A range of novel techniques is available to the plant breeder today to complement classical breeding methods. The new options are based on the integration of advances in plant cell biology with those in plant molecular biology. Plant cell, tissue and organ cultures provide efficient systems for transformation, for the achievement of wide crosses and for the production of variation through spontaneous and induced mutation, while permitting effective isolation of desired genotypes by in vitro selection. This book presents a critical appraisal of the methodologies of plant genetic manipulation for advanced undergraduates, postgraduates, researchers and plant breeders, and provides guidance on the choice of breeding options. The latter depends on the breeding system of the crop, the breeding objective and the tissue culture systems applicable to the target genotype(s).