Miscanthus varieties for increased carbon sequestration and increased usable biomass

Abstract

Low moisture content at harvest is important since green biomass material is not suitable for many applications such as for combustion in power stations. It is unusual to find a Miscanthus variety that is both cold tolerant and / or vigorous but that dries down well in years with mild winters. A mild winter may reduce the amount of usable biomass that is obtained from Miscanthus plants, including from cold hardy varieties that will stay green and fail to dry down properly at the end of a season unless there is a heavy prolonged frost. To address this issue, the present description relates to the production of increased usable biomass yield that may be obtained at harvest from Miscanthus plants that are cold tolerant, vigorous, and which also have good dry down properties during mild winters. The present methods include plants and methods for regenerating plants from a cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, and then selecting one or more regenerated plants that produce increased usable biomass and / or increased carbon sequestration.

Description

[0001]MISCANTHUS VARIETIES FOR INCREASED CARBON SEQUESTRATION AND INCREASED USABLE BIOMASS FIELD OF THE INVENTION The invention pertains to methods for producing usable biomass from Miscanthus plant cultivars and methods for selecting novel varieties with improved carbon sequestration. BACKGROUND Plants with enhanced usable biomass are useful for energy production, combustion, carbon sequestration, horticulture and other applications. Having made commitments to a low carbon economy, the governments in many countries are now mandating the planting of large acreages of crops specifically intended for replacement of fossil fuels and / or for carbon sequestration. Miscanthus, a monocot C4 grass genus of the Saccharum complex from the family Poaceae, tribe andropogoneae, subtribe saccharinae, is a perennial grass that has the potential to produce considerable biomass with the ability to grow with little fertilizer input and on marginal land. Miscanthus varieties are often characterized by good water use and nutrient use efficiency, and general non-invasiveness. Miscanthus varieties have thus gained attention as a biofuel crop because of their ability to yield high amounts of high-quality lignocellulosic material and also to sequester significant amounts of carbon in a single year and over the lifetime of the plants. There are more than a dozen documented naturally occurring species of Miscanthus; the genus possesses a basic chromosome number of 19, with diploid and tetraploid species being common. Common species are M. sinensis, M. sacchariflorus, M. floridulus, M. transmorrisonensis, and M. condensatus, and researchers have bred and / or selected from these to produce new varieties. Such varieties include Nagara (‘MBS 7001’; Deuter, United States Patent PP22,033, issued July 19, 2011) and Miscanthus x giganteus (M x giganteus), both of which are triploids resulting from a cross between the diploid M. sinensis and the tetraploid M. sacchariflorus. Triploids are especially favored since their sterility reduces the potential for invasiveness. Other hybrid varieties that originated from a M. sinensis x M. sacchariflorus crosses include ‘MBS 7002’ (Deuter, United States Patent PP22047), ‘MBS 7003’ (Deuter, United States Patent PP23681), and ‘MBS 1001’ (Deuter, United States Patent PP22127). Herein, we present novel methods of selection of new varieties of Miscanthus that have been specifically selected for improved traits that are indicative of improved carbon sequestration and / or the production of increased quantities of usable biomass. Triploid Miscanthus plants, including `Nagara` can be used as hardy sterile hybrid varieties with a vigorous growth habit. However, the growth rate and ultimately the amount of usable 1    biomass produced by ‘Nagara` is affected to a large degree by its growing environment. To improve the diversity of germplasm available for growers and different end uses, new varieties are needed. New improved varieties of Miscanthus can be produced by crossing the tetraploid Miscanthus sacchariflorus with the diploid Miscanthus sinensis and selecting the derived plants with improved characteristics. Furthermore, a means of improving sterile vegetative varieties, which are not amenable to crossing, is through mutagenesis and selection. Mutagenesis can be induced intentionally by application of mutagens such as chemicals or radiation or can occur spontaneously during cell division. The latter is well documented to occur during laboratory cell culture procedures, including when plantlets have been regenerated from callus tissue, or under field conditions where a population of plants is grown over several seasons. One approach that can be used to create new a new improved variety from an existing variety is to generate genetic variation by subjecting the existing variety to cell culture and then selecting from amongst plants that are regenerated from the cultured cells. Such new improved varieties are sometimes referred to as cultivars. When a cell containing an induced mutation is obtained, the cell can be propagated and regenerated into a selected new plant or plant organ which is genotypically different to the original variety, and which can itself be further propagated to produce a new variety. This methodology is often followed by plant breeders to develop new varieties of sterile crops. Typically, a breeder will select from an existing plantation a “sport” or “bud sport” which is a plant part that exhibits an altered trait (often a morphological difference) from the rest of the plant and which is caused by a chance genetic mutation. Such a genetic mutation may comprise a base substitution, or deletion or rearrangement of one or more nucleotides, or in some instances may be the result of an epigenetic change, including but not restricted to methylation or histone acetylation, which in turn, results in a visible or measurable phenotype. The breeder will then propagate clonal plants from the sport and compare them in one or more additional field trials to control plants, which often comprise plants of the parental variety that yielded the sport, to demonstrate stability of the trait in the new variety. At the end of the growing season, Miscanthus biomass may be harvested after the plants return much of their nitrogen to the plant material below the soil and have dried down above the soil. Low moisture content at harvest is an important quality for biomass material to be suitable for combustion. Some varieties of Miscanthus are cold hardy and vigorous but these varieties generally do not dry down well in years that have a mild winter, particularly if there is a wet period immediately preceding the harvest and no heavy prolonged frost. As the global climate changes and winters become milder, including in regions that have routinely experienced very 2    cold winters in years past, there is an increased need for Miscanthus cultivars that are vigorous and also dry down effectively, irrespective of the prevailing conditions. Lower moisture and nitrogen content influence the extent to which biomass is usable are preferable in material used for combustion. However, for some end uses of Miscanthus biomass such as fermentation, biogas, or silage production, higher moisture and / or nitrogen content at harvest would be advantageous. Varieties of Miscanthus that are high yielding and have higher moisture and / or nitrogen content at harvest than other available triploid varieties are desirable for such alternative end uses. Features such as higher moisture and nitrogen content are often accompanied by a visible retention of chlorophyll in the aerial parts of the plant which is known as a “stay-green” phenotype. Miscanthus is especially favored as a crop for carbon capture and sequestration as it forms an extensive underground network of rhizomes which remain as organic matter in the soil after the above-ground plant material has been harvested. Indeed, over time, Miscanthus significantly adds to and improves the soil profile, and the crop can be used to regenerate degraded cropland which has been depleted of topsoil and nutrients. We have identified several predictive phenotypic features of Miscanthus which can be used to select new varieties which have improved carbon sequestration. These include an altered angle of rhizome bud outgrowth, an increase in leaf biomass (leaves fall onto the soil surface prior to harvest and a proportion of the leaf biomass remains in the soil thereafter, following decomposition), and / or an increase in shoot height which may reflect the general overall vigor and photosynthetic capacity of a variety. SUMMARY OF THE INVENTION Methods are disclosed to produce increased quantities of usable biomass and / or increased carbon sequestration and to excel at establishment and show good growth characteristics including during cold and particularly prolonged cold periods, rapid and vigorous growth, and suitable dry-down qualities after a heavy prolonged frost. Usable biomass may be improved due to the fact that, at harvest, the Miscanthus plant has less moisture content after tiller initiation has ceased and the leaves of the plant are no longer green or have very little green color (that is, the leaves are “no longer substantially green”). A reduction in moisture content of a harvested plant, which is inversely related to improvement in dry biomass, may be observed relative to a control Miscanthus plant grown under identical conditions and harvested at the same time. However, it should be noted that increased biomass may not necessarily be associated with increased carbon sequestration. For example, increased above ground biomass may be inversely correlated with below ground rhizome growth (and consequent carbon sequestration), in 3    instances where a plant allocates more fixed carbon to its shoot system at the expense of root development. The Miscanthus plant may exhibit at least a 5%, at least a 10%, at least a 15%, at least a 20%, at least a 25%, or at least a 50% or more of a biomass yield increase aggregated over at least three seasons, and at least 5% lower moisture content after tiller initiation has ceased and leaves are no longer substantially green, relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. The reduction of moisture content, a process sometimes referred to as “dry down”, of the selected Miscanthus plant relative to the control plant may result in as much as least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture than that observed in the control plant. Furthermore, the Miscanthus plant may exhibit at least a 5%, at least a 10%, at least a 15%, at least a 20%, at least a 25%, or at least a 50% or more increase in carbon sequestration aggregated over at least three seasons. The methods include obtaining a plant, plant cell, cutting or rhizome from a source plant that resulted from a cross of Miscanthus sacchariflorus x Miscanthus sinensis, which in some instances includes a source plant of the Miscanthus variety ‘MBS 7001`, also known as `Nagara`, growing one or more plants from said plant, plant cell, cutting or rhizome, and selecting an improved plant relative to a control Miscanthus plant that is grown under identical conditions and harvested at the same time, wherein the selected plant has one or more traits that contribute to better carbon sequestration and / or better biomass yield or reduced moisture content at harvest. In one iteration, the one or more of the source plants may be subjected to mutagenesis prior to selection for the improved traits. These traits include greater vigor, greater stem length, greater leaf biomass, greater leaf area, increased height, increased biomass, increased organ size, increased shoot number or density (note that “stem” and “shoot” are often used interchangeably), increased stem thickness, reduced stem thickness when combined with increased shoot number, increased canopy cover, decreased lodging, cold tolerance, increased recovery from brackling, reduced stem nitrogen content, improved water use efficiency, reduced leaf retention, increased senescence, increased carbon content (e.g. percentage of carbon per unit mass of tissue), increased energy content (note that “energy content” and “calorific content” and “caloric content” are often used interchangeably) and less ash yield following combustion. In particular, an increase in shoot number or density combined with a reduction in stem thickness may be desirable as these traits elevate overall biomass while promoting efficient dry-down, 4    leading to an increased yield of usable biomass. Additionally, reduced stem thickness favors the production and / or combustion qualities of biomass pellets or “brickettes” which are sold as a fuel. Indeed, dry biomass is known to burn more efficiently than wet biomass in power stations and produces less ash following combustion. A low content of the element Chlorine in the biomass feedstock is also considered desirable for power generation uses. The control plant may be any of a number of suitable Miscanthus varieties and may include M x giganteus, M. sacchariflorus, M. sinensis, or ‘MBS 7001` itself before it is used as a source for progeny plants with the improved traits. