DS and IT increased moderately with increased Nitrogen level.

The idea for this book was conceived by the late Dr. Irvine A. Watson of the University of Sydney, and he developed the first outline. I was then invited by Dr. Watson to share in its writing. Unfortunately, shortly there after, recurring heart problems forced him to curtail his activities and with draw from the project. He died before the book could be completed. Dr. Watson's intention was to produce a very practical book that would provide wheat breeders with all of the information necessary to breed success fully for resistance to the three wheat rusts: leaf rust, stem rust, and yellow rust. It was intended to be very specific in describing procedures to be used and at the same time provide all of the necessary theoretical background. I hope that I have been successful in meeting these objectives. The book assumes that the reader has some knowledge of plant pathology, genetics, and plant breeding. Extensive use has been made of the literature, but it was not possible to cite all of the papers on a given topic. In making a choice, an attempt was made to choose key papers or more recent papers that provided references to the earlier literature. Acknowledgements This book was written partly at the University of Saskatchewan and partly at the University of California, Davis, while I was on a sabbatical leave.

This book comprehensively introduces stripe rust disease, its development and its integral control. Covering the biology, genetics, genome, and functional genomics of the pathogen, it also discusses host and non-host resistance, their interactions and the epidemiology of the disease. It is intended for scientists, postgraduates and undergraduate studying stripe rust, plant pathology, crop breeding, crop protection and agricultural science, but is also a valuable reference book for consultants and administrators in agricultural businesses and education.

Plant diseases and pests are a major constraint to agricultural production despite the various measures used to control them. Chemical control, although often e~~ective, may pose environmental hazards and is relatively expensive, especially in developing countries where it may be completely uneconomic. Control through genetically mediated resistance to diseases and pests, is both cheap and environmentally sa~e and at present most diseases and pests o~ staple ~ood crops are controlled through some form of resistance. One of the basic problems in the use of resistance is its ~re quent lack of durability; very often a type of resistance is used that 'breaks down' after a certain period. The temporary nature of this resistance, due to the development of new strains of pest or pathogen able to overcome it, has seriously hindered the improvement o~ the yield potential of many crops as a continuing effort is needed to replace old cultivars who resistance has failed, with new ones. Following Vanderplank's now classical publications (1963, 1968) which differentiated horizontal and vertical resistance, studies on several host-parasite systems have shown that di~ferent types of resistance can be distinguished genetically and epidemiologically, and on the ability o~ the pests or pathogens to adapt to them. A knowledge of how resistance operates at the population level has also opened up possibilities of 'managing' relatively simple resistance types in such a way that a stable host-pathogen system can be pro duced with a minimum of crop loss.