This volume contains the proceedings of an international symposium on the durability of disease resistance in plants. Durability of resistance in plants is a highly desired quality influenced, among other things, by the adaptability of the pathogen populations, cultivation methods, phytosanitation and the kind of resistance used. The chapters cover a wide variety of subjects, ranging from the analysis of some of the world's most important pathosystems; the genetic variation in pathogen populations and the variation in the hosts; the present efforts at breeding durable resistance, viewed from both the biotechnological and the classical approaches, is also covered. This volume provides an opportunity for all those scientists, breeders and pathologists who are interested in the durability of disease resistance to obtain an insight into the research that is currently going on world-wide.

From February 24 -28, 1992 an international symposium on Durability of Disease Resistance was held at the International Agricultural Centre in Wageningen, the Netherlands. The symposium, organized by the Department of Plant Breeding of Wageningen Agricultural University and the Centre for Plant Breeding and Repro­ duction Research, CPRO-DLO, was part of the DGIS funded programme Durable Resistance in Developing Countries. Without any form of prevention or protection nearly all crops will be seriously or even severely damaged by a range of pathogens. In modern agriculture man has been able to control many if not most pathogens using i) pesticides, ii) phyto­ sanitary methods such as control of seed and plant material in order to start a crop disease free, iii) agronomic measures such as crop rotation, iv) disease resis­ tance or combinations of these measures. Over the years the use of pesticides has increased enormously and so did the pro­ blems associated with pesticide use, such as environmental pollution and building of resistance and tolerance to these pesticides in the pathogens. The use of resis­ tance too increased strongly over the years and here too problems arose.

This volume contains the proceedings of an international symposium on the durability of disease resistance in plants. Durability of resistance in plants is a highly desired quality influenced, among other things, by the adaptability of the pathogen populations, cultivation methods, phytosanitation and the kind of resistance used. The chapters cover a wide variety of subjects, ranging from the analysis of some of the world's most important pathosystems; the genetic variation in pathogen populations and the variation in the hosts; the present efforts at breeding durable resistance, viewed from both the biotechnological and the classical approaches, is also covered. This volume provides an opportunity for all those scientists, breeders and pathologists who are interested in the durability of disease resistance to obtain an insight into the research that is currently going on world-wide.

From February 24 -28, 1992 an international symposium on Durability of Disease Resistance was held at the International Agricultural Centre in Wageningen, the Netherlands. The symposium, organized by the Department of Plant Breeding of Wageningen Agricultural University and the Centre for Plant Breeding and Repro­ duction Research, CPRO-DLO, was part of the DGIS funded programme Durable Resistance in Developing Countries. Without any form of prevention or protection nearly all crops will be seriously or even severely damaged by a range of pathogens. In modern agriculture man has been able to control many if not most pathogens using i) pesticides, ii) phyto­ sanitary methods such as control of seed and plant material in order to start a crop disease free, iii) agronomic measures such as crop rotation, iv) disease resis­ tance or combinations of these measures. Over the years the use of pesticides has increased enormously and so did the pro­ blems associated with pesticide use, such as environmental pollution and building of resistance and tolerance to these pesticides in the pathogens. The use of resis­ tance too increased strongly over the years and here too problems arose.