Background Information on Cowpea

Cowpea is a tropical legume crop of African origin. Most recent speculation on the crop’s center of origin focuses on a band of diversity of wild cowpea stretching across southern Africa from Namibia to Mozambique, with a center of speciation in the Transvaal region of South Africa.  Nevertheless, the center of greatest diversity of cultivated cowpea is in the northern guinea savanna regions of west Africa.  In many fields, as a result of hybridization, almost continuous variation exists between the more elite, large-seeded varieties of cultivated cowpea, the small-seeded, more weedy varieties, and true wild species of cowpea.  Cultivated cowpea has been shown to cross regularly with wild cowpea growing on the periphery of fields in east Africa.  Cowpea plant remains dating to 1500 B.C. have been discovered in a cave dwelling in Ghana.

Cowpea is an extremely resilient crop, and is cultivated under some of the most extreme agricultural conditions in the world.  Cowpea varieties grown in the Sahel and on the fringes of the Sahara are drought and heat tolerant.  Other cultivars are tolerant to acid soils, extremely poor soil fertility, and shading from other crops.  Cowpea’s highly diverse plant architecture has allowed farmers to development varieties which fill a wide range of unique niches:  highly determinate cowpea varieties are grown for grain in monoculture situations, while spreading types are grown as a dual-purpose (grain/fodder) crop inter-planted with cereals, and as a relay crop using residual moisture.

Cowpea is cultivated for its leaves, green pods, grain and stover.  While all parts of the plant are used to some degree in each region of the continent, in west Africa cowpea is primarily grown for its grain and stover (cowpea haulms contain 20% protein and are highly sought after as cattle feed), while in eastern and southern Africa it is cultivated primarily for its leaves.  Cowpea grain is consumed directly following boiling, as a component of meals which also include porridge made from cereals or root crops.  Cowpea grain cakes (made from mashed and fried seed) are also sold as a fast food along roadsides in Nigeria.  In eastern and southern Africa, cowpea leaves are commonly added to sauces and served with porridge, or boiled and consumed in a manner similar to spinach.

Current estimates place annual world cowpea grain production at 3 million MT (Singh et. al., 1997).  Approximately 64% of this is grown in west and central Africa, which accounts for 80% of total production in Africa.  Nigeria, in turn, accounts for upwards of 75% of production in west and central Africa (FAO, 1999). However, it is also an important crop in marginal areas of eastern and southern Africa in Sudan, Somalia, Mozambique and southern Zimbabwe.  Most cowpea is grown as an intercrop with cereals, and little of the harvest reaches regional markets.  The sole important export market for cowpea is believed to be from Niger to Nigeria, which is the world’s largest consumer of cowpea.

The central challenge to increasing cowpea yields in Africa is most probably insect resistance.  Cowpea suffers from a wide range of insect pests, including bruchids, Maruca pod borers, and thrips.