Loss of Agro-biodiversity – A serious threat to Food and Nutrition Security in Africa.

Agro-biodiversity or agricultural biodiversity is a subset of biodiversity that encompasses all of the genetic resources (plant genetic resources, animal genetic resources, microbes and pollinators genetic resources) related to food and agriculture. Agro-biodiversity includes all the varieties of crops, livestock breeds, fish species, soil microbes and pollinators (bees, insects, etc.) including all of their wild relatives that support agricultural ecosystems and productivity.

Africa, which is home to more than 50 000 known plant species, 1 000 mammal species and 1 500 bird species, is increasingly experiencing major losses of its large and diverse heritage of flora and fauna to genetic erosion.

Genetic erosion is the reduction in the number of local varieties (landraces) of a plant/animal and also the reduction in the number of wild crops (uncultivated crops)/animals which support food security.

Causes of genetic erosion include replacement of traditional varieties with modern varieties/breeds or hybrids, environmental degradation, urbanization and land clearing through deforestation and bush fires.

Global attention is on plant genetic resources as it is the most important component in food.

Since the advent of agriculture several centuries ago, African farmers have selected varieties based on desirable traits of the plants including ease of harvest, adaptation to day length, pests and disease resistance, non-shattering seed heads, storability, high and reliable regeneration rates, nutritional quality and phenotypic appearance (e.g. size, shape, texture). Traditional crop improvement from centuries of selection by farmers has produced a myriad of landraces, mostly with localised distributions and developed to suit the needs of the farmers who created them.

The major production goal of African farmers is crop diversity, both in terms of growing a number of different crops and different varieties of each crop and this plays a crucial role in the maintenance of household food and nutrition security.

Farmers in different communities in Africa had cultivated several local varieties of cereals, legumes, tuber crops, oil crops, horticultural crops etc. but in the last century, majority of these varieties are diminishing as a result of introduction of hybrid varieties. Communities which have lost local landraces have found it difficult to regain access to them. Also, hundreds of uncultivated food plants in the wild like African pear, velvet tamarind, walnut etc. are drastically reducing in numbers as a result of deforestation. These great reductions in different crop varieties and the continuous loss of wild food crops pose a grave threat to food and nutrition security in Africa.

As African farmers numbering in the millions have turned away from their traditional landraces, the knowledge of how to maintain the hand-selected lines that performed well in particular habitats and conditions has fallen victim to even greater erosion than the loss of landraces itself.  This erosion of indigenous knowledge which accompanies genetic erosion may as well be damaging to the local community as the loss of the genetic material itself.

Examples of Global Genetic Erosion:

• In Benin Republic, average rates of landrace losses were calculated to be 27 % for sorghum landraces in 15 villages and 31 % for Guinea yam in 135 villages.
• In Ethiopia, erosion in barley varieties was 65% between 1994 and 2010.
• In United States, total number of carrot varieties was 287 in 1903 but declined to 21 by 1983. Varieties of sweet-corn was 307 in 1903 but reduced to 12 by 1983.
• In China, of almost 10,000 varieties of wheat in use in 1949, only about 1000 remained by the 1970s.
• ·More than 30,000 varieties of rice once cultivated in India, today over 75% of India’s rice is limited to 1 - 10 varieties.

 Though modern varieties/hybrids of crops were developed for desirable traits like better yield, greater uniformity, improved colour, disease resistance etc. the loss of genetic diversity reduces the potential for these modern crops to adapt to, or be bred for, changing conditions and so directly threatens long-term food security. To continue to develop the needed traits in plants, plant breeders constantly require fresh infusions of genes from these domesticated local varieties and wild varieties. Agricultural biodiversity is not just a raw material for industrial agriculture; it is also the key to food security and sustainable agriculture because without this diversity, options for long-term sustainability and agricultural self-reliance are lost especially in the face of changing climate.

For example, in the 1970s, when the Indian rice crop was devastated by the Tungro virus, scientists had to analyze 17,000 varieties of rice before finding a single wild variety that was resistant to this virus. What might the consequences have been if this variety had been lost?

