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.

Ensuring the safety of African food crops

aflasafeâ„¢ team: Ranajit Bandyopadhyay, Joseph Atehnkeng, Charity Mutegi, Joao Augusto, Juliet Akello, Adebowale Akande, Lawrence Kaptoge, Fen Beed, Olaseun Olasupo, Tahirou Abdoulaye, Peter Cotty, Abebe Menkir, and Kola Masha, with several national partners

Ground-breaking research by scientists at IITA and partners is ensuring safe food and health for Africans.

IITA, in collaboration with the United States Department of Agriculture – Agricultural Research Service (USDA-ARS) and the African Agriculture Technology Foundation (AATF), has developed a natural, safe, and cost-effective biocontrol product that drastically cuts aflatoxin contamination in African food crops.

Aflatoxins are highly toxic chemical poisons produced mainly by the fungus Aspergillus flavus in maize and groundnut, and on yam chips, but which also affect other high-value crops such as oilseeds and edible nuts. The fungal chemicals cause liver cancer and also suppress the immune system, retard growth and development, lead to chronic liver disease and cirrhosis, and death in both humans and animals. Livestock are also at risk and poultry are particularly susceptible. Cattle are not so susceptible but if they are fed with contaminated feed the toxin “Aflatoxin M1” passes into the milk.

The biocontrol product – aflasafe™ uses native strains of A. flavus that do not produce aflatoxins (called atoxigenic strains) to “push out” their toxic cousins so that crops become less contaminated in a process called “competitive exclusion”. When appropriately applied before the plants produce flowers these native atoxigenic strains completely exclude the aflatoxin producers.

IITA recommends broadcasting 10 kg/ha aflasafe™ by hand on soil 2–3 weeks before the flowering stage of maize to prevent the aflatoxin- producing fungus from colonizing and contaminating the crop while it remains in the field and subsequently in storage. Even if the grains are not stored properly, or get wet during or after harvest, the product continues to prevent infestation and contamination.

The reduction of aflatoxin in maize fields is greater with the application of aflasafe™ than with the deployment of putative low-aflatoxin maize lines. For example, field studies during 2010 and 2011 in Nigeria established that aflatoxin reduction was 16–72%, due to resistant maize hybrids, 80–92% with aflasafe™, and 80–97% with the combined use of resistance and aflasafe™.

Field testing of aflasafe™ in Nigeria between 2009 and 2012 consistently showed a decrease in contamination in maize and groundnut by 80–90% or more.

In 2009, Nigeria’s National Agency for Food and Drug Administration and Control registered aflasafe™ and permitted treatment of farmers’ fields to generate the data on product efficacy for obtaining full registration. In 2011, IITA distributed about 14 t of aflasafe™ to more than 450 maize and groundnut farms, enabling farmers to achieve an 83% reduction in contamination.

The success of the project has led to the expansion of biocontrol research in Burkina Faso, Ghana, Kenya, Mozambique, Senegal, Tanzania, and Zambia.

Between 2004 and 2006, nearly 200 Kenyans died after consuming aflatoxin-contaminated maize. In 2010 over 2 million bags of maize in Kenya’s Eastern and Central provinces were found to be highly contaminated and were declared as non-tradable.

Research conducted by Leeds University and IITA found that 99% of children at weaning age are exposed to health risks linked to aflatoxin in Bénin and Togo.

Across the world, about US$1.2 billion in commerce is lost annually due to aflatoxin contamination, with African economies losing $450 million each year. Aflatoxins are also non-tariff barriers to international trade since agricultural products are rejected that have more than the permissible levels of contamination (4 ppb for the European Union and 20 ppb for USA).

IITA has identified separate sets of four competitive atoxigenic strains isolated from locally grown maize to constitute a biocontrol product called aflasafe KE01â„¢ in Kenya and aflasafe BF01 in Burkina Faso and aflasafe SN01 in Senegal.

The adoption of this biocontrol technology with other management practices by farmers will reduce contamination by more than 70% in maize and groundnut, increase crop value by at least 5%, and improve the health of children and women.

In 2012, G20 leaders launched a new initiative – AgResults – which included aflasafe™ in Nigeria as one of the first three pilot projects to encourage the adoption of agricultural technologies by smallholder farmers.

IITA’s experience in Nigeria has shown that the cost of biocontrol (about $1.5/kg with a recommended use of 10 kg/ha) is affordable for most farmers in the country.

The biocontrol product aflasafe SN01 can potentially reinstate groundnut exports to the European Union lost by Senegal and The Gambia due to aflatoxin contamination. The World Bank has estimated that in Senegal, an added capital investment cost of $4.1 million and 15% recurring cost would attract a 30% price differential to groundnut oil cake. Exports are expected to increase from 25,000 to 210,000 t. The increased export volume and price would annually add $281 million to groundnut exports. For confectionery groundnut, adherence to good management practices would increase export value by $45 million annually.

Currently, a demonstration-scale manufacturing plant for aflasafeâ„¢ is under construction at IITA with a capacity to produce 5 t/h. Market linkages between aflasafeâ„¢ users, poultry producers, and quality conscious food processors are also being created to promote aflasafeâ„¢ adoption, in collaboration with the private sector.

Costs and benefits
Biocontrol of aflatoxin is one of the most cost-effective control methods, with the potential to offer a long-term solution to aflatoxin problems related to liver cancer in Africa. Cost-effectiveness ratio (CER) of treating all maize fields in Nigeria with aflasafeâ„¢ is between 5.1 and 9.2, rising to between 13.8 and 24.8 if treatments were restricted to maize intended for human consumption. Up to 162,000 disability-adjusted life years (DALYs) can be saved annually by biocontrol in Nigeria.

