The improvement of quality traits in food and industrial crops is one of the most important goals in plant breeding. Improved crop quality is considered to be of great economic value for both developed and developing countries. This publication highlights mutation induction as a highly efficient means of altering the genetic constitution of a crop and, thereby, enhancing the development of new crop varieties. It summarizes the results of an IAEA coordinated research project which employed physical and molecular mapping techniques in characterizing and developing advanced mutant lines of various crops, such as cotton with improved fibre quality, rice with novel starch content, oilseed rape with high oleic acid content, and pepper and tomato with high beta carotene content.