Hormone levels of indole-3-acetic acid (IAA) (A) and its conjugate form, IAA-Aspartic acid (IAA-Asp) (D); and the expression levels of IAA biosynthetic genes,
(C), in the pericarp of low and high seed weight-to-berry weight (SB) berries. Prevéraison cluster stages were two- and one-week before véraison (2-wk PV and 1-wk PV). IAA and IAA-Asp levels were quantified by LC-MS/MS using four replicates. Gene expression was measured by qRT-PCR and expression levels are relative to low-SB berries at 2-wk PV (n = 5). Gene expressions were also measured at mid-véraison (MV) cluster stage. Significant differences between low- and high-SB at each cluster stage are indicated by asterisks (Student’s t-test, p < 0.05). Significant differences of each SB group between the ripening stages are denoted by different letters (lower and upper case letters are used for low- and high-SB berries, respectively (Tukey’s HSD, p < 0.05)).