Developing aflasafeTM

Joseph Atehnkeng, j.atehnkeng@cgiar.org, Joao Augusto, Peter J. Cotty, and Ranajit Bandyopadhyay

Aflatoxins are secondary metabolites mainly produced by fungi known as Aspergillus flavus, A. parasiticus, and A. nomius. They are particularly important because of their effects on human health and agricultural trade. Aflatoxins cause liver cancer, suppress the immune system, and retard growth and development of children. Aflatoxin-contaminated feed and food causes a decrease in productivity in humans and animals and sometimes death. Maize and groundnut are particularly susceptible to aflatoxin accumulation, but other crops such as oilseeds, cassava, yam, rice, among others, can be affected as well. Aflatoxin accumulation in crops can lower income of farmers as they may not sell or negotiate better prices for their produce. Because of the high occurrence of aflatoxin in crops, many countries have set standards for acceptable aflatoxin limits in products that are meant for human and animal consumption.

Natural populations of A. flavus consist of toxigenic strains that produce variable amounts of aflatoxin and atoxigenic strains that lack the capability to produce aflatoxin. Carefully selected and widely distributed atoxigenic strains are applied on soil during crop growth to outcompete and exclude toxigenic strains from colonizing the crop. The biocontrol technology has been used extensively in the USA with two products AF36 and afla guard® available commercially. In Africa, aflasafeTM was first developed by IITA in partnership with the United States Department of Agriculture – Agricultural Research Service (USDA-ARS) and the African Agriculture Technology Foundation (AATF). It is currently at different stages of development, adoption, and commercialization in at least nine African countries. Multiyear efficacy trials in farmers’ fields in Nigeria have showed reduced aflatoxin concentration by more than 80%.

Survey to collect and dispatch samples
Product development begins with the collection of crop samples in farmers’ stores across different agroecological zones in each country. Samples collected are mainly maize and groundnut because they are the most susceptible to aflatoxin accumulation at crop maturity, during processing, and storage. Soil samples are collected from fields where these crops were grown to determine the relationship between the Aspergillus composition in the soil and the relative aflatoxin concentration in the crop at maturity.

Import and export permits are required if crop and soil samples are shipped outside a country. The crop samples are analyzed for aflatoxin to obtain baseline information on aflatoxin levels in the region/country and the relative exposure of the population to unacceptable limits of aflatoxin.

Isolation and characterization of Aspergillus species
Aspergillus species are isolated from the crop samples to identify the non-aflatoxin-producing species of A. flavus for further characterization as biocontrol agents. The isolates are identified and grouped into L-strains of A. flavus, SBG, A. parasiticus, and further characterized for their ability to produce aflatoxin by growing them on aflatoxin-free maize grain. Aflatoxin is extracted from the colonized grain using standard protocols to determine isolates that produce aflatoxin (toxigenic) and those that do not produce aflatoxin (atoxigenic). The amount of aflatoxin produced by toxigenic strains is usually quantified to determine the most toxigenic strains that will be useful for competition with atoxigenic strains.

Understanding genetic and molecular diversity
The genetic diversity of the atoxigenic strains is also determined molecularly by examining the presence or absence of the genes responsible for aflatoxin production in each strain. The absence of these genes explains why potential biocontrol isolates would not produce aflatoxin after release into the environment. Amplification of any given marker is taken to mean that the area around that marker is relatively intact, although substitutions and small indels outside the primer binding site may not be detected. Non-amplification could result from deletion of that area, an insertion between the primers that would result in a product too long to amplify by polymerase chain reaction (PCR), or mutations in the priming sites. Non-amplification of adjacent markers is probably best explained by very large deletions.

Identification of vegetative compatible groups
Vegetative compatible group (VCG) is a technique used to determine whether the highly competitive atoxigenic isolates are genetically related to each other. In nature A. flavus species that are genetically related belong to the same VCG or family; those that do not exchange genetic material belong to different VCGs. This is an important criterion for selecting a good biocontrol agent to ensure that the selected biocontrol strains do not “intermate” with aflatoxin-producing strains after field application. With this technique, the distribution of a particular VCG within a country or region is also determined. A VCG that is widely distributed is likely to be a good biocontrol agent because it has the innate ability to survive over years and across different agroecologies. On the contrary, atoxigenic VCGs that have aflatoxin-producing members within the VCG are rejected; atoxigenic VCGs that are restricted to a few locations may also not be selected.

Initial selection of competitive atoxigenic strains
The in-vitro test determines the competitive ability of the atoxigenic isolate to exclude the toxigenic isolate on the same substrate. The competition test is conducted in the laboratory by co-inoculating the most toxigenic isolate with atoxigenic strains on aflatoxin-free maize grains or groundnut kernels. Grains/kernels inoculated with the toxigenic strain or not inoculated at all serve as controls. After incubation and aflatoxin analysis, atoxigenic isolates that reduce aflatoxin by more than 80% in the co-inoculated treatments are selected for unique vegetative compatible grouping.

Selection of candidate atoxigenic strains and multiplication of inocula
aflasafe™ is composed of a mixture of four atoxigenic strains of A. flavus previously selected from crop samples. To select the four aflasafe strains, initially 8-12 elite strains belonging to atoxigenic VCGs are evaluated in large farmers’ fields. Two or three strain mixtures, each with 4-5 elite strains, are released in separate fields by broadcasting at the rate of 10 kg/ha in maize and groundnut at about 30-40 days after planting. The atoxigenic strains colonize organic matter and other plant residues in the soil in place of the aflatoxin-producing strains. Spores of the atoxigenic strains are carried by air and insects from the soil surface to the crop thereby displacing the aflatoxin-producing strains. The four best strains to constitute aflasafeTM are selected based on their ability to exclude and outcompete the toxin-producing isolates in the soil and grain, move from the soil to colonize the maize grains or groundnut kernels in the field, and occur widely and survive longer in the soil across many agroecological zones. The use of strain mixture in aflasafe™ is likely to enhance the stability of the product as more effective atoxigenic strains replace the less effective ones in specific environments. The long-term effect is the replacement of the toxigenic strains with the atoxigenic VCGs over years.