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1, 2 and 3 show measurements of overall biomass yield, mature plant height, and shoot density, respectively. Each parameter taken at the end of three consecutive seasons. Diagonally-striped bars indicate year 1, dark grey bars indicate year 2 and white bars indicate year 3. “GIG” refers to M x giganteus. Figure 1 shows yield in 5 tonnes / hectare increments on the y axis and indicates that in year 1, yields of 1.4 - 2.5 tonnes / hectare of dry yield were achieved with non-significant differences between genotypes. In year 2, GIG increased to 9.8 tonnes / hectare of dry yield, but this yield was significantly exceeded by all genotypes with M117 producing 18 tonnes / hectare. In year 3 yields of dry matter were more uniform. Figure 2 illustrates how in year 1, M117 reached a height of 1 m. In year 2, M116 was tallest at 2.75 m. In year 3, the tallest was GIG at 3.11 m. All genotypes with the exception of M116 showed increasing crop height over the first 3 years of growth. Figure 3 shows that the new genotypes M116, M117, M118 and M119 gave much higher numbers of shoots per unit area than GIG. The highest shoot number was achieved by M116 in year 1. Although shoot numbers doubled on GIG in year 2, the new genotypes produced twice as many shoots. In year 3, although M116, M117 and M118 all produced around twice the number of shoots as GIG, M119 showed parity with GIG. The population dynamics between the other new genotypes showed different trends over the 3 years. Genotypes M116 and M119 exhibited decreasing stem populations year over year, whereas all others showed a trend towards achieving a peak population. With the possible exception of year three for M119, all of the new genotypes M116, M117, M118 and M119 produced more shoots that GIG even when compared to Year 3 when GIG produced its most shoots. Figure 4 shows dry down progression wherein moisture content in leaf and stem tissue are displayed over the season in year 3. Moisture contents at harvest were similar for all genotypes in years 1 and 2; all achieved moistures of 20% or less. However, at the end of year 3, the early 5    spring prior to harvest was very wet and the season did not have a strong winter frost (as is becoming increasingly common). These conditions will occur during the lifetime of a perennial crop, and it is important that harvesting can occur. It is commercial practice to monitor the post winter moisture contents to determine proximity to harvest time. During the last year (year 3) the genotypes being trialed were monitored in a comparable manner to commercial crops. Significant differences in moisture content were observed between the genotypes: GIG and M116 showed different dehydration trends to other genotypes. For these genotypes a typical drying curve was observed reaching a value of recording of about 20% at harvest. All other genotypes showed constant moisture content of circa 40% until the end of the harvest window (when new stems emerge). Overall, M116 showed the most advantaged dry-down characteristics. Symbols in Figure 4 refer to: GIG (M x giganteus) M116 M117 M118 X M119 Figure 5 compares a Miscanthus plant that was asexually propagated from an initial plant selected from a population of plants descended from tissue cultured cells of Nagara (larger, dark green plant in foreground on left) and a control Miscanthus plant of a commercial variety M x giganteus “Illinois” clone (smaller, lighter plant; in foreground on right). Plants are shown in June of year 2 after planting. Figure 6 compares the appearance of rhizome buds of a Miscanthus plant that was asexually propagated from an initial plant selected from a population of plants descended from tissue cultured cells of Nagara (Fig.6a) and a control M x giganteus “Illinois” plant (Fig.6b). The rhizome buds of the plant derived from Nagara are generally long, pointed, heavily scaled, protrude from the below ground rhizome at an angle less than 45°, and commonly touch the rhizome. The rhizome buds of the control plant (medium length in this image) are pointed, less heavily scaled, and protrude from the below ground rhizome at an angle of 90°. Bars show the rhizome bud angle relative to the rhizome. The unique rhizome bud angle of the Nagara derived plants may be associated with improved traits described herein, and selection of plants with an angle less than 45° may be used to obtain plants with the improved traits. Figure 7 shows an improved variety of Nagara, “Nagara Select” (2), as compared to a different population of plants derived from the original Nagara variety (1) and Miscanthus 6    giganteus (3) in September of year 3 after planting. Note that the Nagara Select plants have visibly increased height of greater than 30 cm and were observed to have an increase in leaf biomass and thinner stems than the plants in the comparison clumps (1) and (3). The person in the foreground is approximately six feet in height. Figure 8 shows the average stem thickness (in mm) of two derivative populations of Nagara (right pair of bars) as compared to control plants of the variety Illinois and of the variety M x giganteus (left pair of bars). The regenerated Miscanthus plant has an improved trait profile relative to control plants including better carbon sequestration and / or more vigorous growth and / or cold hardiness with good dry down characteristics in years with mild winter and a period of high rainfall preceding the harvest. Other traits that are associated with Miscanthus plants having this rhizome bud appearance may include darker leaf coloration, increased tiller number, improved stand establishment (which may reduce the need for replanting), increased usable biomass of at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, wherein the increased usable biomass results in greater aggregate yield, at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% ash content at harvest, at least 0.1% lower chlorine content, at least 0.5% lower chlorine content, at least 1% lower chlorine content, at least 5% lower chlorine content, at least 10% lower chlorine content, at least 15% lower chlorine content, at least 17% lower chlorine content, at least 25% lower chlorine content, or at least 50% lower chlorine content in stems, after tiller initiation has ceased and leaves are no longer substantially green, at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture content at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season, a height of the regenerated Miscanthus of at least 30 cm greater than the height of a M. sinensis, a M. sacchariflorus, or an M. Giganteus "Illinois" control plant or a comparison plant also derived from a M. sinensis x M. sacchariflorus cross, or more vigorous growth or cold hardiness with good dry down characteristics in a year with a mild winter and a period of high rainfall preceding the harvest. DETAILED DESCRIPTION OF THE INVENTION It will be readily apparent to the skilled artisan that various substitutions and modifications may be made in the invention disclosed herein without departing from the scope and spirit of the invention. 7    It is noted that as used herein, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to "a plant" or "a variety" includes one or a plurality of such plants or varieties, and a reference to "a stress" is a reference to one or more stresses and equivalents thereof known to those skilled in the art, and so forth. DEFINITIONS The term "plant" includes whole plants, shoot vegetative organs / structures (for example, leaves, stems and tubers), roots, flowers and floral organs / structures (for example, bracts, sepals, petals, stamens, carpels, anthers and ovules), seed (including embryo, endosperm, and seed coat) and fruit (the mature ovary), plant tissue (for example, vascular tissue, ground tissue, and the like) and cells (for example, guard cells, pollen cells, egg cells, and the like), and progeny of same. The class of plants that can be used in the method of the invention is generally as broad as the genus of Miscanthus, or may be applied more narrowly to Miscanthus species, subspecies cultivars, varieties, and / or hybrids. A "control plant" as used in the present invention refers to a plant cell, seed, plant component, plant tissue, plant organ or whole plant used to compare against an instant Miscanthus plant for the purpose of identifying an enhanced phenotype in the instant plant. A control plant may in some cases be a parental Miscanthus plant line, or a species, subspecies, cultivar, variety, or hybrid that is an often-used or recognizable variety, for example, Miscanthus `MBS 7001` or Miscanthus x giganteus, or the Miscanthus x giganteus `Illinois` clone, or a different plant that has resulted from a cross between M. sinensis and M. sacchariflorus. Generally, a control Miscanthus plant or variety is grown under very similar, essentially identical, or identical conditions to an experimental plant. The term “source Miscanthus plant” as used herein typically refers to a plant which is a descendant, through one or more generations of vegetative propagation, of a plant that was an F1 progeny plant of a M. sinensis x M. sacchariflorus cross. “Tissue culture” or “Cell culture” or “in vitro propagation” as used herein refers to a process whereby plant cells or tissue are multiplied by human intervention through growth in a non-soil based medium, to produce materials for planting and / or regeneration into whole plants. Typically, cells or tissues are grown in sterile media, which may be liquid or solid agar and which may contain one or more plant growth regulator chemicals, in a petri dish or a vessel in a laboratory setting. In certain instances, callus cell proliferation is induced and the callus is subsequently regenerated into differentiated plantlets, which are then planted in soil and grown to maturity. The media typically contain nutrients in addition to any plant growth regulator 8    chemicals. In some instances, a first medium is used to promote cell division and callus formation, which favors the generation of genetic mutation during cell division (and consequently the production of genetic diversity) in the callus cell population, and then the callus is transferred to media which promotes plantlet regeneration. As an example, callus induction medium may contain 13.6 μM 2,4-D and / or 0.44 μM benzyladenine (BA) and callus regeneration medium may contain around 1.3 μM NAA and / or around 22 μM BA, as published by Kim et al., 2010, GCB Bioenergy 2, 192–200. A "trait" refers to a physiological, morphological, biochemical, or physical characteristic of a plant or particular plant material or cell. Usable biomass yield by measuring tolerance to water deprivation or cold, or by the observation of the expression level of a gene or genes, e.g., by employing Northern analysis, RT-PCR, microarray gene expression assays, or reporter gene expression systems, or by agricultural observations or analysis such as reduced moisture content at harvest after tiller initiation has ceased and leaves are no longer substantially green. One or more of the source plants may be subjected to mutagenesis prior to selection for the improved traits. The traits include, but are not limited to, greater vigor, stem length, stem thickness, leaf biomass, leaf area, leaf breadth, height, biomass yield, shoot number or density, decreased lodging, cold tolerance, nitrogen content, reduced stem nitrogen content, altered chlorophyll content, increased stem:leaf biomass ratio, increased canopy cover, recovery from brackling, less ash yield following combustion, water deficit tolerance, low nutrient tolerance, hyperosmotic stress tolerance, cold tolerance, drought tolerance, salt tolerance, reduced leaf retention, increased water use efficiency, increased nutrient use efficiency, increased carbon content, increased photosynthetic capacity or reduction in percentage composition of undesirable elements such as chlorine (the latter being known to cause corrosion in power stations). Any suitable technique can be used to measure the amount of, comparative level of, or difference in the instant and control plants. Increased or improved or enhanced "yield" or "plant yield" refers to increased plant growth, increased crop growth, increased biomass, increased usable plant matter at harvest, increased carbon content, increased calorific content of harvested material (e.g. greater energy content per unit mass of crop matter, measured in units such as KJ / Kg) and / or increased plant product production, and is dependent to some extent on temperature, plant size, organ size, planting density, light, water and nutrient availability, and how the plant copes with various stresses, such as through temperature acclimation and water or nutrient use efficiency. For example, Miscanthus was reported to provide a yield of up to 18-20 tonnes of dry matter per hectare per year in one trial in Germany, but with significant variation in dry matter yield between sites in 9    the first four years after planting (Jones and Walsh, ed. (2001) Miscanthus for Energy and Fibre, James & James, London, at page 62). Harvestable yields of Miscanthus in Europe have been reported to range from 10 to 40 tonnes of dry matter per hectare per year (Lewandowski et al, (2000) Biomass and Bioenergy 19: 209-227; Heaton et al.2008b. supra). Heaton et al. have reported that fully established plants Miscanthus can provide typical autumn yields of dry matter ranging from 10 to 30 tonnes per hectare per year, depending on local agronomic conditions (Heaton et al. (2004) Mitigation and Adaptation Strategies for Global Change 9: 433-451). “Increased carbon sequestration” as used herein refers to an increase in the amount of organic carbon-based matter that is incorporated into the soil profile by a given Miscanthus plant as compared