Tackling the banana menace

Lava Kumar, l.kumar@cgiar.org, and Rachid Hanna, r.hanna@cgiar.org

Banana bunchy top disease (BBTD) is emerging as a serious threat to banana and plantain production in several regions in West-Central and Southern Africa. IITA is undertaking research to understand the factors leading to the increase in BBTD incidence and spread with the ultimate goal of developing integrated strategies to protect bananas from this menace.

BBTV-infected plants in field. Photo by L. Kumar, IITA
BBTV-infected plants in field. Photo by L. Kumar, IITA
The livelihoods of over 70 million people are intimately linked to banana (banana and plantain), a major food staple and premier fruit. It occupies an important position in the agricultural economies in sub-Saharan Africa (SSA). Banana plantations produce fruits all year round, providing farmers with food and income, even during fallow seasons, thus contributing to food security.

Various types of banana are grown in SSA: plantain in the humid lowlands of West and Central Africa; highland cooking banana in East Africa; and introduced dessert banana in all the subregions.
The world’s greatest variability in the crops is held in West and Central Africa for plantain and Great Lakes Zone in Eastern Africa for highland banana. These regions are considered as secondary centers of banana diversity.

The foe
Bunchy top disease caused by banana bunchy top virus (BBTV) is emerging as a serious threat in several regions in Central and Southern Africa. This disease, first reported from Fiji in 1889, has been dubbed as one of the most destructive plant viral diseases. BBTV has been found in Asia, Africa, Australia, and the South Pacific islands. It belongs to the genus Babuvirus of the family Nanoviridae. The virus readily spreads in vegetative material such as corms and suckers. It also relies on the banana aphid, Pentalonia nigronervosa, its sole biological vector.

Banana with typical bunchy top disease symptoms. Photo by L. Kumar
Banana with typical bunchy top disease symptoms. Photo by L. Kumar
BBTV curtails plant growth, resulting in unproductive plants. Leaves of infected plants have pale chlorotic margins, dark green dots, and streaks along the veins which often extend down the midrib and petiole. Emerging leaves become progressively smaller and choked in the throat of the plant creating the “bunchy” appearance at the top.

Plants infected at an early age rarely produce fruit and eventually die. Those infected at a later growth stage may produce bunches, often with deformed fruits, but suckers have typical symptoms and remain unproductive. Due to the high destructive potential of BBTV on biological diversity and human activities, the Invasive Species Specialist Group (ISSG) of the World Conservation Union (IUCN) included BBTV in the list of 100 of the World’s Worst Invasive Alien Species.

Formidable challenges
Usually viral diseases are effectively controlled through the use of resistant sources. So far, banana varieties resistant to BBTV have not been found. Some types are tolerant or express symptoms relatively slowly. Eradication and exclusion are the only options found to be effective in controlling BBTV. These phytosanitary approaches rely heavily on early detection and destruction of the diseased mats, coupled with strict quarantine and indexing procedures to prevent further spread.

For instance, in Australia, strict legislation prevents the transfer of plant material from infected to uninfected areas. Skilled workers conduct regular inspection to identify and destroy any plant displaying disease symptoms. Thus, disease incidence has been kept at a very low level.

However, rigorous enforcement of phytosanitary procedures is expensive and extremely difficult to implement in SSA where socioeconomic conditions are poor and capacity is inadequate. In addition, banana cultivation is mainly carried out by subsistence farmers and large areas occur in the wild. Under these conditions, eradication is very difficult and this can affect livelihoods of the farmers. More research is necessary to devise control strategies that are congenial for application in SSA.

Distribution map of BBTV and the banana aphid in Africa. Map by IITA
Distribution map of BBTV and the banana aphid in Africa. Map by IITA
BBTV distribution in Africa
In Africa, the virus was first reported from Egypt over a century ago. In the 1950s, it was reported from Central Africa. The origin of this virus is not clear, but it may have been introduced into Africa through infected suckers brought by migrants from South Asia. Subsequent spread might have occurred from the movement of infected suckers by humans and natural spread by the vector aphids.

Despite its presence for at least five decades, the disease attracted very little attention until its recognition in the mid-1990s in Burundi, Malawi, and Rwanda where it was causing serious epidemics.

Our surveys from 180 sites in West, Central and Southern Africa point to 1994-1996 as the years when there was widespread appearance of the disease.

Presently, BBTV has been identified in Angola, Burundi, Cameroon, Congo, DR Congo, Equatorial Guinea, Gabon, Malawi, Mozambique, Rwanda, and Zambia.

Banana aphid and biocontrol
The banana aphid is widespread in SSA. Considerable variations in abundance were observed in our studies depending on locality, banana variety, and season. The aphid is likely to be responsible for much of the local spread of the disease and to some extent its long distance transport. Unlike annual crops, where the fallow period acts as a check for vectors, the perennial nature of banana allows aphids to survive all year round, aiding virus spread.

Aphid control will play a significant role in BBTD management.

