Digitaria exilis is a species of grass that is referred to as findi or fundi in areas of Africa such as The Gambia, with the English common names white fonio, fonio millet, hungry rice, and acha rice.
It is the most important of a diverse group of wild and domesticated Digitaria species known as fonio that are harvested in the savannas of West Africa. The grains are very small. It has potential to improve nutrition, boost food security, foster rural development and support sustainable use of the land.
Fonio has continued to be important locally because it is both nutritious and one of the world's fastest growing cereals, reaching maturity in as little as six to eight weeks. It is a crop that can be relied on in semi-arid areas with poor soils, where rains are brief and unreliable.
The small grains make it difficult and time-consuming to remove the husk. Traditional methods include pounding it in a mortar with sand, while more recent methods include a fonio husking machine. The grains are used to make foods such as porridge.
Description The fonio is an annual, erect herbaceous plant which reaches stature heights from 30 to 80 centimeters. The ears consist of two to five narrow part ears, which are up to 15 centimeters long. The spikelets comprise a sterile flower and a fertile flower, the latter of which gives rise to the fonio grain. The grain is a caryopsis, which remains surrounded by glumes and husks. Its size is very small, only 1.5 mm (around 2,000 seeds to 1 gram). The colour ranges from white, yellow and purple.
Fonio matures faster than all other cereals. Some varieties can already be harvested 42–56 days after sowing. Others ripen more slowly, usually in 165–180 days.
The genetic diversity of D. exilis varies from region to region in Africa. For example, not much genetic diversity was detected among the domesticated D. exilis landraces from Mali.Koreissi-Dembélé, Y., Fanou-Fogny, N., Hulshof, P., & Brouwer, I. (2013). Fonio (Digitaria exilis) landraces in Mali: Nutrient and phytate content, genetic diversity and effect of processing. Journal of Food Composition and Analysis, 29(2), 134-143. In contrast, large levels of genetic diversity were detected among the domesticated D. exilis landraces of the Upper Niger River Basin of West Africa.Adoukonou-Sagbadja, H., Wagner, C., Dansi, A., Ahlemeyer, J., Daïnou, O., Akpagana, K., & Friedt, W. (2007). Genetic diversity and population differentiation of traditional fonio millet (Digitaria spp.) landraces from different agro-ecological zones of West Africa. Theoretical and Applied Genetics, 115(7), 917-931. The many different landraces of D. exilis are affected differently by the various processing methods.Ballogou, V., Sagbo, F., Soumanou, M., Manful, J., Toukourou, F., & Hounhouigan, J. (2015). Effect of processing method on physics-chemical and functional properties of two fonio (Digitaria exilis) landraces. Journal of Food Science and Technology, 52(3), 1560-1577.
Chemistry Compared to starches like D. iburua and Eleusine coracana, D. exilis has more branched molecules. This was an important finding because although it has more branched molecules, it has fewer chains than the other starches which is unusual chemically. Aside from these differences, most other chemical characteristics were very similar to rice which was not surprising because D. exilis and rice are both starches of the A. crystalline type.Jideani, IA, Takeda, Y, Hizukuri, S (1996). Structures and physicochemical properties of starches from acha (Digitaria exilis), ibunra (D-ibunra), and tamba (Eleusine coracana). Cereal Chemistry 73: 677-685. Additionally, the microstructure of D. exilis was studied, and it was discovered that it is very similar to the grain millets. Researchers found that D. exilis is most abundant in protein bodies and that most of the protein is located towards the center of the cell. The specific structure of Digitaria exilis was analyzed and it was found that it is surrounded by thin bracts and two glumes. The caryopsis, a type of fruit that contains a pericarp that is fused with a thin seed coat, of the D. exilis contains several layers that serve the purpose of protecting the endosperm and embryonic tissues.Irving, DW, Jideani, IA (1997). Microstructure and composition of Digitaria exilis stapf (acha): a potential crop. Cereal Chemistry 74: 224-228.
The composition of fonio can differ depending on what part of the world you are in. The main differences are in the protein and fiber content. This information could be useful in giving people dietary advice if their diet is lacking a certain protein or fiber.Barikmo, I, Outtara, F, Oshaug, A (2004). Protein, carbohydrate and fibre in cereals from Mali-how to fit the results in a food composition table and database. Journal of Food Composition and Analysis 17: 291-300.
Varieties
Identified varieties of Digitaria exilis are:Blench, Roger. 2012. Vernacular names for African millets and other minor cereals and their significance for agricultural history. Archaeological and Anthropological sciences.
var. gracilis - Kankan region (Guinea) var. stricta - Casamance (Senegal), Guinea, Mali, and Burkina Faso var. rustica - Casamance (Senegal), Guinea, Mali, and Burkina Faso var. mixta - Guinea var. densa - Togo
Etymology The name (borrowed by English from French) is from Wolof foño.Christian Seignobos and Henry Tourneux, Le Nord-Cameroun à travers ses mots: Dictionnaire de termes anciens et modernes: Province de l'extrême-nord (KARTHALA Editions, 2002; ), p. 107.
