The Key descriptors for fonio millets consist of an initial minimum set of characterization and evaluation descriptors for Digitaria exilis Stapf and Digitaria iburua Stapf of the family Poaceae. This strategic set aims at facilitating access to and utilization of these species and it does not exclude the addition of other descriptors later. This work has been done jointly with the ICAR-Indian Institute of Millets Research (ICAR- IIMR), the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), the ICAR-National Bureau of Plant Genetic Resources (ICAR-NBPGR) and the FAO International Treaty on Plant Genetic Resources for Food and Agriculture. The descriptor list is based on a draft list of descriptors for fonio developed by Dr Raymond Vodohuè and a group of scientists. Subsequently, internet searches were carried out looking for the most updated information on relevant characteristics and traits. The original list was afterwards integrated with evaluation traits. Special attention was given to the inclusion of descriptors relevant to germplasm utilization, including nutritional traits and biotic and abiotic stresses of particular importance in the context of emerging adverse weather events, which are expected to intensify under current and future climate challenges. The key set of access and utilization descriptors was defined through an online survey, in which 28 experts from 23 different organizations and universities from 16 countries participated. The results of the survey were subsequently validated in consultation with a Core Advisory Group (see “Contributors”) led by ICAR-IIMR, ICAR-NBPGR and ICRISAT. The strategic set of data standards is designed to facilitate access to and utilization of plant genetic resources for food and agriculture. Together with passport information (Alercia, A. et al. 2015), descriptors are critical to the effective sharing of characterization and evaluation data and to the efficient use of plant genetic resources for food and agriculture.
Elangovan, M., Hariprasanna, K., Pandey, S., Pradheep, K., Vetriventhan, M., Alercia, A., Cerutti, A.L. and Lopez, F. 2023. Key descriptors for fonio millets. ICAR-Indian Institute of Millets Research, Hyderabad, Telangana, India; ICAR-National Bureau of Plant Genetic Resources, New Delhi, India; International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, Telangana, India and FAO on behalf of the International Treaty on Plant Genetic Resources for Food and Agriculture, Rome, Italy. https://doi.org/10.4060/cc8563en.
Record the growth habit on plot basis at flowering.
| Code | Term | Description |
|---|---|---|
| 1 | Erect | |
| 2 | Prostrate | |
| 3 | Spreading |
Record the height of main tillers on five randomly selected plants from the ground level to the tip of inflorescence at physiological maturity.
Record the average number of nodes per culm of main tillers on five randomly selected plants at maturity.
Legend:
Low (2-3)
Medium (4-5)
High (>5)
Record the average number of basal tillers at ground level or from the basal nodes on five randomly selected plants at maturity.
Record the average number of racemes on the main panicle of five randomly selected plants at maturity.
Legend:
No branching
Low branching (1-2 racemes)
Medium branching (3-4 racemes)
Strong branching (>4 racemes)
Record the predominant leaf colour observed on three leaves from five randomly selected plants in a plot, at vegetative stage. Use RHS Colour Chart codes if available.
| Code | Term | Description |
|---|---|---|
| 1 | Light green | |
| 2 | Dark green | |
| 3 | Purplish | |
| 99 | Other | Specify in the Notes descriptor |
Record the blade pubescence of three leaves from main tillers of five randomly selected plants in a plot, at flowering.
Legend:
Absent
Sparse
Dense
Record the level of leaf senescence assessed as a visual observation on a plot basis, at physiological maturity.
Legend:
Leaves almost green
Leaves moderately green
Leaves almost dry
Leaves completely dry
Measure from the topmost node of main tiller to the base of the inflorescence of five randomly selected plants, at flowering.
Record the predominant colour of inflorescence at physiological maturity.
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Green | |
| 3 | Red | |
| 4 | Purplish | |
| 99 | Other | Specify in the Notes descriptor |
Record the extent to which the panicle is exserted above the flag leaf sheath of five randomly selected main tillers at physiological maturity.
