This is true not only of the new high-yielding rice and wheat varieties developed at experimental stations in Mexico and the Philippines, but also of most new varieties in North America and Western Europe. The growth in chemical fertilizers in the nineteenth century depended upon new knowledge in chemistry, whilst their modern multiplication depended upon the heavy chemical industries. This is even truer of pesticides and herbicides. These advances have required far more specialized knowledge than farmers would possess, and the cost of research and development has been beyond the resources of even groups of farmers. The state. has thus been the prime-mover in agricultural research in the developed countries over the last century
(Russell 1966; Petersen, 1980).