Rice is the staple food of the populations of two islands in the Indian Ocean:Reunion Island and Madagascar. To guarantee their food autonomy, these islandshave carried out agricultural innovations around rice farming: PAPRiz in Madagascarand Riz Reunion in Reunion Island. These innovations are similar in the dimensionscovered (process, product, and organizational innovations) but differ in their scope.The study explores how an agricultural innovation is diffused to stakeholders andhow they are involved in. With documentary analysis and interviews, the comparisonof the ecosystems of these two agricultural innovations shows some differences instructuring: the Reunion ecosystem is in the creation stage, whereas the ecosystem ofMadagascar is in the maturity stage. The evolution of these ecosystems shows the im-portance of the structuration of the ecosystem. Public institutions can play this role toconverge the interests of stakeholders. These stakeholders must be enrolled in theecosystem via actions by a legitimation of the knowledge.