This is the first manual presenting a set of protocols for production of doubled haploids (DH) in 22 major crop plant species including 4 tree species. It contains various protocols and approaches of DH production proven for different germplasm of the same species. The protocols describe in detail all steps of DH production - from donor plants growth conditions, through in vitro procedures, media composition and preparation, to regeneration of haploid plants and chromosome doubling methods. The users of this manual will be able to choose among microspore versus anther cultures, wide hybridisation or gynogenesis, the most suitable method for production of DH in particular laboratory conditions for their plant material. Numerous colour illustrations should help in this decision. The user will also find information on organization of a doubled haploid laboratory, basic DH media and on associated simple cytogenetic methods for ploidy level analysis. The practical protocols are supplemented with the list of published DH protocols for other crop plants and separate chapters dealing with major applications of DH in breeding, mutant production, transgenesis, and genetic mapping and genomics. The book was prepared by the Plant Breeding and Genetics Section of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture in close co-operation with the EU program 'COST 851' on 'Gametic cells and molecular breeding for crop improvement'.