Alternative technologies development requires overcoming knowledge deficit in Technological Innovation Systems. New systems building operates through strategic modes, including partner and intermediary modes, which intentionally develop organizational and network resources. Our objective is to deepen the understanding of these collaborative strategies, by analyzing the role of contracting in value chains on the development of organizational and network knowledge resources for system building. Drawing on the case study of the grain legumes sector in Europe, which is critical for agrifood sustainability, we analyze how production contracts (PC) support partner and intermediary system building modes. Results show that PC are deliberately chosen to overcome knowledge deficit: PC foster knowledge resources at the organizational level by securing investment, and at the network level by increasing socio-technical interactions, data sharing, workforce, training and advice. This study contributes to a better understanding of collaborative system building modes and could be further developed to any sector.