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Simple Summary: Marginal land is characterized by low crop productivity and is sometimes additionally contaminated. Such marginal land however presents a large opportunity to produce non-food biomass from perennial grasses with low risks of Indirect Land Use Change (low ILUC). Miscanthus spp. and Arundo donax also known as giant reed are leading bioenergy crops due to their high biomass productivity, but yields can be limited by insufficient water supply or phytotoxic levels of heavy metals. Drought and heavy metals are the most serious abiotic stress and negatively affect crop growth and development. The current study was conducted to identify the most drought and heavy metal (Zn) tolerant hybrid among seven novel Miscanthus hybrids and seven Arundo clones. Based on the morpho-physiological and biochemical analysis, the M. sinensis × M. sacchariflorus hybrid GRC 10 and Arundo clone PC1 were the most drought and Zn stress tolerant. The findings of this study provide a foundation for further investigations of the molecular and physiological mechanisms and recommendations for the cultivation of GRC 10 hybrid line and Arundo PC1 in marginal land. High-yield potential perennial crops, such as Miscanthus spp. and Arundo donax are amongst the most promising sources of sustainable biomass for bioproducts and bioenergy. Although several studies assessed the agronomic performance of these species on diverse marginal lands, research to date on drought and zinc (Zn) resistance is scarce. Thus, the objective of this study was to investigate the drought and Zn stress tolerance of seven novel Miscanthus hybrids and seven Arundo clones originating from different parts of Italy. We subjected both species to severe drought (less than 30%), and Zn stress (400 mg/kg−1 of ZnSO4) separately, after one month of growth. All plants were harvested after 28 days of stress, and the relative drought and Zn stress tolerance were determined by using a set of morpho-physio-biochemical and biomass attributes in relation to stress tolerance indices (STI). Principal component analysis (PCA), hierarchical clustering analysis (HCA) and stress tolerance indices (STI) were performed for each morpho-physio-biochemical and biomass parameters and showed significant relative differences among the seven genotypes of both crops. Heatmaps of these indices showed how the different genotypes clustered into four groups. Considering PCA ranking value, Miscanthus hybrid GRC10 (8.11) and Arundo clone PC1 (11.34) had the highest-ranking value under both stresses indicating these hybrids and clones are the most tolerant to drought and Zn stress. In contrast, hybrid GRC3 (−3.33 lowest ranking value) and clone CT2 (−5.84) were found to be the most sensitive to both drought and Zn stress. [ABSTRACT FROM AUTHOR]

Climate change and man-made pollution can have a negative impact on the establishment of Miscanthus plants in the field. This is particularly important because biomass can be produced on marginal land without conflicting with food crops. The establishment success depends on the hybrid chosen, the cultivation method, the climatic conditions, and the concentration of pollutants in the soil. There are several ways to increase the survival rate of the plants during the first growing season and after the first winter. One of them is the application of biochar and photodegradable plastic mulch, which can provide a solution for soils polluted with trace elements (TMEs). The aim of this study was to investigate the application of plastic mulch and biochar separately and in combination at the planting stage for two Miscanthus hybrids planted by the rhizome method (TV1) and seedling plugs (GNT43) on soils contaminated with trace metal elements (Pb, Cd, Zn). TV1 seems unsuitable for TME-contaminated field cultivation, as the survival rate was <60% in most treatments studied. The selected treatments did not increase the survival rate. Furthermore, the application of plastic mulch in combination with biochar resulted in a significant reduction of this parameter, regardless of the hybrid studied. The applied agrotechnology did not influence the TME accumulation in the aboveground plant parts in TV1, while Pb and Cd in GNT43 showed significantly higher values in all treatments. Contrary to expectations, biochar and plastic mulch applied separately and together neither increased survival nor reduced the accumulation of toxic TMEs during establishment on soil contaminated with TMEs and after the first growing season. [ABSTRACT FROM AUTHOR]

Agroecosystems provide numerous ecosystem services (ESs) such as provisioning, regulating, habitat and cultural services. At the same time, the management of these agroecosystems can cause various negative impacts on the environment such as the generation of greenhouse gas emissions. However, the way humans manage agroecosystems often focuses only on the production of agricultural goods, which yield monetary benefits in the short term but do not include the positive and negative external effects on ESs. In order to enable a holistic assessment of the economic and environmental costs and benefits, the current study combines the production costs, the monetary value of the ESs provided and the monetization of the environmental impacts caused by the management of agroecosystems using the perennial crop miscanthus as an example. Depending on the scenario assessed, the cultivation of miscanthus leads to a net benefit of 140 to 3051 EUR ha−1 yr−1. The monetary value of the ESs provided by the miscanthus cultivation thereby considerably outweighs the internal and external costs. The approach applied allows for a holistic assessment of the benefits and costs of agroecosystems and thus enables management decisions that are not only based on the biomass yield but include the various interactions with the environment. [ABSTRACT FROM AUTHOR]

