Protoplast Electrofusion and Regeneration in Potato

Protoplast fusion and subsequent in vitro plant regeneration, leading to somatic hybridization, offer opportunities for transferring entire genomes from one plant into another, regardless of the interspecific crossing barriers. In contrast to techniques for plant transformation that are aimed at single-gene transfer, protoplast fusion is needed when polygenic traits are concerned, as is frequently encountered in the genetics of higher plants. Several Solanaceous species, including potato, have been used with greater success than other higher plant species in somatic hybridization because they are more responsive to the protoplast regeneration process. There are two commonly used procedures to induce cell fusion, namely polyethylene glycol (PEG)-induced protoplast fusion and protoplast electrofusion. These procedures have been the subject of several reviews indicating that electrofusion is generally more efficient (1 –5 ). Electrofusion is superior to PEG-induced protoplast fusion in the following aspects:

1.	Simplicity of the fusion process;
2.	Less toxicity and less physical damage to the protoplasts;
3.	Large fusion volume allowing more protoplasts to be treated; and
4.	Fine control of the fusion process with the availability of commercial electrofusion equipment.