Three model plant species are studied at INRA: Arabidopsis thaliana (or Thale cress), Medicago truncatula and rice. Most of the research conducted in the Plant Breeding and Genetics Department involves analysing the organisation and functionality of the genome, analysing natural variability and studying the evolutive mechanisms within the different populations of these species.

These three species have been adopted by the international community, in particular because of the small size and the simplicity of their genome compared to that of most cultivated species. The complete nucleotide sequence of the Arabidopsis genome was published in December 2000. Beyond the basic knowledge provided by genomic studies on these species, the resemblance between the genome of these model species and of related species (such as rapeseed, pea and wheat) can be exploited to accelerate research on crops species.

A large part of the research conducted in the Plant Breeding and Genetics Department aims at defining the function of genes of these model species. To do so, the researchers are participating in developing tools to explore these different functions. For example, a collection of Arabidopsis thaliana mutants was constituted by random insertion of a DNA fragment in the genome. The 60 000 insertion lines obtained are available for the international community. The disruption of the mutated gene and the resulting phenotype make it possible to define biological functions.

In the same way, in association with the CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), scientists of the Department are taking part in constituting an insertion collection in rice to determine the function of the genes of this species.

The research in genomics increasingly uses natural variability to identify the genes of interest: adaptation of the plant to environmental constraints, resistance to pests and pathogens, genes controlling plant development, genes involved in specific physiological processes, etc. To do so, collections of natural populations of Medicago truncatula and Arabidopsis thaliana have been constituted and are being characterised. These collections are essential for creating effective plant material for studying genetic and physiological bases of biological functions of fundamental and applied interest.