Fig. 2

Profiling of metabolites among different apple accessions. a PCA analysis of all metabolites in other wild accessions, M. sieversii, heirlooms, and cultivars. b Differentiation of metabolites between M. sieversii/ heirloom and heirloom/ cultivar comparisons. c Box plots for the contents of flavonoids (quercetin 7-O-rutinoside, quercetin-3-O-rutinoside, and quercetin-3-O-robinobioside) and phenolic acids (isochlorogenic acid A, isochlorogenic acid B, and isochlorogenic acid C) with large fold changes between M. sieversii and heirloom groups. d PCA analysis between the “Ralls Janet” and “Golden Delicious” pedigrees, and e between high-weight (≥ 300) and low-weight (≤ 90) domesticated apples. t[1] and t[2] represent the first and second principal component. R2x[1] and R2x[2] indicate the proportion of variance explained by t[1] and t[2], respectively. The colored dots indicate different apple accessions and the ellipses indicate the 95% confidence interval for each data set