Intra-varietal diversity for agronomic traits in 'Garnacha Blanca'

'Garnacha Blanca' is a somatic variant derived from 'Garnacha Tinta', an old variety with large genetic and phenotypic variability. In this work we have studied for two years the phenotypic variation existing in 'Garnacha Blanca' for yield and quality related traits in accessions from 14 sampling locations of ancient vineyards in the Ebro Valley, Spain. The results showed high variability among the accessions in many of the traits studied in 'Garnacha Blanca'. Different accessions could be distinguished both years using several traits, including two important traits in terms of quality and yield: bunch compactness and yield per plant. A large environment effect, intrinsic to the 'Garnacha' group, enhances phenotypic variation among years, what requires increasing the number of bunches and years for clonal characterization in this variety. The dimensions of the berry showed the least variability, while traits related to bunch architecture like bunch length were discriminant and also stable.