At a Planning Conference on "Utilization of the Genetic Resources of the Potato, II" held 24-28 October 1977, at the International Potato Center (CIP), at which the International Board for Plant Genetic Resources (IBPGR) was present, a Working Group drew up a list of descriptors and descriptor states for the cultivated potato.
Huaman, Z., Williams, J. T., Salhuana, W., & Vincent, L. (1977). Descriptors for the Cultivated Potato. Rome: Bioversity.
Code indicating the colour which covers most of the surface of the tuber, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | White-cream | |
| 2 | Yellow | |
| 3 | Orange | |
| 4 | Brownish | |
| 5 | Pink | |
| 6 | Red | |
| 7 | Purplish–red | |
| 8 | Purple | |
| 9 | Dark purple-black |
Code describing a secondary colour on the surface of the tuber, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | White–cream | |
| 2 | Yellow | |
| 3 | Orange | |
| 4 | Brownish | |
| 5 | Pink | |
| 6 | Red | |
| 7 | Purplish–black | |
| 8 | Purple | |
| 9 | Dark purple–black |
Code representing the pattern of distribution of the secondary colour in the tuber, expressed as: (See figure 1)
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Eyes – when the secondary colour is confined to the eyes only | |
| 2 | Eyebrows – when the secondary colour is present in the eyebrows only | |
| 3 | Splashed – when the secondary colour is fined to areas around the eyes | |
| 4 | Scattered – when the secondary colour is distributed at random in one or more areas around the tuber | |
| 5 | Spectacled – when areas around the eyes do not show secondary colour and the reminder of the tuber is pigmented. | |
| 6 | Stippled – when the surface of the tuber is more or less uniform covered with spots | |
| 7 | Other |
Code stating the type of tuber skin, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Smooth | |
| 2 | Rough | Flaky |
| 3 | Partially netted | |
| 4 | Totally netted | |
| 5 | Very heavily netted | |
| 6 | Other |
Code indicating the flesh colour present in most of the tuber, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Cream | |
| 3 | Yellow-cream | |
| 4 | Yellow | |
| 5 | Red | |
| 6 | Violet | |
| 7 | Purple | |
| 8 | Other |
Code representing a secondary flesh colour in the tuber, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | White | |
| 2 | Cream | |
| 3 | Yellow – cream | |
| 4 | Yellow | |
| 5 | Red | |
| 6 | Violet | |
| 7 | Purple | |
| 8 | Other |
Code stating the pattern of distribution of the secondary flesh colour, expressed as: (See Figure 2)
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Scattered spots | |
| 2 | Scattered areas | |
| 3 | Narrow vascular ring | |
| 4 | Broad vascular ring | |
| 5 | Vascularring medulle | Pith |
| 6 | All flesh exept medulla | Pith |
| 7 | Other |
Code describing the tuber outline, expressed as: (See figure 3)
| Code | Term | Description |
|---|---|---|
| 1 | Compressed (oblate) - major axis is the shortest axis | |
| 2 | Round - an almost circular outline. | |
| 3 | Ovate - an outline resembling an egg. The broadest part is within 1/3 of the distance from the stolon end | |
| 4 | Obovate - an outline which is inversely ovate and broadest within 1/3 of the distance from the apical end (rose or eye end). | |
| 5 | Elliptic - an outline showing the same breadth when measured at equal distance from both the stolon and apical ends. The outline is slightly acute at each end. | |
| 6 | Oblong - an almost rectangular outline with the sides nearly parallel but the corners rounded. The length/breadth ratio should not be more than 3/2 | |
| 7 | Long-Oblong - an oblong outline with a length/breadth ratio closer to 2/1 | |
| 8 | Elongate - a long rectangular outline with a length/breadth ratio equal to or more than 3/1 |
Code representing those variants of tuber shape which cannot be described under general tuber shape. It is expressed as follows: (See figure 4)
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Flattened - when the length of a transverse section, at any point of the tuber, is more than three times longer than its breadth | |
| 2 | Clavate - resembling an elongated club, thickened at one end | |
| 3 | Reniform - shaped like a kidney | |
| 4 | Fusiform - spindle-shaped, tapering gradually at both ends | |
| 5 | Falcate - curved or shaped like a sickle or horseshoe | |
| 6 | Spiral - long and coiled | |