Initial data from a separate study in Nigeria suggest that farmers will receive a return of from 20 to 60% on investment in aflasafeâ„¢ from the sale of maize harvested from treated fields to poultry feed manufacturers and quality-conscious food processors.

Donor support
Research and development efforts on aflasafe™ have been supported by the following donors: Bill & Melinda Gates Foundation, USAID, USAID-FAS, AATF, Commercial Agriculture Development Project of the Government of Nigeria, The World Bank, Austrian Development Cooperation (ADC), Deutsche Gesellschaft für Internationale Zusammenarbeit, GmbH (GIZ), the European Commission (EC KBBE-2007-222690-2 MYCORED), and Meridian Institute. In addition, IITA has received support from Belgium, Denmark, The German Federal Ministry for Economic Cooperation and Development (GTZ BMZ), Ireland, Norway, Sweden, Switzerland, and the UK Department for International Development (DFID).

References
Atehnkeng, J., P.S. Ojiambo, M. Donner, T. Ikotun, R.A. Sikora, P.J. Cotty, and R. Bandyopadhyay. 2008. Distribution and toxigenicity of Aspergillus species isolated from maize kernels from three agroecological zones in Nigeria. International Journal of Food Microbiology 122 (1-2): 74-84.
Atehnkeng, J., P.S. Ojiambo, T. Ikotun, R.A. Sikora, P.J. Cotty, and R. Bandyopadhyay. 2008. Evaluation of atoxigenic isolates of Aspergillus flavus as potential biocontrol agents for aflatoxin in maize. Food Additives and Contaminants 25 (10): 1266-1273.
Bandyopadhyay, R., M. Kumar, and J.F. Leslie. 2007. Relative severity of aflatoxin contamination of cereal crops in West Africa. Food Additives and Contaminants 24 (10): 1109-1114.
Diedhiou, P.M., R. Bandyopadhyay, J. Atehnkeng, and P.S. Ojiambo. 2011. Aspergillus colonization and aflatoxin contamination of maize and sesame kernels in two agroecological zones in Senegal, Journal of Phytopathology 159 (4): 268-275.
Donner, M., J. Atehnkeng, R.A. Sikora, R. Bandyopadhyay, and P.J. Cotty. 2009. Distribution of Aspergillus section flavi in soils of maize fields in three agroecological zones of Nigeria. Soil Biology and Chemistry 41 (1): 37-44.
Donner, M., J. Atehnkeng, R.A. Sikora, R. Bandyopadhyay, and P.J. Cotty. 2010. Molecular characterization of atoxigenic strains for biological control of aflatoxins in Nigeria. Food Additives 27(5): 576-590.
Egal, S., A. Hounsa, Y.Y. Gong, P.C. Turner, C.P. Wild, A.J. Hall, K. Hell, and K.F. Cardwell. 2005. Dietary exposure to aflatoxin from maize and groundnut in young children from Bénin and Togo, West Africa. International Journal of Food Microbiology 104 (2): 215-224.
Kankolongo, M.A., K. Hell, and I.N. Nawa. 2009. Assessment for fungal, mycotoxin and insect spoilage in maize stored for human consumption in Zambia. Journal of the Science of Food and Agriculture 89 (8): 1366-1375.
Oluwafemi, F., M. Kumar, R. Bandyopadhyay, T. Ogunbanwo, and K.B. Ayanwande. 2010. Bio-detoxification of aflatoxin B1 in artificially contaminated maize grains using lactic acid bacteria. Toxin Reviews 29 (3-4): 115-122.
Wu, F. and Khlangwiset, P. 2010. Health and economic impacts and cost-effectiveness of aflatoxin-reduction strategies in Africa: case studies in biocontrol and postharvest interventions. Food Additives and Contaminants: Part A, 27: 496-509.

Multi-CGIAR center initiative launched

The African Development Bank (AfDB) has approved a US$63.24 million fund package for the implementation of a 5-year, multi-CGIAR center project dubbed “Support to Agricultural Research for Development of Strategic Crops in Africa” (SARD-SC).

SARD-SC is a research, science, and technology development initiative aimed at enhancing the productivity and income derived from cassava, maize, rice, and wheat—four of the six commodities that African heads of states, through the Comprehensive African Agricultural Development Program, have defined
as strategic crops for Africa.

The project will be co-implemented by three Africa-based CGIAR centers: IITA, Africa Rice Center, and the International Center for Agricultural Research in the Dry Areas. IITA is also the executing agency of the project. Another CGIAR center, the International Food Policy Research Institute, provides
support to the other centers.

The SARD-SC allows—for the first time ever in a single project—a continental coverage of the food security challenges in Africa.

The project’s goal is to enhance food and nutrition security and contribute to poverty reduction in the Bank’s low-income regional member countries by working across the full value chain of each crop and addressing both food costs and employment creation. Through its value chain approach, SARD-SC will also contribute to crop-livestock integration. Its target beneficiaries are farmers and consumers, farmers’ groups including youth and women, policymakers, private sector operators, marketers/traders, transporters, small-scale agricultural machinery manufacturers, and institutions.

Hartmann: Social science is crucial

DG Hartmann. Photo by IITA.
DG Hartmann. Photo by IITA.

What motivated you to go into international research?
I have to go far to answer that question. I grew up in a very, very poor home where my parents had to worry about how to feed us tomorrow. I think that had something to do with it. So when I was at the University of Florida as a professor, I was teaching development economics. But this was simply about theoretical models. The challenge for us to do something real solid on the ground was really itching in my head. When the opportunities came, I always went for them. I worked in Cuba, Panama, Nicaragua, Cameroon, and Malawi, among other places. And then I not only found enjoyment doing what I was doing but also a lot of satisfaction from doing the real things that I was teaching in theory. It also helped fulfill a hidden desire to help those who were as I used to be.