to another plant. Various approaches can be used to measure carbon sequestration, including13C isotope-based methodologies applied to soil core samples from plots of plants, as detailed by Nakajima et al., 2018, Carbon Management 9(4) 415-423. “Usable biomass yield” or “Usable biomass” refers to the amount, or quantity, of organic material that is produced or harvested that can be utilized for a desired end-use such as energy production (e.g., combustion to provide heat energy or electrical energy from power generation), fermentation, silage production, animal feed, or material applications, for example, animal feed, animal bedding, construction materials, substates for paper making, or fiber for application in textiles). Usable biomass generally needs to be sufficiently low in moisture to be suitable for production of energy or the production of these materials. The yield of usable biomass may improve with a drying method including leaving the stand in the field at the end of a growing period or by artificial means. At the end of dry-down, the water content (also sometimes referred to as moisture content) in the biomass of the present description may be in the range of 0.1 to 50% by mass, 0.1 to 40% by mass, 0.1 to 30% by mass, 0.1 to 20% by mass, or 0.1 to 10% by mass. A reduction in water content in a selected plant compared to a control plant may be in the range of 0.1 to 1%, 0.1 to 2%, 0.1 to 5%, 0.1 to 10%, 0.1 to 25%, or 0.1 to 50%. Generally speaking, for power generation end uses, it is preferable for biomass to have an overall water content of less than 30%. Usable biomass yield may increase due to increased carbon composition, which element usually ultimately accounts for more than 40% of the mass of the harvested crop material. An increase in carbon composition (e.g., mass of carbon per overall mass of tissue, which is also sometimes referred to as carbon content) in a selected plant compared to a control plant may be in the range of 0.1 to 0.25%, or 0.1 to 0.5%, 0.1 to 0.75%, 0.1 to 1%, 0.1 to 1.25%, 0.1 to 2.5% or 0.1% to 5%. Usable biomass yield may also increase because of reduced chlorine content, which element usually ultimately accounts for more than 0.01% of the mass of the harvested crop material. Typically, an overall level of not more than 10    0.3% chlorine is desirable for end-uses such as combustion for power generation. A reduction in chlorine content (e.g., measured as mass of chlorine per overall mass of tissue) in a selected plant compared to a control plant may be in the range of 0.1 to 1%, or 0.1 to 5%, 0.1 to 10%, 0.1 to 25%, or 0.1% to 50%. Usable biomass yield may also increase because of an increase in the calorific content of the harvested crop material. An increase in calorific content (e.g., measured in units of KJ / Kg) in harvested material of a selected plant compared to a control plant may be in the range of 0.1 to 0.2%, or 0.1 to 0.5%, 0.1 to 1%, 0.1 to 2.5%, 0.1% to 5% or 0.1 to 10%. The Miscanthus variety “Nagara” or “MBS 7001 (US Plant Patent PP22,033, supra) was originally selected for its vigorous growth from a selection field which was established from seedlings. The seedlings were obtained from seeds of a polycross of tetraploid Miscanthus sacchariflorus and diploid M. sinensis plants. `MBS 7001`is a sterile triploid plant; hence, it cannot be readily reproduced sexually. `MBS 7001` was generated by crossing a single large- stemmed M. sacchariflorus genotype from Japan as a female parent with a population of 15 M. sinensis plants as pollen donors. From this cross, seedlings were obtained and planted in a field. Based on field observations, one triploid variety having high biomass was selected and propagated and designated as `MBS 7001` Miscanthus X giganteus is also a sterile triploid resulting from a cross between M. sinensis and M. sacchariflorus. Miscanthus X giganteus autumn yields in lowland areas in Europe are typically higher than 25 tonnes per hectare per year, and Miscanthus X giganteus could provide a hypothetical yield of 27-44 tonnes of dry matter per hectare per year with a mean yield of 33 tonnes of dry matter per hectare per year in `Illinois` (Heaton et al. (2004) supra). Miscanthus X giganteus can thus yield, under various conditions of growth, biomass of at least 10, at least 15, at least 20, at least 25, at least 27, at least 30, at least 33, at least 35, at least 40, at least 44 tonnes or more of dry matter per hectare per year. It is expected that the enhanced triploid varieties of Miscanthus described herein can produce similar biomass yields, ranging from, for example, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 105%, at least 110%, at least 115%, at least 120%, at least 125% or more of the biomass yield of a control sterile triploid Miscanthus X giganteus crop at substantially the same stage of development and grown under substantially the same, or the same, environmental conditions as the enhanced triploid varieties, or, in other words, enhanced triploid varieties are expected to yield at least 75% to at least 125% or more of 10 to 44 tonnes or more of dry matter per hectare per year. A “non-naturally occurring Miscanthus plant” is one that is not obtained directly from nature, but is created by human intervention by methods that may include but are not limited to breeding, selection, transgenesis, gene-editing, propagation, micropropagation, division of plant 11    tissue using a human-made tool or machine, tissue culture, in vitro propagation, or regeneration from cell or tissue culture using media which contains plant growth regulators or other chemicals. “Substantially green” refers to the appearance of a plant or plant part that is noticeably and primarily green in color and does not yet have substantial chlorophyll degradation due to senescence or nitrogen remobilization from above ground tissues. Carotenoids such as anthocyanin and xanthophylls do not significantly contribute to the color of the plant. For the purposes of this description, a “mild winter” may be defined by conditions of: (i) an average daily low temperature in the months of November, December and January inclusive of equal to or greater than -0.3° Celsius; (ii) 43 or fewer days of air frost during the months of November through January inclusive; or (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm. "Planting density" refers to the number of plants that can be grown per acre. For crop species, planting or population density varies from a crop to a crop, from one growing region to another, and from year to year. Using corn as an example, the average prevailing density in 2000 was in the range of 20,000-25,000 plants per acre in Missouri, USA. A desirable higher population density (a measure of yield) would be at least 22,000 plants per acre, and a more desirable higher population density would be at least 28,000 plants per acre, more preferably at least 34,000 plants per acre, and most preferably at least 40,000 plants per acre. The average prevailing densities per acre of a few other examples of crop plants in the USA in the year 2000 were: wheat 1,000,000-1,500,000; rice 650,000-900,000; soybean 150,000-200,000, canola 260,000-350,000, sunflower 17,000-23,000 and cotton 28,000-55,000 plants per acre (Cheikh et al. (2003) U.S. Patent Application No.20030101479). For Miscanthus, a typical initial planting density is 10,000 plants per hectare (Scurlock (1999) Miscanthus: A Review of European Experience with a Novel Energy Crop, U.S. Department of Energy, Publ. ORNL / TM-13732, at page 6). However, propagules of Miscanthus are often planted at the time of establishment of a plantation at densities in the range of 25,000 – 50,000 planting units per hectare. A desirable higher population density for each of these examples, as well as other valuable species of plants, including Miscanthus, would be at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 50%, or higher, than the average prevailing density. Green biomass may not be suitable material, for example, for burning in power stations (a process also sometimes referred to as “co-firing” when the biomass is combusted with other substrates), but may be desirable for fermentation or silage production. “Dry-down” refers to a 12    lowering of the moisture content of the above ground portion of the plant at the end of or after the growing season and the transport of nitrogenous compounds from the above ground to the below ground portion of the plant. At harvest, the Miscanthus plant has less moisture content at harvest, generally after tiller initiation has ceased and leaves of the plant are no longer green or are no longer substantially green. Reduction in moisture content of a harvested plant is inversely related to improvement in dry biomass. “Brackling” refers to a phenomenon where the top portion of a crop, which is heavy with leaf material, collapses over, often following a period of sustained rain. The phenomenon is undesirable as it limits the ability to harvest with farm machinery and thereby leads to reduced yield. Thus, varieties are desirable which are less susceptible to brackling and / or which show an increased recovery from brackling. DESCRIPTION OF THE SPECIFIC EMBODIMENTS Miscanthus varieties generally do not exhibit vigorous growth or cold hardiness with good dry down characteristics in years that happen to have a mild winter combined with a period of high rainfall preceding the harvest. Typically, hardy Miscanthus varieties that are cold tolerant or vigorous will stay green and fail to dry down properly at the end of a season unless there is a very heavy prolonged period of freezing. This problem is exacerbated in geographic regions that typically have harsh winters, but which are beginning to experience more mild winters as a result of climate change. With regard to biomass from Miscanthus, what is particularly needed for end uses such as combustion in power stations are varieties that can be planted in cold regions, for example, in northern North America, Eastern Europe, and Asia, where the winters are still typically very cold, but where the crop will still dry down and be saleable in years where the winter is relatively warm and wet (and which are becoming more frequent). The Miscanthus plants of the instant description may exhibit at least a 5%, at least a 10%, at least a 15%, at least a 20%, at least 25%, or at least a 50% or more of a biomass yield increase aggregated over at least three seasons, and at least 5% lower moisture content after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. EXAMPLES Example 1. Statements embodying certain aspects of the present disclosure 13    A. A method for increasing the carbon sequestration and / or the usable biomass yield of a Miscanthus plant by at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, the method comprising selecting a Miscanthus plant obtained from a Miscanthus sacchariflorus x Miscanthus sinensis cross (for example, MBS 7001) that at harvest has less moisture content after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time. B. The method of Statement A, wherein the selected Miscanthus plant is obtained from a tissue culture regenerated cell, rhizome, or cutting of the Miscanthus sacchariflorus x Miscanthus sinensis cross that is propagated and grown into a mature Miscanthus plant. C. The method of Statement A or Statement B, wherein the mature Miscanthus plant is selected for said less moisture content after tiller initiation has ceased and leaves are no longer substantially green relative to the control Miscanthus plant. D. The method of Statement A or B, wherein the mature Miscanthus plant is selected for thinner stems, increased leaf biomass, altered angle of rhizome bud outgrowth, increased shoot density, and / or full senescence at harvest relative to the control plant. E. The method of Statement A, wherein the selected Miscanthus plant is obtained from a Miscanthus ‘MBS 7001` plant or a cell, rhizome, or cutting of a Miscanthus ‘MBS 7001` plant. F. The method of Statement A, wherein the selected Miscanthus plant has at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture than the control Miscanthus plant. G. The method of Statement A, wherein the control plant is Miscanthus ‘MBS 7001` or Miscanthus x giganteus or a different plant of a Miscanthus sacchariflorus x Miscanthus sinensis cross. H. A method for producing a Miscanthus plant that has increased usable biomass yield at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant; the method comprising: growing a regenerated plant from a tissue culture regenerated cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross (for example, MBS 7001), and selecting a regenerated plant to create a selected plant that has an improved trait that results in increased usable biomass yield relative or increased carbon sequestration versus the control Miscanthus plant grown under identical conditions and harvested at the same time. 14    I. The method of Statement H, wherein the cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross is from Miscanthus ‘MBS 7001`. J. The method of Statement H, wherein the control Miscanthus plant is Miscanthus ‘MBS 7001` or Miscanthus x giganteus or a different plant of a Miscanthus sacchariflorus x Miscanthus sinensis cross. K. The method of Statement H, wherein the improved trait is selected from the group including greater vigor, altered angle of rhizome bud outgrowth, stem length, leaf area, leaf biomass, height, usable biomass yield, shoot density, increased stem thickness, decreased lodging, improved recovery from brackling, cold tolerance, greater