Abstract.  A crucial issue in the theory of technological change--the transformation of knowledge into commodities in agriculture--is examined through the role that technoscience played in the transformation of rapeseed (Brassice Campestris and B. napus) from a minor crop used largely for marine lubricants into a major global competitor in edible oil markets.  The study is based on a content analysis of the worldwide bibliography of rapeseed.  A network approach is used to show that the emergence and successful development of the rapeseed commodity subsector included three simultaneously occurring and interacting developments: production of the new knowledge, modification of commodities, and extension of rapeseed production networks.  Implications of the network approach for the analysis of agricultural development are discussed.