Cowpea is a multipurpose legume crop cultivated around the world, especially in semi-arid areas.
Grown on more than 11.5 million hectares in Africa, Southeast Asia, and some countries in the Americas, cowpea is the third most important pulse worldwide. It is widely planted in semi-arid regions because of its ability to produce in dry and hot conditions. Cowpea seeds are highly nutritious, thanks to a high protein content (c. 25%). Its leaves are an important food source for some cultures in Africa. Cowpea is also used for animal feed and green manure.
The International Institute of Tropical Agriculture (IITA) and the International Livestock Research Institute (ILRI) have together developed dual-purpose cowpea varieties for human and animal consumption during the dry season, which are receiving wide acceptance among farmers in West Africa.
Cowpea is used primarily as a pulse, but the leaves and green peas are eaten as a vegetable and it provides fodder for livestock.
Cowpea is a useful, shade-tolerant cover crop, adding fertility to the soil. The species includes 11 sub-species and many relatives, some grown as minor legumes and forage crops.
Cowpea is an annual plant with a large tap root and alternate trifoliate leaves with ovate leaflets. It shows considerable diversity in growth habit, flower and seed coat colour. The standard flowers vary in colour from white, cream and yellow to purple. The seeds may be smooth or wrinkled and range in colour from white, cream or yellow to red, brown or black. The seeds have a marked hilum surrounded by a dark aril. The center of diversity of cowpea is in West Africa. The region remains the main center of production.
Cowpea is regenerated by seeds and is largely self pollinating but some care has to be taken to maintain genetic integrity because up to 2% outcrossing has been reported.
Cowpea originated in Sub-Saharan Africa and spread to East and West Africa, and then Asia. In Asia, it evolved into a vegetable form known as yardlong bean. The crop was introduced to America with the slave trade in the 17th century.
The largest genebank collections are held by IITA in Nigeria and the USDA at the Southern Regional Plant Introduction Station in Georgia. Other large collections are held by the World Vegetable Center in Taiwan and the N.I. Vavilov Research Institute of Plant Industry in Russia.
Genesys lists information on more than 30,000 accessions, 60% of which are landraces or traditional cultivars. The largest holdings are safeguarded at the International Institute of Tropical Agriculture (IITA) and the USDA-ARS genebanks.
The global strategy for the conservation of cowpea genetic resources compiles 20 recommendations to effectively conserve and use the diversity of the crop. These include: encourage safety duplication of existing collections; promote basic plant research (e.g. resolve taxonomic issues, and characterize viruses and diseases in centers of origin); perform and document evaluation and characterization of existing germplasm; and develop molecular tools to identify duplicates among collections.
- Plant Genetic Resources Research Institute (PGRRI, Ghana)
- National Agriculture Genetic Resources Center (NAGRC - Nepal)
- Agricultural Plant Genetic Resources Conservation and Research Centre (APGRC)
- Plant Resources Center (PRC, Vietnam)
- National Centre for Genetic Resources and Biotechnology (NACGRAB)
- Ethiopian Biodiversity Institute (EBI)