Miscanthus holds a great potential in the frame of the bioeconomy, and yield prediction can help improve Miscanthus' logistic supply chain. Breeding programs in several countries are attempting to produce high-yielding Miscanthus hybrids better adapted to different climates and end-uses. Multispectral images acquired from unmanned aerial vehicles (UAVs) in Italy and in the UK in 2021 and 2022 were used to investigate the feasibility of high-throughput phenotyping (HTP) of novel Miscanthus hybrids for yield prediction and crop traits estimation. An intercalibration procedure was performed using simulated data from the PROSAIL model to link vegetation indices (VIs) derived from two different multispectral sensors. The random forest algorithm estimated with good accuracy yield traits (light interception, plant height, green leaf biomass, and standing biomass) using 15 VIs time series, and predicted yield using peak descriptors derived from these VIs time series with root mean square error of 2.3 Mg DM ha−1. The study demonstrates the potential of UAVs' multispectral images in HTP applications and in yield prediction, providing important information needed to increase sustainable biomass production. [ABSTRACT FROM AUTHOR]

Biomass from M. × giganteus has great promise for use within the bioeconomy sectors, but to maximise environmental benefits, crops must produce high yields while minimising energetically costly inputs. Complex interactions between soil conditions, climatic variations, plant maturity and genotype influence yields and nutrient dynamics, which in turn impacts crop sustainability. To investigate the flux of growth and nutrients in response to a changing environment, M. × giganteus was grown in southwest Poland and sampled monthly (June–November) from 2010 to 2012. Measurements examined the interaction between plant growth and leaf development, and nutrient (N, P, K, Ca and Mg) concentrations of rhizomes, stems and leaves. The three growth years studied were markedly different for growth and meteorological conditions. Between 2010 and 2011, above ground biomass yield increased significantly from 16.5 ± 0.4 t ha−1 to 20.1 ± 0.5 t ha−1. The 2012 rhizome weights at the beginning of the growth season were halved due to extreme frost; however, resulting yield was similar (19.9 ± 0.6 5 t ha−1). Final yield from all three years were successfully predicted using MISCANFOR, and modelling indicated crop yield was water-limited. The seasonal flux of N and K from rhizome to stems and leaves then back to the rhizome at the onset of senescence was as expected in 2010 and 2011. In 2012, no such trend was evident especially for N suggesting different macronutrient sources from rhizome and soil improves the resilience of perennial crop yield across a range of diverse growth conditions. [ABSTRACT FROM AUTHOR]

Predictions of future climate scenarios indicate that yields from perennial biomass crops (PBCs) growing in the Mediterranean region are likely to decline due to prolonged drought. Among PBCs, Miscanthus grasses with C4 photosynthesis combine high yield potentials and water use efficiencies. However, the standard commercial clone M. x giganteus (Mxg), with minimal stomatal regulation, is too sensitive to drought for reliable yields in the Mediterranean regions. This paper screened a diverse panel of thirteen Miscanthus genotypes (M. sinensis, M. floridulus, M. sacchariflorus and Mxg) to identify which types could maximize yield under summer drought conditions typical in the South Mediterranean climate. In the second growing season, significant differences were observed for plant height (from 63 to 185 cm), stem number (from 12 to 208 stems plant−1), biomass yield (from 0.17 to 6.4 kg DM plant−1) and whole crop water use efficiency (from 0.11 to 7.0 g L−1). Temporal variation in net photosynthesis, stomatal conductance, transpiration rate and instantaneous water use efficiency identified different strategies adopted by genotypes, and that genotypes selected from M. floridulus and M. sinensis were better adapted to rainfed conditions and could produce six times more biomass than the Mxg. These accessions are being used as parents in experimental breeding aimed at producing future seed-based drought resilient hybrids. [ABSTRACT FROM AUTHOR]

Miscanthus, a C4 perennial grass native to Eastern Asia, is being bred to provide biomass for bioenergy and biorenewable products. Commercial expansion with the clonal hybrid M. × giganteus is limited by low multiplication rates, high establishment costs and drought sensitivity. These limitations can be overcome by breeding more resilient Miscanthus hybrids propagated by seed. Naturally occurring fast growing indigenous Miscanthus species are found in diverse environments across Eastern Asia. The natural diversity provides for plant breeders, the genetic resources to improve yield, quality, and resilience for a wide range of climates and adverse abiotic stresses. The challenge for Miscanthus breeding is to harness the diversity through selections of outstanding wild types, parents, and progenies over a short time frame to deploy hybrids that make a significant contribution to a world less dependent on fossil resources. Here are described the strategies taken by the Miscanthus breeding programme at Aberystwyth, UK and its partners. The programme built up one of the largest Miscanthus germplasm collections outside Asia. We describe the initial strategies to exploit the available genetic diversity to develop varieties. We illustrate the success of combining diverse Miscanthus germplasm and the selection criteria applied across different environments to identify promising hybrids and to develop these into commercial varieties. We discuss the potential for molecular selections to streamline the breeding process. [ABSTRACT FROM AUTHOR]