Abstract

Japanese plum has an excellent place in the fruit production in Chile, being an interesting target for fruit quality and functional-food value improvement. Related with the latter aspect, one of the objectives of University of Chile Japanese plum-breeding program is to develop new selections with enhanced fruit functional compound content. A suitable strategy to improve the efficiency of selection process (a slow and expensive relatively long generational time and the presence of self-incompatibility in the species) is the use of molecular markers genetically associated to mutations responsible for phenotypic variation. In the year 2015, we started to explore the phenotypic variability of plum fruit polyphenol content as a first step in the characterization of the genetic mechanisms underlying this complex trait. For this aim, we are analyzing the anthocyanin and low-molecular weight phenols (LMWP) profile in a small collection of 12 Japanese plum commercial varieties. For each cultivar, skin and flesh tissues of fruits sampled at two different ripening conditions (E1 and E2), were subjected to methanolic maceration and organic extraction to obtain extracts enriched in anthocyanins and LMWP, respectively. HPLC-DAD analysis of the extracts is revealing the presence of 8 anthocyaninrelated and 16 LMWP-related peaks. In the former, and employing HPLC-qTOF-MS2 qualitative analysis, we have detected the presence of cyanidin 3-rutinoside, as well as 3-monoglucosides of cyanidin, petunidin, peonidin, pelargonidin and delphinidin. Peaks putatively associated to cyanidin 3-glucose and cyanidin 3-rutinoside show the highest concentration in all red-skinned cultivars. As expected, the compound distribution across fruit tissues and ripening conditions is strongly dependent on the cultivar. Correlation of phenolic compounds and phenological and fruit quality traits (determined on the same analyzed fruits) is also shown. These preliminary data confirm a genotype-dependent phenolic content, suggesting that breeding for health-promoting fruits is a completely feasible activity.