Seed apex curvature in key Spanish grapevine cultivars

New methods of image analysis may contribute to the morphological description of seed shape and cultivar classification in Ampelography. We recently proposed a method based on the comparison of seed images with geometric figures, defined by mathematical equations for the identification and classification of grapevine cultivars. Representative cultivars of Vitis vinifera, conserved in the Spanish collection of IMIDRA, were classified in ten groups according to the similarity of their seeds with geometric models. Complementary to this method, we propose here the analysis of curvature in the seed apex and the quantification of curvature values in the seed images. Curvature is a parameter that indicates the variation of the slope values along the points of a continuous curve. A set of points along the surface of the seed images are marked and used to obtain the Bézier Curves corresponding to seed profiles. The curvature values along the curves are calculated and represented. According to the variation of their curvature and distribution of maximum curvature values, the cultivars are classified in three groups. The groups formed on the basis of curvature analysis are related to the classification based on geometrical figures. Curvature in the apex describes an important morphological aspect at the basis of the classification by shape. ‡ ‡ §