Banana aphids are found between the whorls of the pseudostem and newly emerged leaves. Photo by L. Kumar
Banana aphids are found between the whorls of the pseudostem and newly emerged leaves. Photo by L. Kumar
The banana aphid is exotic to Africa and lacks indigenous natural enemies. Classical biological control is being explored that includes testing known natural enemies and exploration for new ones for introduction into Africa. IITA has successfully used this approach to control several exotic pests. Biological control could minimize the local spread of the disease, and perhaps reduce it to very low levels, when coupled with tolerant varieties.

Prospects
At present, BBTV spread is not controlled in SSA. Besides its effect on food security, the virus poses a serious threat to the diversity of plantain and highland banana.

Understanding its disease ecology, demographics of distribution, vector biology and ecology, awareness creation, and conventional and nonconventional approaches to tackle the virus and vector is expected to provide a reprieve in the medium term and sustainable solutions in the long term.

Biotech in Nigeria: The journey so far

IITA scientist in Biotech Lab. Photo by O. Adebayo
IITA scientist in Biotech Lab. Photo by O. Adebayo
Nigeria, the world’s largest grower of cassava, producing over 40 million tons per year, is seeking to adopt the use of modern biotechnology tools in agriculture, but efforts are stymied by the absence of a biosafety law.

The passage of the bill by the Nigerian Parliament will launch the country into the production and commercialization of genetically modified organisms (GMO) with the capacity to increase crop production, ensure food security, and improve rural livelihoods.

“The passage of the bill will be great,” said Dr Oyekanmi Nash, Program Director, West African Biotechnology Workshop Series. “Biotechnology holds the key to some of our problems in agriculture and health, and the earlier we tap into it, the better,” he added.

Background
Currently, Nigeria’s population of more than 140 million with an annual growth rate of 2.9% demands increased agricultural production to guarantee food security.

This means traditional agricultural practices, characterized by the use of poor seedlings, must give way to modern tools to allow agriculture to grow by double digits from the current average of about 6%. Such a growth will conserve government revenues from being used in importing food items.

According to government figures, the country spends about US$3 billion annually on food importation. The situation was worse in 2008 when food prices hit the roof, aggravated by the negative effects of severe drought on agricultural production in the northern parts of the country, and high energy costs when crude oil reached $150 per barrel.

“With the turn of events now and for us to meet our food demand in the future, we should apply modern biotech in crop production,” Nash said.

He commended IITA for setting up a modern biotech laboratory in Nigeria, saying that the establishment of such a multimillion dollar laboratory in Nigeria was a reflection of the institute’s commitment to fight poverty in Africa and improving rural livelihoods.

Fluorescence-based genotyping for DNA fingerprinting of plants and pathogens. Photo by IITA
Fluorescence-based genotyping for DNA fingerprinting of plants and pathogens. Photo by IITA
Challenges in introducing GMOs
If the biosafety bill is passed, Nigeria will join other African nations, such as Burkina Faso, Egypt, and South Africa in cultivating GMO crops.

It is expected that the entrance of GMOs will increase crop productivity, lower the cost of production, guarantee food security, and improve both the health and livelihoods of resource-poor farmers who make up more than 70% of the rural population.

The absence of a biosafety law is the problem. In addition, research and development in GM crops are indeed in their infancy in Nigeria as very few establishments in the national agricultural research system have developed the critical mass of human capacity and the infrastructural requirements that would lead to the accelerated development of transgenic materials.

A communiqué issued last year by stakeholders, including the National Biotechnology Development Agency (NABDA) said that other limitations in the commercialization of GMO crops included poor capital equipment, irregular energy, inadequate water supply, and ineffective use of information and communication technology, among others.

The meeting further noted the obvious deficiencies in both the teaching and learning curricula at all school levels and accordingly recommended vibrant and dynamic curricula to generate appropriate labor to meet research and development needs in biotechnology activities.

biotech-milestonesBiotech and Nigeria’s vision 2020
In the next 11 years, Nigeria intends to be ranked among the top 20 economies of the world. Achieving this goal requires adopting policies and options that will lead to improved agriculture and food security among other benefits.

For Nigeria, experts say this will include genetic improvement in the priority crops such as sorghum, cassava, cotton, yam, banana, plantain, maize, wheat, gum arabic, cowpea, and soybean that are of critical importance to the nation.

Prof. Bamidele Solomon, Director-General of NABDA, which has the mandate to promote, coordinate, and regulate biotechnology across the country, said his agency would ensure that the cutting-edge technology of biotech promotes a healthy environment, ensuring national food security and providing affordable health care delivery as well as the alleviation of poverty.

While 2020 appears rather far away, not taking proactive steps toward tackling the present challenges facing the full implementation of biotech will certainly make Vision 2020 a mirage, as far as food security is concerned. This is indeed a wake-up call. The earlier we act, the better.