Assessing relative efficacy of aflasafeâ„¢
Field deployment to test efficacy of aflasafeâ„¢ is carried out in collaboration with national partners and most often with the extension services of the Ministry of Agriculture. Awareness is created by organizing seminars with extension agents and farmers. During the meetings presentations are made on the implication of aflatoxin on health and trade thereby increasing their knowledge on the impact of aflatoxins. aflasafeâ„¢ is then introduced as a product that prevents contamination and protects the grains before they are harvested and during storage. Efficacy trials are carried out in fields of farmers who voluntarily agree to test the product. Field demonstrations on the use of aflasafeTM are supervised and managed by the extension agents and farmers. Farmers are trained not only on the biocontrol technology but also on other management practices that enhance better crop quality.

Farmers are also educated on the need to group themselves into cooperatives, aggregate the aflasafeâ„¢-treated grains to find a premium market with companies that value good quality products. Market linkage seminars and workshops are organized between aflasafeâ„¢ farmers, poultry farmers, and the industries to ensure that the farmers get a premium for producing good quality grains and the industries get value for using good quality raw materials for their products.

A success tale on improving two legume crops in Africa

Ousmane Boukar (o.boukar@cgiar.org), Tahirou Abdoulaye, Manuele Tamó, Hesham Agrama, Hailu Tefera, Christian Fatokun, and Steve Boahen
O. Boukar, Cowpea Breeder; T. Abdoulaye, Socioeconomist, IITA, Ibadan, Nigeria; M. Tamó, Legume Entomologist, IITA, Benin; H. Agrama and H. Tefera, Soybean Breeders, IITA, Malawi; C. Fatokun, Cowpea Breeder, IITA, Ibadan, Nigeria; S. Boahen, Legume Specialist/Agronomist, IITA, Mozambique

Cowpea and soybean are cultivated by poor and middle-income farmers as a sole crop or as intercrop with maize and other cereals for their protein-rich grains which are consumed in different forms. The haulms from plant residues and the dry pod walls of both crops are good sources of quality fodder for livestock.

Improved cowpea varieties being tested in a field trial. Photo by L. Kumar.
Improved cowpea varieties being tested in a field trial. Photo by L. Kumar.

The two crops contribute substantially to sustain crop production through their ability to fix atmospheric nitrogen, some of which is left behind in the soil after harvesting for subsequent crops. IITA and its partners have been involved in improving legume production systems for several decades. An overview of these efforts is presented in this article.

Cowpea
Cowpea―indigenous to sub-Saharan Africa (SSA), is grown on about 14 million ha worldwide, with over 84% of this area in SSA. Between 1985 and 2007, the rate of growth was 4.5% in land area planted to cowpea, 4.5% in grain yields/ha, and 5.9% in quantity of cowpea produced. These data indicate that the increase in the quantity of grain produced over the period resulted mainly from an expansion in the land area and less from an improved yield/unit area. In well-managed experimental stations, yields of up to 2 t/ha can be obtained but globally the average yield is about 450 kg/ha.

Several abiotic and biotic factors keep the productivity of cowpea low in African farmers’ fields. Notable among these are drought, poor soil fertility, inappropriate agronomic practices, an array of fungal, viral, and bacterial diseases, and parasitic flowering plants (Striga and Alectra). Cowpea is particularly susceptible to infestation by several insects with devastating effects on plants in the field and seeds in storage.

Efforts in genetic improvement have been and are still being made to develop varieties with resistance to these various yield-limiting factors and in various research institutions across SSA, iIITA, and other advanced research institutions. Cowpea breeders from these various institutions meet regularly to share information and exchange ideas on the way forward.

Elite lines generated from IITA’s breeding nurseries are shared with interested colleagues from the national research institutions who evaluate these at their stations and in farmers’ fields. Those that perform well are recommended for release in the respective countries. For example, in Mali, a cowpea line IT99K-499-35 was recently adopted by many farmers in the Segou area and because of its superior performance and resistance to Striga, given a local name, Jinguiya which means ‘hope’.

Under the Tropical Legumes II (TL II) project, several new cowpea varieties [IT97K-499-35 (in 2008), IT89KD-288 and IT89KD-391 (in 2009), IT99K-573-1-1 and IT99K-573-2-1 (in 2011)] were released in Nigeria. Regional trials are being conduced for two cowpea lines (IT97K-1122 and IT00K-1263) identified through farmers’ participatory selection as part of the TL II project in Tanzania to facilitate their official release. In 2011, three IITA cowpea lines (IT97K-1069-6, IT00K-1263, and IT82E-16) were released in Mozambique; and IT99K-494-6 was released by Bunda College in Malawi as an Alectra-resistant variety in 2011.

Legume scientists in a disease resistance screening trial. Photo by L. Kumar.
Legume scientists in a disease resistance screening trial. Photo by L. Kumar.

Research into integrated pest management (IPM) for cowpea has resulted in the development and deployment of biopesticides including the use of entomopathogenic organisms combined with botanicals, and biological control agents such as hymenopteran parasitoids which attack and feed on some of the cowpea pests. An example is the mixture of a specific entomopathogenic virus capable of infecting and killing the legume pod borer Maruca vitrata with aqueous formulations of neem oil. This has proved to be as effective as the use of conventional insecticidal sprays. With regard to biological control, a small parasitic wasp which attacks the flower bud thrips, another major pest of flowering cowpea, has been introduced and established in most of Bénin and parts of Ghana, It has been reported to reduce the thrips population on wild alternative host plants by up to 40%.

The development of improved cowpea varieties has so far depended on conventional breeding methods. However, efforts are being made to apply molecular breeding tools to cowpea improvement. Fairly saturated genetic linkage maps of cowpea have been produced in several laboratories. The linkage maps have been used for the detection of DNA markers associated with resistance/tolerance to Striga, drought, macrophomina, and bacterial blight, and seed characteristics such as size. A few of the markers have been converted to user-friendly markers which will make them readily available for breeders in the national systems. Molecular markers are contributing to progress in variety development.

