Table 4.
Description and coding of the assessed Malus floral phenotypic traits
| No. | Phenotypic trait | Trait description (grade) and coding |
|---|---|---|
| 1 | Flower density | Dense (0); Medium (1); Sparse (2) |
| 2 | Inflorescence type | Corymbiform (0); Umbellate (1) |
| 3 | Buds adhered per inflorescence | No (0); Yes (1) |
| 4 | Flower type | Single (0); Semi-double (1); Double (2) |
| 5 | Flower shape | Flat (0); Shallow cup (1); Deep cup (2) |
| 6 | Flower diameter | Assessed in mm |
| 7 | Petal color at the balloon stage | Yellow green (0); White (1); Pinkish White (2); Light pink (3); Deep pink (4); Rose (5); Light red-purple (6); Deep red-purple (7); Deep red (8); Dark red-purple (9) |
| 8 | Petal outside color | White (0); Pinkish white (1); Light pink (2); Deep pink (3); Rose (4); Light red-purple (5); Deep red-purple (6); Dark red-purple (7) |
| 9 | Petal margin inside color | White (0); Pinkish white (1); Light pink (2); Light red-purple (3); Deep red-purple (4); Dark red-purple (5) |
| 10 | Petal center inside color | White (0); Pinkish white (1); Light pink (2); Light red-purple (3); Deep red-purple (4); Dark red-purple (5) |
| 11 | Petal base inside color | White (0); Pinkish white (1); Light pink (2); Light red-purple (3); Deep red-purple (4); Dark red-purple (5) |
| 12 | Petal relative position | Separated (0); Touching (1); Overlapping (2) |
| 13 | Petal number per flower | Counted |
| 14 | Petal shape | Circular (0); Oval (1); Ovate (2); Obovate (3); Elliptic (4); Narrow elliptic (5) |
| 15 | Petal surface wrinkle | No (0); Yes (1) |
| 16 | Petal with prominent veins | No (0); Yes (1) |
| 17 | Petal margin with incisions | No (0); Yes (1) |
| 18 | Petal length | Assessed in mm |
| 19 | Petal width | Assessed in mm |
| 20 | Petal length / Petal width | Calculated |
| 21 | Claw length | Assessed in mm |
| 22 | Sepal color | Green (0); Reddish green (1); Red-purple (2) |
| 23 | Sepal apex shape | Acuminate (0); Acute (1) |
| 24 | Sepal deflexed | No (0); Yes (1) |
| 25 | Sepal pubescence | Dense (0); Sparse (1); None (2) |
| 26 | Sepal length | Assessed in mm |
| 27 | Sepal width | Assessed in mm |
| 28 | Sepal length / Sepal width | Calculated |
| 29 | Receptacle color | Green (0); Reddish green (1); Red-purple (2) |
| 30 | Receptacle pubescence | Dense (0); Sparse (1); None (2) |
| 31 | Relative length of sepals and receptacle | Longer (0); Same length (1); Shorter (2) |
| 32 | Peduncle habit | Upright (0); Drooping (1); Weeping (2) |
| 33 | Peduncle color | Green (0); Reddish green (1); Red-purple (2) |
| 34 | Peduncle pubescence | Dense (0); Sparse (1); None (2) |
| 35 | Peduncle length | Assessed in mm |
| 36 | Peduncle thickness | Assessed in mm |
| 37 | Pistil number per flower | Counted |
| 38 | Style color | Light green (0); Yellow green (1); Light red-purple (2); Deep red-purple (3) |
| 39 | Style base with pubescence | No (0); Yes (1) |
| 40 | Stamen number per flower | Counted |
| 41 | Anther with red-purple membrane | No (0); Yes (1) |
| 42 | Anther color | White (0); Light yellow (1); Yellow (2); Orange (3) |
| 43 | Filament color | White (0); Light red-purple (1); Deep red-purple (2) |
| 44 | Relative position of stigmas and anthers | Below (0); Same level (1); Above (2) |
Qualitative traits were directly observed in the field, and the final values of quantitative traits were calculated as the mean value of 30 replicates. Hierarchical number coding system was applied for the qualitative traits following the order from ancestral to evolutionary as far as possible. Consecutively arranged non-negative integers 0, 1, 2, 3, ..., were taken for expression. The dimorphic traits with an evolutionary relationship that was difficult to determine were generally coded as 1 (Yes) and 0 (No). No coding was applied for the quantitative traits and the mean values of the 30 replicates were directly used for further analysis