Our paper shows how the shift from a linear process of innovation to an iterative and participative innovative network can lea d to the adoption of a technology better suited to the issues of sustainable development in LDC. Our research is based on the case of the Haitian agriculture, focusing on the development of the Minisett technology, which allows a better propagation of the yam plants among farms. We analyse the evolution of that technology during the last 20 years, through "Technological System" approach. We interviewed 26 experts (researchers, technicians, NGO leaders, farmers). We also carried out surveys of 106 farmers in three regions of Haiti, in order to assess the condition of Minisett adoption and its impact on yam farms. We show first that the involvement of producers in the constitution of this technology and its greening have opened the way for the successful adoption of Minisett which has had a determining influence over the significant increase in yam production in Haiti, the extension of the plantations and the level of producers' incomes. This article also explains the role of institutional change and "innovation brokers" in this innovation process. Finally this work makes a positive contribution to agro-ecological innovation in its ability to play a key role in the food security process and highlights the role of action-research in this type of innovation.