IITA is collaborating with Purdue University, USA, in implementing the Purdue Improved Cowpea Storage (PICS) project on the hermetic storage of cowpea grain in Nigeria, Bénin, Togo, and Cameroon. From 2008 to 2010, IITA and its partners disseminated hermetic triple-layer bags for storage in more than 13,500 villages in the cowpea-producing areas of Nigeria, Cameroon, Togo, and Bénin. This project addresses one of the most important constraints to cowpea production which is grain damage in storage. Furthermore, by not using any type of chemical, this hermetic storage method is protecting farming families and consumers from accidents from the mishandling of and poisoning by the chemicals used in cowpea storage. To date, farmers have purchased more than 30,000 PICS bags in these countries.

IITA is also collaborating in an adoption study that will provide information about the reach of the technology. Another study on analysis of the supply chain of the PICS bags in the same four countries will help to improve the farmers’ access to the PICS bags through a better distribution network.

Soybean
Soybean is a fairly new crop in SSA and has few biotic constraints. Fewer than 400 ha were planted to soybean in SSA during the 1980s but this exceeded the 1-million ha mark by 2007. Grain yield/ha increased from about 900 kg/ha in the 1980s to >1000 kg/ha between 2005 and 2007. Initially most varieties grown in parts of SSA had the problem of seed longevity. Farmers could not store seeds successfully from one cropping season to the next. This problem has now been solved so that seeds of the newly developed varieties remain viable over a longer period. Another constraint to soybean production was pod shattering, which resulted in seeds being lost in the field. Farmers could not leave their crop to dry in the field before harvesting without losing some of the grain. The varieties that have been developed at IITA have tolerance to pod shattering, and resistance to rust─a fungus (Phakopsora pachyrhizi) that causes significant yield losses, especially in the moist savanna agroecology. Some genotypes of soybean are noted for their abilities to reduce the seed bank of Striga hermonthica, a parasitic weed which can cause serious damage to cereal crops.

Farmers admiring improved soybean varieties. Photo by IITA.
Farmers admiring improved soybean varieties. Photo by IITA.

Several elite lines from IITA’s breeding nursery have been evaluated in many countries in SSA and found to perform well in farmers’ fields. Some of these have been recommended for release in the different countries. For example, rust-resistant TGx1835-10E and TGx1987-62F have been released in Nigeria; TGx1740-2F was released in Malawi; TGx-1485-1D, TGx1740-2F, TGx1904-6F, TGx1908-8F, and TGx1937-1F were released in Mozambique in 2011. These were the first batch of varieties ever released in Mozambique. The development of improved varieties also involved farmers’ participation in selection, which made it possible for farmers to have some knowledge on performance of the lines being selected, thus facilitating rapid adoption and dissemination. IITA, in collaboration with Laval University in Canada, completed genotypic [using single nucleotide polymorphism (SNP) markers] and phentotypic characterization of 300 soybean genotypes for rust resistance and symbiotic performance.

In addition to efforts on genetic improvement of soybean, major emphasis has been placed on promoting and using soybean to encourage consumption, and thus create markets for farmers to sell their produce. Recipes were developed to promote the use of soybean grain for food. This promotional activity was necessary because the crop was new in many parts of the region and people were not familiar with how it could be best used as food. Vegetable oil millers were also encouraged to accept soybean as a raw material from where good quality oil could be extracted.

Legumes fix atmospheric nitrogen in their root nodules through the symbiotic association between the crop and rhizobium, a free-living soil bacterium. Legume seeds are inoculated with the rhizobium before sowing to increase the number of rhizobium available to the plant for infection and nodule formation, and subsequently enhance the quantity of the nitrogen fixed. Soybean is one such crop that requires rhizobium inoculation if a good crop is to be established on soils with no existing rhizobia or inadequate number if rhizobia.

At IITA, some soybean varieties have been developed which are capable of fixing atmospheric nitrogen using the native rhizobium present in the soil. These varieties which require no inoculation before sowing are characterized by promiscuous nodulation. Growing such varieties will save the farmers some expense and the time needed to purchase the inoculants with which the seeds are treated.

Conclusions
Decades of collaborative research efforts on genetic improvement of these two important legume crops involving scientists in the national agricultural research systems of different countries in SSA, IITA, and advanced research institutions in Europe and North America have resulted in the development and promotion of different improved varieties to meet the preferences of farmers and consumers. Improved varieties developed through this partnership have been released in over 70 countries around the world, which signifies the success of this partnership for legume crop improvement.

Further efforts will focus on use of innovative approaches to pyramid pest and disease resistance genes into improved lines and varieties; application of molecular markers to rapidly introduce genes for simply inherited desirable traits into popular varieties; and genetic modification using recombinant DNA technology to produce insect-resistant cowpea varieties (Bacillus thuringiensis or Bt cowpea for resistance to the Maruca pod borer). Efforts will be continued to address diseases, such as the need to develop improved cowpea and soybean lines with combined resistance to different fungal, bacterial, and viral pathogens. The factors that influence tolerance to drought in cowpea require further elucidation, as this would facilitate progress in developing new varieties with enhanced drought tolerance.

In Kanti Rawal’s footsteps

Remy S. Pasquet (rpasquet@icipe.org), Dominique Dumet (d.dumet@cgiar.org), and Sunday E. Aladele (sundayaladele@yahoo.com)

Cowpea is a rich source of dietary protein for millions in West Africa. Photo by IITA.
Cowpea is a rich source of dietary protein for millions in West Africa. Photo by IITA.

Cowpea, Vigna unguiculata (L.) Walp. is the major legume crop in the African lowlands. It is the main protein supply of half of the population in sub-Saharan Africa.

Nigeria is the most populous country in West Africa, and also produces the largest amount of cowpea. Its urban population is growing in leaps and bounds, and thus, it is also importing a lot of cowpea from all its neighbors

Cowpea is considered by several authors as having been domesticated in Nigeria or within a larger area including Nigeria (i.e., Vaillancourt and Weeden 1992). In addition, the first wild cowpea accession was collected in northern Nigeria by J.M. Dalziel, a British botanist, and this led Piper (1913) to propose the African origin of cowpea1.

