The application of RAPD markers for potato cultivar identification

Where morphological techniques had failed, closely related potato cultivars were differentiated using random amplified polymophic DNA (RAPD) analysis based on the polymerase chain reaction. Total gemomic DNA was extracted from young sprout tissue from harvested tubers. Of 63 10-mer oligonucleotide primers screened, 51 primers produced a total of 256 amplification products of which 33 were polymorphic between the cultivars assessed. Polymorphic bands were selected to produce cultivar-specific markers to identify correctly suspect material in commercial plantings. Furthermore, a cultivar-specific RAPD marker was shown to be sufficiently robust and stringent for the identification of potential cultivar contamination in the field. DNA titration experiments revealed that a specific marker for cv. Sebago could be detected in a DNA admixture at a ratio of 1 x cv. Sebago to 5 x cv. Exton. A commercial block of cv. Exton was thus randomly sampled and the level of cultivar purity assessed.