ABSTRACT
Farmers use various seed systems to obtain seeds for their next crop. The diversity of seeds determines, together with other aspects of the farming system, the biodiversity in farmed areas. Conservation strategies for crop genetic resources distinguish ex situ, on-farm, and in situ components. The on-farm management of such resources is highly influenced by the seed systems that farmers use. Next to primary and secondary centres of diversity, we will introduce a tertiary source of diversity, based on the creation of new diversity through modern breeding. The impact of different seed systems on the management of crop genetic diversity is analysed. Effects on diversity depend on the position of the farming system in terms of diversity bottlenecks, the access to genetic diversity for farmers and breeders, and the technologies used in breeding. Scientific breeding in formal seed systems has proven to increase diversity in farmers’ field. Farmers’ seed systems do harbour diversity, but likely need support from formal seed system operators in order to manage sufficient levels in the current changing climate and demographic conditions. Policies and laws may need to be adapted to allow for sufficient access to both technologies and genetic resources to support diversity both in farmers’ and formal seed systems.
