This Minimum List of Descriptors for Plantains was developed for the West and Central African Regional Workshop on Plantain Characterization at CARBAP, Cameroon in May 2015, and further fine-tuned after the workshop. It is a compilation of descriptors from the Minimum List of Descriptors for Musa plus several descriptors from the 1996 Descriptors for Banana book that are highly discriminating for plantains as identified by the Expert Team of the Organization Committee of the workshop.
For any question, remark and feedback on these guidelines, please contact Rachel Chase (r.chase@cgiar.org) or Nicolas Roux (n.roux@cgiar.org).
THE APPROPRIATE DEVELOPMENT STAGE FOR OBSERVATION: The best time to take photos and document the descriptors is when the fruit are green-ripe or yellowing (“harvest time”), and the rachis is at least 45 cm long (15 inches). This is separate from the instance of a single ripe fruit generally observed on the first or the second hand of the bunch. Also, do not confuse harvest time with ripe fruit affected by diseases, insect bites or birds.
All descriptors should be scored at harvest except for descriptors 6.3.1, 6.3.3, 6.3.4b, 6.3.6, that should be recorded at flowering time (emergence of the inflorescence) to avoid the desiccation of the petiole margin that often occurs at harvest time.
For all colour descriptors, colour should be determined with the appropriate colour chart and out of direct sunlight. The best time to observe colour descriptors is in the morning when the light is clearer than in the afternoon. Score the closest colour to the choices given (e.g. if dark green is not given as a choice, choose green).
For all flower descriptors (6.6.2 - 6.6.13) the material should be fresh as it oxidizes and changes colour rather quickly. For the fruit descriptors (6.7.1 - 6.7.19) observation must be done on several fruits in order to reflect the dominant case.
Taxonomic Advisory Group (TAG) 2016. Minimum Descriptor List for Plantains. Bioversity International, Montpellier, France.
Recorded from the base of pseudostem to emerging point of the peduncle
| Code | Term | Description |
|---|---|---|
| 1 | ≤2 | |
| 2 | 2.1 to 2.9 | |
| 3 | ≥3 |
Measured by the number of emitted foliage leaves (or their scars) that are at least 10 cm wide. The scars are the dried-up bases of the petioles of past leaves. Along the pseudostem, the leaves are arranged in two spirals. Count the number along one spiral and multiply by 2. Tip: Mark the number of leaves on the pseudostem as it grows to avoid having to count scars since planting.
| Code | Term | Description |
|---|---|---|
| 1 | <32 | Small |
| 2 | 32-38 | Medium |
| 3 | >38 | Giant |
Recorded without removing the external sheaths. The colour of oldest dry sheaths should not be considered. (Chart A)
| Code | Term | Description |
|---|---|---|
| 1 | Green-yellow | |
| 2 | Medium green | |
| 3 | Green | |
| 4 | Dark green | |
| 5 | Green-red | |
| 6 | Red | |
| 7 | Red-purple | |
| 8 | Blue | |
| 9 | Chimerical | |
| 10 | Other |
In relation to the parent plant. Observed on the tallest sucker. Recorded at harvest time
| Code | Term | Description |
|---|---|---|
| 1 | Taller than parent plant | |
| 2 | More than 3/4 of the height of the parent plant | |
| 3 | Between 1/4 and 3/4 of the height of the parent plant | |
| 4 | Inhibited |
Record the relative surface area coverage by blotches. Look at several plants if possible to get an overall idea. Observe at lowering time.
| Code | Term | Description |
|---|---|---|
| 1 | No pigmentation | |
| 2 | Sparse blotching | <20% |
| 3 | Moderate blotching | 20%-50% |
| 4 | Extensive pigmentation | >50% |
| Code | Term | Description |
|---|---|---|
| 1 | Orange-brown | mahogany, like in Pisang Mas |
| 2 | Brown | |
| 3 | Black-purple | |
| 4 | Other |
The third leaf (Leaf III) is counted from the last leaf produced before bunch emergence. Cut the petiole halfway between the pseudostem and the leaf blade and examine the cross section. Observe at flowering time.
