## 2 Materials and Methods
### Genotyping  
Genomic DNA was isolated from fully developed young leaves of three different plants for each accession using the GenEluteTM Plant Genomic DNA Miniprep Kit (Sigma-Aldrich, St. Louis, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Plant Part** & **Descriptors** & **Expressions** & **Abbreviation** \\ \hline Plant & Height & 1 = very short, 3 = short; 5 = medium; & 23 1 \\ Plant & Growth habit & 7 = tall; 9 = very tall & 23 1 \\ Plant & Anthocyanin coloration & 3 = upright; 5 = semi-upright; 7 = spreading & 13 \\ Plant & of stem & 1 = absent or very weak; 3 = weak; & 14 \\ Plant & Foliage structure & 1 = medium; 7 = strong; 9 = very strong & 14 \\ Plant & Foliage structure & 1 = stem type; 2 = intermediate type; & 12 \\ Plant & Flower frequency & 3 = leaf type & 1 = absent or very low; 3 = low; & 24 \\ Leaf & Openness & 1 = closed; 3 = intermediate; 5 = open & 16 \\ Leaf & Presence of secondary leaf leafs & 3 = weak; 5 = medium; 7 = strong & 17 \\ Leaf & Anthocyanin coloration & 1 = absent or very weak; 3 = weak; & 19 \\  & on midrib of upper side & 5 = medium; 7 = strong; 9 = very strong & 20 \\ Leaf & Width in relation to length of lateral leaflets & 3 = narrow; 5 = medium; 7 = broad & 20 \\ Leaf & Frequency of coalescence of lateral leaflets & 1 = absent or very low; 3 = low; & 21 \\  & Anthocyanin coloration & 5 = medium; 7 = high; 9 = very high & 26 \\ Flower & on pedunc of & 1 = absent or very weak; 3 = weak; & 27 \\  & infloresescence & 5 = medium; 7 = strong; 9 = very strong & 28 \\ Flower & Intensity of anthocyanin coloration on inner side of corolla & 1 = absent or very weak; 3 = weak; & 29 \\  & Extent of anthocyanin coloration on inner side of corolla & 1 = absent or very small; 3 = small; & 30 \\ Flower & Colorado on inner side of corolla & 5 = medium; 7 = large; 9 = very large & 31 \\ Tuber & Shape & 1 = round; 2 = short oval; 3 = oval; & 32 \\  & & 4 = long-oval; 5 = long; 6 = very long & 33 \\  & & 1 = light beige; 2 = yellow; 3 = red; 4 = red & 34 \\ Tuber & Color of skin & parti-colored; 5 = blue; 6 = blue & 35 \\  & & parti-colored; 7 = reddish brown & 36 \\ Tuber & Color of base of eye & 1 = white; 2 = yellow; 3 = red; 4 = blue & 35 \\  & & 1 = white; 2 = cream; 3 = light yellow; & 36 \\ Tuber & Color of flesh & 4 = medium yellow; 5 = dark yellow; & 37 \\  & & 6 = red; 7 = red parti-colored; 8 = blue; 9 = & 38 \\  & & blue parti-colored & 39 \\ Tuber & Average tuber number & Number & 30 \\ Tuber & Average tuber weight & Weight (kg) & 31 \\ Tuber & Average tuber number & & 32 \\  & (<40 mm) & Number & 33 \\ Tuber & Average tuber number & & 34 \\  & & & \\ Tuber & Average tuber number & & 35 \\  & & & \\  & & & \\  & & & \\  & & & \\ \end{tabular}  
* Numbering adopted by GlBA (Gruppo di lavoro Biodiversita in Agricolura, [[http://dspace.inea.it/handle/inea/745](http://dspace.inea.it/handle/inea/745)]([http://dspace.inea.it/handle/inea/745](http://dspace.inea.it/handle/inea/745))).  
\end{table} 
Table 1: List of the descriptors used in the morpho-agronomic characterization of the potato varieties. MO, USA). Genotyping was carried out with five microsatellite (SSR) primer pairs chosen based on their previously assayed discrimination power in a larger collection of potato varieties [12; 37; 38]. All SSRs were recommended at CIP (International Potato Center, www.cipotato.org) based on quality criteria, genome coverage, and locus-specific information content (Table A1). SSR-PCR and capillary electrophoresis were performed, as reported by [PERSON] et al. [39]. The alleles for SSR locus of each potato genotype were assigned with their molecular size and scored as present (1) or absent (0) using GeneScan Analysis software (version number 3.1, Applied Biosystems, Foster City, CA, USA). A similarity matrix was calculated using the Dice coefficient [40] with the program DendroUPGMA ([[http://genomes.urv.es/UPGMA/](http://genomes.urv.es/UPGMA/)]([http://genomes.urv.es/UPGMA/](http://genomes.urv.es/UPGMA/))) [41].