Somatic hybridisation of two plants is a tissue-culture based breeding technique and is carried out by so-called protoplast fusion (cells without cell wall = protoplasts): Cells of two plants to be crossed are freed from their cell wall and fused together using electric current and various reagents. The resulting fused cell possesses properties of both parent cells, some of which cannot be inherited via sexual crossing. Particularly worthy of mention here are properties of the plastids, e.g. chloroplasts and mitochondria, which can only be passed on sexually from the mother plant to the offspring. Thus, our protoplast fusion is a key technology to transfer the so-called cytoplasmic male sterility (CMS), which is mediated by the mitochondrial genome, into varieties. In this way, we enable the production of high-yielding hybrid seed.
In addition to controllable fusion of the cytoplasm, nuclear fusion and duplication of chromosome sets can also be achieved.
A cell fused as desired is then regenerated into an adult plant in tissue culture, propagated and used for further breeding or directly for cultivation.
The aim of the whole process is to generate a non-genetically modified but optimised crop, ornamental or medicinal plant. Thousands of fusions can be carried out in a very short time, e.g. to create a new pool with high genetic diversity, to produce polyploid and thus usually more vigorous offspring or to overcome crossing obstacles between species/varieties that are difficult to cross. It is also possible to produce species hybrids of two closely related plant species. An example of this are hybrids of poplar and aspen or of two peppermint species which Phytowelt has bred and registered in the past.