Another good example of biodiversity preservation is the new rice for Africa (NERICA) developed by Africa Rice Centre in Côte d’Ivoire. African rice, Oryza glaberrima has been cultivated for 3,500 years and is well adapted to the African environment. African rice has profuse vegetative growth, which serves to smother weeds, it is also hardy, pest-resistant, drought resistant, low-labour and suited to a variety of African conditions.  However, African rice has relatively low yields. Oryza sativa  is indigenous to Asia and has been widely accepted following its introduction because of its higher yielding potential, non-shattering and superior grain qualities but asian varieties are poorly adapted to African conditions as their cultivation requires abundant water. Also, asian rice cannot compete with weeds due to their semi-dwarf phenotypes and are susceptible to pests and diseases in African conditions. Today, O. glaberrima is completely abandoned in favour of O. sativa in rice production.

 African rice was domesticated from wild African rice, Oryza barthii and it has many great varieties but over 75% of it has been lost including the wild varieties as a result of Asian rice cultivation.

The new rice for Africa was created by crossing some preserved varieties of O. glaberrima and O. sativa to produce nerica varieties which possess the traits of the two parents. If the varieties of O. glaberrima had been totally lost, development of nerica varieties will be impossible.

Also, the number of non-domesticated plants that are collected from the wild to bridge hunger gaps is far more diverse, often ecology- and culture-specific. In Nigeria, the rate of loss of the diversity of these species is alarming and this calls for more urgent actions. Otherwise, some species will go into extinction in the course of the next decade.

According to 2008 FAO Country Report on Plant Genetic Resources, some of the wild food crops in Nigeria include:

