Introduction

Transgenic crops will almost certainly have a viable future, providing they deliver what is really desired by farmers and consumers. It is useful to remember that the only benefits that any new crop varieties ever deliver in plant breeding terms are agronomically useful traits. If the same traits can be delivered by other, more accessible, breeding technologies, especially at lower cost and with less regulatory encumbrance, then, all things being equal, transgenesis may not necessarily be the favoured route. For example, during the Green Revolution, semi-dwarf crop traits were developed in the absence of transgenesis. Now that we know the identity of the genes involved in these traits, we could in future use transgenesis to create semi-dwarf varieties of other crops, including many of the orphan crops in Africa. Indeed, Japanese breeders have recently identified a new set of semi-dwarf traits in rice, plus the corresponding genes, and the use of these genes in transgenic varieties could result in a doubling of yields in the crop. However, even in this case, it is not absolutely necessary to use transgenesis to modify these genes. Because the position and nature of the genes are known, molecular markers have been developed that will enable breeders to select mutants carrying the desired semi-dwarf phenotype. In this case, a company or pubic sector breeder could, in principle, choose between transgenic and non-transgenic methods.