This article examines how agriculture and agribusiness research mobilizes the concept of Innovation System (IS). A literature review of the evolution of this concept provides an analytical framework based on theoretical context, scope, and use. Assuming this framework, a bibliometric analysis of international journals on the subject of innovation and agriculture shows the existence of four knowledge communities that variously question the specific, or not, character of innovation (and IS) in this sector. The current challenge is to promote exchanges between these communities, particularly between those that apply the evolutionary approach to innovation and those that seek to build their own concepts from economics and rural sociology.