Table 2 Component loadings and mean principal component (PC) scores, showing the association between the total and constituent anthocyanin contents and the expression levels of the biosynthetic and regulatory genes, as determined using a principal component analysis

Upstream genes

 PAL1

0.14

0.29

0.24

 PAL2

− 0.06

0.36

0.26

 C4H

− 0.09

0.34

0.24

 4CL1

− 0.04

0.37

0.25

 CHS

0.22

− 0.01

− 0.19

 CHI

0.23

0.01

− 0.09

 F3H

0.21

− 0.05

0.19

 F3´H

0.23

− 0.08

− 0.03

Downstream genes

 FLS1

0.23

0.02

0.11

 DFR

0.23

− 0.03

0.15

 ANS

0.23

− 0.08

0.12

 UGT75C1

0.22

− 0.01

− 0.17

 UGT78D2

0.23

0.03

0.10

Regulatory genes

 MYB12

0.23

0.04

− 0.05

 MYB111

0.22

− 0.03

− 0.22

 PAP2

0.22

0.08

0.10

 MYB113

0.23

0.01

− 0.05

 BrTT8

− 0.11

− 0.34

0.17

 TTG1

0.20

0.11

− 0.15

 TT19

0.22

− 0.03

0.21

Anthocyanin components

 C3-dig5-gl

− 0.04

− 0.38

0.23

 C3-s-dig5-gl

0.21

− 0.10

0.28

 C3-sop5-m.gl

0.23

− 0.01

− 0.07

 Mal3-(p-c)gl py de

0.21

− 0.03

0.28

 Pe3-(6-ac)-gl

0.20

0.01

− 0.37

 C3-(p-c)digl5-gl

− 0.12

− 0.33

0.15

Total anthocyanin

0.09

− 0.35

0.23

Eigenvalue

18.22

6.07

2.10

% of the variation explained

67.5

22.5

7.0

Cumulative % of the variation explained

67.5

90.0

97.0

Genotype

Mean PC score ± SD

 Asia

0.57 ± 0.09 B

0.36 ± 0.12 B

− 2.37 ± 0.20 C

 Rs306

− 3.31 ± 0.02 C

3.28 ± 0.11 A

0.89 ± 0.09 A

 Rs035

6.45 ± 0.04 A

− 0.29 ± 0.08 C

0.96 ± 0.08 A

 Rubea

− 3.72 ± 0.02 D

− 3.35 ± 0.07 D

0.52 ± 0.04 B