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Table 2 Phenotypic scores measured during examination of exocarp under 200x magnification as well as macrostructure traits (indicated by ‘macro scale’) using images of whole fruit

From: Peridermal fruit skin formation in Actinidia sp. (kiwifruit) is associated with genetic loci controlling russeting and cuticle formation

Phenotypic Trait


Max. dead cell

Maximum number of peridermal layers observed

Min. dead cell

Minimum number of peridermal layers observed

Cuticle %

Coverage of cuticle over fruit exocarp (0 to 100% scale)

Periderm depth

Mean number of peridermal layers

Trichome density (0:3)

0,1,2,3 scale; 0 no trichomes to 3 high density

Lignified trichome (0/1)

scored 0 (no lignin) or 1 (lignified)

Suberized trichomes (0/1)

scored 0 (no suberization) or 1 (suberized) trichomes

Cuticle thickness (0:3)

0,1,2,3 scale; score 0 (cuticle not present) to 3 (thickest cuticle)

Microcracking (0:3)

0,1,2,3 scale; score 0 (no microcracks) to 3 (extensive microcracking)


Epidermal (0) or peridermal (1) phenotype (> 2 peridermal cell layers)

Russet %

Percentage of surface covered with periderm (macro scale)

Semi Russet

Partial russet ranging from 20 to 80% (1) or not semi russet (0) (macro scale)