How has it been working for IITA this past 10 years?
To put it very simply, it has been the best job of my life. I always try to transform myself, so I never want to stay on one job forever. I have had several jobs, but this one has been the best. I could not have designed a more fulfilling job.

What has been your experience at IITA?
I came to IITA and I never knew about the CGIAR systems in institutions of this kind. It was a fantastic surprise to find the kind of people I found in IITA. Looking back, I would say that the biggest, most beautiful surprise since I got to IITA is the dedication of staff here; I have never seen people so dedicated. Staff give almost their all. They put in a lot of long hours; we work most weekends with staff and they are not paid overtime. So, I think they just believe in what they are doing, and this is the most beautiful thing that any administration could ever want. Three years ago, we did a survey of the scientists. All of them said they enjoyed working for IITA because it gives meaning to their lives. I found that the most satisfying input. When you have that kind of people, everything is possible.

What are some of the major changes that you have made in IITA?
Well, I was quite lucky, I think, because unlike some places where a Director General leaves and a new one comes to demolish things and rebuild things in a different way, I was lucky and appreciative that my predecessor had done a good job, and so I did not have to demolish much, actually, anything. I had to build on what he left. So that was very productive.

One thing that I hope that we’ve achieved is to put IITA on a most stable footing. The second thing is, and this is to credit most of the scientists and the administrators and people like DDG-R4D Paula Bramel, the R4D focus that we brought. Now all the scientists think that way. We had an external review last year and when the head of that review was leaving, he called me aside and asked, “What did you do here?” I said, “What do you mean?” He said, “We tried to do this R4D thing in Australia and it was only at the level of the senior administrators,” but the way he had found it here, it permeated all levels, whether it is in the official questions or the unofficial questions scientists talked about. For this success I credit the R4D group. That is very important because it really shapes how the institute behaves and how it focuses; it never takes its eye off the poor.

If you were given the opportunity to start over, what would you do differently?
I wouldn’t do anything differently. I would accelerate some things because we’d predicted in 2002 the changing environment we are now in but what I did not predict was the speed with which the CGIAR would change. And so I would do some things faster. I would move to constructing the hubs more quickly. I would consolidate staff much faster than we have been doing. We tried to do it in a way that would not disrupt the “nice” pace, but the CGIAR changed abruptly in a very different way. So, I would not change the strategies we put in place in 2002 but I would accelerate the speed at which we worked.

IITA's biggest contribution is in the area of food productivity, according to Hartmann. Photo by IITA.
IITA's biggest contribution is in the area of food productivity, according to Hartmann. Photo by IITA.
In what area has IITA contributed the most?

I think IITA’s biggest contribution has been in the area of food productivity, the combination of helping farmers produce more with better varieties, like the soybean story. Many countries are now producing much better than they did before.

Nobody else has the capacity to deal with biological threats because it requires being able to work across borders. National systems, no matter how good they are, cannot work across borders. It is harder for them. IITA can do that easily.

So we really have powerful and helpful capacity. If you bring these two together—dealing with biological threats and improving the productivity of crops—I think that is what IITA has been able to contribute.

What needs to be done to strengthen those areas where you feel IITA is not as strong as it should be?
You are being very diplomatic. You should have asked “What is IITA’s weakness?”
No matter how good you are in your profession you always look for ways to improve and must even be your own hardest critic. In IITA, there are very clear areas where we are weak and we need to strengthen them. In the old days, the CGIAR groups of donors funded us 100%. Now they only fund about one-third, so IITA must find the other two-thirds. The intelligence of knowing where donors are going is weak; the ability is weak to respond to donors when they need something; we don’t have good capacity in making bidding proposals and enough success in winning proposals and that is an area where we really need to work. We need people to be sensitive in each country about how our donors are thinking, changing; where they are going; and then we need a capacity to put this together into winning proposals. The competition is cut-throat and we would not be given any project or funding just because we say we are good. We have to produce good proposals. While we have good people, we can produce the good science. The ability to put it all together in a cohesive competitive proposal is still inadequate in IITA.

This issue of R4D Review is focused on social science and IITA’s impact. How do you see the performance of the social science group in IITA?
The social science group in IITA is crucial, because it is really the broom that brings things together and makes them work to the benefit of the people you want to help.

When IITA started, the emphasis was mostly on the breeding program, which was fine at that time. We were expected simply to produce better plants but more and more the poor and donors were getting frustrated; they wanted to see impact on the ground and you cannot get impact if you don’t understand how things work. For example, when we introduced soybean in Nigeria, IITA was a laughing stock. Nobody expected that Nigerians would be consuming so much soybean, but the IITA staff, being very sensitive, worked on the social dimensions of soybean—not on producing new varieties alone. They looked at what Nigerians ate, how they cooked their food, etc. Today those doubting people are not laughing at IITA any longer and Nigeria has become the largest producer of soybean in Africa. This is social science… so social science is a vital dimension to our biological science.


Most times you wear a hat. Is there a special reason?

(Laughs) I was once interviewed here by the BBC and they asked me if I always wear a hat and I said, yes, even in the shower. I don’t know…when I came to Nigeria my daughter looked at different albums from her grandparents and collected pictures of me from my youth and made a collage. As we were putting it in the house, we noticed, to our surprise, that I had been putting on a hat since I was a kid. I don’t know what brought it about but it seems to be a habit; I was just not aware of it at the time.

Some people like to wear certain clothes or suits or ties, or some guys will never go to work without a tie. I don’t go to work without my hat.

Akin Adesina: Making agriculture work for farmers

Minister Akin Adesina. Photo by IITA.
Minister of Agriculture and Rural Development Akin Adesina. Photo by IITA.

Sir, you have a tall order for yourself and for the Ministry in particular. Could you tell us your program priorities?
The tall order is not one that I actually set. The tall order was set by the people of Nigeria in terms of expectations from the political class. When President Goodluck Ebele Jonathan was endorsed by the people in a huge way, he told Nigerians, “I will never, never let Nigerians down” That is the order.

