Sugar And Acid Contents In Peach And Nectarine Derived From Different Countries And Species

Sugar and acid contents were investigated in 99 peach germplasm, including 24 Chinese local and 19 Chinese bred cultivars for fresh market, 2 Xinjiang cultivars, 5 wild species of China, 33 European & American fresh and canned, and 16 Japanese fresh and canned cultivars. The main objectives are to further understand the characteristics of sugar and acid contents in these peach germplasm and compare the difference in sugar and acid contents among peach germplasm so as to offer information for germplam conservation and application. The main results were as following:1. The major sugar and acid in peaches are sucrose and malate. Sucrose accounted for about 73% of the total sugar, and malate about 60% of the total acid contents in fruits.2. Through principal component analysis (PCA) , the main correlations among sugar and acid content in 99 peach germplasm were analyzed. Almost all sugars and acids analyzed exhibited positive loadings for the first principal component (PC1), and PC1 could be use as a general flavour component. Sucrose content in fruits had positive correlation with sorbitol. There were significant positive correlations between malate and citrate, and between quinate and shikimate in fruits. It indicated that PCA could effectively visualize correlation patterns among sugar and acid contents in the 99 peach germplasm.3. Mean sucrose content was the highest in fruits from Chinese local cultivars for fresh market, significantly higher than those from European & American canned cultivars, while the lowest sucrose content was found in the wild species. Fructose content in fruits from European & American fresh and canned, Chinese bred and Japanese fresh cultivars was significantly higher than that from Chinese local cultivars and the wild species. Total acid content of the wild species was the highest, and European & American fresh cultivars had significantly higher acid contents than that from the other three groups. The malate and citrate contents in fruits from European & American fresh and canned cultivars were significantly higher than those from Chinese and Japanese cultivars.4. Mean fructose, malate, citrate and total acid content were significantly higher in nectarines than in peaches, indicating that it could be more likely to obtain parental varieties with high acidity from nectarines than from peach in breeding. Flesh color did not affect sugar content. Mean malate, citrate and total acid contents were significantly higher in yellow-flesh peach than in white-flesh peach. There were higher mean sucrose and total sugar in semi-freestone peach. Mean malate, citrate and total acid content were significantly higher in freestone peach than in semi-freestone and clingstone peaches. Flesh texture did not affect sugar and acid contents.