“The interdependent set of seed-related physical activities, the firms and individuals which perform such activities, and the network of trading and other institutional arrangements which facilitate coordination among such activities and participants can be regarded as constituent elements of national seed systems. Each national seed system is normally composed of numerous sub-systems, geared toward different crops and farmer clienteles”
Jaffee, S., Srivastava, J., 1992. Seed system development: the appropriate roles of the private and public sectors, World Bank discussion papers. World Bank, Washington, D.C.