Modélisation de la dispersion de transgènes à l'échelle de paysages agricoles

Rapport scientifique de fin de contrat. Appel d'offres : impact des OGM

Managing arbuscular mycorrhizal fungi in cropping systems

Market globalization, demographic pressure, and environmental degradation have led us to reconsider many of our current agricultural systems. The heavy use of chemical inputs, including fertilizers and pesticides, has resulted in pollution, decreased biodiversity in intensively-farmed regions, degradation of fragile agro-ecosystems, and prohibitive costs for many farmers. Low input sustainable cropping systems should replace conventional agriculture, but this requires a more comprehensive understanding of the biological interactions within agro-ecosystems. Mycorrhizal fungi appear to be the most important telluric organisms to consider. Mycorrhizae, which result from a symbiosis between th…

Assessing the indirect and long-term ecological impacts of innovation in agriculture is a real challenge: the GM example

All innovation in agriculture constitutes a significant and complex ecological disturbance, even if limited to a single and simple action. Indeed, whatever the nature and objective of the action, a large number of ecological processes are affected and numerous discontinuities may occur within the agro-ecosystem, in both time and space. As the GMO example illustrates, it is not sufficient to focus on direct effect of innovation, it is necessary to forecast mid- and long-term impacts of innovation with respect to the environment. Modelling phenomena appear then to be a key element to achieve this goal.

Legumes in 21st century Europe: present and future importance in agri-food systems? New challenges for reseach.

Intensification of agriculture since 1950 has globally led to the decline of grain legume crops, which currently represent less than 3 % of arable crops in France and Europe. Nevertheless, legumes have several major assets (i) as plant proteins for animal feed and human food and (ii) as plants fixing atmospheric N2 and thereby saving nitrogen inputs in cropping systems, and (iii) as diversification crops. The analysis of forage and grain legume producing systems in France showed that the dominant system results in a lock-in of the different factors limiting legume insertion into the current systems. But legumes could have a major role to play in the agroecological transition towards more su…

Modelling the effect of genotype on gene flow between rapeseed volunteers and crops. Integration into the GeneSys model

International audience

Analysis of necessary adjustments of farming practices

Using the GENESYS model quantifying the effect of cropping systems on gene escape from GM rape varieties to evaluate and design cropping systems.

Gene flow in rapeseed is a process taking place both in space and over the years and cannot be studied exclusively by field trials. Consequently, the GENESYS model was developed to quantify the effects of cropping systems on transgene escape from rapeseed crops to rapeseed volunteers in neighbour plots and in the subsequent crops. In the present work, this model was used to evaluate the risk of rape harvest contamination by extraneous genes in various farming systems in case of co-existing GM, conventional and organic crops. When 50 % of the rape varieties in the region were transgenic, the rate of GM seeds in non-GM crop harvests on farms with large fields was lower than the 0.9 % purity t…

Utilisation des modèles GeneSys-Colza et Mapod-Maïs pour raisonner des stratégies de ségrégation de filières et évaluer la faisabilité de certains seuils de pureté dans différents systèmes de culture et de production

National audience

Transition vers des systèmes agricole et agroalimentaire durables : quelle place et qualification pour les légumineuses à graines ?

Cet article propose une analyse historique du processus de verrouillage du système agroalimentaire en défaveur des légumineuses à graines, à l’aune des théories évolutionnistes. Plusieurs mécanismes d’autorenforcement permettent de comprendre pourquoi ces espèces sont de moins en moins cultivées en France face à un système agro-industriel qui s’est spécialisé en faveur des céréales, favorisant à l’amont l’usage d’engrais azotés de synthèse et limitant à l’aval les investissements pour les légumineuses en alimentation humaine. Cet article s’interroge alors sur les perspectives de déverrouillage.

Effets des systèmes de culture et des génotypes sur les contaminations génétiques des récoltes de colza

National audience

Modélisation des effets des systèmes de culture sur les flux géniques hors de nouvelles variétés de colza vers les repousses. Intégration et évaluation des effets variétaux

National audience

Contamination of rapeseed harvest by volunteers of other varieties : a study of intergenotypic competition

Rapeseed volunteers in rapeseed crops can cause contamination in harvest through pollen and seeds. The aim of the study was to predict pollen and seed production by volunteers in winter rapeseed crops according to the genotypes of the crop and the volunteers. Firstly an experimental analysis of intraspecific competition was carried out in 2000 and 2001 on two and six genotypes, respectively. The main competition period begins with vegetation onset and affects pollen and seed production of the volunteers. Relations between density, height, yield and number of flowers were developed based on results from experiments and literature. Knowing the densities and heights of volunteers and crop on t…

Introduction of genotypic effects into Genesys-Rape : the example of height and male sterility

Abstract The aim of this study was to introduce effects of rape genotypes on gene flow between rape populations into the existing GeneSys - Rape model and to simulate the influence of existing rapeseed cultivars on gene flow between rapeseed populations in time and in space. The GeneSys - Rape input variables are the regional field pattern, crop successions, cultivation techniques and genotype of cropped cultivars. The main output variables are, for each year and plot, the number of individuals per square meter and the genotype proportions in the harvest. Results comprised: (1) sensitivity analyses of the model to cultivar characteristics, which showed the importance of pollen emission on g…