The genetically modified potato lines contain a maximum of three different two Rpi-genes from S. bulbocastanum and other related Solanum species conferring improved resistance to P. infestans. The Rpi-genes belong to the class of NbARC-LRR genes(also known as NBS-LRR genes). Many conventional potato varieties also contain additional NbARC-LRR-genes that have been introgressed from wild Solanum species. An intended effect of the introduced trait is an increased survivability in potato fields exposed to P. infestans. This possible selective advantage, however, is of importance only in the agricultural field, and will not improve the survivability in the surrounding environment. The reduced need for fungicides on these lines can easily be identified as an environmental benefit.
No difference with respect to persistence in agriculturally utilised habitats or invasiveness into natural habitats as compared to conventional potato varieties is expected. Through the measures which are taken during the release, distance from or absence of conventionally cultivated potatoes or wild species, the possibility of any gene transfer can be virtually ruled out. Even in the very improbable event that pollen were to be transferred to genetically unmodified potato plants, no consequences are to be expected, since potato propagation conventionally takes place via tubers and not via seeds. The interactions of the genetically modified potato line with non-target organisms and the effects resulting from this will be comparable to those with conventional potato varieties. Furthermore, no toxic or allergenic effects are expected on the basis of the improved resistance to P. infestans. No effects on biogeochemical processes are expected, other than those that apply also to conventional potatoes.

The purpose of the experiments is twofold:
1) Mixtures of true to type, resistant (R) and susceptible (S) plants are studied as a model for R/R mixtures after break through of one of the Rpi-genes or Rpi-gene cassettes. The purpose is to establish relationships between the mixing ratio of resistant/susceptible and the resulting (beneficial) spatial and temporal delay of epidemic progress. The results give insight in the added value of- and ideal composition of true to type dynamic cultivars and the most durable way to deploy them in time and space.
2) Monitoring of the P. infestans population for adaptation (virulence) to newly introduced Rpi-genes and Rpi-gene cassettes. This information is crucial for strategies for durable deployment of Rpi genes.