PT  - JOURNAL ARTICLE
AU  - Roberta Triolo
AU  - Jean Philippe Roby
AU  - Antonella Plaia
AU  - Ghislaine Hilbert
AU  - Simona Buscemi
AU  - Rosario Di Lorenzo
AU  - Cornelis van Leeuwen
TI  - Hierarchy of Factors Impacting Grape Berry Mass. Separation of Direct and Indirect Effects on Major Berry Metabolites
AID  - 10.5344/ajev.2017.16087
DP  - 2017 Oct 30
TA  - American Journal of Enology and Viticulture
PG  - ajev.2017.16087
4099  - http://www.ajevonline.org/content/early/2017/10/25/ajev.2017.16087.short
4100  - http://www.ajevonline.org/content/early/2017/10/25/ajev.2017.16087.full
AB  - Final berry mass, which is a major quality factor in wine production, is the result of the integrated effect of biotic and abiotic factors that can influence also the berry composition. Under field conditions, the interactions between these factors make the study of the variability of berry mass and composition difficult. Depending on the observation scale, the hierarchy of the impact degree of these factors can vary. The present work was designed to study the simultaneous effect of the major factors influencing berry mass and composition in order to create a hierarchy according to their impact degree. A second objective was to separate the possible direct effect of factors on berry composition from an indirect effect mediated through their impact on berry mass. Vine water and nitrogen status of six blocks, located on a sandy and a gravelly soil, were monitored during two following years. Berries from Cabernet franc were analyzed from veraison to harvest. At each sampling date, fresh berry mass, berry seed mass and number, sugar content and concentration and malic concentration were recorded. All studied factors significantly impacted the final berry mass, but vine water status represented the most impacting factor. The interaction between factors sometimes seemed to hide the significant effect of some of them on berry compounds. Nevertheless, we showed by means of appropriate statistics that all factors had a direct impact on berry sugar and malic concentration, although their order of impact varied according to the metabolites considered. Conversely, the effect of factors significantly impacting berry sugar content is mediated through their impact on fresh berry mass.