Context

Every year, around 1,000 additional hectares of miscanthus are implanted in France, reflecting the growing recognition of this crop’s value among growers, local authorities, private individuals, and industry. However, only one clone -- the interspecific hybrid Miscanthus x giganteus -- is currently cultivated nationwide. This genetic uniformity poses a risk to the miscanthus sector in the event of climatic extremes and/or emerging disease. To anticipate these risks and to enhance the multiple ecosystem services provided by miscanthus, the cross-border BioEcoAgro research team is characterizing and developing Miscanthus sinensis varieties selected for high biomass production and their potential to restore agroecosystems.

Four breeding populations and two collections of potential progenitors

Breeding challenges

Miscanthus sinensis is a non-domesticated and resilient species currently unaffected by major diseases. Consequently, it requires minimal management and very limited inputs on terms of nitrogen fertilizer, phytosanitary treatments, or irrigation. Its cultivation aligns well with the agroecological transition toward sustainable agriculture, being both economically viable and environmentally friendly – especially in drinking-water catchment areas and/or on agricultural lands that are difficult to valorize due to pedoclimatic constraints and/or limited access to farm infrastructure.

As a perennial species, M. sinensis plantations established today will directly face future climate change. The BioEcoAgro team studies the impact of projected 2050 climatic condition on miscanthus physiology to anticipate future breeding needs and develop varieties resilient to abiotic stresses. Its perennial nature also lengthens the breeding cycle, making it essential to account for plant age when predicting mature biomass production from early-stage measurements.

Miscanthus is cultivated for its multipurpose biomass and various ecosystem services by a wide diversity of stakeholders with contrasted expectations: from the farmer producing animal bedding or horticultural mulch, to local authorities aiming to protect drinking water quality or supply renewable energy for municipal buildings, to individuals seeking to enhance their gardens’ aesthetic and ecological value. The goal is then to identify sets of traits that can be co-selected for specific uses. For instance, nitrogen-extracting varieties would be ideal for nitrate-polluted drinking water-catchment areas, while others could be adapter to fragile or degraded lands. Conversely, varieties designed for hedgerows to reduce soil erosion or pesticide drifts near habitations, do not need to share the same traits as those cultivated for intensive biomass production.

M. sinensis can be propagated clonally and displays several ploidy levels. To prevent any risk of invasiveness through seed dispersal, the selection of triploid varieties is essential. The BioEcoAgro team focuses on M. sinensis species precisely because of its non-spreading rhizome, which remains confined within the cultivated area. Since vegetative multiplication allows clonal propagation, it is unnecessary to genetically fix parental lines, each clone can constitute a variety. Depending on performance, progenies from a single cross can be directly deployed as agricultural variety in the first generation, provided tools are available to predict mature production from early growth ages. To achieve this, BioEcoAgro is currently developing genome wide prediction and phenomic prediction methods.

Since 2011, the cross-border BioEcoAgro team has been engaged in a long-term M. sinensis breeding program, using modern breeding technologies such as polyploidization, molecular marker development, genomic selection and phenomic prediction to create varieties meeting current and future agriculture needs. The ultimate goal is to produce sterile varieties adapted to diverse present and future pedoclimatic conditions as well as the requirement of the different sectors. Plant multiplication and diffusion will be ensured by Agri-Obtentions and private partners.

Long term breeding for qualitative and service-oriented varieties

The Miscanthus sinensis breeding program is currently developing and will follow several key steps:

1. Characterization and identification of potential progenitors within the Chinese and horticultural collections, along with discovery of potential new QTLs through GWAS and progeny studies.
2. Tetraploidization of selected diploid progenitors.
3. Creation of a diploid male heterotic pool and a tetraploid female heterotic pool, with evaluation of the effect of polyploidization.
4. Development of new controlled crosses.
5. Evaluation of present and future progenies in isolated plants designs, including characterization of ecophysiological parameters.
6. Assessment of the most promising individuals (current and incoming) in field plots, ideally in multi-environment trials, and allocation to the different sectors.
7. Study of propagation parameters for elite individual during the multiplication phase, conducted by AgriObtention or private partners.

Once validated, this breeding pipeline could yield a new variety in approximately ten years.

 Note: some of the initial material has already begun to be valorized. The choice to focus on progenies originally aimed to meet dual research and breeding objectives.