THE APPLICATION OF RAPD MARKERS FOR POTATO CULTIVAR IDENTIFICATION

Where morphological techniques had failed, closely related potato cult ivars were differentiated using random amplified polymophic DNA (RAPD) analysis based on the polymerase chain reaction. Total gemomic DNA wa s extracted from young sprout tissue from harvested tubers. Of 63 10-m er oligonucleotide primers screened, 51 primers produced a total of 25 6 amplification products of which 33 were polymorphic between the cult ivars assessed. Polymorphic bands were selected to produce cultivar-sp ecific markers to identify correctly suspect material in commercial pl antings. 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 reveale d that a specific marker for cv. Sebago could be detected in a DNA adm ixture at a ratio of 1 x cv. Sebago to 5 x cv. Exton. A commercial blo ck of cv. Exton was thus randomly sampled and the level of cultivar pu rity assessed.