canopy cover, reduced stem nitrogen content, reduced moisture content, reduced stay green, reduced nitrogen off-take, reduced stem thickness combined with increased shoot number, increased water use efficiency, increased carbon content, lower chlorine content, increased calorific content, increased stem calorific content, increased leaf calorific content, increased stem:leaf biomass ratio, and less ash yield following combustion relative to the control Miscanthus plant. L. A method for producing a Miscanthus plant that has reduced moisture content at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant; the method comprising: growing a regenerated plant from a tissue culture derived cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross (for example, MBS 7001), and selecting a regenerated plant to create a selected plant that has an improved trait that results in reduced lower moisture content relative to the control Miscanthus plant grown under identical conditions and harvested at the same time. M. The method of Statement L, wherein the cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross is from Miscanthus ‘MBS 7001`. N. The method of Statement L, wherein the control Miscanthus plant is Miscanthus ‘MBS 7001` or M x giganteus or a different plant of a Miscanthus sacchariflorus x Miscanthus sinensis cross. O. The method of Statement L, wherein the improved trait is selected from the group: increased carbon sequestration,greater vigor, stem length, leaf area, height, usable biomass yield, shoot density, reduced stem thickness, reduced stem thickness combined with increased stem number, decreased lodging, improved recovery from brackling, cold tolerance, greater canopy cover, reduced stem nitrogen content, reduced moisture content, reduced stay green, reduced nitrogen off-take, increased water use efficiency, reduced leaf retention, increased stem:leaf biomass 15    ratio, increased stem calorific content, and less ash yield following combustion relative to the control Miscanthus plant. P. The method of Statement L, wherein said selected plant and said control plant are grown in a mild winter defined by conditions of: (i) an average daily low temperature in the months of November, December and January inclusive of equal to or greater than -0.3° Celsius; (ii) 43 or fewer days of air frost during the months of November through January inclusive; or (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm. Q. The method of Statement L, wherein the selected plant displays greater vigor than the control plant. R. The method of Statement L, wherein the selected plant is grown over one or more seasons prior to selection for the improved trait and / or lower moisture content relative to the control Miscanthus plant grown under identical conditions. S. The method of Statement L, wherein the regenerated plant is subjected to a temperature of less than 0° C on at least 17 days during the months of November, December and January of one winter. T. A method for decreasing moisture content at harvest of a Miscanthus plant; the method comprising: growing a regenerated plant from a tissue cultured cell, rhizome, or cutting of Miscanthus sacchariflorus x Miscanthus sinensis cross, and selecting a regenerated plant with an improved trait relative to a control plant to create a selected plant that has decreased moisture content at harvest when the regenerated plant is grown under conditions of a mild winter defined by conditions of: (i) an average daily low temperature in the months of November, December and January inclusive of equal to or greater than -0.3° Celsius; (ii) 43 or fewer days of air frost during the months of November through January inclusive; and / or (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm; relative to a control Miscanthus plant grown under identical conditions. U. The method of Statement T, wherein the regenerated plant is obtained from a Miscanthus ‘MBS 7001` plant or a cell, rhizome, or cutting of a Miscanthus ‘MBS 7001` plant. V. The method of Statement T, wherein the control plant is Miscanthus ‘MBS 7001` or M x giganteus or a different plant of a Miscanthus sacchariflorus x Miscanthus sinensis cross. 16    W. The method of Statement T, wherein the selected plant has an improved trait of increased carbon sequestration, greater vigor, stem length, leaf area, height, usable biomass yield, shoot density, reduced stem thickness, reduced stem thickness combined with increased stem number, decreased lodging, improved recovery from brackling, cold tolerance, greater canopy cover, reduced stem nitrogen content, reduced moisture content, reduced stay green, reduced nitrogen off-take, increased water use efficiency, reduced leaf retention, increased stem:leaf biomass ratio, increased stem calorific content, and less ash yield following combustion relative to the control Miscanthus plant. X. The method of Statement T, wherein the selected Miscanthus plant is selected for thinner stems, increased shoot density, and / or full senescence at harvest relative to the control Miscanthus plant. Y. The method of Statement T, wherein the selected plant displays greater vigor than the control plant. Z. The method of Statement T, wherein said selected plant and said control plant are grown in a mild winter defined by conditions of: (i) an average daily low temperature in the months of November, December and January inclusive of greater than -0.3° Celsius; (ii) 43 or fewer days of air frost during the months of November through January inclusive; and (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm. AA. The method of Statement T, wherein the selected plant is grown over one season or more than one season prior to selection for the improved trait and / or lower moisture content relative to the control Miscanthus plant grown under identical conditions. AB. The method of Statement T, wherein the selected plant is subjected to a temperature of less than 0° C on at least 17 days during the months of November, December and January of one winter. AC. A non-naturally occurring Miscanthus plant that has reduced moisture or nitrogen content at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant, which is produced by growing a regenerated plant from a tissue- cultured cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, and selecting a regenerated plant to create a selected plant that has an improved trait that results in reduced lower moisture or nitrogen content relative to the control Miscanthus plant grown under identical conditions and harvested at the same time. 17    AD. The non-naturally occurring Miscanthus plant of Statement AC, wherein the improved trait is selected from the group including increased carbon sequestration, greater vigor, stem length, leaf biomass, leaf area, height, usable biomass yield, shoot density, reduced stem thickness, reduced stem thickness combined with increased stem number, decreased lodging, improved recovery from brackling, greater canopy cover, cold tolerance, reduced stem nitrogen content, reduced stay green, reduced nitrogen off-take, increased nitrogen remobilization, increased water use efficiency, reduced leaf retention, increased stem:leaf biomass ratio, increased stem calorific content, and less ash yield following combustion. AE. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a tissue cultured cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross (for example, MBS 7001), that has at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture and at least 0.1% greater carbon composition, at least 0.25% greater carbon composition, at least 0.5% greater carbon composition, at least 0.75% greater carbon composition, at least 1% greater carbon composition, at least 1.5% greater carbon composition, or at least 5% greater carbon composition after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. AF. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a tissue-cultured cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, that has at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower moisture content and at least 0.1% greater calorific content, at least 0.25% greater calorific content, at least 0.4% greater calorific content, at least 0.5% greater calorific content, at least 1% greater calorific content, at least 2.5% greater calorific content, at least 5% greater calorific content, or at least 10% greater calorific content after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. AG. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, that has at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower moisture content and at least 5% lower ash yield, at least 10% lower ash yield, at least 15% lower ash yield, at least 17% lower ash yield, at least 20% lower ash yield, or at least 50% lower ash yield, after tiller initiation has ceased and leaves are 18    no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to winter season. AH. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, that has at least a 10% increase in stem density, 20% increase in stem density, 30% increase in stem density, 40% increase in stem density, or 50% increase in stem density and at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower moisture content after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. AI. The non-naturally occurring Miscanthus plant of Statement AH wherein the lower moisture content is associated with a smaller stem diameter and a greater aggregate yield over at least two seasons relative to the control Miscanthus plant. AJ. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a tissue-cultured cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, that produces at least a 10% increase in biomass aggregated over at least three seasons and at least 5% lower moisture content after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. AK. A non-naturally occurring Miscanthus plant which is produced by growing a regenerated plant from a tissue-cultured cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, that has at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower moisture content and at least 0.1% lower chlorine content, at least 0.5% lower chlorine content, at least 1% lower chlorine content, at least 5% lower chlorine content, at least 10% lower chlorine content, at least 15% lower chlorine content, at least 17% lower chlorine content, at least 25% lower chlorine content, or at least 50% lower chlorine content, after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season. AL. The non-naturally occurring Miscanthus plant of any of Statements AE – AK wherein the winter season comprises a mild winter defined by conditions of: (i) an average daily low temperature in the months of November – January inclusive of equal to or greater than -0.3 19    degrees Celsius, (ii) 43 or fewer days of air frost during the months of November – January inclusive or (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm. AM. The non-naturally occurring Miscanthus plant of any of Statements AE – AK wherein the reduced moisture content arises from reduced stem thickness. AN. The non-naturally occurring Miscanthus plant of any of Statements AE – AK wherein the plant is a progeny plant of a plant selected from genotype M116. AO. A method for producing a Miscanthus plant that has increased moisture and nitrogen content at harvest after tiller initiation has ceased relative to a control Miscanthus plant; the method comprising: growing a regenerated plant from a cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, and selecting a regenerated plant to create a selected plant that has an improved trait that results in increased moisture or nitrogen content relative to the control Miscanthus plant grown under identical conditions and harvested at the same time. AP. The method of Statement AO, wherein the improved trait is selected from the group including greater stay green, vigor, stem length, leaf area, height, usable biomass yield, shoot density, stem thickness, decreased lodging, recovery from brackling, reduced senescence, increased chlorophyll content, increased green coloration, increased photosynthesis, and cold tolerance relative to the control Miscanthus plant. AQ. A non-naturally occurring Miscanthus plant that has increased moisture and nitrogen content at harvest after tiller initiation has ceased relative to a control Miscanthus plant, which is produced by growing regenerated plant from a cell, rhizome, or cutting of a Miscanthus sacchariflorus x Miscanthus sinensis cross, and selecting a regenerated plant to create a selected plant that has an improved trait that results in increased moisture or nitrogen content relative to the control Miscanthus plant grown under identical conditions and harvested at the same time. AR. The non-naturally occurring Miscanthus plant of Statement AQ, wherein the improved trait is selected from the group including greater stay green, vigor, stem length, leaf biomass, height, usable biomass yield, shoot density, stem thickness, decreased lodging, recovery from brackling, reduced senescence, increased chlorophyll content, increased green coloration, increased photosynthesis, and cold tolerance. AS. The non-naturally occurring Miscanthus plant of either of Statements AQ or AR wherein the plant is a progeny plant of a plant selected from genotype M117, M118, or M119. Example 2. 