This book focuses on the previously neglected interface between the conservation of plant genetic resources and their utilisation. Only through utilisation can the potential value of conserved genetic resources be realised. However, as this book shows, much conserved germplasm has to be subjected to long-term pre-breeding and genetic enhancement before it can be used in plant breeding programmes. The authors explore the rationale and approaches for such pre-breeding efforts as the basis for broadening the genetic bases of crop production. Examples from a range of major food crops are presented and issues analysed by leading authorities from around the world.