Agricultural innovation in the last fifty years: some lessons from socio-economic approaches - A synthesis of the analysis concerning the agricultural research and innovation processes is proposed in this paper. It focus on the parallel between the transformation of the agribusiness sectors on the one hand, and the evolution of the analytical framework on the other hand. A first set of studies has been developed from the 60's, and address the effect of the innovation to the evolution of agriculture, with two different perspectives. The American economists focus mainly on the analysis of the productivity, and the French economists analyze more particularly the transformation of both the production systems and the social networks within agriculture. A second set of studies, developed more recently, analyze the conception and the implementation of innovation. The choice of these analyses is justified because of the evolution of the agribusiness chains, and an increased interest for questions related to the products' quality. Such innovations result from the interaction of multiple actors and, as a consequence, the role of the research institutions needs to be revisited.