B.B. Singh, email@example.com
Cowpea was a relatively minor tropical legume about 50 years ago, but it is now emerging as one of the most important food legumes in the 21st century because of its early maturity and ability to fit as a niche crop in multiple cropping systems. There has been more than a 6-fold increase in the world cowpea production in the last few decadesâ€”a quiet revolution that is greater in magnitude compared to that of cereals and all other pulses.
Based on FAO data and correspondence with scientists in different countries, annual cowpea production has increased from about 0.87 million tons in 1961 to 1.2 million tons in 1981 to 2.4 million tons in 1991, to more than 6.3 million tons in 2008. The major increases have been in Niger, Nigeria, Mali, Burkina Faso, Senegal, Tanzania, Uganda, Congo, Myanmar, India, and Brazil. These successive increases in cowpea production over time have occurred due to the concerted efforts and coordinated cowpea research and development activities of IITA and its national, regional, and international partners over the last four decades and the release of new improved short-duration cowpea varieties in different countries.
It is expected that cowpea production will significantly increase in the coming decades also as more short-duration and pest-resistant varieties become available and cowpea cultivation makes further inroads as a niche crop in the cereals and root crops-based systems.
Significant advances in cowpea research
Cowpea originated in the southern African region several thousand years ago and spread to the different parts of the world covering over 65 countries in Asia and Oceania, the Middle East, Southern Europe, Africa, Southern USA, and Central and South America. The nitrogen-fixing crop with great versatility was entrenched into local cropping and food systems. It was given indigenous names such as â€˜lobiaâ€™ in India, â€˜kundeâ€™ in east Africa, â€˜beansâ€™ and â€˜wakeâ€™ in Nigeria, â€˜niebeâ€™ in francophone Africa, â€˜southern peaâ€™ and â€˜blackeye peaâ€™ in the USA, â€˜feijÃ£o caupeâ€™, in Brazil, and a host of other names in different countries around the world.
Its nutritious young leaves, green pods, green seeds, and dry grains are used in various food preparations, while the nutritious fodder is fed to livestock and the crop residue in the field contributes to improved soil fertility.
Limited efforts in cowpea improvement began in a few countries in the 1960s but it was the establishment of IITA in 1967 that gave cowpea some well-deserved attention. IITA actively collaborated with its NARS partners in catalyzing and supporting research on cowpea improvement and distributing improved cowpea materials.
Cowpea research received another boost when the USAID-funded Bean/Cowpea CRSP (now The Dry Pulses Project) became operational in the 1980s as it complemented IITAâ€™s efforts in strengthening cowpea research and development in Africa. The recently established Network for Genetic Improvement of Cowpea for Africa (NGICA) has further strengthened cowpea research in the region.
The major successes include a collection and use of over 15,000 germplasm lines and development of a range of improved varieties with diverse maturity, plant type and seed type combined with high protein, iron, zinc, and resistance to major biotic and abiotic stresses. Using a combination of field and laboratory screening, several varieties have been developed with combined resistance to cowpea yellow mosaic, blackeye cowpea mosaic, and many strains of cowpea aphid-borne mosaic, Cercospora, smut, rust, Septoria, scab, Ascochyta blight, bacterial blight, anthracnose, nematodes, Striga, Alectra, aphid, thrips, and bruchid.
Similarly, using simple screening methods for tolerance for heat, drought, and low P, major varietal differences for all the three traits have been identified and incorporated into improved varieties. Also, varieties with 30% protein and enhanced levels of iron, zinc, and other micronutrients have been identified.
Joint efforts are being made by IITA, The Dry Pulses project, advanced laboratories in the USA and Australia, African Agricultural Technology Foundation (AATF), NGICA, and Monsanto Corporation to exploit biotechnological tools and complement conventional methods for improving insect resistance in cowpea. Efforts are also under way to develop markers and protocols for marker-assisted selection (MAS) for Striga resistance and other traits in cowpea.
