These guidelines, recently revised in 2019, aim to establish a standardised procedure for the routine morphological characterization of banana plants. Photographs are provided to help score the minimum descriptors.
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). All descriptors should be scored at harvest except for descriptors 6.3.1, 6.3.3, 6.3.4a, 6.3.4b, 6.3.6, 6.3.7 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 (6.7.3 - 6.7.11) observation must be done on several fruits in order to reflect the dominant case.
Taxonomic Advisory Group (TAG) 2010. Minimum Descriptor List for Musa. Revised 2019. 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 |
Remove the outermost sheath from the pseudostem and look at the exposed surface of the underlying pseudostem. The values 5 (pink-purple), 6 (red-purple) and 7 (purple) must be chosen only if the pigmentation is uniform, and green tinges are not observed. (Chart A)
| Code | Term | Description |
|---|---|---|
| 1 | Watery green | |
| 2 | Light green | |
| 3 | Green | |
| 4 | Cream | |
| 5 | Pink-purple | |
| 6 | Red-purple | |
| 7 | Purple | |
| 8 | Others |
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 |
Margin is the part of the petiole that can be bent outwards/inwards. Observe at flowering time.
| Code | Term | Description |
|---|---|---|
| 1 | Winged | |
| 2 | Not winged |
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 |
Observation should be made at shooting. Record on the last developed leaf at flowering stage.
| Code | Term | Description |
|---|---|---|
| 1 | No contrast between margin and petiole | without a colour line along |
| 2 | Contrast between margin and petiole | with a contrasting colour line along |
Use colour chart A. Observation should be made before shooting, on a developed sucker or on another plant of the same accession. Look at the visible face (future lower face) of the cigar leaf before it is unfurled and before the plant flowers.
| Code | Term | Description |
|---|---|---|
| 1 | Green | |
| 2 | Red-purple | |
| 3 | Other | specify on answer sheet |
| Code | Term | Description |
|---|---|---|
| 1 | Hairless | |
| 2 | Slightly hairy | |
| 3 | Very hairy, short hairs | Similar to velvet touch |
| 4 | Very hairy, long hairs | >2 mm |
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 | all fruit are attached to a unique crown coiled around the stalk |
| 4 | Spiral | |
| 5 | Other |
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 |
| Code | Term | Description |
|---|---|---|
| 1 | Bare | |
| 2 | Neutral flowers on one to few hands only near the bunch | rest of stalk is bare |
| 3 | Male flowers/bracts above the male bud | rest of stalk is bare |
| 4 | Neutral/male flowers and presence of withered bracts on the entire stalk | |
| 5 | Neutral/male flowers on the whole stalk without persistent bracts | still firmly attached to the rachis |
| 6 | Small bunch from neutral/hermaphrodite flowers just above the male bud | |
| 7 | Other |
“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). Measure the length (y) of male bud at harvest (see figure).
| Code | Term | Description |
|---|---|---|
| 1 | Short | y <= 20 cm |
| 2 | Medium | 20 cm < y < 30 cm |
| 3 | Long | >= 30 cm |
“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 |
Alignment of bracts at the apex of the male bud
| Code | Term | Description |
|---|---|---|
| 1 | Convolute | |
| 2 | Moderately imbricate | |
| 3 | Highly imbricate |
Refers to the last lifted bract. Best to record as bract has lifted up to the horizontal.
| Code | Term | Description |
|---|---|---|
| 1 | Revolute | rolling |
| 2 | Not revolute | not rolling |
| Code | Term | Description |
|---|---|---|
| 1 | Yellow | |
| 2 | Green | |
| 3 | Red | |
| 4 | Red-purple | |
| 5 | Purple-brown | |
| 6 | Purple | |
| 7 | Blue | |
| 8 | Pink-purple | |
| 9 | Orange-red | |
| 10 | Other |
| Code | Term | Description |
|---|---|---|
| 1 | Whitish | |
| 2 | Yellow or green | |
| 3 | Orange red | |
| 4 | Red | |
| 5 | Purple | |
| 6 | Purple brown | |
| 7 | Pink-purple | |
| 8 | Other |
| 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 |
Observed on the mid-hand of the bunch
| Code | Term | Description |
|---|---|---|
| 1 | ≤12 | |
| 2 | 13-16 | |
| 3 | ≥17 |
at maturity
| 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 |
| Code | Term | Description |
|---|---|---|
| 1 | Pointed | |
| 2 | Lengthily pointed | like plantain |
| 3 | Blunt tipped | plateau at tip |
| 4 | Strongly bottle necked | wider under tip than number 2 |
| 5 | Rounded |
Observe before cutting the bunch as relicts may fall off.
| Code | Term | Description |
|---|---|---|
| 1 | Without flower relicts | |
| 2 | Few flower relicts | <20% of the fruits with relicts |
| 3 | Persistent flower relicts | >20% of the fruits with relicts |
| 4 | 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 |