Por Elsa Gonçalves (Instituto Superior de Agronomia da Universidade de Lisboa).
The genotypes within an ancient grapevine variety are markedly different with respect to the most important cultural and oenological traits. These differences within the ancient variety justify the selection and permit to respond to new demands of growers and consumers and to adapt the variety to new environmental contexts. In Portugal, the grapevine selection methodology is strongly supported by quantitative genetics and all the issues related to the selection process are answered through the application of the theory of mixed models. In this work the linear mixed models applied in the first stage of grapevine selection are described. The study is focused on the quantification of intra-varietal genetic variability of economically important traits and on the prediction of genetic gains resulting from the selection of a superior group of genotypes.