Abstract
The post 'green revolution' era of the 20th century with the numerous success stories in various parts of the world has fostered a new 'gene revolution' i.e. a more science based agronomy approach in order to warrant food security for an increasing world population in the actual context of global warming, climate variability and change, the sustainable intensification and improvement of crop production systems regarding the selection of resistance and/or tolerance to stresses should be more than ever the primary goal in plant breeding. This new vision of agriculture prompts the scientific community together with the policy makers to reconsider and redefine agriculture practices for the Third Millennium. Among the multiple threats to agriculture, the increase of temperature associated with the increased humidity, due to displacement of rain isohyets will have a tremendous impact on all living creatures including microbial pathogens. The FAO/IAEA Joint Centre in NAFA/IAEA, by promoting the use nuclear techniques including mutation induction as tools for breeding new improved crop varieties has contributed to enhance the impact of this science based approach in agriculture in developing countries.
The IAEA has provided several hundreds of agricultural research institutes in Member States the capacity in terms of human resources as well as in provision of high performance germplasm through the development of several thousands of interesting mutants in crop plants. These mutants with desirable characteristics have either been directly released for cultivation or used in hybridisation programmes with other mutants and/or cultivars to develop new elite genotypes/cultivars. The success of these mutation breeding programmes relies on the selection of 'positive mutant lines' bearing the trait of interest. On the other hand, it is clear now that many wild/original plant genetic resources vital for the present and future agricultural development are threatened by genetic erosion due to the spread of modern commercial agriculture. This, combined with the climate changes mentioned above, has increased the vulnerability of existing crops to pests, pathogens and environmental stresses. This situation led the FAO International Technical Conference on Plant Genetic Resources, the World Food Summit Plan of Action and the International Treaty on Plant Genetic Resources for Food and Agriculture to strongly recommended that increased attention be given to building capacities to characterize, evaluate, improve and use plant genetic resources in a sustainable manner. Subsequently IN the FAO/IAEA Joint Centre, a project was designed under the Subprogramme 2.1.1: Sustainable Intensification of Crop Production with the overall objective to develop early mass screening techniques to obtain banana plants tolerant to fungal diseases. In fact, the selection of the proper mutants has been the bottleneck in all mutation induction breeding programmes and the difficulty is even enhanced when it comes to screening for disease resistance.
It is therefore absolutely necessary to establish reliable, rapid and high throughput screening techniques for disease resistance in local germplasm as well as in putative mutant lines. Recent project represent a continuation of some previous IAEA activities which were focused on induced mutations against plant diseases. Thus, papers presented in this book highlight increasing cross-cutting techniques using plant tissue culture, irradiation-induced mutation, molecular markers technology, isolation and characterization of mutants for the selection of disease resistant lines. The compilation of this volume has demanded an active participation of a number of breeders, plant physiology and phytopathology specialists. The formidable task of correspondence with authors of the chapters in this volume and the splendid cooperation among participants in the preparation of the manuscripts have led to very extensive and well documented chapters in accordance with the guidelines provided by IAEA publications. As editors, we would like to acknowledge our thanks to Drs. Pierre J.L. Lagoda and Manoela Miranda for discussions, suggestions and critical reading of the manuscript. The book contains a total of 20 chapters.
The first two chapters review the impact of induced mutations and in vitro selection on breeding of disease and pest resistant cultivars. Various aspects must be considered while choosing the most suitable in vitro selection technique for a given plant-pathogen interaction. The choosing of selection agent is very much dependent on their origin, method of preparation, content of active substances, and effective use for screening or in vitro selection. Furthermore the book covers radiation-induced mutations, in vitro and in vivo mass screening methods developed for fruits, legumes, vegetables, and tuber crops, and with greater emphasis on banana (Musa spp.) having 6 chapters owing to it as a source of nutrition, food security and great impact on socio-economic aspects. Methods of screening against the most deadly disease of banana (Black sigatoka and Fusarium wilt), which are of great threat to banana sustainable production, are well covered. The book also includes various screening techniques (in vitro selection against Black sigatoka in banana by using fungal toxin juglone) for the selection against the deadly diseases of crops such as vegetables (melon and other cucurbits, onion, tomato, lettuce), industrial crops (black pepper), legumes (chickpea, peas, soybean), fruits (apple, pine apple), and tropical crops (cassava, cowpea, maize, and yam). This book will be of great value to international scientists and plant breeders engaged in disease resistance mutation breeding and biotechnology programmes for sustainable food production, enhancing food security, nutrition, and employment generation. All manuscripts were reviewed by the competent reviewers and revised accordingly.