To some extent, this partly explains why Nigeria was the first country surveyed for cowpea accessions by IITA’s then Genetic Resources Unit. Between 1970 and 1973, Kanti Rawal traveled 38,000 km around Nigeria and Niger. He collected wild cowpea accessions as well as numerous accessions of domesticated cowpea.

According to his map, he collected wild cowpea in 68 places (Rawal 1975). Unfortunately, over the years, the passport data of these accessions were lost and, today, the place of collection is known for only four out of the 40 accessions still maintained at IITA.

Regarding Nigeria, Rawal (1975) wrote in the abstract of his paper: “As in the case with many cultivated species, Vigna unguiculata (L.) Walp. has a wild form growing in secondary forests and derived savannahs and a companion weed form adapted to disturbed habitats such as roadside ditches and fields. Evidence of introgressive hybridization between weedy and cultivated forms has been presented. The zone of extensive natural hybridization corresponds to the cultivation area of northern Nigeria and Niger and may well extend to Upper Volta (now Burkina Faso) and Senegal.”

Rawal gave very good descriptions of what he called the wild and weed forms. His wild forms were samples of subsp. baoulensis (A.Chev.) Pasquet; the weed forms were samples of subsp. unguiculata var. spontanea (Schweinf.) Pasquet. We (Pasquet and Padulosi in press) believe that the first subspecies belongs to the secondary gene pool of cowpea and the second to the primary gene pool. However, since Rawal’s material is mostly lost2, the assessment of the diversity of wild cowpea from Nigeria is impossible in the absence of new collection missions in the country.

In addition, factors such as climate change, increased incidence of pests and diseases, cultural change, or the adoption of improved lines are also likely to affect the diversity of cowpea and wild Vigna in the near future. To avoid the irreversible loss of Vigna and to secure highly viable Vigna diversity, the Global Crop Diversity Trust in association with IITA and Nigeria’s National Centre for Genetic Resources and Biotechnology (NACGRAB) organized a collecting mission for wild Vigna germplasm in 2010. The mission covered 27,000 km in Nigeria between 14 October and 7 December and collected 260 accessions (242 of var. spontanea and 18 of subsp. baoulensis . In addition, 13 populations were sampled for further population genetic analysis.

In comparison with the Rawal missions that took place in 1971–73, we surveyed more localities within a shorter time. Unlike Rawal, we focused on wild cowpea only and benefited from a much better road network, especially in northern Nigeria where we were driving more than 600 km/day. In the end, there is a general agreement between the results of Rawal’s survey and our own in terms of geographical distribution of both subspecies.

In the northern ranges, we often encountered wild cowpea in fields or at roadsides. Wild cowpea plants are easy to spot in the field, as they twine 2–3 m above soil level on sorghum or pearl millet stems. Domesticated cowpea are prostrate or short and erect but usually not twining.

Based on the ecological definition of a weed, which is ”an uncultivated plant taxon that benefits from human impacts or ’disturbance’,” var. spontanea is a weed mainly encountered in disturbed places, such as in fields and gardens, at roadsides, and sometimes within towns (sewage ditches, grassy places); it was not observed within Yankari National Park. However, to some extent, var. spontanea is also a weed in the economic sense of the word since it is usually pulled out from the fields by farmers. It usually appears as isolated plants or isolated patches of fewer than 20 plants or as a few plants forgotten by the farmer while weeding.

In some places, we found fields with as many wild cowpea as domesticated cowpea (SP 815, Katsina State, for example). We suspect that, in these places, farmers were primarily interested in fodder. Var. spontanea is obviously a good fodder plant and farmers primarily cultivating cowpea for fodder would not choose to lose time weeding wild cowpea.

Domesticated cowpea close to var. spontanea (white arrow), SP 949, Borno State, Nigeria. Source: R. Pasquet, i<em/>cipe.” title=”domesticated-cowpea-close-to-var-spontanea” width=”300″ height=”252″ class=”size-medium wp-image-2510″ /></a><figcaption class=Domesticated cowpea close to var. spontanea (white arrow), SP 949, Borno State, Nigeria. Source: R. Pasquet, icipe.

Since experiments have proved pollen flow between wild and domesticated cowpea at over 30 m distances (Fatokun and Ng 2007), we checked if domesticated cowpea was grown within 30 m of the collecting sites for wild cowpea. This occurred frequently (70%) in the northern part of the range which is also the main cowpea production area. Our survey confirms Rawal’s (1975) conclusion. There are numerous situations in Nigeria in which domesticated cowpea and wild cowpea exchange genes. Therefore, its diversity may not be much higher than that of the domesticated gene pool. An evaluation of diversity among the collected material would help confirm or disprove this assumption.

The potential hybridization between wild and cultivated forms has implications for the transgenic Bt cowpea which are presently under confined field trials in Nigeria (www.aatf-africa.org/userfiles/Cowpea-Project-brief.pdf). If the Bt gene could move through the pollen from transformed to wild plants, further careful studies need to evaluate the advantage given by the Bt gene to a wild cowpea plant and whether Bt cowpea poses any risk to biodiversity.

References
Fatokun CA and Ng Q. 2007. Outcrossing in cowpea. J Food Agric Environ 5:334–338.

Pasquet and Padulosi. In press. Genus Vigna and cowpea (V. unguiculata (L.) Walp.) taxonomy: current status and prospects. Presented at the 5th World Cowpea Research Conference, Saly, Senegal, September 2010.

Piper CV. 1913. The wild prototype of the cowpea. US Dept. Agric. Bureau Plant Ind. Circular 124: 29–32.

Rawal KM. 1975. Natural hybridization among wild, weedy and cultivated Vigna unguiculata (L.) Walp. Euphytica 24(3):699–707.

Vaillancourt RE and Weeden NF. 1992. Chloroplast DNA polymorphism suggests Nigerian center of domestication for the cowpea, Vigna unguiculata (Leguminosae). Am. J. Bot. 79-10:1194–1199.

