A seed system is the economic and social mechanism by which farmers’ demands for seed and the various traits they provide are met by various possible sources of supply .

Two different types of seed systems (i.e. formal and informal) are widely known. The formal seed system is characterized by a clear chain of activities, usually starting with plant breeding and promotion of materials for formal variety release and maintenance. Regulations exist in this system to maintain variety identity and purity as well as guarantee physical, physiological and sanitary quality. Seed marketing takes place through officially recognized seed outlets, and by way of national agricultural research systems.

The informal seed system on the other hand embraces most other ways in which farmers access seed. The same functions of selection, multiplication, dissemination and storage take place in the informal system as in the formal, but they take place as integral parts of crop production rather than as discrete activities.

There is a growing recognition of a third type of seed system, the intermediate seed system. This system is characterized by entrepreneurial farmers and farmer groups that produce and market crops that are not covered by the formal seed system. In Uganda these groups are called Local Seed Businesses (LSBs) that produce Quality Declared Seed (QDS), which is inspected by the Ministry of Agriculture, but sold within their communities.

Kansiime, M. K., & Mastenbroek, A. (2016). Enhancing resilience of farmer seed system to climate-induced stresses: Insights from a case study in West Nile region, Uganda. Journal of Rural Studies, 47, 220–230.