So my task as Minister of Agriculture is derived from the President’s commitment to Nigerians. I have to make sure that Nigeria’s agriculture delivers in such a way that we can feed Nigerians; that we put a lot of the youth to work; that we can reduce our import dependency; that we can get a new generation of young farmers back into agriculture; that we can diversify the economy from relying just on petroleum; that we can get our crops—cocoa, oil palm, and cotton—competitive and back into the market. My task is to make sure that Nigeria can feed itself with pride and to make sure that Nigeria does not become a dumping ground for food; we should be a net exporter of food.

In practical terms, how will you achieve this?
If you want to rebuild a house, you first figure out what’s wrong with the house before you start putting your structures in place. Nigeria used to be the largest player in palm oil. We were producing 60% of the global production; today, zero. We used to account for 30% of cotton production, just like groundnut; today, we are almost near zero… And so my task is, first and foremost, to bring a new sense of order to the disorder in the agricultural sector.

Today, we must rapidly raise productivity; make improved seeds, hybrids, and fertilizers available to farmers; make sure they have access to finance; and improve their access, so they can actually begin to produce a lot of food for the domestic markets.

The second thing that we have done is to launch the Cassava Green Revolution. As you know, Nigeria produces 45 million t of cassava; we are the largest producer in the world, but we account for 0% in terms of global value addition. For our Cassava Green Revolution, we want our farmers to make money, and they’ll be getting better markets when their cassava is actually processed, for example, as starch, ethanol, glucose, chips for livestock feed and, of course, gari.

We have also launched a Green Revolution for sorghum and a Green Revolution for sweetpotato, because sweetpotato, especially the orange-fleshed kind, allows us to add beta-carotene for kids. In terms of cash crops, we are looking at cocoa and oil palm.

What has been the response of the private sector? How do you intend to bring them into your strategy?
The private sector is the engine of growth. Every time you unlock the power of the private sector, you will create a lot of jobs and have significant amounts of growth. Agriculture is a business, so we need the private sector in the seed set-up. For example, in this country we have about 11 seed companies that are functional. Those seed companies need access to financing to be able to expand their production from the current level of about 5000 t to a million t. That means that they must have access to land and financing—for processing and seed-processing equipment—long-term investment, not just working capital. And so, the Ministry is putting together a venture capital fund that will enable our seed companies to get access to the financing that they need.

What role could partners such as IITA and NGOs play in your strategy?
First and foremost, I cut my teeth in research, actually working for the CGIAR. I also worked in IITA in the 1990s. I am enormously proud of IITA, of what it IITA does, and its impact on Nigeria and all of Africa. Why are the international agricultural research centers (IARCs) such an important system? There’s a history to that. When the Green Revolution started in Asia, it happened because the International Wheat and Maize Improvement Center (CIMMYT) in Mexico and the International Rice Research Institute (IRRI) in the Philippines worked on new varieties of wheat and rice that rapidly increased farmers’ yields by three or four times.

Launching a Green Revolution in cassava in Nigeria. Photo by IITA.
Launching a Green Revolution in cassava in Nigeria. Photo by IITA.

That particular situation lifted a billion people out of poverty in Asia. The basis of that was the IARCs. In Africa, the prime center of the system is IITA. IITA has done well. There was a time when we had a problem with the cassava mealybug that was destroying cassava all over Africa. IITA helped to develop a biocontrol program that dealt with it and with a billion dollars worth of benefits. In fact, it is probably the best research ever in the world in terms of biocontrol for any given thing when it comes to rate of return.

IITA was behind the Maize Revolution in the northern Guinea savanna of Nigeria in the 1980s. IITA released new varieties of maize that turned the entire northern Guinea savanna from relying on sorghum to producing maize as a cash crop.

Let’s look at IITA and soybean. Nigeria never used to grow soybean; we were importing it. The Nigerian Government supported IITA then; some people said we shouldn’t. In fact, some foreign Governments said, “If you support IITA, we would not fund IITA any longer.” The Nigerians said, “No, we will support IITA” and they did. IITA then released the TGx varieties in the northern Guinea savanna. Today, Nigeria is the largest producer of soybean in Africa. IITA also continues to work on developing better, high-yielding varieties of maize and soybean. In addition, IITA is working on aflasafeTM which is dealing with the huge problem of aflatoxin contamination in the north.

This shows that one cannot get far without research. It’s not just IITA; we have other IARCs here, such as AfricaRice, CIMMYT, International Center for Research in the Semi-arid Tropics (ICRISAT), and the International Livestock Research Institute (ILRI), all working in Nigeria and all in their own way having significant impact. I believe that for us to achieve the Green Revolution, IITA and other organizations have to put more effort in pushing out appropriate technologies to farmers. There has to be better coordination and synergy between the IARCs and our national institutes. When India achieved its Green Revolution, most of the people who did the work were from the Indian Agricultural Research Council. For Nigeria, we want our national agricultural research centers strengthened so as to be level partners with IITA.

At the end of the day, we have to make sure that there is R4D, research for development, not research for research. IITA and other centers are pioneering this area, making sure that agricultural research is relevant to the needs of the end user.

If you look at investment in agricultural research, it has the highest rate of return of anything—higher than that from health and education. If you can just increase the productivity of agriculture in Nigeria by 10%, you can lift 70 million people out of poverty. Obviously, that requires investment in research. My own desire is that the donors that are supporting IITA continue to support IITA and other IARCs still more because we need them for our Green Revolution.

