Morphometric Analysis Reveals New Data in the History of Vitis Cultivars

Seeds of different <i>Vitis</i> cultivars (<i>V. vinifera</i> subsp. <i>vinifera</i>) have an interesting diversity of shapes, ranging from the small seeds of high solidity and low aspect ratio in some species of <i>Vitis</i> and <i>V. vinifera</i> subsp. <i>Sylvestris</i> to other morphological types with elongated stalks, characteristic of the more recent cultivars, suggesting a transition with alterations in seed shape associated with groups of cultivars. <i>J</i>-index analysis is a morphometrical technique that measures the percentage similarity of seed images with geometric models. Three models based on the outlines of reference cultivars (a model based on the Spanish female cultivar Hebén; and mixed models for French and German Chenin and Gewürtztraminer, both related to Savagnin Blanc; and Regina dei Vigneti and Muscat Hamburg, related with the Muscat group) have been applied to select the average outlines (Aos) resembling these models from a collection of cultivars maintained at IMIDRA. Three groups resulted, called Hebén, Chenin, and Regina, with 15, 25, and 18 cultivars, respectively. Principal component analysis (PCA) with the Fourier coefficients of the Aos for these cultivars and seeds of other species of <i>Vitis</i> and <i>V. vinifera</i> subsp. <i>sylvestris</i> showed differences between groups. Specific Fourier coefficients were related with geometric properties of the seeds, circularity, roundness, aspect ratio, and solidity as well as with diverse measurements of curvature allowing to establish hypothesis about the change in geometric properties along the evolution of cultivars.