We exploit the genetic potential of natural biodiversity by modern biochemical and molecular biology technologies. This will reveal highly specific, endogenous factors influencing the quality and quantity of our clients' products. For an optimal exploitation of the available potential, these factors scattered in different varieties and even species must be combined within a single plant prototype. In order to develop new plant varieties with improved qualitative and quantitative traits, we use somatic hybridization by electrofusion of isolated protoplasts.
Somatic hybridization means the combination of nuclear and cytoplasmic genetic information by fusion of somatic cells. The transfer of genes beyond the restrictions of sexual reproduction and crossing species boundaries has made somatic hybridization an important tool in combining useful characteristics of different organisms. Another limitation of genetic engineering, the transfer of only a restricted number of genes and traits, is avoided by somatic hybridization. It is possible to increase the number of chromosomes and to design polyploidal plants in order to increase yield (heterosis effect). Three forms of hybridization can be distinguished namely intraspecific, interspecific and intergeneric hybridization.

Intraspecific hybridization

Protoplast fusion of sexual incompatible plants result in highly heterogenous hybrids. These hybrids may reveal the so called "hybrid vigour", meaning improved growth characteristics based on the heterosis effect. For that reason protoplast fusion is used in breeding programs of various species.

Interspecific hybridization

The transfer of genetic information from wild to cultivated species is of considerable interest for crop improvement. In most cases, however, it is hindered by incompatibility barriers. Protoplast fusion allows to bring about limited genes for example disease resistance from wild species into cultivars. This has been done in S. tuberosum and other crop species.

Intergeneric hybridization

The Tomatoffel - a product of
intergeneric hybridization

Combinations between distantly related species that are impossible by conventional crossing procedures can be realized by protoplast fusion. Although combining distantly related species result in asymmetric hybrids with reduced fertility, these may serve as bridges to transfer desirable new genes to species of interest.

Phytowelt GmbH makes use of intra- and interspecific hybridization as well as intergeneric hybridization, mainly focusing on members of the genus Solanum and Mentha. This allowed us to produce a high number of intra- and interspecific hybrids between S. tuberosum and several wild species and even intergeneric hybrids between S. bulbocastanum and Lycopersicon esculentum . One of this intergeneric hybrids revealed a potato like phenotype, but with yellow tomato like flowers. Yellow potato flowers, which typically are white to blue/violet, were never observed until that time.

Preconditions for the routine application of somatic hybridization are the availability of high quality in vitro plant material and protoplasts, mastering of regeneration and a well functioning system of hybrid selection. Modern biotechnology with it's improved methods of analysis enables us to use traditional methods of plant breeding in a sophisticated way beyond the limitations of the past.