20    Plants of the variety MBS 7001, MBS 7002, MBS 7003, or MBS 7004 are established in a field trial site and allowed to grow for a period including at least one winter season. An individual sport is selected from a plant of the existing population which appears to be visibly more vigorous, have increased leaf biomass, have an altered angle of rhizome bud outgrowth, darker green, taller, or have thinner stems than the population of MBS 7001 plants. The sport is propagated through rhizome cuttings which are established in field trials and shown on average to have a usable biomass yield and / or increased carbon sequestration of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 100% greater than control plants of the original MBS 7001 MBS 7002, MBS 7003, or MBS 7004 variety. Example 3. Crosses were made between the tetraploid species Miscanthus sacchariflorus and the diploid species Miscanthus sinensis, from which four different descendant F1 plants were selected. Material derived from each of these plants was subjected to cell culture, plantlets were regenerated and a population of 200 plants from each was regenerated. The cell culture derived populations were assigned the codes M116, M117, M118 and M119 respectively, and hereafter referred to as genotypes. The population M116 was derived from the same original progenitor plant that gave rise to the variety ‘MBS 7001`, also known as `Nagara` (Deuter, United States Patent PP22,033, issued July 19, 2011). The population M117 was derived from the same original progenitor plant that gave rise to the variety ‘MBS 7002` (Deuter, United States Patent PP22047). The population M118 was derived from the same original progenitor plant that gave rise to the variety ‘MBS 7003` (Deuter, United States Patent PP23681). Each of the populations was subjected to a blocked field trial at Taunton in the county of Somerset, United Kingdom which spanned three winters, during which growth characteristics and various phenotypes were recorded. Climatic data for the period of the trial was logged in UK Met Office records from a nearby weather station at Yeovilton, Somerset. After the end of the trial, individual “center- plants” which sustained desirable features were selected from the blocks in the field trial site and further propagated through rhizome cuttings to establish nursery populations suitable as a source of material for propagation and bulk-up of material for establishment of high yielding commercial plantations. MATERIALS AND METHODS 21    The 200 plants from each Miscanthus genotype, M116, M117, M118 and M119 were planted in a block trial at a site in Taunton, Somerset, UK. M x giganteus was used as a control for the trials, using rhizomes previously held in cold store for a period of approximately three months. The trial was based on four randomized blocks; with each block containing a 25 m2plot planted at two plants / m2. Plots consisted of five rows with ten plants in each row. Only the center three rows (15 m2) were recorded at harvest with the other rows acting as guards. A seedbed, of medium clay loam soil, was worked down in such a manner that a fairly fine tilth was available at planting. Soil samples taken in October of the first year, following planting, showed a pH of 6.1, and indices of 3 (28.4mg / l available), 2, (153 mg / l) and 4 (201mg / l) for P, K and Mg, respectively, indicating a satisfactory supply of these essential elements. These indices were generally not found to have changed substantially after the final harvest at the end of the third year. Levels of P and K did show a decrease of 20% and 17% over the 3 years respectively. Plants and rhizomes were planted by hand into weed-free soil in May of the first season. Immediately following planting, watering took place. Post- planting no further watering or irrigation occurred Plant canopy height and shoot number per plant were assessed at the end of each growing season (Spring) on 3 plants in the middle row of each plot. Harvesting took place in the first two seasons in February once stems and leaves had reached a uniform brown, dry status. Harvest dates were timed to be within the harvest window typically used for commercial Miscanthus crops in the vicinity. Due to the very slow maturation of the trial genotypes in the final season, year 3, final harvesting was delayed until March. Even at this late stage, stems of M117, M118 and M119 were still visibly green, which was reflected in the high moisture contents. Leaf and stem samples were taken from the third-year harvest and analyzed by at a UK power station for elements crucial in the combustion process. The analysis procedure followed for this was typical for assessment of any biomass fuels used at UK power stations for co-firing with coal. RESULTS Yields In year 1, yields of 1.4 - 2.5 Tonnes per hectare were achieved (dry matter) with non- significant differences between genotypes. In year 2, M x giganteus increased to 9.8 Tonnes per hectare, but this yield was significantly exceeded by all genotypes with M117 producing 18 Tonnes per hectare. In year 3 yields were more uniform. The highest yields were achieved by M 22    x giganteus and M117 at approximately, 24.5 Tonnes per hectare exceeding that produced by other genotypes. Canopy height In year 1, M117 reached a height of 1m, whereas in year 2, M116 was tallest at 2.75m. In year 3 tallest was M x giganteus at 3.11m. All genotypes with the exception of M116 showed increasing crop height during the first 3 years of growth. Images of all three genotypes taken in year 2 revealed differences in the growth patterns. All new genotypes exhibited increased leafiness compared to M x giganteus, and higher stem populations. Shoot numbers All new genotypes exhibited much greater shoot number than M x giganteus, with the greatest shown by M116. Although shoot numbers doubled on M x giganteus in year 2, the other genotypes produced twice as many shoots. In year 3 although M116, 117 and M118 all produced around twice the number of shoots as M x giganteus, M119 showed parity with the latter. The population dynamics between genotypes showed different trends over the 3 years genotypes M116 and M119 showed decreasing stem populations, whereas all others showed a trend towards achieving a peak population. Stem strength It was observed in year 3 that in every replicate of M116 the crop had lodged in the center of the plots, which made counting of plants in the middle row difficult. Already, by mid-June of the year following the final harvest, every replicate of this genotype has again lodged badly, presumably due to stem weakness following strong winds and rain. These effects were not observed in any other genotypes. Moisture content at harvest Harvest moisture contents at harvest were similar for all genotypes in years 1 and 2, all achieved moistures of 20% or less. In these years, the winters were relatively mild, but the early spring (January) was relatively dry. However, in year 3, the season once again did not have strong winter frost (as is becoming increasingly common), but there were prevailing wet conditions in the early spring (January) prior to harvest. Such conditions will occur in some seasons during the lifetime of a perennial crop, and it is important that harvesting can still occur. In year 3 significant differences were observed between the genotypes. It is commercial practice to monitor the post winter moisture contents to determine proximity to harvest time. During the year 3 harvest the trial crops were monitored as per commercial crops. M x giganteus and M116 showed different dehydration trends to other genotypes. For these genotypes a typical 23    drying curve was observed reaching a value of recording circa 20% at harvest. All other genotypes showed constant moisture content of circa 40% until the end of the harvest window (when new stems emerge). Samples of cane at harvest showed that the genotypes that did not dry down did so due to failure to senesce. In addition, the new genotypes all showed leaf retention which increased crop moisture content. The only new genotype that did achieve full senescence (M116) had stems that were thinner than the other genotypes. The finding that M116 exhibited thinner stems associated with lower moisture content and better dry down profile compared to GIG combined with the increased shoot density and the increased aggregate biomass of M116 over the three seasons, indicated that M116 can provide a greater usable biomass yield for end uses such as pelleting and / or combustion than M. x giganteus and the other genotypes. Indeed, the presence of thinner stems may be advantageous for the production of biomass pellets, especially if the material is being blended with other biomass, such as biomass of other Miscanthus varieties with thicker stems. Figures 1, 2 and 3 show measurements of overall biomass yield, mature plant height, and shoot density, respectively. Each parameter taken at the end of three consecutive seasons. Light grey bars indicate year 1, dark grey bars indicate year 2, and white bars indicate year 3. Fuel Quality While longer term markets exist for biomass crops, the immediate markets are in combustion and in particular co-firing with coal. It is essential for satisfactory trading that crops of Miscanthus conform to typical fuel specifications. Results from analyses of leaves and stems of Miscanthus varieties, sampled at year 3 harvest, are shown in Table 1, Table 2, and Table 3. At harvest, all genotypes were found to have satisfactory levels of chlorine and sulfur below commercial levels. However, genotype M117 was found to be within 15% of the limit for chlorine; this is important as the element poses a concern to end users due to its corrosive effects upon combustion in power stations. It is likely that this would have been caused in part due to the reduced senescence (and hence lack of leaching) during the winter months. Levels of chlorine in the stems of M117 were found to be approximately double those in M x giganteus, whereas those in the stems of M116 were more than 35% lower than in M x giganteus. Table 1. Analysis of stems for combustion properties, year 3 harvest Overall Units GIG 116 117 118 119 24    Volatile matter % 81.70 83.60 77.70 79.20 79.40 Fixed carbon % 16.00 15.10 19.00 18.00 17.70 Table 2. Analysis of leaves for combustion properties, year 3 harvest Overall Units GIG 116 117 118 119 Moisture Total % 10.30 11.20 11.70 12.20 12.20 Table 3. Analysis of total biomass material for combustion properties, year 3 harvest Overall Units GIG 116 117 118 119 Moisture Total % 209 197 446 449 438 25    Ash levels also differed significantly between genotypes. Those that retain significant leaf material (M117, M118, M119) had ash levels over 40% higher than M x giganteus. The levels of ash are typically higher in leaf material than in stems. Ash levels were not in excess of limits but their removal is a cost factor for power stations. Higher levels of leaf material can also pose problems in subsequent processing, as it is correlated to silica content which is abrasive. Typically, silica levels re 4-5 times higher in leaves than in stems, so it is generally undesirable if a variety has an increase in leaf:stem biomass or if a variety has enhanced leaf retention. Only two genotypes were able to dry down sufficiently to meet commercial target moisture requirements for combustion uses in year 3 (GIG, M116; of the two, M116 was superior and exhibited lower moisture content combined with lower ash yield, lower chlorine content, and lower nitrogen content but a higher overall carbon percentage in stems compared to GIG). Material from the other genotypes would have been unsuitable for baling or for commercial sale for combustion uses. Energy contents were relatively similar between genotypes, with an average of 19,172 GJ / t with less than 1.5% variation. Overall leaf material produced 5% less energy than stems due to the higher ash content. Nitrogen use The genotypes did display substantial differences in the level of nitrogen at harvest. This is potentially due to the reduced senescence during the winter months. M116 exhibited the lowest levels of stem nitrogen compared to the other genotypes and M x giganteus. Reduction in N- content of harvested biomass material can be considered as a desirable nutrient use efficiency trait and this was exhibited in genotype M116 in comparison the other genotypes and M x giganteus. DISCUSSION Although yields increased substantially from year 1, the large increase with the genotypes over M x giganteus in year 2 was not experienced in year 3, where all types have produced a similar yield, with M x giganteus giving the highest at 24.5 Tonnes per hectare. Shoot density was consistently greater in the case of M116, M117 and M118 versus M x giganteus, whereas with M119 produced similar numbers of shoots / stool to those seen in M x giganteus. However, a general inverse effect was observed with shoot weight, with that being greater in M x giganteus and M119 versus M116, M117 and M118. At year 3 harvest was that despite delaying harvest from February, the time proposed in the trial protocol when stems of M x giganteus are usually brown, moisture levels of stems from M117, M118 and M119 were much higher. Moisture levels in these genotypes remained high and as a result they were over the maximum baling or supply limit at harvest in year 3. Since 26    these samples were still visibly green, it is clear that the winter temperatures in the UK were not sufficient to produce a total winter kill of the crops. The enhanced greenness of some cultivars also influenced the nitrogen off-take which could have significant negative economic implications for certain end uses such as combustion in power stations. By contrast to M117, M118, and M119, stems of M116 and M x giganteus were brown and lacked green coloration at harvest. Figure 