Molecular tools for clone identification: the case of the grapevine cultivar 'Traminer'

In viticulture, biotype identification problems have traditionally been solved using ampelography, ampelometry and chemical traits analysis. However, these tools have resulted in several false attributions, in particular when used at the clonal level. The availability of relatively cheap, reliable and reproducible tools to identify genetic differences at the clonal level would greatly facilitate the work of clonal patenting. In this work, 24 accessions of 'Traminer' cultivars were characterized using molecular markers. Three different approaches were applied: simple sequence repeats (SSR), amplified fragment length polymorphism (AFLP) and methyl-sensitive amplified length polymorphism (MSAP). Results showed that SSRs were not a powerful tool for clonal distinction. In contrast, the AFLP technique was able to distinguish 16 out of the 24 cultivars, even though the average similarity was high (97.1%). The MSAP technique was used to evaluate qualitative differences in the degree of DNA methylation among clones. Results suggest that morphological differences among clones are probably due to the synergetic effect of genetic and epigenetic modifications, and that clonal identification could be greatly improved using molecular tools such as AFLP and MSAP.