David Chikoye: Think of the big picture

David Chikoye
David Chikoye

David Chikoye is the IITA Director for R4D responsible for managing the southern African hub and two programs—the Cereals and Legumes (CLP), and the Horticulture and Tree Crops Programs.

Why did IITA choose Zambia as the hub for the southern African region?
From a historical perspective, IITA has been operating in southern Africa for over 25 years. In fact, we operated in 12 out of 13 countries in southern Africa. We were looking at each country in terms of the contribution to agriculture vis-à-vis policies, the ease of doing work, i.e., the social amenities, and (more importantly), the availability of partners. Zambia was centrally located, and the Government’s policies over time have been pro-agriculture. In Zambia, there is easy access to private farms and also to the NARES.

How crucial is southern Africa to IITA’s mandate?
IITA serves the needs of sub-Saharan Africa. In West Africa, we have made significant progress, especially in Nigeria where the headquarters is located. For instance, in soybean, when we started, Nigeria was not near the countries that were high producers of the crop but now, it is the highest producer in Africa, with about 600,000 ha planted to the crop. What this means is that it is now important for us to start transferring some of the knowledge from the west to the other parts of Africa. The southern African region has challenges similar to those in West Africa, therefore the successes we have made in the west can be transferred to the south with little modification. This has been our strategy.

What is going on in the hub?
Our strategy has been to collect and also interact with our colleagues in southern Africa and use the knowledge which has been generated over time to start testing in southern Africa. Some of the things we have been doing include testing varieties, management and agronomic and postharvest practices, as well as cross-cutting activities such as the training of NARES partners.

Do you see any radical change in the way IITA does its work because of the CG reforms?
In the short run, nothing will radically change. What has happened is that the CG reforms have split some of our programs. For instance, the CLP has been split into two—maize goes into the maize consortium research program (CRP) and legumes go to the legume component of the CRP. Also some of our programs have been consolidated. For example, roots and tubers have been consolidated with banana and plantain, making the program bigger. The Opportunities and Threats program fits very well with the Markets CRP. These to me are minor modifications in the short run. So when you look at the way we manage our programs at IITA, I don’t think anything significant will change although in the long run we might need to make some adjustments. The CG reforms will entail that we do full cost recovery. That means that the way we do business has to change. In summary, the CG reforms have their advantages and disadvantages but generally, they are for the good of the institute.

What would you consider the most significant achievement of the CLP?
The CLP has really made a lot of progress in terms of developing high- yielding varieties together with crop management practices. We have also developed several postharvest technologies. In addition, there has been a wide adoption of these technologies and to me, those are significant developments.

For instance, Striga is a major problem for cereals—maize, rice, sorghum, etc. It has been estimated that Striga alone causes annual losses of about US$7 billion. That negatively affects more than 100 million people. We have been able to develop Striga-resistant or tolerant maize varieties. In cowpea, we have been able to develop varieties that are tolerant of pests and diseases. Significant achievements have been made in this program.

Cowpea market in Nigeria. Photo by IIA.
Cowpea market in Nigeria. Photo by IIA.

What makes it difficult for cowpea to attract the private sector?
Let us look at it this way: cowpea is an African crop compared with maize and soybean that came from other continents. Those crops, by their nature, have attracted a lot of commercial interest. For instance, in maize, the commercial sector is very much interested in marketing seeds—hybrids—but not for cowpea. For soybean, there is a lot of commercial interest in the poultry sector.

Cowpea is a traditional crop—grow it, harvest it, and eat it. It offers a lot of benefits, of which we may not be sufficiently aware. For us to move the crop forward, we need to go into serious advocacy. Again if you look at most programs, they have biases for cereal crops. If you look at maize in most countries, there is some subsidy in terms of input supplies, fertilizer, etc. Nothing like this exists for cowpea but cowpea is relatively easier to grow.

What role can cowpea play in southern Africa?
Over the last 10−15 years, we have had this problem of drought, so I see cowpea diversifying the maize-based system, especially in years when drought will become more pronounced. Southern Africa is again hit by HIV and AIDS. Those people that are affected need nutritious foods. Cowpea, being a protein food, can help to provide some of the nutritional needs. Lastly, livestock production in the region is also significant. Therefore the dual-purpose cowpea will have a significant role to play by providing fodder for livestock. Looking at the bigger picture, cowpea can have a big role to play in solving poverty in Africa.

How can IITA work better with partners?
IITA can contribute to solving poverty but our efforts alone are not enough. We need to look at our comparative advantage; that is in upstream and strategic research. Where we don’t have the comparative advantage, we should look for partners. Traditionally, we work with the NARES but now with the CG reforms, we need to tap into and strengthen our linkages with the private sector. Let’s take advantage of the skills the private sector has, especially in marketing technologies. These guys are good in marketing and they have existing channels which they use in promoting their technologies.

How can scientists become better communicators?
Scientists are good communicators especially in communicating among peers, e.g., in seminars and conferences and publishing in scientific journals. This is so because they all speak the same language. But this is only one component. We need to talk to donors, policymakers, and other people. The question is: can these groups understand our jargon? The answer is usually, no, they can’t. Most scientists need to be retrained on communicating their science to the layperson. This is one of the issues about which IITA’s Director General Hartmann had been reminding scientists—if you work in the lab, think of the big picture. We need to work with the Communication Office and the media to train scientists in communicating effectively to end users.

Any words of wisdom for colleagues?
I don’t think I am qualified to pass words of wisdom. What I want to reemphasize is that the challenges in Africa are many: poverty, malnutrition, etc. IITA is a means that we can use to resolve some of these problems. So as we work for IITA, let’s not forget the big picture—let’s think about the end users.

The time to act is now

Cowpea seedling. Photo by IITA.
Cowpea seedling. Photo by IITA.

For too long, a versatile crop, capable of providing huge benefits for health and wealth stayed on the sidelines, largely below its economic potential and comparatively neglected by research. More recently, however, interest in this grain legume has greatly increased and its benefits have been more widely appreciated and publicized.