| 7 | Digitate - resembling a hand or a fist | |
| 8 | Concertina-shaped - resembling a concertina | |
| 9 | Tuberosed - covered with few or many small lumps and tubers. It includes those shaped like a pineapple, a cluster of grapes, and raised internodes |
Code indicating the depth of the eyes in the tuber, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Protruding | |
| 2 | Shallow | |
| 3 | Medium | |
| 4 | Deep | |
| 5 | Very deep |
Code representing the number of eyes per tuber, expressed as:
Legend:
Few Less than 5
Intermediate
Many More than 20
Code representing areas of distribution of eyes, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Predominantly apical | |
| 2 | Evenly distributed |
Code describing the colour which covers most of the surface of the sprout, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | White-green | |
| 2 | Pink | |
| 3 | Red | |
| 4 | Violet | |
| 5 | Purple | |
| 6 | Other |
Code which indicates the presence of a secondary colour in the sprout, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | White–green | |
| 2 | Pink | |
| 3 | Red | |
| 4 | Violet | |
| 5 | Purple | |
| 6 | Other |
Code which represents the distribution of the secondary colour in the sprout, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | At the base | |
| 2 | At the apex | |
| 3 | Lightly scattered throughout | |
| 4 | Heavily scattered throughout | |
| 5 | Other |
Code indicating the colour of the stems, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Green only | |
| 2 | Red-brown only | |
| 3 | Purple only | |
| 4 | Cream with some red–brown | |
| 5 | Cream with purple | |
| 6 | Red–brown with some green | |
| 7 | Purple with some green | |
| 8 | Other |
Code for shape of stem in traverse section, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Round | |
| 2 | Angular |
Code for the presence and shape of the stem wing, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Straight | |
| 2 | Undulate | |
| 3 | Dentate |
(See figures 5 and 6) Code describing the degree of leaf dissection, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Undissected –entire leaves | |
| 2 | Pinnatilobed –leaves with lobes extending almost to the midribs | |
| 3 | Scarcely dissected-leaves with terminal and primary lateral leaflet only | |
| 4 | Weakly dissected-leaves with terminal and primary lateral leaflets and some secondary interjected leaflets on the rachis | |
| 5 | Medium dissected-leaves with terminal ad primary lateral leaflet and interjected leaflets from the second to the fifth order on the rachis | |
| 6 | Strongly dissected-leaves with terminal and primary lateral leaflet, interjected leaflets of the second, third etc. Order on the rachis and one to three interjected leaflets on the petiolules | |
| 7 | Very strong dissected-leaves with terminal and primary lateral leaflets, interjected leaflets of the second, third, etc. order on the rachis and more than three interjected leaflets on the petiolules and/or rachidules | |
| 8 | Other |
Code representing the degree to which the lower surfaces of the leaves are covered by hairs (trichomes), expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Glabrous - when hairs are absent | |
| 1 | Glabrescent –when the pubescence is very sparse | |
| 2 | Pubescence | |
| 3 | Strongly pubescent |
Code representing the degree to which the upper surfaces of the leaves are covered by hairs (trichomes), expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Glabrous - when hairs are absent | |
| 1 | Glabrescent –when the pubescence is very sparse | |
| 2 | Pubescence | |
| 3 | Strongly pubescent |
Code describing the type of hairs in the lower surface of the leaves, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Simple –simple trichomes | |
| 2 | Simple and glandular –simple trichomes and glandular trichomes bearing a sticky four 0 –lobed head | |
| 3 | Simple and glandular - simple trichomes and glandular trichomes with a sticky droplet at the tip | |
| 4 | Simple and glanular –simple trichomes and both types of glandular trichomes present | |
| 5 | Other |
Code representing the calyx colour, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | Green only | |
| 2 | Red only | |
| 3 | Purple | |
| 4 | Green with some red | |
| 5 | Green with some purple | |
| 6 | Red with some green | |
| 7 | Purple with some green |
(See figure 7)
Legend:
