The history of agricultural research and development (R&D) has never been static. Its philosophies, concepts and principles continue to change and to impact on present-day practices. It is imperative to understand and draw lessons from the old and new perspectives, which inform agricultural R&D processes and policy formulation in developing countries. The interest of this paper is, therefore, to draw relevant lessons that can explain the dynamics,of the innovation systems at the grassroots in sub-Saharan Africa in particular.

Mainstream agricultural research has focused primarily on technical and biological aspects and is aimed at controlling or manipulating nature through the use of external inputs, such as
agricultural chemicals or super seed. In developing countries, the results of this research have benefited some resource-rich farmers in well-endowed areas, were suitable to only a limited
extent for poorer farmers in the more favourable areas, and were - in most cases - completely inappropriate for small-scale farmers in marginal areas, e.g. in the mountains or the drylands.