Optimizing the use of repositories to define clone profiles: the example of Petit Verdot N

Abstract

In the context of climate change, clones could be a way of adaptation and need to be investigated. Repositories of clones are primarily dedicated to diversity maintenance while specific experimental plots with replicates are designed for clone characterization. However, all these field experiments are time consuming and expensive to maintain. Moreover, clone repositories are becoming increasingly the unique genetic diversity reservoir. The objective of our study was to define how a repository could be used for the agronomical characterization of the clones. Therefore detailed agronomical and environmental characterizations were performed to analyze the environmental variability and the proportion of the phenotype explained by the genetic variability was assessed. During 2 years, a repository for Petit Verdot N, with 86 clones (including clones 400 and 1058), located in the Bordeaux area (France), was studied. Vine water status was homogeneous as demonstrated with pre-dawn and stem water potential as well as ¹³C measurements. Vine nitrogen status was assessed by measuring nitrogen content of the leaves and yeast assimilable nitrogen in the juice. Clones were characterized for pruning weight, yield components and technological and phenolic maturity.The multivariate analysis of fruit composition at maturity and yield components enables to define several groups of clones. These different profiles can be used to obtain a better adaptation of the variety to different environmental and production contexts. The variability for Petit Verdot N was highest for yield components and malic acid content. In conclusion, by integrating the nitrogen and water status analyses and by planting with replicates, clone characterization within a repository would highlight profiles that could be used for different environmental and production contexts.