The production of potato, as an important source of food has high annual yield losses due to late blight. Despite intensive research and breeding work, there is still no approved cultivar that bears a durable resistance. In the present study it was determined which wild relatives of the cultivated potato carry resistance to late blight and how this can be made accessible for progress in potato breeding. Based on this literature search, 85 species were found to have a resistance potential and about half of them are not yet further characterised. In addition, it was explained which new methods could be used to make potato breeding faster and more efficient in the future. Another aim of this work was to characterise the JKI potato gene pool for late blight resistance. An examination of the pre-breeding clones for various resistance genes from wild relatives revealed that individual clones carry up to four of these resistance genes. As further investigations, two genome-wide association studies were performed. In the first, five QTL were detected on chromosomes 1, 7, 10 and 11, in the second, two marker-trait associations were detected on chromosomes 9 and 11. Finally, it was analysed whether the amount of organic nitrogen fertilisation can influence late blight infestation in cultivars and pre-breeding clones. It was shown that the influence is marginal. Overall, however, in contrast to the cultivars, the clones were hardly or not at all infected at all fertilisation levels, so that they carry great potential for resistance breeding. The results of this work can be used in potato breeding to develop cultivars with a possibly durable late blight resistanceweiterlesen