But in addition, our Government also needs to look at the amount of money we are spending on agriculture compared to what was agreed at the NEPAD—countries were to put 10% of their budget into agriculture. If we are at 3% and less, we need to change that and be able to come back to 10%. Mali, Niger, Burkina Faso, Malawi, Kenya, and Ethiopia are all at 10% and more, and we have more mouths to feed than they have. So, we can’t just simply say we are relying on external institutions; we must have sufficient resources to drive the agriculture change process. Also, domestically, research pays off enormously.

As a former member of staff in IITA, what are the areas you think need to be strengthened?
IITA must ensure that its available technologies such as cassava varieties that give 40—50 t/ha reach farmers. Secondly, IITA needs to get back into what it used to do before: training national scientists, providing them with opportunities to come in and spend sabbaticals at IITA. At the end of the day, it is the national institutions that will have to deliver the change, but you need strong national partners to work with.

The other thing that I think is crucial is for IITA is to work more on markets. It needs to make sure that the value-chains for commodities such as maize or cassava really work. I really admire what DG Hartmann has done in that area. He’s putting the focus on markets. This is very important and I hope IITA will continue to do more of that.

Agriculture is not just about food, says Minister Adesina. Photo by IITA.
Agriculture is not just about food, says Minister Adesina. Photo by IITA.

Finally IITA needs to look at policy. When the Green Revolution happened in Asia, there were policies that drove the changes. The CG centers did not just leave the varieties there; they pushed and drove the necessary changes. So, there needs to be strong policy advocacy from IITA and other centers to help farmers have access to seeds, fertilizers, markets, and infrastructure. In the case of technology, don’t just produce technology and assume that, somehow, the technology will find its way to the farmer’s field. Stick with it, work with the Ministry of Agriculture; work with Government to make sure that the technology actually is in the farmer’s field and that it works.

Who is your role model?
I have two role models. My first role model is my father, who was a farmer. In those days, he used to work on people’s farms as a laborer with my grandfather. After days of hard work and at the age of 14, my father couldn’t read and write. He said agriculture wasn’t paying for him to go to school. Fortunately a Good Samaritan came around and saw him on the farm and took him to Lagos. That’s how my father was educated and eventually became a Government Auditor. That’s the only reason why you are interviewing me now; it’s because somebody sent my father to school.

My father told me that there are so many people who had missed opportunities in life just because agriculture was not working for them. So he taught me very early in life that if I ever found myself in a position to make a difference, especially for farmers, I should make sure agriculture work would for them. He said agriculture was not just about food; it’s about creating wealth for farmers, providing an income to send their kids to school and have a better life. And that has always been the guiding light in my profession: making sure that agriculture works for millions of poor farmers.

My second role model is Dr Norman Borlaug, the father of the Green Revolution in Asia, who inspired me so much. I believe in all that I do. I am driven by the fact that one day, I’ll give an account to God for the responsibilities and opportunities given me to change the lives of people. So it’s not just academic work; it’s a life mission for me, to make sure that agriculture works to transform the lives of our people. So in between my father teaching me the right values and Dr Borlaug showing me that it can be done, I have a very tall order to fill indeed.

Plant health matters

To ensure food security in Africa, plant health matters need to be given immediate attention. Photo by J. Oliver, IITA.
To ensure food security in Africa, plant health matters need to be given immediate attention. Photo by J. Oliver, IITA.

Efforts by national and international research systems during the last two decades have contributed to nearly doubling the production of major staple foods including cassava, maize, yam, and banana in Africa. Most of these gains, however, have come about as a result of an expansion of the planted area, but crop production per unit area of the land is lower than anywhere else in the world.

Yet the continent is expected to improve food production dramatically, doubling or tripling the existing capacity, to feed over 200 million undernourished people1. Although new varieties have contributed to improve crop production, productivity, and quality, their performance has been constrained by suboptimal conditions, such as declining soil fertility, drought, attacks by pests and diseases, and lack of good quality planting material.

The current approach—expanding the area under agriculture to increase food production—is unsustainable and results in significant ecological damage. This realization worldwide is driving the search for newer options to intensify agriculture within the existing area.

We believe that ensuring plant health is pivotal to increase productivity and the strategy of intensifying sustainable agriculture2. The compelling reason for this is that biological threats, such as diseases, pests, and weeds are directly responsible for reducing crop yields by at least one-third3, and at least half of these losses could easily be averted using simple and affordable technologies and practices that prevent diseases and pests from affecting plants and produce. Ensuring plant health, therefore, is one of IITA’s most important R4D strategies to improve agricultural productivity and food security and reduce poverty.

This issue highlights some of the technologies and strategies developed and promoted by IITA and its partners for plant health protection.

The value of plant health management cannot be underestimated given the precarious nature of agricultural systems in Africa with the evolution, establishment, and quick spread of pests and diseases, such as fruit flies, cassava brown streak and banana bacterial wilt.

Although plant health protection measures are relatively easy to adopt, considerable training, awareness creation, and financial support are required to improve skills and infrastructure in national systems to foster the technology transfer to farms where plant health matters.

True national defense is a huge offensive force against biological threats to food systems.

1 FAO. 2010. The State of Food Insecurity in the World 2010. FAO, Rome.
2 www.bis.gsi.gov.uk/foresight
3 Oerke EC. 2006. J. Ag. Sci. 144: 31–43.

Edition 4, March 2010

Biodiversity and NRM
Biodiversity conservation is key
Insect biodiversity for NRM
Why manage noncrop biodiversity
A research park for Africa
Unlocking the diversity of yam
Cassava: improver of soils
Participatory yam conservation strategies
Smart NRM approaches
DNA barcodes for pathogens
A new food security crop?

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African yam bean: a food security crop?

Daniel Adewale, d.adewale@cgiar.org

Read the Ukranian translation by Martha Ruszkowski

Diversity in color, color pattern, structure, texture, brilliance, etc. of African yam bean seeds. Photo by D. Adewale, IITA.
Diversity in color, color pattern, structure, texture, brilliance, etc. of African yam bean seeds. Photo by D. Adewale, IITA.

