can sequester carbon into soil previously under annual arable crops, providing potential additional income in carbon credits. The advantages and disadvantages of different plant types are explained to show herbaceous perennials hold special promise as bioenergy crops. C4 photosynthesis allows greater efficiencies in the conversion of sunlight energy to biomass energy, and of nitrogen and water use. However, few plants in temperate climates use this more efficient process. One exception is the rhizomatous perennial grass Miscanthus, which is a C4 plant and exceptionally cold tolerant. Miscanthus is now being grown commercially in the European Union (EU) for direct combustion in local-area power stations. It may also have longer-term potential as a feedstock for other bio-based industry. The lessons learned from trials of this crop in the EU are summarized, potential yields in Illinois predicted and a tentative comparison of the economics of growing Miscanthus versus traditional row crops developed. Overall, the results suggest that Miscanthus could yield an average of 33 t of dry matter per hectare in Illinois. At current energy prices the crop would be profitable, if grown for 4 or more years, even without subsidy. [ABSTRACT FROM AUTHOR]

Abstract: We report on a replicated spaced-plant trial in Wales of 244 diverse Miscanthus accessions grouped by classical taxonomy into M. sinensis, M. sacchariflorus and M. x giganteus. Large differences in cell wall composition were detected between taxonomic groups. Significantly higher concentrations of NDF (88.19, 85.59 and 85.03 %DW; S.E.D. of 0.300; P < 0.001); ADL (11.76, 10.15 and 9.07 %DW; S.E.D. of 0.087; P < 0.001) and cellulose (47.09, 42.94 and 42.50 %DW; S.E.D. of 0.255; P < 0.001); and significantly lower concentrations of hemicellulose (29.43, 32.50 and 33.46 %DW; S.E.D. of 0.130; P < 0.001) were present in the samples from M. x giganteus compared to the other groups. Growth year and the interaction between taxonomic group and growth year had smaller significant effects. Strong correlations were found between ADL and cellulose (R = 0.72), and hemicellulose (R = −0.76) in the M. x giganteus samples but correlations were weaker for M. sacchariflorus (R = 0.66 and −0.59) and M. sinensis (R = 0.46 and −0.40). Eleven genotypes had been assessed previously in the U.K. during the European Miscanthus Improvement (EMI) programme. These generally had higher concentrations of ADL and hemicellulose, and lower concentrations of cellulose than were reported for the U.K. site during the EMI study. These results suggest that cell wall composition and ADL concentration in particular, is highly stable between growth years but is affected by site location. Furthermore, there are differences in cell wall composition between Miscanthus taxonomic groups that may prove valuable for breeding new varieties that are compositionally matched to conversion process. [Copyright &y& Elsevier]

Abstract: There is growing interest in using perennial grasses as renewable fuels for generating electricity and for producing bio-ethanol. This paper examines the costs of producing two bioenergy crops, switchgrass and miscanthus, in Illinois for co-firing with coal to generate electricity. A crop-productivity model, MISCANMOD, is used together with a GIS to estimate yields of miscanthus across counties in Illinois. Spatially variable yields, together with county-specific opportunity costs of land, are used to determine the spatial variability in the breakeven farm-gate price of miscanthus. Costs of transporting bioenergy crops to the nearest existing power plant are incorporated to obtain delivered costs of bioenergy. The breakeven delivered cost of miscanthus for an average yield of 35.76tha−1 in Illinois is found to be less than two-thirds of the breakeven price of switchgrass with an average yield of 9.4tha−1. There is considerable spatial variability in the breakeven farm-gate price of miscanthus, which ranges between 41 and 58 $t−1 across the various counties in Illinois. This together with differences in the distances miscanthus has to be shipped to the nearest power plant causes variability in the costs of using bioenergy to produce electricity. The breakeven cost of bioenergy for electricity generation ranges from 44 to 80 $t−1 DM and is considerably higher than the coal energy-equivalent biomass price of 20.22 $t−1 DM that power plants in Illinois might be willing to pay. These findings imply a need for policies that will provide incentives for producing and using bioenergy crops based on their environmental benefits in addition to their energy content. [Copyright &y& Elsevier]