Cowpea, or black-eyed pea, is one of the few crops that could positively influence the nutritional status in sub-Saharan Africa. Grown by farmers mostly in West Africa, it is increasingly gaining prominence in the fight against hunger and poverty.

This is reflected in its dual roles as a source of protein for humans that is cheaper than animal products and a way to raise the quality of livestock through improving their feed. Cowpea also provides higher returns on investment than other crops grown in the region where it thrives best.

Harvesting cowpea. Photo by IITA
Harvesting cowpea. Photo by IITA

Unfortunately, support for cowpea research has been relatively low, unlike that for other crops such as wheat and potatoes. Consequently, this has limited the improvement of cowpea.

The situation is not being helped by the negative impact of climate change and unfavorable abiotic factors in the regions where the crop is mostly grown.

Over the years, IITA and its international and local partners have developed solutions to tackle the constraints faced by this “wonder” crop.

These include the development and deployment of improved, Striga-resistant, drought-tolerant, and early maturing varieties. More recently, work is ongoing to produce varieties resistant to the damaging legume pod-borer (Maruca).

Close-up of a cowpea flower. Photo by Christine Peacock
Close-up of a cowpea flower. Photo by Christine Peacock

The impact of these varieties on rural livelihoods and poverty is slowly but surely being felt.

Advances in science could help to further raise cowpea yield. With more resources now going into cowpea research and farmers’ participation in variety selection, even better performing varieties should be available soon.

These efforts have already produced positive results in the target regions but only on a relatively small scale when set in the context of all sub-Saharan Africa.

The task before stakeholders is to join hands with IITA now to advance this crop and to save Africa. The time to act is now.

Recipes

1 Akara

Ingredients
1/2 pound dried black-eyed peas/ cowpeas
2 onions
1 red pepper
Salt
Ground white pepper
Olive oil
2 ripe tomatoes
1 green pepper
1/4 cup chopped parsley leaves

Directions
1. Soak peas for 24 hours or overnight in lots of water. Drain. Peel the outside skin from the peas.
2. In a processor, pulse the 1 onion and red pepper to coarsely chop. Add soaked peas and puree to a paste. Transfer to a bowl and using a whisk, whisk the mixture adding salt, white pepper and just a little soaking liquid — not too much as the mixture needs to retain its shape for frying.
3. Using an ice cream scoop, form into balls about the size of a ping-pong ball. Drop into a pot of hot olive oil, heated to around 180 ËšC. Fry until golden brown. Remove and drain on a paper towel-lined plate. Season again with salt and pepper.
4. To serve, make a quick dipping sauce by pulsing 2 de-seeded tomatoes, 1 onion, 1 green pepper, and some parsley in food processor. Add olive oil and season with salt and pepper to make a chunky salsa.

2 Lobia (Black Eyed Beans Curry)

Ingredients
2 cups Lobia (black eyed beans)
1 1/2 tsp
Salt to taste
1 1/2 tsp ground coriander
3/4 tsp ground cumin
1/2 tsp ground turmeric
2 tbsp oil
1 small onion, chopped
2 large cloves garlic, chopped
1 (3/4-inch piece) ginger root, peeled and chopped
1/2 tsp Scant cumin seeds
1 medium tomato, chopped

Directions
1. In pot soak beans overnight in water to cover generously. Next day, drain beans, cover with fresh water and bring to boil.
2. Add salt, coriander, cumin and turmeric. Simmer until beans are just tender, about 30 to 45 minutes.
3. Heat oil in deep saucepan. Add onion, garlic, ginger, and cumin.
4. Fry 10 minutes and add tomato. Cook another 5 minutes and add lobia (black eyed beans) and cooking liquid. Continue to simmer, uncovered, until lobia are soft but not completely dissolved. Mixture should be soupy.

Lobia Tomato Masala Curry

Ingredients
1 cup cooked black eyed beans
1 onion, chopped
¼ tsp cumin seeds
¼ tsp fenugreek seeds
Salt
Oil
Chopped coriander leaves

Grind:
2 tomatoes, chopped
½ tsp peppercorns
1 tsp coriander seeds
1 tsp fennel seeds
2 tsp poppy seeds
1 tsp cumin seeds
5 garlic pods
3 dry red chillies

Directions
Dry fry the peppercorns, coriander seeds, poppy seeds, cumin seeds, and fennel seeds and simmer for a while. Add the fried seeds and tomatoes, garlic pods with 1 cup water and grind them coarsely. Then add ¼ cup of the cooked black eyed beans to the spices and grind everything as a fine paste.

Heat oil in a pan, add the cumin seeds n fenugreek seeds and let them splutter. Add the chopped onion and stir them until they turn translucent. Next, add the grounded paste and simmer for a while. The mixture will stick very easily to the bottom of the pan, so keep on stirring, adding enough water and salt to the gravy. Once the oil separates from the gravy, add the rest of the black eyed beans and cook the mixture for a few more minutes. Add the chopped coriander leaves, and then turn off the stove.

3 Red-Red (Cowpea stew, also known as Black Eyed Pea Stew)
A traditional Ghanaian recipe for a classic stew of black-eyed peas in a tomato and red palm oil sauce that’s usually served with fried plantain. It might have bene named for the combination of red pepper and red palm oil.

Ingredients
240 g black-eyed peas (cooked)
1 medium onion, sliced
2 large tomatoes, finely chopped
1/2 tbsp chilli powder
2 tbsp red palm oil (or 2 tbsp groundnut oil + 1/2 tsp paprika)
salt and black pepper to taste

Directions
1. Soak the black-eyed peas in water for at least an hour or overnight. After soaking them, rub them together between your hands to remove the skins. Rinse to wash away the skins and any other debris. Drain them in a colander.
2. Mash the black-eyed peas and set aside.
3. Heat the oil in a pan and cook the onion and tomatoes until soft. Add all the remaining ingredients (including the peas) and simmer for 10 minutes.
4. While peas and sauce is simmering, prepare fried plantains.
5. Serve peas and plantains side by side on a plate.