Biodiversity assures the evolutionary continuity of species. The collection and conservation of diversity within species are a safeguard against the loss of germplasm. They provide a buffer against environmental threats and assure continual and sustainable productivity. Global food security is becoming shaky with increasing dependence on a few major staple crops. This has resulted in an alarming reduction not only in crop diversity but also in the variability within crops.

The conservation and maintenance of agrobiodiversity of neglected and underutilized plant species such as African yam bean (AYB) in seed banks aim at contributing to food security and preventing a potential food crisis. Increasing the use of underutilized crops is one of the better ways to reduce nutritional, environmental, and financial vulnerability in times of change (Jaenicke and Pasiecznik 2009); their contribution to food security is unquestionably significant (Naylor et al. 2004, Oniang’o et al. 2006). Among other things, the consumption of a broader range of plant species ensures good health and nutrition, income generation, and ecological sustainability.

Potentials of African yam bean
The plant (Sphenostylis stenocarpa) is one of the most important tuberous legumes of tropical Africa. It is usually cultivated as a secondary crop with yam in Ghana and Nigeria. A few farmers who still hold some seed stocks, especially the white with black-eye pattern, plant it at the base of yam mounds in June or July. The crop flourishes and takes over the stakes from senescing yam. It flowers and begins to set fruits from late September and October. The large bright purple flowers result in long linear pods that could house about 20 seeds.

The seed grains and the tubers are the two major organs of immense economic importance as food for Africans. This indigenous crop has huge potential for food security in Africa. However, there are cultural and regional preferences. In West Africa, the seeds are preferred to the tubers but the tubers are relished in East and Central Africa (Potter 1992). The crop replaces cowpea in some parts of southwestern Nigeria (Okpara and Omaliko (1995). Researchers (Uguru and Madukaife 2001) who did a nutritional evaluation of 44 genotypes of AYB reported that the crop is well balanced in essential amino acids and has a higher amino acid content than pigeon pea, cowpea, and bambara groundnut.

Tuber yield per stand of AYB accession TSs96 at Ibadan, 2006. Photo by D. Adewale, IITA.
Tuber yield per stand of AYB accession TSs96 at Ibadan, 2006. Photo by D. Adewale, IITA.

Apart from the use of soybean as an alternative to animal protein, protein from other plant sources is not often exploited. The protein content in AYB grains ranged between 21 and 29% and in the tubers it is about 2 to 3 times the amount in potatoes (Uguru and Madukaife 2001, Okigbo 1973). AYB produces an appreciable yield under diverse environmental conditions (Anochili 1984, Schippers 2000). Another positive contribution of the crop to food security is the identification of the presence of lectin in the seeds, which could be a potent biological control for most leguminous pests.

Biodiversity
Although the vast genetic and economic potentials of AYB have been recognized, especially in reducing malnutrition among Africans, the crop has not received adequate research attention. Up to now, it is classified as a neglected underutilized species or NUS (Bioversity 2009). Devos et al. (1980) stressed that the danger of losing essential germplasm hangs over all cultivated food crop species in tropical Africa, especially those not receiving research attention. The quantity and availability of AYB germplasm is decreasing with time. At one time, Klu et al. (2001) had speculated that the crop was nearing extinction; its inherent ability to adapt to diverse environments (Anochili 1984, Schippers 2000) may have been responsible for its continual existence and survival. Nevertheless, scientists think that the genetic resources of AYB may have been undergoing gradual erosion.

IITA keeps some accessions of the crop, but otherwise, its conservation in Nigeria is very poor and access to its genetic resources is severely limited. Seeds of AYB seem to be available in the hands of those who appreciate its value, i.e., the elderly farmers and women in a few rural areas in Nigeria. The ancient landraces in the hands of local farmers are the only form of AYB germplasm; no formal hybrid had been produced as yet.

Improvement of the crop is possible only when the intraspecific variability of the large genetic resources of the species is ascertained. The genetic resources of AYB need to be saved for use in genetic improvement through further exploration in tropical Africa and for conservation.

African yam bean plant showing mature pods ready for harvest. Photo by Daniel Adewale, IITA.
African yam bean plant showing mature pods ready for harvest. Photo by Daniel Adewale, IITA.

Understanding AYB
Eighty accessions (half of the total AYB collection under conservation in the IITA genebank) were assessed for diversity using morphological and molecular methods. Thirty selected accessions were further tested in four ecogeographical zones in Nigeria to understand their productivity and stability. The breeding mode was also studied.

Findings show that each of the 80 accessions of AYB has a unique and unmistakable genetic entity, promising to be an invaluable genotype as a parent for crop improvement. Morphologically, two groups have evolved: the tuber forming and the nontuber forming.

Grain yield differed among individual accessions and across the four agroecologies. The average grain yield across the four diverse environments in Nigeria (Ibadan, Ikenne, Mokwa, and Ubiaja) was ~1.1 t/ha; however, grain yield at Ubiaja was well above 2 t. Most agronomic and yield-determining traits had high broad sense heritability and genetic advances, assuring high and reliable genetic improvement in the species. AYB is both self fertilizing and an outcrosser; the latter trait is exhibited at about 10%.

The good news is improvement through hybridization is possible within the species.

References
Anochili, B.C. 1984. Tropical Agricultural Handbook. Pages 48–50 in Food Crop Production. Macmillan Publishers, London, UK.

Bioversity International. 2009. http://www.bioversityinternational.org/scientific_information/themes/neglected_and_underutilized_species/overview.html [25 February 2010].

Devos, P., G.F. Wilson, and E. Delanghe. 1980. Plantain: Genetic resources and potential in Africa. Pages 150–157 in Genetic Resource of Legumes in Africa edited by Doku, E.V. Proceedings of a workshop jointly organized by the Association for the Advancement of Agricultural Science in Africa and IITA, Ibadan, Nigeria, 4–6 January 1978.