4 shows dry down progression wherein moisture content in leaf and stem tissue are displayed over the season in year 3 where M116 showed the most favorable dry down profile. The maximum acceptable moisture content for material used for combustion is typically around 30% moisture versus overall biomass. Following winter frosts, considerable differences were seen between cultivars in terms of the drying curves (Figure 4). This is an important component of perennial grass production, as it permits spring harvesting. For large-scale production, material needs to be baled or compacted (to produce pellets, cubes, for example). This process cannot occur if the moisture levels are too high, compaction is not efficient, but more importantly, crop material will not store for long periods, and will rot. This is especially the case when harvesting follows a mild winter and a period of high rainfall preceding the harvest, such as for example, where the high rainfall comprises a monthly average of at least 65mm in the 3 months prior to harvest, or an aggregate of at least 195mm across the 3 months prior to harvest. In a commercial situation, the very green types would have been relatively unsuitable for end uses such as combustion with the more mature M x giganteus and M116 being well suited for such uses. In general, the new genotypes, and particularly M116, had lower stem diameter which would facilitate increased crop drying and pelleting therefore can be considered a beneficial trait. However, M116 was also noted to exhibit brackling, but it apparently recovered from this effect. The yield of a Miscanthus crop has to be considered in the context of the suitable characteristics for a particular targeted end use. Most markets require that, for scale, the crop has a suitable moisture content at the end of the season to allow for machine harvest, subsequent baling, storage, and in some cases compaction into cubes or pellets. Analyses of the crop harvested in March of the final year (Table 2) revealed satisfactory levels of chlorine and sulfur for co-firing with coal, although M117 was near the acceptable limit. M116 was the best genotype in this regard and showed an improved trait of low chlorine content of stems versus the control M. x giganteus. Ash levels were 40% higher than M x giganteus from 3 of the 4 genotypes, potentially due their ability to retain leaves longer than M x 27    giganteus (note that leaf fall was almost complete with this control cultivar at harvest). (However, it should be noted that higher levels of ash are more of concern for smaller scale combined heat and power (CHP) projects or heating project uses, and less of an issue for fermentation, for example). Notably, ash levels were lower from M116 versus GIG, which can thus be considered an improved trait relative to the control. Data from a nearby UK meteorological office weather station at Yeovilton for the period of trial are shown in Table 4. Table 4. Data from a UK meteorological office weather station at Yeovilton for the period of trial Mean daily Mean daily Total maximum minimum Number of Total sunshine n .0--.3.6.8.1.2.4.2.6.0.8.8.5.2.0.1.9.0.7.6.1.6.9.3.5.8.8 28   Year 3 9 18.9 9.0 0 34.0 147.6Year 3 10 15.3 6.9 2 36.8 117.5.8.8.6.1.6.3C • After three years all genotypes reached peak yields of between 20 to 24.5 tonnes per hectare dry matter. • The new genotypes (M116-9) showed increased yield over M x giganteus in year 2 of growth. • The new genotypes showed higher stem populations as a consistent attribute and exhibited increased retained leaf matter. • Interesting differences were noted between the genotypes in stem density phenotype. M119 showed an apparent peak stem levels being reached after year 2, followed by a decrease or even a crash in stem density in the subsequent year. • Yield of usable biomass varies significantly between genotypes. Significant differences in usable biomass have been found based on differences in levels of ash following combustion and chlorine content. Energy content also appeared elevated in stems of M116 versus M x giganteus and the other genotypes. • Harvest quality also varies due to lack of winter die back, and leaf retention, which negatively influence moisture levels. In these regards, M116 has improved quality versus the other genotypes; in particular its lower stem diameter favors dry down. • Levels of nitrogen off-take are different compared to the M x giganteus. This has potentially important implications both from a cost and from an environmental perspective, as biomass crops need to have low input requirements. In this regard, M116 has improved quality versus the other genotypes. • Increased levels of carbon content of the tissue are a potentially beneficial trait since this indicates an improvement of the ability of a genotype to act as a carbon sink. In this regard, M116 has improved quality versus the other genotypes. • The genotype M116, which derived from the same original F1 plant as Miscanthus ‘MBS 7001` exhibited lower stem N levels than M. x giganteus and the other genotypes. This was not expected. Lowered N levels are often associated with a plant being visibly less green during 29    growth but ‘MBS 7001` was reported in US patent PP22033 to be slightly greener during in the growing season than M. x giganteus. Example 4. Tissue culture derived plantlets of the Miscanthus variety ‘MBS 7001`, also known as `Nagara`, which originally resulted from a cross of Miscanthus sacchariflorus x Miscanthus sinensis, were established in a field in Somerset, England and grown for three years and examined as part of a field trial during which the plants were maintained and kept weed free. Following the end of the trial, the plants were left to continue growing, during which time they formed dense clumps. It was noted that certain individual plants at the center of clumps were taller, darker, and visibly healthier and more vigorous than the surrounding plants. These more vigorous plants were selected and rhizomes were collected, and vegetatively propagated, to establish a new population of "Nagara Select" for use as source progenitor material for growing plantations of Miscanthus for the harvesting of usable biomass for applications such as biofuel pellets for combustion, packaging materials, containers, and / or construction material. Progenitor plants that were propagated from the selected rhizomes were tested by growing them alongside control plants including the commercial variety "Illinois", plants derived from the original Nagara line, and several other varieties in a field plot that was subject to freezing temperatures during the winter months. Plants were phenotypically observed in the third week of June of the second growing year and it was noted that Nagara Select plants were visibly taller (i.e., more than 30 cm), larger, darker green, thinner stems, exhibited increased leaf biomass, and had accumulated more usable biomass than the comparison varieties. Additionally, the rhizomes of Nagara Select plants consistently exhibited a new phenotype that had not been previously reported for Nagara, comprising a more acute angle of rhizome bud outgrowth relative to that observed in the rhizomes of controls (e.g., M. giganteus “Illinois” control plants). (Figure 6). Increased biomass may not necessarily be associated with increased carbon sequestration. For example, plants derived from the variety Nagara (‘MBS 7001’) have thinner stems than M x giganteus plants, which also derive from an M. sinensis x M. sacchariflorus cross. On a per stem basis, Nagara plants may have reduced biomass versus controls, but the variety produces more usable biomass on a per field basis since the thinner stems are better for information into pellets that are used for combustion. Nagara plants with such reductions in stem biomass may have increased carbon sequestration based on soil core sample measurements taken from the field where the plants are grown. 30    Example 5: In vitro cultured populations of Miscanthus plants derived from the materials assigned the codes M118 and M119 as described in Example 3 along with control M x giganteus plants are subjected to a long-term study to assess carbon sequestration over a period of at least 18 years or at least 20 years. The level of soil organic carbon (“SOC”) from the center of plots containing the Miscanthus plants is considered to be a proxy for carbon sequestration by the plants into the surrounding soil. SOC was measured by the methods described by Zatta et al., 2014. GCB Bioenergy, 6(4), 360–370. A replicated plot trial is established and SOC levels are calculated after year 12, in year 18 and / or in year 19 and or in year 20, and / or in years 21 or later. The mean SOC level in the plot for M116, and / or M117 and / or M118 and / or M119 is found to be higher than the mean SOC level in the M x giganteus plot. Example 6: Statements embodying certain additional aspects of the present disclosure Statement 6.1. A method of selecting Miscanthus plants with increased usable biomass and / or improved carbon sequestration, the method including: (a) subjecting cells from variety MBS 7001, MBS 7002, or MBS 7003 to tissue culture and regenerating plantlets; (b) planting a multitude of plantlets from step (a) and allowing the plants to grow for at least 4 months; (c) selecting an individual plant that exhibits a trait selected from: increased vigor, increased leaf biomass, increased height, increased shoot number, reduced stem thickness, darker coloration, and / or an altered angle of rhizome bud outgrowth, as compared to a control plant; wherein the one or more plants have improved carbon sequestration and / or increased usable biomass as compared to the control plants. 6.2. The method of Statement 6.1, wherein the trait is an altered angle of rhizome bud outgrowth. 6.3. The method of Statement 6.2, wherein the angle between the rhizome bud and the stem is less than 85 degrees, less than 65 degrees, less than 45 degrees or less than 30 degrees. 31    6.4. The method of Statement 6.3, wherein the angle between the rhizome bud and the stem is less than 45 degrees. 6.5. The method of Statement 6.1, wherein the trait is increased leaf biomass. 6.6. The method of Statement 6.1, wherein the trait is increased shoot height. 6.7. The method of any of Statements 6.1 to 6.6, additionally comprising: (d) producing a population of plants by propagating the selected plant of step (c) via the making of cuttings, rhizome propagules, or via tissue culture. 6.8. The method of Statement 6.7, additionally comprising: (e) subjecting one or more plants from step (d), or vegetatively propagated descendants of plants from step e., in a field trial compared to one or more control plants of the variety M. x giganteus, M. Illinois, or control plants that are also derived from a M. sinensis x M. sacchariflorus cross, and demonstrating that the one or more plants have an improved trait that is indicative of improved carbon sequestration and / or increased usable biomass as compared to the control plants. 6.9. The method of Statement 6.8,wherein the improved trait in step (e) is chosen from the group: increased usable biomass, reduced chlorine content, reduced ash following combustion, increased leaf biomass, increased stem thickness, reduced stem thickness, increased height, increased vigor, or an altered angle of rhizome bud outgrowth, wherein the angle is less than 85 degrees, less than 65 degrees, less than 45 degrees or less than 30 degrees.   6.10. A method of selecting plant propagules for the production of usable biomass, the method comprising: (a) in a plot, planting one or more Miscanthus plants regenerated from tissue cultured cells resulting from a plant is the descendant of a Miscanthus sacchariflorus x Miscanthus sinensis cross and allowing said regenerated plants to grow for a period of time that includes at least one winter season; (b) selecting from amongst the one or more regenerated Miscanthus plants one or more selected Miscanthus plants that exhibit increased carbon sequestration, a greater size, 32    greater height, greater vigor, or darker coloration than one or more other plants in the plot to produce a population of one or more selected plants; (c) collecting rhizome material from the one or more selected Miscanthus plants; (d) propagating one or more new Miscanthus plants from the collected rhizome material; (e) planting the new Miscanthus in a second plot with one or more control plants; (f) confirming that the test plants have either larger size, increased height, increased leaf biomass, darker coloration, or an altered angle of rhizome bud outgrowth after a period of time that includes at least one winter season, and (g) multiplying cells and / or dividing tissue from the rhizomes collected in step (c) or step (e) to produce the propagules used for planting of the crop, by culturing the cells or tissue on agar plates containing a plant growth hormone and / or by using either a human made tool or a machine to divide the cells or tissue. 6.11. The method of Statement 6.10, wherein step (f) comprises confirming that the test plants have an angle of rhizome bud outgrowth of less than 85 degrees, less than 65 degrees, less than 45 degrees or less than 30 degrees. 6.12. The method of Statement 6.10 or Statement 6.11, wherein the plant which is the descendant of a Miscanthus sacchariflorus x Miscanthus sinensis cross belongs to variety MBS 7001, MBS 7002, or MBS 7003. 6.13. Use of a plant selected by the method of Statements 6.1-6.12 for producing biomass. 6.14. A plant selected by the method of Statements 6.1-6.12. 33

