The potential of genetic manipulation in plant cell cultures for plant breeding

In vitro culture of somatic cells of higher plants allows the plant breeder to apply the techniques of microbial genetics to specific breeding problems in crop plants. The basic techniques of callus and suspension culture, haploid plant culture from pollen, protoplast isolation, culture and fusion, and totipotency in plant cell cultures are reviewed. The genetical approaches which have application or potential application to plant breeding are also reviewed. These include selection of mutations in cell cultures, studying host-pathogen inter-relationships, transfer of genetic information into cells through uptake of native DNA, uptake of whole metaphase chromosomes or viral-induced transduction and interspecific hybridization through somatic cell fusion. The major difficulty to the application of many of these techniques to plant breeding programs is the inability to regenerate whole plants from somatic cells in some of the major crop plants. Some techniques such as mutant selection have been and are presently applicable in some crops, but others such as somatic cell fusion still require additional refinement before they will become generally applicable in a plant breeding situation. A survey is made of the present status of the culture methods possible in several important crop plants.