Jaenicke, H. and N. Pasiecznik. 2009. Making most of underutilized crops. LEISA Magazine, 25(1):11–12.

Klu, G.Y.P., H.M. Amoatey, D. Bansa, and F.K. Kumaga. 2001. Cultivation and uses of African yam bean (Sphenostylis stenocarpa) in the Volta Region of Ghana. The Journal of Food Technology in Africa 6:74–77.

Naylor, R.L., W.P. Falcon, R.M. Goodman, M.M. Jahn, T. Sengooba, H. Tefera, and R.J. Nelson. 2004. Biotechnology in the developing world: a case for increased investment in orphan crops. Food Policy 29:15–44.

Okigbo, B.N. 1973. Introducing the yam bean (Sphenostylis stenocarpa) (Hochst ex. A. Rich.) Harms. Proceedings of the first IITA Grain Legume Improvement Workshop, 29 October–2 November 1973, Ibadan. Nigeria. pp. 224–238.

Okpara, D.A. and C.P.E. Omaliko. 1995. Effects of staking, nitrogen and phosphorus fertilizer rates on yield and yield components of African yam bean (Sphenostylis stenocarpa). Ghana Journal of Agricultural Science 28:23–28.

Oniang’o, R.K., K. Shiundu, P. Maundu, and T. Johns. 2006. Diversity, nutrition and food security: the case of African leafy vegetables in Hunger and poverty: the role of biodiversity. Report of an International Consultation on the role of biodiversity in achieving the UN Millennium Development Goal of freedom from hunger and poverty edited by Ravi, S.B., I. Hoeschle-Zeledon, M.S. Swaminathan, and E. Frison. Chennai, India, 18–19 April 2005. M.S. Swaminathan Research Foundation, Chennai, India. pp. 83–100.

Potter, D. 1992. Economic botany of Sphenostylis (Leguminosae). Economic Botany, 46: 262-275.

Schippers, R.R. 2000. African indigenous vegetables: An overview of the cultivated species. Natural Resources Institute/ ACP-EU Technical Centre for Agricultural and Rural Cooperation, Chatham, UK. pp. 89–98.

Uguru, M.I. and S.O. Madukaife. 2001. Studies on the variability in agronomic and nutritive characteristics of African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich. Harms). Plant Production and Research Journal 6:10-19.

Dominique Dumet: Safeguarding agrobiodiversity for the future

Dominique Dumet showing seeds, IITA genebank. Photo by J. Oliver.
Dominique Dumet showing seeds, IITA genebank. Photo by J. Oliver.

As the head of IITA’s Genetic Resources Center (GRC), Dominique Dumet says she is something between a curator and an administrator. She is involved in conservation (field bank, seed bank, and in vitro bank, which includes cryopreservation for clonal crops), checking inventory, improving processes and workflows, transferring technology, and computerizing the system. In addition, she is involved in recruiting staff and selecting students, germplasm distribution and acquisition, research in plant genetic resources, staff management, research project development and proposal writing, and communication to donors on special projects and about germplasm at IITA during scientific meetings.

She is primarily interested in ex situ conservation and particularly low temperature biology and its application to conservation systems (cryopreservation, sanitation). She has an overview of all domains of germplasm conservation and takes part in various research projects as a collaborator to “add value to the germplasm.” She no longer considers herself a researcher, since she spends most of her time administering the genebank and planning or writing proposal or reports. This International Year of Biodiversity, she explains what GRC plans in support of promoting biodiversity conservation.

Why is biodiversity conservation important? What are your priorities?
Our work is very important. We try to reduce the rate of irreversible loss in the biological diversity that is used in agriculture. All conservation aspects are important, but maybe the conservation sensu stricto comes first if we have to choose as we have a responsibility towards the international community and if we do not work well, all may suffer from our mistakes.

What do you like about working in Africa? In your field of specialization?
I am proud of my job. I hope I contribute to improving the well being of the poorest even if for one iota. I also like being in an environment very different to the one in which I grew up.

In vitro biology and cryopreservation in particular is my field of specialization. Cryopreservation fascinates me as I find it amazing that we can stop the life of a tissue and bring it back again whenever we want to do so. In the frozen stage, all biochemical or biological processes stop—that means that everything stops moving at one moment—and then the magic of life makes it start again so long as physical and chemical parameters are adequate (cooling and thawing temperature, osmotic pressure, light, growth regulators, etc.).

What are your challenges and constraints at work?
The challenges are to maintain the bank at international standards and to keep all the accessions alive. Some constraints include unforeseen requests which make us work under pressure as we still have our routine activities, and new concepts that make our system obsolete.

Collection recording with barcode inventory system, IITA genebank. Photo by O. Adebayo, IITA.
Collection recording with barcode inventory system, IITA genebank. Photo by O. Adebayo, IITA.

How do you make the many visitors to GRC understand and appreciate what you are doing?
I give information on the basic concepts of diversity, I explain why we need to conserve it ex situ (out of the natural environment) because of the genetic erosion taking place in the field. Then I explain how we maintain it via seeds or field and in vitro banks, depending on the crop. I also show some examples of diversity, e.g., cowpea seed collection and the variation observed at seed coat. I provide some background on the gaps in the collection based on GIS. And I generally conclude with the International Treaty and access to plant genetic resources for food and agriculture (PGRFA).

Please cite some concrete steps being taken by IITA in biodiversity conservation.
IITA was involved in collecting genetic resources as early as the 1970s so we do have a long history in investing in biodiversity conservation. Many collecting missions have been organized and germplasm has been also acquired from many national collections. The majority of the collections have now been described at agromorphological level, but we are still working on it for maize, for example. We have to characterize any new accessions coming into the bank.