Irregular
Regular
(See figure 8)
| Code | Term | Description |
|---|---|---|
| 1 | Stellate | |
| 2 | Semi-stellate | |
| 3 | Pentagonal | |
| 4 | Rotate | |
| 5 | Very rotate |
Code indicating the colour present in most of the corolla, expressed as:
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Light red | |
| 3 | Intense red | |
| 4 | Light blue | |
| 5 | Intense blue | |
| 6 | Light purple | |
| 7 | Intense purple | |
| 8 | Yellow |
Code indicating the presence of a secondary colour in the corolla, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | White | |
| 2 | Light red | |
| 3 | Intense red | |
| 4 | Light blue | |
| 5 | Intense blue | |
| 6 | Light purple | |
| 7 | Intense purple |
3.5.6 Distribution of Secondary Flower Colour Code which indicates the pattern of distribution of the secondary flower colour, expressed as: (See figure 9)
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | White acumen –adaxial surface | |
| 2 | White acumen –abaxial surface | |
| 3 | White acumen or both surfaces | |
| 4 | Star – adiaxal surface | |
| 5 | Stripe –adaxial surface | |
| 6 | Stripe –abaxial surface | |
| 7 | Stripe –both surfaces | |
| 8 | Stippled | |
| 9 | Other |
Code describing the presence of red or blue anthocyanin pigments in the anthers, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Pigmented anther stripe | AS |
| 2 | Pigmented anther tip | PA |
| 3 | AS and PA | |
| 4 | Other |
(See figure 10)
| Code | Term | Description |
|---|---|---|
| 1 | Normal | |
| 2 | Shrivelled | |
| 3 | Partly fused column | |
| 4 | Free and divergent column |
| Code | Term | Description |
|---|---|---|
| 0 | None | |
| 1 | Little | |
| 2 | Abundant |
Code representing the presence of red or blue anthocyanin pigments in some parts of the pistil. Pigmented ovary walls are determined in transverse section of the ovary. The pigment is expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Pigmented stigma | PS |
| 2 | Pigmented ovary | PO |
| 3 | Pigmented ovary wall | OW |
| 4 | PS and PO | |
| 5 | PS and OW | |
| 6 | PO and OW | |
| 7 | PS, PO and OW | |
| 8 | Other | E.g. pigmented style |
| Code | Term | Description |
|---|---|---|
| 1 | Normal | |
| 2 | Irregular appearance | |
| 3 | Fusion of pistil with anther |
| Code | Term | Description |
|---|---|---|
| 1 | Shorter than another and straight | |
| 2 | Shorter than another and S shaped | |
| 3 | Equal to anther | |
| 4 | Longer the anther | |
| 5 | Much longer than anther |
(See figure 11)
| Code | Term | Description |
|---|---|---|
| 1 | Capitate | |
| 2 | Clavate | |
| 3 | Bilobed | Or split apart |
Code describing the degree of flowering which should be recorded at the peak of the flowering period, expressed as:
Legend:
No buds
Bud abortion
Flowering scarce
Flowering moderate
Flowering profuse
| Code | Term | Description |
|---|---|---|
| 0 | No | |
| 1 | Yes |
Legend:
Short
Medium
Long
| Code | Term | Description |
|---|---|---|
| 1 | Single | |
| 2 | Few | 2 – 5 |
| 3 | Intermediate number | |
| 4 | Many | More than 20 |
| Code | Term | Description |
|---|---|---|
| 1 | Below the middle | |
| 2 | At the middle | |
| 3 | Above the middle |
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Present |
| Code | Term | Description |
|---|---|---|
| 0 | No | |
| 1 | Yes | |
| 2 | Undetermined |
| Code | Term | Description |
|---|---|---|
| 1 | Round | |
| 2 | Oval | |
| 3 | Short conical | |
| 4 | Long conical | |
| 5 | Pyriform |
| Code | Term | Description |
|---|---|---|
| 0 | Green | |
| 1 | With white spots | |
| 2 | With white streaks | |
| 3 | Verrucose | |
| 4 | Green with pigmented spots | |
| 5 | Green with pigmented streaks | |
| 6 | Predominantly |
Legend:
None
Low
Medium
High
Legend:
None
Low
Medium
High
Code indicating the distribution of the pigmented present in the botanical seed, expressed as:
| Code | Term | Description |
|---|---|---|
| 0 | Absent | |
| 1 | Small pigmented spot | |
| 2 | Large pigmented spot | |
| 3 | Pigmented embryo | |
| 4 | Whole seed completely pigmented | |
| 5 | Other |
Code indicating the type of growth habit at the beginning of flowering of the accession being evaluated, expressed as:
| Code | Term | Description |
|---|---|---|
| N/A | Coding table was not provided. |
| Code | Term | Description |
|---|---|---|
| 1 | Single | |
| 2 | Branching |
Legend:
Single
Few 1–3
Medium
Many
Legend:
Short
Medium
Tall