Molecular Characterization of Somatic Hybrids

Gene flow between sexually incompatible plant species is restricted by the evolutionary boundaries in sexual crosses. Somatic cell hybridization and DNA transformation have opened new horizons for combining genes from unrelated species (Jain et al. 1992; Lindsey 1992). If the gene of interest has been cloned, transformation systems such as the Agrobacterium method (Horsch et al. 1987), direct gene transfer (Jain 1993), biolistic delivery system (Lindsey 1992) and microinjection (Neuhaus et al. 1987) provide the most efficient way of introducing it into a foreign host genome. When the goal is to transfer several genes or when the genes of interest are unidentified, protoplast fusion and related techniques, however, offer an alternative approach for alien gene transfer (see also Chaps. 8 and 9).