Recently we organized a meeting and survey to develop the cowpea global conservation strategy (Trust-funded). We will have the same strategy developed for yam in 2010 (we are also organizing the Trust-funded expert meeting for this). We are developing more efficient conservation processes such as cryopreservation (this lowers costs but also limits genetic variation during storage). We are fingerprinting the collections of clonal crops to identify germplasm at accession level. This will further guide our collecting missions.

Do you think governments everywhere are serious about biodiversity conservation?
That depends on the country. The richer ones certainly take more serious action—but the poorest (or the less organized) do not have this ‘luxury’. I think all understand the value of biodiversity but as it is a long-term investment to store and as the return on investment is not guaranteed, countries either ignore it or do little about it.

What is the state of agrobiodiversity in Africa?
It is not too bad, compared to other continents—my view on this is that Africa has not yet undergone its Green Revolution (but this opinion may be controversial). However, things may change very quickly, especially now that Africa is seen as a big field where agriculture can take off. Somehow, if we are successful in producing high-yielding crops the adoption rate of such high potential crops may quickly wipe away natural diversity, including (but not only) the landraces (varieties developed by farmers over thousands of years). When the elite genotype replaces older varieties it makes the low performing one obsolete and it increases the rate of planting (as it can generate higher revenue). We have to be vigilant about this since we, as breeders of improved varieties, are partly responsible. There is a conflict of interest between agriculture intensification and conservation of biodiversity.

Do farmers understand the need to conserve seeds or genetic resources for future generations?
In general I would think they are the first one to know about biodiversity but they may not be aware of the amplitude of the “erosion” of species.

Some are already organized in community based genebanks and there are participatory conservation projects within the CGIAR but I do not know enough about the topic. This may be an important complementary approach, but participatory conservation may be difficult to sustain. Besides in community based conservation, the incentive is cultural preference. That means only materials of immediate interest for the farmers are kept.

Bambara groundnut seeds. Photo by J. Oliver, IITA.
Bambara groundnut seeds. Photo by J. Oliver, IITA.

What is the status of IITA’s seed shipment to Svalbard in Norway?
We had planned on sending more than 20,000 accessions of cowpea and its relatives, bambara groundnut, maize, and soybean in the next few years. Cowpea makes up the majority of the accessions that we are sending. There is a bit of deviation from the original plan but we are more or less on track.

Being the lead person in agrobiodiversity conservation in the Institute, how do you plan to mark the UN International Year of Biodiversity?
We plan to raise awareness about biodiversity among the youth, i.e., high school students and adults in the local community. We will organize quiz contests, tree planting activities, excursions to the IITA forest and to the genebank; produce information materials (videos, flyers, handouts) and set up roaming exhibits and posters.

We also plan to organize seminars and a field or biodiversity/community day for students, farmers, and residents in the local community. We will be coordinating with partners from the University of Ibadan, local schools, Alliance Française, and other organizations, such as the National Center for Genetic Resources and Biotechnology, Nigeria Institute of Horticulture, and University of Abeokuta.

What would be your message to colleagues about biodiversity conservation?
Don’t just conserve; educate as well.

Safeguarding local varieties ensures food security

Cassava pile after harvest. Photo by IITA.
Cassava pile after harvest. Photo by IITA.

Cassava is a food security crop to more than 600 million people in the developing world, providing incomes to resource-poor farmers, improving their livelihoods, and serving as a buffer against food crises.

The strategic importance of cassava, however, is being threatened, especially in Africa, as local varieties are in danger of disappearing because of genetic erosion and other human and natural factors.

“In Guinea, for instance, about seven local cassava varieties are fast disappearing. This is risky, especially for cassava since it is a clonal crop,” according to Paul Ilona, IITA Senior International Trials Manager. Clonal crops are those propagated through cuttings or other plant parts, not by seeds.

Genetic erosion is a process whereby the already limited gene pool of an endangered species of plant or animal diminishes even more when individuals from the surviving population die out without getting a chance to breed within their endangered low population.

Both local and improved cassava varieties alike create a robust gene pool, offering choices for breeders in future breeding programs. However, the loss of genes from the extinction of some local varieties could limit future improvement programs. The endangered varieties may hold key traits that could offer possible solutions to hunger and poverty in the future.

Woman selling cassava, local market, Nigeria. Photo by IITA.
Woman selling cassava, local market, Nigeria. Photo by IITA.

To prevent the genetic erosion of cassava, IITA and the Institut de Recherche Agronomique de Guinée (IRAG) have stepped up efforts to save native African varieties with the collection of 73 local varieties from Guinea, West Africa.

These varieties are now conserved under ex situ conditions at IITA’s Genetic Resources Center (GRC) in Ibadan, Nigeria. They form part of a collection to safeguard the continent’s plant genetic resources. The collecting mission in that West African country last year was funded by the Global Crop Diversity Trust (GCDT), IRAG-Guinea, and IITA.

“The conservation of local varieties provides hope for future cassava breeding programs and helps to guarantee food security in Africa,” says Dominique Dumet, GRC Head and coordinator of the collecting mission.

Ilona says the loss of native cassava varieties might limit the number of genes available for breeders to work with. “For breeders, any time we lose (crop) genes, it hurts. That is why the conservation of local cassava varieties at GRC is important to us,” he says.

Apart from cassava, the IITA-GRC holds over 25,000 accessions of major African food crops, including cowpea, yam, soybean, bambara nut, maize, and plantain/banana. IITA shares these accessions without restriction for use in research for food and agriculture.

The collecting mission makes Guinea the fourth country, after Angola, Togo, and Bénin, to allow IITA to collect and share their germplasm with other countries, since the International Treaty on Plant Genetic Resources for Food and Agriculture went into force in June 2004.