S/N	Crop	Common Name	Relative Importance (Food security, economic and social)
1	Adansonia digitata	Baobab tree	Leaves used as vegetable fruit and for fruit drinks; source of fibre, savanna plant.
2	Aframomum melegueta	Alligator pepper	Seed used as spice in conjunction with kola; also used in ritual observance; forest/savanna
3	Afzelia africana	Akpalata	Seed used as condiment for thickening soup; leaves used as fermented vegetables.
4	Artocarpus communis	Breadfruit	Big seedless edible fruit eaten like yam.
5	Baillonella toxisperma	Imi-igbo (yoruba)	Fruit pulp edible and seed is a good source of oil. Forest plant.
6	Blighia sapida	Akee-apple	Seed and edible, forest plant.
7	Bosquesa angolensis (Trileplsium Madagascarlense)	Oze; Saworo (yoruba)	Nut eaten roasted in African breadfruit, forest plant.
8	Borassus aethiopicum	Ope-okunkun	Fruit pulp edible; young ridicule used as vegetables; also tapped as palm wine.
9	Brachystigia spp.	Achi	Seeds used as condiment for thickening soup. Forest plant.
10	Butyrospernum paradoxum subspParkii	Shea butter	Fruit pulp edible; seeds are source of oil and fat (ori); savanna plant.
11	Canarium schivenfuttii	Ube; Okpoko	Fruit eaten; source of fat, oil veneer plywood, forest plant.
12	Ceiba pentandra	Silk cotton tree; Araba	Leaves used as vegetables; source of kapok, savanna plant.
13	Chrysophyllum albidum	African star apple;Agbalumo (yoruba)	Fruit pulp edible and good for jam; forest plant.
14	Cola gigantean	Ebenebe	Seeds used as condiment for thickening soup, savanna plant.
15	Cola pachycarpa	Achicha	Testa eaten fresh; forest plant.
16	Cola lepidota	Achicha	Testa eaten fresh; forest plant.
17	Dacryodes edulis	African pear	Fruits eaten with maize; source of oil & fat; kernel suitable for animal feed formulation; forest plant.
18	Dennettia tripetala	Nmimi (Igbo) Igberi (yoruba)	Fruit eaten fresh; served as kola;useful for insecticide preparation; forest plant.
19	Detarium spp.	Ofo	Seeds used as condiment for thickening soup, similar to ogbono; savanna plant.
20	Dialium guineanse	Velvet tamarind Awin (yoruba)	Seed eaten fresh; very good source vitamin C; suitable for fruit drink and jelly; savanna and forest plant.
21	Dioscoreophyllum Cumminsii	Serendipity-berry	Fruit pulp is edible; 2500 sweeter than cane sugar with protein as sweetening agent, therefore potential source of diabetic sugar; leaves and tubers as vegetables; forest plant.
22	Ficus capensis	Opoto (yoruba)	Leaves use as vegetables; fruits eaten; leaf is also good browse; forest and savanna plant.
23	Garcinia kola	Bitter kola;	Seeds eaten fresh; served as kola; high medicinal value; reputed snake repellant; forest plant.
24	Garcinia polyantha	Bitter kola	Seed edible and eaten fresh; forest plant.
25	Hidegardia barteri	Ufuku (Ibo) Okurugbedu (yor)	Seeds used as condiment for thickening soup; stem bark use as fibre; forest and savanna plant.
26	Irvingia gabonensis var. excelsa	African mango	Fruit pulp eaten; suitable for fruit drink and jam; kernel used as ogbono in thickening soup; kernel as ogbono; forest plant.
27	Tamarindus indica	Tamarind	Fruit pulp eaten fresh; suitable for fruit drink and garnish for fish. Savanna plant.
28	Phoenix dactylifera	Date palm	fruit with sweet mesocarp; plant grows in the dry north but eaten nationwide.
29	Cyperus esculentus	Imumu (yoruba) Tigernut	Plant of savanna with edible juicy tubers on rhizomes.
30	Tetracarpidium conophorum	Wanut	Seeds edible; very high in protein; source of conophor oil (drying oil); forest plant.
31	Tetrapleura tetraptera	Ushakirisha (Ibo); Aidan (yoruba)	Seeds used as spice for flavouring yam pottage; fruits used medicinally; forest plant.
32	Treculia africana	African breadfruit;	Nuts boiled as beans or rice roasted as in groundnut; suitable for bread; biscuits and cake; leaves and fruits pulp good as browse and fodder; forest plant.
33	Vitex doniana	Oriri or oori (yoruba)	Fruit pulp edible and sweet; good for jam and jelly with other fruits e.g. Spondies mombin; leaves used as vegetable; savanna and forest plant.
34	Xylopia eathiopica	Uda (Ibo); Erinje (yoruba)	Seeds used as spice; fruits used medicinally in pot herb; forest plant.
35	Zyzgium guinense	Igi oro	Fruit pulp edible and bark used for dyeing clothes; savanna plant.
36	Ricinodendron heudelotii	Okwe (Ibo); Putu (yoruba)	Seed used for edible oil extraction; condiments; leaves used as browse and for wrapping of foodstuff; forest plant.
37	Spondias momoin	Hog plum	Fruits eaten fresh; suitable for jelly and drinks; savanna/forest plant.
38	Strychnus spinosa	Atako (yoruba)	Fruit pulp edible; savanna plant.
39	Syncepalum dulficicum	miraculous berry;	Fruit pulp edible; could be used as sweetening agent; make bitter taste sweet for sometimes; forest plant.
40	Lendolphis oweriensis	Utu (Ibo); Panukuru (yoruba)	Fruits eaten fresh; suitable for jam and jelly; forest plant.
41	Kondia whitei	Adoo	Fruits edible eaten fresh; served as kola; forest plant.
42	Monodora myristica	African nutmeg;	Seeds used as spice; forest plant.
43	Uvaria chamae		Ripe fruit pulp is eaten; the plant is a re-growth shrub in forest.
44	Piper guineense		Dried black berries and the red; fresh fruit are used in flavouring foods; it is a forest scardent- climbing plant.

Call to action

Africa countries should adopt Community based Biodiversity management which will enable farming communities to document, conserve and utilize their genetic resources and associated knowledge in a sustainable manner.

African countries should set up more gene banks for plant and animal genetic resources. In Nigeria, the only centre responsible for collection and preservation of genetic resources is National Centre for Genetic Resources and Biotechnology (NACGRAB).

There should be adequate funding all year round for the gene banks.

There should be commitment towards systematic collection, domestication improvement, evaluation and conservation of wild plants harvested for food.

 Written by Kehinde S.Jimoh