Efficacy of ampelographic and phyllometric tools for the validation of grapevine Vitis vinifera L. biodiversity in Slovenia

Due to the high biodiversity of grapevine varieties, many ampelographic methods have already been improved and different combinations of morphologic description and measurements introduced. In the current research, we studied fourteen red grapevine varieties of Vitis vinifera L. using ampelographic and morphologic methods to evaluate the significance of Organisation Internationale de la Vigne et du Vin (O.I.V.) code lists and phyllometry regarding the varietal diversity. In addition, graphic reconstruction method was applied and improved to form a typical varietal mature leaf. The 38 morphological parameters were evaluated and additionally 22 morphometrical parameters on several leaves per variety were measured. Statistical analysis was carried out, PCA (principal component analysis) was performed taking into account equations calculated from different leaf variables, and the qualitative variables proposed by the O.I.V. were proceeded to cluster analysis. The combination of morphologic descriptors and phyllometric measurements proved to be complementary more than comparable methods. The results of the evaluation of O.I.V. descriptors showed a high level of varietal diversity, whereas varieties of Barbera type Bovcon and Pokalca as well as Barbera standard and Syrah showed some similarities. The most different variety in the group studied according to O.I.V. descriptors was Touriga national. The PCA analysis showed the first three components responsible for more than 82% of the discriminating power. The reconstruction determinants were relations between depth of lateral sinuses and lateral veins (PC1), relation between first left lateral vein and central vein, relation between first right lateral vein and central vein (PC2), sum of angles between veins, relation between length of petiole and central vein and depth of the lateral sinuses (PC3). The enumerated relations enable and additionally improve the leaf reconstruction. At the varieties Sladkocrn and Refosk the shallowest lateral sinuses and at Tinta pinheira the deepest ones were observed whereas Plovdina and Touriga national showed shorter lateral veins (L1d, L1g) in comparison with the main vein (L). The morphological descriptions and morphometric reconstructions of leaves gave a significant contribution to understanding the grapevine phenotypical biodiversity.