Claims

CLAIMS What is claimed is:

1. Use of a non-naturally-occurring first Miscanthus plant to produce a regenerated Miscanthus plant that has an improved trait relative to a control plant grown under identical conditions and harvested at the same time, wherein: the first Miscanthus plant is the result of a Miscanthus sacchariflorus x Miscanthus sinensis cross but the first Miscanthus plant is not a plant of the variety M x giganteus; a plurality of plants propagated from the first Miscanthus plant is grown through one or more generations; a second Miscanthus plant is selected from the plurality of plants from the first Miscanthus plants for the presence of an improved trait relative to a control plant; and the regenerated Miscanthus plant is obtained from the second Miscanthus plant by growing the regenerated plant from a cell, rhizome, or cutting of the second Miscanthus plant; and wherein the improved trait results in increased carbon sequestration and / or increased yield of usable biomass from the regenerated Miscanthus plant relative to a control Miscanthus plant grown under identical conditions and harvested at the same time, and wherein: the improved trait is: (a) darker green leaf coloration and / or increased leaf biomass; (b) altered angle of outgrowth of rhizome buds that protrude from a main rhizome stem, wherein the angle relative to the main stem is less than 30°, less than 45°, less than 65°, or less than 85°; (c) increased overall biomass of at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, wherein the overall increased biomass results in greater aggregate biomass yield; (d) at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower ash levels following combustion of harvested biomass; or (e) at least 0.1% lower chlorine content, at least 0.5% lower chlorine content, at least 1% lower chlorine content, at least 5% lower chlorine content, at least 10% lower chlorine content, at least 15% lower chlorine content, at least 17% lower chlorine content, at least 25% lower chlorine content, or at least 50% lower chlorine content in stems; (f) at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture content at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to a control Miscanthus plant grown under 34   identical conditions and harvested at the same time after the plants have been subject to a winter season; (g) a height of at least 30 cm greater than the height of an M. sinensis, M. Sacchariflorus, or a M. x giganteus control plant or a control plant that is also derived from a M. sinensis x M. Sacchariflorus cross; or (h) more vigorous growth or cold hardiness with good dry down characteristics in a year with a mild winter and a period of high rainfall preceding the harvest; or (i) lower stem nitrogen level relative to a control Miscanthus plant at harvest; or (j) increased level of soil organic carbon in the plot in which the Miscanthus plant is grown as compared to the level of soil organic carbon in a control plot containing an M. x giganteus control plant, where the soil organic carbon measurements are taken at least six years after planting or at least 12 years after planting or at least 18 years after planting.

