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'.

During the last thirty years, most increases in agricultural production were achieved through high input agrieulture in areas with fertile soils and sufficient water. Intensive methods of production with high levels of nitrogen fertilizer and pesticides were often accompanied by environmental degradation and in some instances by pollution of the food supply. However, rapid population growth has also led to increasing use of marginal lands, where adverse soil and climatic eonditions are serious constraints to food production. These areas are even more sensitive to ecological destabilization. Environmentally sound systems of food production and land use are essential for meeting the food security needs of developing countries. To do this, greater genetic variability is needed within the best crop genotypes available for the areas in need coupled with better management praetices and crop rotations. These requirements can only be realized if suitable crop varieties are bred. These should be varieties with a much shorter growing period, suitable for rotation, increased tolerance or resistance to diseases and pests as weil as to drought and salinity and other adverse soil and climatic conditions.

China was the first country to use cytoplasmic male sterility to develop hybrid rice for commercial use in 1973. In 1986 more than 8 million hectares of hybrid rice were planted in China, which is one fourth of the total rice area and produces one third of the total rice in the country. Hybrids usually out yield the leading commercial varieties by -20-30%, giving an average yield advantage of 1 to 1. 5 t/ha, because of their better morphological traits, higher physiological efficiency, better resistance to major diseases and insects, and wide adaptability to various agro-ecological stresses. IMPROVEMENT OF HYBRID RICE A. Mutation techniques Almost all of the cultivated F1 rice hybrids in China are developed from cytoplasmic male sterile and restorer lines. According to surveys made in recent years, more than 30 sources of cytoplasmic male sterility in rice can be identified, among which only six are being commercially used (Table 1). Wild rice with aborted pollen (WA) cytosterility system is the most popular one in use to develop male sterile lines (MS line) in China. The main technique available for developing stable MS lines is sUbstitution backcrossing of the genome of one species into alien cytoplasm of another. Sufficient backcrosses are required to eliminate all nuclear genes derived from the cytoplasm donor species. A number of studies have shown that using interspecies crosses, such as the cross of wild rice (Q. perennis, Q. sativa, f.

During the last thirty years, most increases in agricultural production were achieved through high input agrieulture in areas with fertile soils and sufficient water. Intensive methods of production with high levels of nitrogen fertilizer and pesticides were often accompanied by environmental degradation and in some instances by pollution of the food supply. However, rapid population growth has also led to increasing use of marginal lands, where adverse soil and climatic eonditions are serious constraints to food production. These areas are even more sensitive to ecological destabilization. Environmentally sound systems of food production and land use are essential for meeting the food security needs of developing countries. To do this, greater genetic variability is needed within the best crop genotypes available for the areas in need coupled with better management praetices and crop rotations. These requirements can only be realized if suitable crop varieties are bred. These should be varieties with a much shorter growing period, suitable for rotation, increased tolerance or resistance to diseases and pests as weil as to drought and salinity and other adverse soil and climatic conditions.