Legend:
Enclosed Panicle is partly or entirely enclosed within the leaf sheath of the flag leaf blade
Partly exserted Panicle base is slightly beneath the collar of the flag leaf blade
Just exserted Panicle base coincides with the collar of the flag leaf blade
Moderately well exserted Panicle base is above the collar of the flag leaf blade
Well exserted Panicle base appears well above the collar of the flag leaf blade
Record compactness of the panicles at physiological maturity.
Legend:
Loose
Intermediate
Compact
Record the length of main axis of raceme from the base to the tip. Average of five randomly selected racemes at physiological maturity.
Record the number of days from sowing until 50% of plants (main tillers) have begun to flower.
Legend:
Very early (≤60 days)
Early (60 to 70 days)
Medium (70-80 days)
Late (80-90 days)
Very late (>90 days)
Record the arrangement of spikelets on the raceme.
| Code | Term | Description |
|---|---|---|
| 1 | Alternate | |
| 2 | Opposite | |
| 99 | Other | Specify in the Notes descriptor |
Record the shape of seeds visually assessed as a single observation on a small seed lot.
| Code | Term | Description |
|---|---|---|
| 1 | Round | |
| 2 | Oblong | |
| 3 | Ellipsoid | |
| 99 | Other | Specify in the Notes descriptor |
Record the predominant seed colour visually assessed as a single observation on a small seed lot.
| Code | Term | Description |
|---|---|---|
| 1 | White | |
| 2 | Pale yellow | |
| 3 | Brown | |
| 4 | Black | |
| 99 | Other | Specify in the Notes descriptor |
Record the weight of 1000 seeds dried to about 11-12% moisture content.
Record the percentage of spikelets remaining on racemes at full maturity. Observed as the extent to which seeds have shattered from the panicle.
Legend:
<10
10-30
>30
Record the ease with which the grains can be dehusked by rubbing between the fingers in a small seed lot.
Legend:
Easy
Difficult
Record the average dry weight of 10 plants randomly selected.
Record the grain to total biomass (dry weight) ratio.
Measure using a Grain Hardness Meter. Otherwise, the scale below can be used.
Legend:
Soft endosperm
Hard endosperm
Record the percentage of lipids content from seed samples randomly collected from the plot.
Record the percentage of crude protein content from seed samples randomly collected from the plot.
Record the percentage of carbohydrate content from seed samples randomly collected from the plot.
Record the calcium content from seed samples randomly collected from the plot.
Record the iron content from seed samples randomly collected from the plot.
Record the zinc content from seed samples randomly collected from the plot.
Abiotic stress susceptibility. Scored as percentage survival from a specific trial to induce stress, under conditions which are clearly specified. Drought trials are often performed under greenhouse conditions or rain-out shelters.
Legend:
Very Low
Low
Intermediate
High
Very High
Abiotic stress susceptibility. Scored as percentage survival from a specific trial to induce stress, under conditions which are clearly specified.
Legend:
Very Low
Low
Intermediate
High
Very High
Abiotic stress susceptibility. Scored as percentage survival from a specific trial to induce stress, under conditions which are clearly specified.
Legend:
Very Low
Low
Intermediate
High
Very High
Abiotic stress susceptibility. Scored as percentage survival from a specific trial to induce stress, under conditions which are clearly specified.
Legend:
Very Low
Low
Intermediate
High
Very High
Abiotic stress susceptibility. Scored as percentage survival from a specific trial to induce stress, under conditions which are clearly specified.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection from a specific trial to induce insect infestation, under natural/artificial infestation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection from a specific trial under natural/artificial inoculation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection from a specific trial under natural/artificial inoculation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection or infestation from a specific trial under natural/artificial infestation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection or infestation from a specific trial under natural/artificial infestation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection or infestation from a specific trial under natural/artificial infestation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High
Biotic stress susceptibility. Scored as percentage infection from a specific trial under natural/artificial inoculation conditions to be specified; state origin of infestation or infection in Notes.
Legend:
Very Low
Low
Intermediate
High
Very High