Evaluation of a large apricot germplasm collection for fruit skin and flesh acidity and organic acids composition

Consumers continuously report a lack of taste in many apricot cultivars currently available on the market, highlighting the necessity of renewing the apricot varietal landscape grown worldwide. Sugars and acids content largely affect sweetness and aroma perception, being an important driving factor of consumers’ preferences and purchase. In this work, a large apricot germplasm collection of 164 accessions was evaluated for several fruit organoleptic attributes: maturity date, fresh fruit weight, flesh firmness, soluble solids content, titratable acidity and organic acid content separated for fruit flesh and skin and dry matter. A major focus was reserved to ten organic acids (cis-aconitate, citrate, fumarate, galacturonate, malate, oxalate, quinate, shikimate, succinate and tartrate) composition in both flesh and skin tissues, quantified by HPLC technique coupled to UHPLC[sbnd]HRMS. Malate, citrate and succinate were the most abundant, accounting for 98.5% and 97.2% of the total organic acids in fruit flesh and skin, respectively. The tested accessions showed consistent fruit acidity contents and almost similar organic acids profiles between flesh and skin, albeit some exceptions of acidity higher in flesh than in skin -and viceversa- occurred. This work highlights an extremely large diversity in apricot germplasm, representing a valuable genetic resource to be long term preserved and exploited in new fruit-quality oriented breeding programs. Also, a better understanding of phenotypic diversity will help the characterization of apricot accessions and a more effective management of germplasm for selecting phenotypes with improved taste.