Ecological theory states that plants cannot simultaneously be efficient at certain tasks, such as acquiring and conserving resources, or be both competitive and stress tolerant. Resulting trade-offs between traits are described as major constraints that drive plant diversification across large taxonomic scales. However, the role of these trade-offs on the rapid adaptation and differentiation of populations within species remains to be elucidated. AraBreed aims at exploring the evolution of complex trait variation and covariation. We monitor the evolution of the model plant Arabidopsis thaliana over several generations in four environments, which differ in resource availability and herbivores abundance. Each experimental population consists of 17,500 recombinant lines, previously generated from crosses between 400 natural accessions. This has the advantage of breaking up ancestral gene complexes and recreating phenotypes thought to be purged in natural populations. Each year, multiple samples are collected to perform population genetic analysis with pool-seq, and plant traits are phenotyped to in investigate ecophysiological trade-offs.