Development and release of improved varieties
Using the vast genetic pool and useful genes already identified, a great deal of progress has been made in breeding a range of high-yielding cowpea varieties with combined resistance to major diseases, insect pests, Striga and Alectra, and drought tolerance. Combining erect plant type with early maturity and resistance to major pests, several new extra-early cowpea varieties have been developed which yield up to 2 t/ha within 60 days compared to <1 t/ha in local varieties, which mature in 100 to 140 days.
Similarly, several medium-maturing dual-purpose varieties have been developed which yield over 2.5 t/ha grain and over 3 t/ha fodder in 75â€“80 days. These varieties have been tested and based on their good performance, over 40 improved varieties have been released in 65 countries covering Africa, Asia, and Central and South America.
The new varieties have been given specific and interesting names such as â€˜Big Buffâ€™ (IT82E-18) in Australia; â€˜Biraâ€™ (TVx 3236) in Angola; â€˜Titanâ€™ (IT84D-449) and â€˜Cubinataâ€™ (IT84D-666) in Cuba; â€˜Asontemâ€™ (IT82E-16), â€˜Ayiyiâ€™ (IT83S-728-13), and â€˜Bengplaâ€™ (IT83S-818) in Ghana, â€˜Akashâ€™ (IT82D-752) (sky) and â€˜Prakashâ€™ (IT82D-889) (light) in Nepal; â€˜Sosokoyoâ€™ (IT84S-2049) in Gambia; â€˜Pkoko Togboiâ€™ (IT85F-867-5) in Guinea Conakry; â€˜Korobalenâ€™ (IT89KD-374) and â€˜Sangarakaâ€™ (IT89KD-245) in Mali; â€˜Dan IITAâ€™ (TVx 3236) (son of IITA) and â€˜Dan Bunkureâ€™ (IT89KD-288), IT90K-76, IT90K-82-2, IT90K-277-2, and IT93K-452-1, in Nigeria; â€˜Melakhâ€™ and â€˜Mourideâ€™ in Senegal; â€˜Pannar 31â€™ (IT82E-16) in South Africa; â€˜Dahal Elgozâ€™ (IT84S-2163) (gold from the sand) in Sudan; â€˜Umtilaneâ€™ (IT82D-889) in Swaziland; and â€˜Bubebeâ€™ (IT82E-16) in Zambia; â€˜Vamban 1â€™ (IT85F-2020), â€˜Pant Lobia-1â€™ (IT98K-205-8), and â€˜Pant Lobia-2â€™ (IT97K-1042-3) in India; and many more.
Cereals-cowpea intensive cropping systems in the tropics
With support from USAID, UK Department for International Development (DFID), GATSBY Foundation, Danish International Development Agency (DANIDA), Canadian International Development Agency (CIDA), and others, several improved intensive cowpea-cereals cropping systems have been developed. The improved strip cropping system involving two rows of cereals and four rows of cowpea has enabled farmers in Nigeria and Niger to produce one to two cowpea crops in the same season while maximizing the cereal yields.
Similarly experiments conducted using 60-day cowpea varieties in northern Nigeria and India have demonstrated successful triple cropping involving â€˜wheat-cowpea-riceâ€™ each year. The additional cowpea crop in the summer season after the wheat harvest not only provides extra employment but it also improves soil fertility and provides nutritious food grain and fodder.
In the wake of increasing global warming and declining rainfall and water table, it is expected that cowpea production will increase in the future using heat- and drought-tolerant 60-day cowpeas as a niche crop in the cereals and root crops systems covering millions of hectares in Asia, Africa, and the Americas. Northern India alone has about 10 million ha under wheat-rice system. An additional crop of 60-day cowpeas as a niche crop between wheat and rice can produce between 10 to 15 million t of cowpea which would double the current pulses production in India.
A similar possibility exists for double cowpea cropping in several parts of Africa and wheat-cowpea double cropping in southern United States covering several million hectares. Brazil is adding thousands of hectares of new land each year under cowpea cultivation.
Thus, there is a need to develop a diverse set of region-specific and niche-specific varieties to expand cowpea cultivation in the world and help improve family food security and nutrition.
B.B. Singh, Visiting Professor
Department of Soil and Crop Sciences,
Texas A&M University, College Station, TX 77840, USA