Genetic gains of selection in ancient grapevine cultivars

Abstract

The genetic diversity accumulated over centuries within ancient grapevine cultivars is the raw material for any genetic selection. The greater the intravarietal variability, the greater will be the gains obtainable from the selection and the capacity of the cultivar to respond to present and future challenges of a viticulture in which the growing of ancient cultivars is valued. Therefore, it should be efficiently evaluated, which involves the establishment of field trials with powerful experimental designs and the fitting of appropriate models for data analysis. The key point is to perform well-planned and accurate phenotyping, because it is a requisite for any efficient genetic selection in grapevine. For quantitative genetics analyses focused on selection, linear mixed models are fitted to large data sets using residual maximum-likelihood estimation. In this work, those models were fitted to yield and must quality traits data from initial field trials of 11 ancient cultivars. The objective was to show that good and accurate phenotyping allows the implementation of efficient polyclonal selection (selection of a superior group of genotypes within one cultivar). The results obtained showed that, for all traits and cultivars studied, it was possible to perform polyclonal selection with high and precise genetic gains of selection, reinforcing the importance of this type of selection for the vine and wine industry.