In the present thesis, economically important Campanula species were selected for interspecific hybridisation to increase the genetic viability in plant breeding material.

To reach this goal, ovule culture was established as an embryo rescue technique to overcome post-fertilisation barriers in selected Campanula species. Furthermore, interspecific hybrids with new phenotypes were investigated at the molecular and morphological level.

The first research part focused on the effect of different ovule isolation times on selected cultivars from different Campanula species. The ovule isolation time had an influence on the number of ovules and germination success in some cross combinations.

In the second research part interspecific hybrids obtained from ovule culture were genotypically and phenotypically characterised by AFLP analysis, flow cytometry and biometrical parameters. Hybridity was confirmed for most of the interspecific hybrids. Intermediate phenotypes compared to the parental species were found for several interspecific hybrids.

The results from this PhD study demonstrated that the genetic viability could be increased in Campanula and reveal valuable information for interspecific hybridisation in general