Fast and reliable strawberry cultivar identification using inter simple sequence repeat (ISSR) amplification

ISSR amplification was evaluated for its applicability to strawberry varietal identification. Eighteen primers based on various di- tri- or tetra- SSR motifs with 3 or 0 5'- selective nucleotides for anchoring were screened against the strawberry genome by agarose gel electrophoresis. PCR conditions were optimised to obtain high quality patterns. Five primers that gave informative patterns were selected and used to characterise, by polyacrylamide gel electrophoresis, 30 strawberry varieties of various geographic and genetic origins. A total of 390 bands, 113 of which were polymorphic ( 30%), were generated using these five primers. Genetic similarity between varieties was estimated using Jaccard's coefficient of similarity. The associations between varieties revealed by UPGMA analysis were consistent with pedigree data. With only one primer, all the varieties were distinguished including those with a common pedigree. Banding patterns were highly reproducible for DNA samples extracted from different tissues ( leaves, sepals, and rhizomes) of the same plant, or from different plants ( clones) of the same variety. ISSR technique is therefore a potentially useful tool for the identification of strawberry varieties because it is simple, fast, cost- effective, highly discriminant and highly reliable.