Variation of organic acids in mature fruits of 193 pear (Pyrus spp.) cultivars

Organic acids play important roles in fruit flavor and nutrition. Here, the organic acid contents of 193 pear germplasm fruits were determined using ultraperformance liquid chromatography (UPLC). The results showed that the organic acids in pear fruit mainly included malic acid, citric acid, quinic acid, oxalic acid and shikimic acid. Correlation analysis showed that these pear cultivars could be separated into the malic acid-dominant and citric acid-dominant types. By comparing organic acid content among the different pear species, we showed that Pyrus ussuriensis had the highest total acid content, followed by Chinese sand pears (Pyrus pyrifolia), Pyrus sinkiangensis, the hybrid breeding (HB) cultivar group, Pyrus bretschneideri, Japanese and Korean (J&K) sand pears (Pyrus pyrifolia) and Pyrus communis. In addition, a positive correlation between acid content and pear fruit ripening period was detected. These fundamental data and results could greatly augment pear breeding programs and provide a comprehensive understanding of pear germplasm resources.