| Code | Term | Description |
|---|---|---|
| 1 | Margins spreading | |
| 2 | Margins erect | |
| 3 | Margins curved inward | |
| 4 | Margins overlapping |
Observation should be made at shooting on the neck, where the petiole and pseudostem meet. Margin is the part of the petiole that can be bent outwards/inwards. Observe at flowering time.
| Code | Term | Description |
|---|---|---|
| 1 | Clasping | |
| 2 | Not clasping |
| Code | Term | Description |
|---|---|---|
| 1 | Green | |
| 2 | Pink-purple to red | |
| 3 | Purple to blue | |
| 4 | Other | Specify in descriptor Notes, 6.8 |
Use colour chart A. Wax removed.
| Code | Term | Description |
|---|---|---|
| 1 | Cream | |
| 2 | Yellow | |
| 3 | Watery green | |
| 4 | Green yellow | |
| 5 | Light green | |
| 6 | Medium green | |
| 7 | Green | |
| 8 | Dark green | |
| 9 | Whitish | |
| 10 | Orange red | |
| 11 | Red | |
| 12 | Pink-purple | |
| 13 | Purple-brown | |
| 14 | Red-purple | |
| 15 | Purple | |
| 16 | Blue |
Descriptor state 4 (red/or pink-purple) is green homogeneously tinged with red (purple green appearance). When pigmentation is scattered, use state 5. (Chart A)
| Code | Term | Description |
|---|---|---|
| 1 | Light green | |
| 2 | Green | |
| 3 | Dark green | |
| 4 | Red or pink/purple | |
| 5 | With purple-brown to blue blotches | |
| 6 | Other |
Angle between the axis of the bunch and the vertical.
| Code | Term | Description |
|---|---|---|
| 1 | Hanging vertically | |
| 2 | Slightly angled | |
| 3 | Hanging at a 45° angle | |
| 4 | Horizontal | |
| 5 | Erect |
Score on fully developed plant with no environmental stress.
| Code | Term | Description |
|---|---|---|
| 1 | Cylindrical | |
| 2 | Truncate | ( = cone shaped) |
| 3 | Asymmetrical | |
| 4 | Spiral | (all fruit are attached to a unique crown coiled around the stalk) |
| 5 | Other |
The bunch should still be on the plant.
| Code | Term | Description |
|---|---|---|
| 1 | Very Lax | (one can easily place a hand horizontally between the hands of fruit) |
| 2 | Lax | (one can easily place one's hand BETWEEN the hands OF fruit) |
| 3 | Compact | (one can place one's finger, but NOT one's hand, between the hands of fruit) |
| 4 | Very compact | (one cannot place one's finger BETWEEN the hands OF fruit) |
Observe only the part of the rachis between the last hand and the male bud.
| Code | Term | Description |
|---|---|---|
| 1 | Falling vertically | |
| 2 | At an angle | |
| 3 | With a curve | |
| 4 | Horizontal or supra-horizontal | |
| 5 | Erect |
Observe only that part of the rachis between the last hand of fruit and the male bud.
| Code | Term | Description |
|---|---|---|
| 2 | Male bud active at harvest time | French type |
| 3 | Male bud exhausted before harvest time | French-Horn (Batard) |
| 4 | Male bud exhausted before maturity | False Horn |
| 5 | Truncated, no male rachis or flowers | Horn |
“w” is the broadest width of the male bud. “x” is the length from the base of the male bud to the point of broadest width ‘w’; “y” is the total length of the male bud. As the figure shows, these parameters express the profile of the bud. Do not measure the dimensions along the bud but rather on a projection/outline of the bud (e.g. trace the outline of the bud on paper). Calculate the ratio w/y (see figure)
| Code | Term | Description |
|---|---|---|
| 1 | Skinny | w/y <= 0.45 |
| 2 | Medium | 0.45 < w/y < 0.55 |
| 3 | Fat | w/y >= 0.55 |
“w” is the broadest width of the male bud. “x” is the length from the base of the male bud to the point of broadest width ‘w’; “y” is the total length of the male bud. As the figure shows, these parameters express the profile of the bud. Do not measure the dimensions along the bud but rather on a projection/outline of the bud (e.g. trace the outline of the bud on paper). Calculate the ratio x/y (see figure).
