ASSESSMENT OF PCR-BASED SIMPLE SEQUENCE REPEATS TO FINGERPRINT NORTH-AMERICAN POTATO CULTIVARS

Seven primer pairs flanking di- and tri-nucleotide repeat sequences, i dentified from previously sequenced regions of the potato genome, were examined for their potential use in DNA-fingerprinting of thirty-nine Solanum tuberosum subsp. tuberosum cultivars (released between 1861 a nd 1988) and one diploid S. phureja breeding line. Of the simple seque nce repeats (SSRs), the primers for six SSRs amplified DNA sequences w ithin the potato genome between cultivars for a total of 14 bands. The polymerase chain reaction (PCR)-based amplification products generate d from each primer pair consisted of 1 to 2 bands per cultivar but ban d variation among cultivars demonstrated up to 4 bands per SSR. A simi larity matrix generated from five SSRs was able to distinguish 24 of t he 40 cultivars. However, when the potato cultivars were grouped by tu ber type (round white-skinned, long white-skinned, russet-skinned, red -skinned, and yellow flesh) only five pairs of cultivars remained indi stinguishable: Atlantic/Katahdin, Belchip/Wauseon, Red LaSoda/Bliss Tr iumph, Red Pontiac/Norland, and Burbank/Spunta. Although SSRs did not generate unique fingerprints for all of the North American genotypes e xamined, the potential to discriminate most cultivars should increase as additional SSRs are identified in potato.