Characterization of fruit quality traits for organic acids content and profile in a large peach germplasm collection

Organoleptic properties play a pivotal role in determining peach fruit quality, affecting both consumers' and market acceptance. In spite of a narrow genetic diversity, peach [Prunus persica L. (Batsch.)] has a remarkable range of fruit taste, mainly driven by the relative amount of sugars and acids. Characterization and exploitation of such variability is a major objective of fruit-quality orientated breeding programmes. In this study, a peach collection of 201 accessions was dissected for important fruit quality traits, with a particular focus on acidity and organic acids content. Fruit acidity was titrated and ten organic acids (oxalate, cis-aconitate, citrate, tartrate, galacturonate, malate, quinate, succinate, shikimate and fumarate) were detected through HPLC and UHPLC-MS. Malate and citrate are the most abundant accounting for the 62 % and the 22.6 % of total organic acids, respectively, and suggesting their largest contribution to the overall peaches acidity. Results reveal also a genotype-dependent contribution of specific organic acids and a low seasonality-effect on peach acidity and organic acid patterns. Collectively, this work provides an overview of the phenotypic variation associated with organic-acid related traits useful for supporting the ongoing breeding works.