4 Hoppin’ John

Ingredients
• 1 1/2 cups dry black-eyed peas
• 1 pound ham hocks
• 1 onion, chopped
• 1/2 teaspoon crushed red pepper flakes
• salt and pepper to taste
• 4 cups water
• 1 1/2 cups long-grain white rice
• 1 cup shredded smoked Cheddar cheese

Directions
1. In a large pan place the peas, ham hock, onion, red pepper, salt and pepper. Cover with water and bring to a boil. Reduce heat to medium-low and cook for 1 1/2 hours.
2. Remove ham hock and cut meat into pieces. Return meat to pot. Stir in the rice, cover and cook until rice is tender, about 20 to 25 minutes. Season to taste with salt and pepper. Sprinkle shredded cheese over top, if desired. Serve.

Trivia

1. Cowpeas are thought to get their name from when they were a key livestock feed in the USA.

2. The cowpea is 25% protein.

3. Fifty two percent of the cowpeas produced in Africa are used for food, 13% are used for animal feed, 10% are used for their seeds, 9% goes to other uses, and 16% are wasted.

4. In the Southern United States eating black-eyed peas on New Year’s Day is considered good luck because they symbolize money.

5. In Yoruba cowpeas are called ewa or ere. In Hausa they are known as wanke. And across the French-speaking regions of West Africa they are called niebe.

Ousmane Boukar: Cowpea improvement for food security and poverty alleviation

Ousmane Boukar, IITA cowpea breeder, Kano, Nigeria. Photo by IITA.
Ousmane Boukar, IITA cowpea breeder, Kano, Nigeria. Photo by IITA.

Ousmane Boukar is IITA’s cowpea breeder and the Station Representative in Kano, Nigeria. He has been with IITA since 2007. As a breeder, his aim is to mine IITA’s germplasm collection of cowpea to identify important additional sources of gene(s) of interest for resistance to both biotic and abiotic stresses, sources of consumers and producers’ preferred traits, etc. This will broaden cowpea’s genetic diversity to contribute efficiently and significantly to cowpea genetic improvement.

Please describe your work.
My work in IITA is exciting and very challenging. IITA offers a lot of opportunities to contribute to the livelihood of millions of people mainly in sub-Saharan Africa through the improvement of the agriculture sector. I believe that playing a role in cowpea improvement means participating in enhancing food security and poverty alleviation of millions of people in Africa.

What are the current thrusts and initiatives on cowpea breeding?
The cowpea breeding program is focused on identifying additional sources of resistance to pests and diseases, combating parasitic weeds, improving drought tolerance and adaptation to low soil fertility. Our strategy is to consolidate the progress so far achieved and to establish a very strong foundation for further genetic improvement. The aim is to increase production in terms of both fodder and grain yields, and those plant and grain characteristics preferred by consumers and producers. Efforts would also be made to enhance the level of micronutrients and protein in cowpea grains. African rural and sub-urban communities will be able to produce more high quality products for human and animal consumption, to improve their health by providing a balanced diet, and their income by providing enough for home consumption and supply to markets.

Major projects associated with cowpea improvement include Tropical Legumes I and II, Purdue Improved Cowpea Storage, Development and promotion of Alectra-resistant cowpea cultivars, the Application of marker-assisted selection for Striga resistance in cowpea, Improving drought tolerance phenotyping in cowpea, Appropriate Variety of Early maturing Cowpea for Burkina Faso (AVEC-BF), and Development of parasitic weed control methods for world food security.

Cowpea field experiments, IITA. Photo by C. Ono-Raphael, IITA.
Cowpea field experiments, IITA. Photo by C. Ono-Raphael, IITA.

What are the major challenges in cowpea improvement?
Cowpea production is limited by numerous factors both biotic and abiotic which could be addressed using the tools from genetic improvement. Several diseases, insect pests, nematodes, and parasitic weeds cause significant cowpea yield loss. Abiotic constraints include drought and heat which also cause significant yield reduction during the seedling and/or reproductive stages of the crop. Another major production constraint is low soil fertility from organic matter and low phosphorus availability, particularly in the soils of the savannas.

The range of production environments and cropping systems and the diverse preferences among consumers and producers for grain, leaves, pods, and fodder, make cowpea breeding very challenging. There is a clear need to develop a range of varieties that meet the diverse requirements combining high yield potential and resistance to the major production constraints.

How do you decide which challenges to address?
Identification of areas of research involves all stakeholders along the cowpea value chain. We consider both the current and long-term needs of our stakeholders. The current needs are determined from observations in our research fields, farmers’ fields, the attitudes of consumers, and in our interactions with farmers, NARS colleagues, NGOs, traditional and political leaders through farmers’ field days, farmers’ participatory varietal selection, and participation in meetings. The long-term needs are based on our own experiences and those of colleagues. This approach guarantees the continued relevance of our research activities. The various projects enable me to have a good interaction with all the stakeholders.

Who are IITA’s partners in cowpea improvement research?
NARES, advanced research institutions (ARI), NGOs, farmers, traditional and political leaders. Our activities on drought tolerance, for example, involve national and international partners (Mali, Niger, Nigeria, Mozambique, Tanzania, Burkina, and Senegal; and University of California, Riverside). Our Striga and Alectra research activities involve both NARS (Burkina, Senegal, Niger, Mali, and Cameroon for Striga and Malawi and Tanzania for Alectra) and ARIs (University of Virginia for Striga and Natural Resources Institute for Alectra). Our partners are involved right from the initial stages of the projects.

Why is cowpea underexploited and underutilized?
The main reason is that cowpea is a crop grown by poor people for consumption and commercial value in the local regions. This makes the crop unattractive to commercial breeding and seed companies and ensures a lower priority for developed countries.

Sub-Saharan Africa accounts for 70% of the world cowpea production. What could be done to ensure that cowpea receives research attention?
Almost all African governments consider agriculture as the main basis of their economic development. Very good strategies are being developed but unfortunately these strategies are not followed through always! Funding for cowpea research will enable the research institutes and universities to compete for external funding. Very few governments are supporting their research institutions by facilitating contacts or lobbying through major donors.

