Traditional breeding research of new fungus resistant grapevine varieties is supported by modern breeding methods to make the tedious selection process faster and more efficient. The main objective is to elucidate the relationship between relevant traits and their genetic basis. Candidate genes for specific traits will be identified in the grapevine genome and functionally tested using methods of genomics and tissue culture. Subsequently, gene-linked molecular markers are developed for marker-assisted selection (MAS) in breeding programs.

Relevant and inheritable traits (e.g. resistances, bunch architecture, growth characteristics, etc.) can be characterized more effectively with modern tools like molecular techniques and bioinformatics. The following methods are used:

• Molecular markers (SSR and SNP markers)
• Genetic and physical mapping strategies
• QTL and association analysis
• Genome sequencing (Sanger and NGS)

The application of these different techniques enables us to determine the position of a specific gene in the genome. After sequencing the genomic locus, specific molecular markers can be deduced to track that specific gene within breeding programs. If different resistances against a single pathogen are identified, various resistance genes could be combined within an individual breeding line using the marker technique (MAS). This results in new grapevines with a more robust and long lasting field resistance.

Functional analysis of candidate genes responsible for fungus resistances are initially tested with tissue culture methods. From susceptible genotypes male flower parts (anthers) are excised for initiation of long-term embryogenic cultures. This tissue is used for gene transfer of candidate genes. After genetic modification in vitro plantlets developed from somatic embryos are cultured under selective conditions. After adaptation to greenhouse conditions the plants can be tested for possible fungal resistance.

These latest biotechnological techniques allow us to rapidly explore the function of specific genes. They help to reveal unknown resistance mechanisms as well as to select suitable seedlings and crossing parents for breeding.