Cultivation
Fonio is one of the ancient African crops, possibly the oldest West African crop as its cultivation seems to have started about 7,000 years ago.Gari, J.A (2002). "Review of the African millet diversity". FAO - Food and Agriculture Organisation of the United Nations. Rome. Italy. pdf The first references to fonio as food are reported from the mid-14th century. D. exilis was originally derived from the wild species D. longiflora.
Significant cultivation is in West Africa from Chad to Cape Verde, south Mali, in western Burkina Faso, eastern Senegal, northern Guinea, north Benin, parts of north central Nigeria such as northern Plateau State, Southern Kaduna, parts of Niger State, Abuja (FCT), Zuru area of Kebbi State, some parts of Nasarawa State and Kogi State, as well as parts of Bauchi State. It is also found in south Niger, where the plant supplies the staple food for several million people. In some regions of Mali, Burkina Faso, Guinea and Nigeria, fonio is the most important or one of the main cereals. White fonio has its main growing region in the highland plateaus of Nigeria, where it is popularly called acha. The second fonio species, iburu or black fonio, is limited to the Jos-Bauchi Plateau in Nigeria and the northern regions of Togo and Benin.
Fonio is grown in parts of the Dominican Republic, first only grown as a weed, but it is now cultivated again.Morales-Payán, J.P., J.R. Ortiz, J. Cicero, and F. Taveras. 2003. "Digitaria exilis as a crop in the Dominican Republic." p. S1–S3. In: J. Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS Press, Alexandria, VA. The European Commission with the EU Regulation L 323/1 of December 19, 2018, approved the commercialization in Europe of fonio as Novel Food, upon the scientific dossier managed and submitted by Italian company Obà Food.
Production and cultivation area (2013) Country Production (tons) Area (hectares) Guinea 429 000 300 000 Nigeria 90 000 165 000 Mali 22 000 34 000 Burkina Faso 20 000 25 000 Ivory Coast 17 000 15 000 Niger 6 000 11 000 Benin 1 300 1 900 Senegal 1 000 1 500 Guinea Bissau 700 600 Total 587 000 554 000
Source:
Yield More than 550,000 ha of fonio are grown each year in West Africa and the production runs at 587,000 tons. Yields are relatively stable, the yield average is currently 1 ton per hectare (ha). In the peripheral regions the yields are less than 500 kilograms and drop when in very poor soils down to 150 to 200 kilograms.
Climate and soil requirements Fonio is cultivated in West Africa under tropical climate, with a pronounced dry season, temperatures between 25 and 30 °C and annual rainfalls of 600 to 1200 mm. Nevertheless, fonio is also grown in higher altitude: over 1000 m, with higher annual rainfalls (1200 to 1500 mm) and colder temperatures (15-25°). Fonio has a well developed root system, which can reach more than one meter depth in the soil. This root system explains the good performance of the plant during the dry season and its adaptation to poor and low fertility soils. Fonio is mainly grown on sandy soils, but can also grow on rocky soils. It also thrives on acidic clay soils with a high aluminium content. On heavy soils, most varieties thrive badly. This crop is low demanding and can cope with unfavourable climate and soil conditions.
Field management Throughout Africa, most of the work is done by hand.
Before sowing The main tasks to do before sowing are the cleaning of the field and ploughing. Sometimes animals are used for ploughing or a daba is utilized to do a superficial scratching.
Sowing and upkeep The sowing time starts with the first rainfalls. This can vary depending on the variety and the geographical area of cultivation. The grains used for sowing are the best grains kept from the precedent harvest and are sown by hand (broadcast seeding). Sometimes the seeds are mixed with sand to have a more homogenous repartition on the soil. The seeds remain on the surface, so successive harrowing by hand or with the daba is needed to bury them slightly in the soil. Normally 30–40 kg/ha of seeds are used, but sometimes more than 70 kg/ha are sown, in order to control weeds at time of emergence. For germination and emergence a temperature of 30 °C is optimal. The germination and growth is rapid, and for the upkeep of the crop only weeding is needed.
Pests Insect pests include:
shoot flies, Atherigona spp. stem borer, Chilo partellus some species of thrips, bugs, and grasshoppers white-backed plant hopper, Sogatella furcifera (vector of the pangola stunt virus)
Harvest and post-harvest processing
Most of the harvesting is still done by hand. As soon as the grains reach maturity, usually in July or August, men cut the fonio with sickles while women and children gather it into sheaves. A motor-driven mower may be used to assist in this. The sheaves must be stored in a dry and well ventilated area to prevent mould formation. During the dry season, sheaves are piled to large stacks in the sun to completely dry them. Threshing is done manually as well. Tractor-driven threshers are rarely used due to higher costs and a higher loss of the small grains. Grains are stored loosely. Hulls must be removed before consumption as they are not digestible. This process is traditionally carried out by women using mortars with sand. After the fifth hulling, the fonio is called "whitened". Adhering grit and sand is washed away with the help of gourds. This process requires a highly skilled woman and up to 10 liters of clean water per one kilogram of fonio. The husk can also be "popped" over a flame and then pounded (a technique used among the Akposso that yields a toasted color grain).