Statistical Procedure for Clonal Preselection of Vitis vinifera L. cv. Tempranillo in the Duero Valley, Spain

Abstract

Clonal selection is a tool used to enhance the quality of indigenous grapevines in many regions. There are two challenges in applying clonal selection to old and widely distributed varieties such as Vitis vinifera L. cv. Tempranillo: the large geographical area covered by the vineyards to be assessed and the limitation inherent in the need to select only a few grapevines from a large population. The quality of grapevines in the Duero Valley region of Spain was investigated. The vines studied, candidates for clonal selection, were chosen after one year of visual assessment conducted on the oldest vineyards. The statistical methodology used was multivariate analysis, specially designed to exploit the wealth of time-specific data generated over the three-year preselection period by building a time dimension into the procedure. The stability of the relationships among viticultural parameters over time was determined using the dual STATIS technique. The STATIS method, in turn, was used to study the stability of the main characteristics of the grapevines. A classification procedure is introduced that shortens the list of preselection parameters to be considered. The increase in the number of individual vines that can be screened by applying the proposed methodology effectively improves the base for clonal selection and, ultimately, the quality of the wine produced.