The reduction of plant sink/source does not systematically improve the metabolic composition of Vitis vinifera white fruit

Abstract The quality of wine grapes depends on the balance between primary and secondary metabolites. Unlike many perennial crops that accumulate starch in fruits before ripening, non-climacteric ripe with no previous carbon reserves. Based assumption fruit sink is limiting metabolite accumulation grapes, bunch thinning performed to limit plant Sink/Source (S/S). We studied effects severe metabolites four families glycosylated aroma precursors (GAPs) at arrest phloem unloading two white grape Vitis vinifera cvs. At level, crop reduction resulted significant losses be accumulated fruits: i.e. up 72% for sugars, 75% organic acids GAPs. Nevertheless, S/S manipulation could not modify GAPs or increase concentration physiologically grape.