| Code | Term | Description |
|---|---|---|
| 1 | High shouldered | x/y <= 0.28 |
| 2 | Medium shouldered | 0.28 < x/y < 0.30 |
| 3 | Low shouldered | x/y >= 0.30 |
Refers to the first external unlifted bract. Flatten bracts to determine shape.
| Code | Term | Description |
|---|---|---|
| 1 | Pointed | |
| 2 | Intermediate | |
| 3 | Obtuse | |
| 4 | Obtuse and split |
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Cream | |
| 3 | Ivory | |
| 4 | Yellow | |
| 5 | Bright yellow | |
| 6 | Orange | |
| 7 | Orange red | |
| 8 | Red | |
| 9 | Red-purple | |
| 10 | Pink/pink-purple | |
| 11 | Brown/Rusty-brown | |
| 12 | Beige-pink | |
| 13 | Silvery | |
| 14 | Light green | |
| 15 | Green | |
| 16 | Dark Green |
| Code | Term | Description |
|---|---|---|
| 1 | Cream | |
| 2 | Yellow | |
| 3 | Orange | |
| 4 | Green | |
| 5 | Other |
Observed on the face opposite to the dehiscence split of the anther (dorsal face). (Chart B)
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Cream | |
| 3 | Yellow | |
| 4 | Grey | |
| 5 | Brown/rusty brown | |
| 6 | Pink/pink-purple | |
| 7 | Black | Anthers aborted |
| 8 | Other |
Measured from the leaf crown to the first hand of fruit
| Code | Term | Description |
|---|---|---|
| 1 | ≤30 cm | |
| 2 | 31 - 60 cm | |
| 3 | ≥61 cm |
Recorded only on the fruits arranged symmetrically around the stalk.
| Code | Term | Description |
|---|---|---|
| 1 | Curved towards stalk | |
| 2 | Parallel to the stalk | |
| 3 | Curved upward | (obliquely, at a 45° angle upward) |
| 4 | Perpendicular to the stalk | |
| 5 | Pendant | |
| 6 | Other |
Observed on the mid-hand of the bunch
| Code | Term | Description |
|---|---|---|
| 1 | ≤12 | |
| 2 | 13-16 | |
| 3 | ≥17 |
Measured as the internal arc of the fruit, without pedicel
| Code | Term | Description |
|---|---|---|
| 1 | ≤15 cm | |
| 2 | 16- 20 cm | |
| 3 | 21- 25 cm | |
| 4 | 26- 30 cm | |
| 5 | ≥31 cm |
Observe the inner fruit in the middle of the mid-hand of the bunch. In case of an asymmetric bunch, score the dominant fruit shape appearing in the bunch.
| Code | Term | Description |
|---|---|---|
| 1 | Straight | |
| 2 | Slightly curved | |
| 3 | Straight in the distal part | |
| 4 | Curved | (sharp curve) |
| 5 | Curved in slight 'S' shape | (double curvature) |
| 6 | Other |
Observe before cutting the bunch as relicts may fall off.
| Code | Term | Description |
|---|---|---|
| 1 | Few flower relicts | (<20% of the fruits with relicts) |
| 2 | Persistent flower relicts | (>20% of the fruits with relicts) |
| 3 | Only base of the style persists |
| Code | Term | Description |
|---|---|---|
| 1 | ≤10 mm | |
| 2 | 11 to 20 mm | |
| 3 | ≥21 mm |
Before they join the rachis at the bract scar. Look up from bottom of bunch.
| Code | Term | Description |
|---|---|---|
| 1 | No visible sign of fusion | |
| 2 | Partially fused | up to 50% of the length of the pedicel |
| 3 | Totally fused | more than 50% of the length of the pedicel |
Recorded at fruit maturity (ripe, but not over-ripe; full yellow stage). (Chart B)
| Code | Term | Description |
|---|---|---|
| 1 | Yellow | |
| 2 | Bright yellow | |
| 3 | Orange | |
| 4 | Grey spots | |
| 5 | Brown/rusty-brown | |
| 6 | Orange red, red or pink/pink purple | |
| 7 | Red-purple | |
| 8 | Black | |
| 9 | Other |
(Chart B). (Ripe, but not over-ripe; full yellow stage)
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Cream | |
| 3 | Ivory | |
| 4 | Yellow | |
| 5 | Orange | |
| 6 | Beige-pink | |
| 7 | Other |