*2.6. Statistical Analysis*

Data were statistically analyzed by a two-way analysis of variance (ANOVA) (year (Y) × rootstock (R)) using SPSS software package version 14.0 (StatSoft, Inc., Chicago, IL, USA). Proteins, metals, total anthocyanins, chlorogenic acid and glycoalkaloids, which were determined only in the second trial (2015), were analyzed via one-factor analysis of variance (ANOVA) using a fixed-effects model for the effect of rootstock treatment. For data expressed in percentage, the arcsin transformation before ANOVA analysis [Ø = arcsin(p/100)1/2] was applied. To separate treatment means within each measured parameter, Tukey HSD test was performed at *p* = 0.05.
