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Prediction of black poplar biofuel production: disentangling omnigenics with transcriptomics. Detecting the Genomic Signal of Polygenic Adaptation and the Role of Epistasis in Evolution

Mise au point et validation d'un procédé miniaturisé pour le criblage à haut débit du potentiel de saccharification de biomasses lignocellulosiques : Application sur des clones de peupliers.. 11es Journées du Réseau Français des Parois

Short‐rotation coppice (SRC) has great potential for supplying biomass‐based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (Populus) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand‐level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (F s) measurements on individual plants vs. stand scale eddy covariance flux data during a 39‐day intensive field campaign in late summer 2011. Daily stem diameter variation (∆D) was monitored simultaneously with F s to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆D (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

Les bioénergies répondent aux trois enjeux de transition énergétique, de développement et d’indépendance. Elles permettent de contribuer au système énergétique par trois vecteurs, la chaleur, le combustible gazeux ou liquide et l’électricité. Tout système durable de bioénergies doit appréhender d’abord des interrogations de disponibilité des biomasses forestières, agricoles et de déchets. Les verrous technologiques s’inscrivent dans les deux voies technologiques majeures : la thermochimie et les biotechnologies. La durabilité a longtemps été un sujet de controverses, maintenant apaisé par les règlements mis en place., The LORVER project (www.lorver.org) aims at developing a chain to produce biomass for industrial purposes, by reusing degraded sites (e.g. brownfield soils) and abandoned materials (e.g. urban or industrial by-products). In the context of circular economy, these abandoned sites and materials must not be viewed as a drawback but as new resources. This project brings together a consortium composed of companies and laboratories having the required expertise to construct this chain, allowing the environmental and economic upgrading of abandoned sites and materials while respecting the principles of sustainable development. After having identified the resource of available sites and byproducts, the approach consists of 1) construct Technosols from by-products, to reach the agronomic properties required for cultivation, 2) implement cultivations (short rotation coppices, hemp, nettle, hyperaccumulator plants), 3) develop processes to produce energy, biochar, fibres, metal-based M.O. compounds, and 4) assess the environmental and economic impacts of the chain. This project, conducted in the Lorraine region (France), will demonstrate the pertinence of the approach.

L’utilisation des ressources lignocellulosiques comme source d’énergie renouvelable devra concilier rendement important, faible empreinte environnementale et composition adaptée à l’utilisation énergétique (combustion, méthanisation, carburants « deuxième génération »). Cet article présente une revue des performances de plusieurs cultures agricoles et forestières pour la production durable de biomasse. Au niveau agronomique, différentes cultures sont comparées pour la production de biomasse, l’exportation d’azote et le ratio azote/carbone, mais aussi pour les réductions de gaz à effet de serre engendrées et le « coût » que cela représente. Enfin, la production d’éthanol par hectare est illustrée et des perspectives d’amélioration génétique pour la bioénergie sont évoquées. Au niveau forestier, la production de biomasse nécessite des plantations à fortes densité, telles que les cultures de taillis à courte rotation (TCR) ou à très coute rotation (TTCR) et la futaie à courte révolution (FCR). La génétique offre d’importantes marges de progrès pour l’optimisation des rendements en TCR. Concernant les FCR, les scénarios dits « semi-dédiés biomasse » sont les plus prometteurs. Ainsi, les graminées C4 pérennes (miscanthus, switchgrass) et les cultures forestières en TCR ou FCR, sont des ressources très complémentaires pour la production durable de biomasse à vocation énergétique et font l’objet, pour plusieurs d’entre elles, d’amélioration génétique à l’INRA., Lignocellulosic feedstocks for renewable energy need to reconcile high yield, a limited environmental footprint and a composition adapted to the industrial procedures for the production of heat and electricity, methane or second-generation transport fuels. This article will review the performance of several dedicated feedstocks for sustainable biomass production. At the agronomic level, feedstocks are compared for their biomass yield, nitrogen export and nitrogen/carbon ratios as well as the reduction of greenhouse gas emissions and corresponding costs. In addition, the productivity of ethanol per ha is illustrated and perspectives for genetic improvement are discussed. Concerning forestry crops, short and very short rotation coppice and “stored coppice” systems are presented including the considerable scope for further genetic improvement and the development of semi-dedicated feedstock strategies. In conclusion, perennial C4 grasses (miscanthus, switchgrass) and trees under a short rotation coppice regime are complementary bioenergy feedstocks and are the object of genetic improvement programs in INRA laboratories.