ABSTRACT
This chapter considers the genetic variation observed in plants derived from protoplasts. Protoplasts offer the advantage of being discrete cellular plating units which may be manipulated in large and uniform populations. Potato represents one of the few examples of plant regeneration from protoplasts of a major crop plant. The genetic variation in plants regenerated from protoplasts, and their progeny, is reflected in phenotypic alterations which have been described in a number of species. The results of experiments on tobacco where plants heterozygous at defined loci were used as donor material for protoplast isolation have revealed that changes at these loci occur as a consequence of culture. A number of species of Nicotians have proved to be very amenable to protoplast culture and the subsequent regeneration of intact plants. The occurrence of karyotypic alterations in cultured plant cells has been well documented.