2. The method of Claim 1 wherein the plurality of plants is produced through cell culture.

3. The use of the non-naturally occurring first Miscanthus plant of Claim 1, wherein the regenerated Miscanthus plant is produced from a cell, rhizome, or cutting of the second Miscanthus plant and the cell, rhizome, or cutting is propagated and grown into a mature Miscanthus plant.

4. The use of the non-naturally occurring first Miscanthus plant of Claim 1, wherein the improved trait used to select the second Miscanthus plant is altered angle of outgrowth of rhizome buds, a rhizome angle of less than 65°, thinner stems, increased tiller density, increased leaf biomass, increased height of 30 cm or more versus a control plant, and / or full senescence at harvest relative to the control plant.

5. The use of the non-naturally occurring first Miscanthus plant of Claim 1, wherein the improved trait is decreased moisture content at harvest when the regenerated plant is grown under conditions of a mild winter defined by conditions of: (i) an average daily low temperature in the months of November, December and January inclusive of equal to or greater than -0.3° Celsius; (ii) 43 or fewer days of air frost during the months of November through January inclusive; and / or 35   (iii) a rainfall in January of greater than 58 mm or at least 98.2 mm; relative to a control Miscanthus plant grown under identical conditions; and / or (iv) an average monthly rainfall in the 3 months prior to harvest of at least 65 mm.

6. The use of the non-naturally occurring first Miscanthus plant of Claim 1, wherein the regenerated plant has less moisture content, a smaller stem diameter, and the greater aggregate yield over at least two seasons relative to the control Miscanthus plant.

7. Usable plant biomass obtained from a regenerated Miscanthus plant that has an improved trait relative to a control plant, wherein: the regenerated Miscanthus plant is grown from a cell, rhizome, or cutting derived from a second Miscanthus plant that has been selected for the presence of the improved trait from a plurality of first Miscanthus plants that originate from a Miscanthus sacchariflorus x Miscanthus sinensis cross and are grown through one or more generations, and wherein: the improved trait is: (a) darker green leaf coloration; (b) altered angle of outgrowth of rhizome buds that protrude from the below ground rhizome wherein the angle is less than 45° or less than 65° or less than 85°; (c) increased overall biomass of at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, wherein the increased overall biomass results in greater aggregate yield; (d) at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% lower ash levels following combustion of harvested biomass; or (e) at least 0.1% lower chlorine content, at least 0.5% lower chlorine content, at least 1% lower chlorine content, at least 5% lower chlorine content, at least 10% lower chlorine content, at least 15% lower chlorine content, at least 17% lower chlorine content, at least 25% lower chlorine content, or at least 50% lower chlorine content in stems; (f) at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50% less moisture content at harvest after tiller initiation has ceased and leaves are no longer substantially green relative to the control Miscanthus plant grown under identical conditions and harvested at the same time after the plants have been subject to a winter season; (g) height of at least 30 cm greater than the height of an M. sinensis, an M. Sacchariflorus, or an M. x giganteus control plant; or 36   (h) more vigorous growth or cold hardiness with good dry down characteristics in a year with a mild winter and a period of high rainfall preceding the harvest; or (i) lower stem nitrogen level relative to the control Miscanthus plant at harvest; or (j) increased level of soil organic carbon in the plot in which the Miscanthus is grown as compared to the level of soil organic carbon in a control plot containing an M. x giganteus control plant, where the soil organic carbon measurements are taken at least 6 years after planting or at least 12 years after planting or at least 18 years after planting.

8. A method of producing one or more plant propagules used for the establishment of a crop that is grown for the production of usable biomass, the method comprising: (a) in a plot, planting one or more Miscanthus plants regenerated from tissue cultured cells resulting from a plant is the descendant of a Miscanthus sacchariflorus x Miscanthus sinensis cross and allowing said regenerated plants to grow for a period of time that includes at least one winter season; (b) selecting from amongst the one or more regenerated Miscanthus plants one or more selected Miscanthus plants that exhibit increased carbon sequestration, a greater size, greater height, greater vigor, or darker coloration than one or more other plants in the plot to produce a population of one or more selected plants; (c) collecting rhizome material from the one or more selected Miscanthus plants; (d) propagating one or more new Miscanthus plants from the collected rhizome material; (e) planting the new Miscanthus in a second plot with one or more control plants; (f) confirming that the test plants have either larger size, increased height, increased leaf biomass, darker coloration, or an altered angle of rhizome bud outgrowth over a period of time that includes at least one winter season, and (g) multiplying cells and / or dividing tissue from the rhizomes collected from plants in step (c) or step (e) to produce the propagules used for planting of the crop, through a process that includes culturing the cells or tissue on agar plates containing a nutrient source, and / or plant growth hormone and / or by using either a human made tool or machine to divide the cells or tissue.

9. Use of a source Miscanthus plant that is not M x giganteus, wherein the source Miscanthus plant is derived from an M. sinensis x M. sacchariflorus cross to produce usable biomass where the source Miscanthus exhibits at least one improved trait as compared to a control plant, wherein the improved trait is chosen from: increased carbon sequestration, increased cold 37   tolerance, increased height, increased tillering, altered angle of outgrowth of rhizome buds that protrude from the below ground rhizome stem wherein the angle is less than 85° or less than 65° or less than 45°, reduced stem thickness, darker coloration, lower ash content following combustion, reduced stem chlorine content, lower stem nitrogen content, and reduced moisture content at harvesting following a winter season as compared to control Miscanthus plant of the variety Illinois, M x giganteus or a control Miscanthus plant that is also derived from a M. sinensis x M. sacchariflorus cross; and wherein the source Miscanthus plant has been selected after one or more generations from a plurality of plants produced from a Miscanthus sacchariflorus x Miscanthus sinensis cross.

10. Use of the source Miscanthus plant of claim 9 wherein the plant is vegetatively propagated through one or more generations from a plant selected from amongst a plurality of field grown plants of the variety “Nagara” (MBS 7001) or plants of the variety MBS 7002, or plants of the variety MBS 7003.

11. Use of the source Miscanthus plant of claim 9 wherein the biomass is used for fuel, pellet production, blending with other biomass, container production, paper production, combustion, electricity generation, construction material, packaging, animal feed, animal bedding, fermentation, or as a chemical feedstock.

12. Use of the source Miscanthus plant of claim 9 wherein the source Miscanthus plant is a non- naturally occurring plant.

13. Use of the source Miscanthus plant of claim 9 wherein the source Miscanthus plant is propagated through cell culture or rhizome cuttings.

14. Use of the source Miscanthus plant of claim 9 wherein the source Miscanthus plant exhibits increased carbon sequestration and / or reduced stem thickness as compared to the control plant.

15. Use of the source Miscanthus plant of claim 9 wherein the source Miscanthus plant exhibits increased carbon sequestration and / or increased height as compared to the control plant. 38   16. Use of the source Miscanthus plant of claim 9 wherein the source Miscanthus plant exhibits increased carbon sequestration and an angle of rhizome bud outgrowth of less than 85 degrees or less than 65 degrees or less than 45 degrees as compared to the control plant.

17. Use of the source Miscanthus plant of claim 13 wherein the cell culture propagation involves growth of the source plant cells on an agar that induces callus formation followed by an agar that induces plantlet regeneration.

18. A method of selecting a novel Miscanthus variety with increased usable biomass and / or improved carbon sequestration, the method including: a. subjecting cells from variety MBS 7001, MBS 7002, or MBS 7003 to tissue culture and regenerating plantlets; b. planting a multitude of plantlets from step a. in a field; c. allowing the plants to grow for at least 4 months, or at least 12 months, or at least 24 months or at least 36 months; d. selecting an individual plant that exhibits a trait selected from: increased vigor, increased leaf biomass, increased height, increased shoot number, reduced stem thickness, darker coloration, and / or an altered angle of rhizome bud outgrowth wherein the angle is less than 85 degrees or less than 65 degrees, or less than 45 degrees, as compared to the surrounding plants; e. producing a population of plants by propagating the selected plant of step d. via the making of cuttings, rhizome propagules, or via tissue culture; f. subjecting one or more plants from step e., or vegetatively propagated descendants of plants from step e., in a field trial compared to one or more control plants of the variety M. x giganteus, M. Illinois, or control plants that are also derived from a M. sinensis x M. sacchariflorus cross, and demonstrating that the one or more plants have an improved trait that is indicative of improved carbon sequestration and / or increased usable biomass as compared to the control plants.

19. The method of claim 18. wherein the improved trait in step f. is chosen from the group: increased usable biomass, reduced chlorine content, reduced ash following combustion, increased leaf biomass, increased stem thickness, increased height, increased vigor, or an altered angle of rhizome bud outgrowth wherein the angle is less than 85 degrees, less than 65 degrees or less than 45 degrees.   39

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