What new tools are being used to hasten cowpea improvement work?
With the rapid advances in plant genomics and molecular biology, new tools are being developed. Also, the use of molecular breeding combined with conventional breeding is becoming possible in cowpea improvement. A few steps are already being applied in cowpea improvement through marker-assisted selection and genetic modification. With the development of the recent well-saturated consensus genetic map, cowpea improvement is ready to benefit from an increased efficiency of selection resulting from the application of molecular breeding. Tropical Legume I phase II will soon give us an opportunity to test the efficiency and effectiveness of molecular breeding in cowpea.

What are the recent developments and breakthroughs in cowpea breeding that farmers and producers, including processors, could look forward to?
Our intensive activities through the Tropical Legumes II project have led to the identification and release of some drought-tolerant breeding lines. For example, in 2008, IT97K-499-35 was released in Nigeria. The performance of this variety has impressed farmers in Mali who named it jiffigui which means “hope”. Additional adaptation trials are being conducted in Mali and Niger for the release of this line.

Another example is IT00K-1263. This has shown good performance in Mozambique and Tanzania and is being considered for release soon in these countries. Additional sources of improved P-use and resistance to aphids, bacterial blight, multiple virus, Striga, and drought have been identified and segregating populations have been developed. New breeding lines with drought tolerance and multiple disease, and insect and Striga resistance will be available in the near future.

Farmers' participatory varietal selection, northern Nigeria. Photo by IITA.
Farmers' participatory varietal selection, northern Nigeria. Photo by IITA.

How do you involve farmers and producers in your work?
Through farmers’ participatory variety selection (FPVS). This consists of bringing groups of farmers to the field where they can select 2 to 3 varieties that they prefer out of about 20−30 lines. Varieties developed through this approach have showed a higher rate of adoption by the farmers. In addition, farmers’ field days and baseline studies enable us to learn from farmers about their main production constraints and their preferences in terms of plant type, maturity type, and grain and fodder quality. All the information collected is being incorporated in our breeding objectives.

How could IITA make stakeholders pay more attention to cowpea?
For more than four decades, IITA scientists had been working on different aspects of cowpea improvement. By documenting the role of cowpea in the livelihood of people in sub-Saharan Africa, the importance of major cowpea production constraints, the progress so far achieved, and strategies for the future, and by maintaining the world’s collection of germplasm for this crop IITA will continue to make donors and other stakeholders more interested on cowpea.

Is mechanization the solution to cowpea’s woes?

The cowpea is one of the most important grain legumes in Africa. Cowpea is both economically and nutritiously significant. Its ability to fix nitrogen efficiently and grow in a wide range of conditions means that the cowpea is also a suitable companion for a wide range of other food and fiber crops.

Farmer beating cowpea pods to open them. Photo by IITA.
Farmer beating cowpea pods to open them. Photo by IITA.

Nigeria is the world’s largest producer of the crop, growing 45% of the global yield. However, this total amount has dropped considerably in the past 30 years, from 61% in 1981 to 45% in 2004. With cowpea playing such a key role in the agriculture and food supply of Nigeria, production and processing practices need to be improved, emphasized Thierno Diallo of IITA’s Postharvest Utilization Unit.

The production and processing begins before the seeds have even been planted. Land clearance involves cutting down trees, pulling up stumps, leveling the land, and extracting roots and stones.

Of all the agricultural operations, land clearance is the most difficult and costly. After this the soil must be properly prepared to create good conditions for the seeds to germinate and grow. This starts with the time- and energy-consuming preparation of the seed bed and includes planting and fertilizing. The plant must then be maintained for its life span. This means preventing weeds, pests, and organisms that cause diseases such as bacteria, fungi, and viruses, from severely affecting the crop, as well as keeping the cowpea irrigated if so required.

When fully mature the plants are ready to be harvested. This involves cutting the dry pods before they are attacked by birds or rodents. After this the pods must be opened to release the grains. This is done in two stages: first, the pods are beaten to open them and then they are scooped up and fanned out to separate the grains from the shells in a process called threshing. The grains are collected and dried to increase quality and shelf life, then stored.

All of these operations are traditionally done by hand or with the help of animals and are thus associated with drudgery. “The mechanization of existing tools and the promotion of efficient farm management techniques could be the way to increase Nigerian cowpea production once again,” Diallo said. Diallo had been involved in designing some processing machines now in use by small industries in Nigeria and other sub-Saharan African countries.

The advantages of mechanization have already been demonstrated with threshing. Traditionally, sticks were used to beat the grains out of the pods but they sometimes broke the seeds, rendering them useless. In the 1990s, IITA introduced a tool called the Fail-safe Flail, which prevented most of the damage to seeds. The motorized multicrop thresher further improved the process as it could do the job of several workers with flails, taking away much of the drudgery. These two devices increased the productivity of threshing. The recent introduction of a fanning system to the multicrop thresher has made it significantly better still.

Fabricating small machines for processing, IITA. Photo by IITA.
Fabricating small machines for processing, IITA. Photo by IITA.

Drying is another area where successful mechanization has been implemented. Farmers used to spread the cowpea grains on the ground to dry under the sun. The introduction of drying platforms has not only made the process more hygienic but also more flexible as it does not depend on the sun any longer. Dryers of various designs and capacities are available, from small drying shelves to medium-capacity cabinet dryers and high-capacity rotary dryers. The larger dryers use fuels such as charcoal, wood, or diesel as the source of heat. Some are equipped with a milling facility to produce flour.

By upgrading to machines such as these a farmer could not only get through the various stages of production faster but also run systems such as irrigation, uninterrupted. This in turn would cut costs and improve overall yields as well as boosting confidence and encouraging more people to grow cowpea.

Furthermore, the high cost of purchasing or renting a machine would be offset by the fact that one machine is now capable of completing many different tasks.

Thus, when it comes to producing and processing cowpea, a move to mechanization is essential to fulfill the demand for the crop in Africa and worldwide, according to Diallo.