Growing cassava in cold Denmark

Kirsten Jørgensen, kij@life.ku.dk, and Birger Lindberg Møller, blm@life.ku.dk

cassava1Cassava, that tropical tuber that is a staple to millions in sub-Saharan Africa, is being grown in freezing Denmark—at the University of Copenhagen. The precious plants are grown in the greenhouse during the dark winter days when the snow is lying on the roof.

The crop has been a prime focus of the University’s research because of its importance as a food security crop and commodity in economic development. It has a high content of cyanogenic glucosides, toxic substances which may constitute a nutritional problem in regions where cassava is the dominant or sole staple food. During processing, cyanogenic glucosides are converted into cyanohydrins, ketones, and hydrogen cyanide. These are all toxic and should not be consumed in excessive amounts.

Cyanogenic glucosides are an ancient group of bioactive natural products present in crop plants, forage plants, and important trees. More than 3,000 plant species are cyanogenic, including cassava, apricot, cherry, clover, flax, barley, sorghum, wheat, bamboo, eucalypt, and poplar. We study most of these plant species to understand these compounds in terms of their synthesis, turnover and regulation, and their biological function. In these studies, we use model plants such as Lotus japonicus. Lotus contains linamarin and lotaustralin, the very same cyanogenic glucosides found in cassava. The genome sequence of Lotus has been sequenced, and the use of transgenic model plants is a key tool in our studies.

Our laboratory was a world-first in isolating all three genes for cyanogenic glucoside synthesis. This work was done in sorghum. We were also a world-first in isolating the genes responsible for cyanogenic glucosides synthesis in cassava.

Embryo culture of Kibaha. Photo by K. Jørgensen
Embryo culture of Kibaha. Photo by K. Jørgensen

Our research aims to control the level of cyanogenic glucosides in different parts of the cassava plant. It involves understanding the regulation of the biosynthetic genes and the turnover and transport processes. We use tools such as the relevant omics platforms for these studies, including metabolomics where we use high-pressure liquid chromatography and mass spectrometry to determine the constituents found in the different cassava tissues as a result of environmental challenges. A second important tool is transcriptomics. In collaboration with IITA researchers, such as Dr Ivan Ingelbrecht, we have designed a cassava DNA chip that allows us to monitor the profile of gene expression and how these profile changes for individual genes respond to plant development, nutritional status, and environmental challenges.

In the long term, we want to produce a virtual model of the cassava plant that would enable us to predict responses during growth and development, and to environmental stimuli. In these studies, changes in cyanogenic glucoside content, in the levels of the enzymes and genes controlling their synthesis, breakdown, and transport are given special attention.

Our studies will provide information on the level of natural variation from one plant to another in terms of interesting characteristics. To facilitate identification of individual plants with interesting properties, high throughput screening technologies have also been implemented. Cassava is a tetraalloploid plant. This makes traditional breeding very time consuming and complicated. The development of transgenic approaches where multiple gene copies may be “knocked out” in a single step offers great opportunities to develop varieties with an optimal content and distribution of cyanogenic glucosides.

Progress in cassava research is slow, because few research groups in the world are working on cassava. Typically, the tool boxes successfully used in wheat, maize, and rice breeding are not available in cassava. This makes breeding of new varieties cumbersome and time-consuming because many of the techniques have to be set up from scratch. One such example is the development of a transformation protocol for cassava that would enable us to knock out or insert new genes in elite cassava cultivars.

Transgenic shoots from TME12. Photo by K. Jørgensen
Transgenic shoots from TME12. Photo by K. Jørgensen

We have devoted a lot of effort to develop such a transformation system. This includes tissue culture work to establish protocols enabling us to produce embryogenic cultures and to regenerate plantlets from these. Likewise, reliable procedures for Agrobacterium-mediated gene transfer for elite cultivars had to be optimized. In this research we took advantage of the pioneering work on cassava transformation carried out at the Swiss Federal Institute of Technology (ETH) in Zürich. The system we now use is robust and we are able to transform elite lines from IITA that are high yielding and that have optimal resistance to disease and pest attack. Our transformation technology has been transferred to IITA. In 2007, we also transferred the technology to obtain cassava transformants to the Danforth Plant Science Centre, USA.

It is important to select the optimal cassava lines for our research. We want to produce cassava lines appropriate for end-users. There is not much value in engineering interesting agronomical traits into lines that have no value to the end users, i.e., the farmers and consumers. This is yet another example where close collaboration with IITA researchers has greatly benefited us. Collaboration with IITA helped us to focus our work on agriculturally important lines.

In the initial phase of our work to reduce cyanogenic glucoside synthesis, we used constitutive promoters such as that from the 35S cauliflower mosaic virus. We have now shifted our focus to using native cassava promoters that more efficiently target the cells in the tubers where, for example, synthesis of cyanogenic glucosides takes place, thus providing better control. The content of cyanogenic glucosides varies among vegetatively propagated and thus genetically identical plantlets. Accordingly, multiple tests at different growth stages have to be carried out to determine the degree of downregulation (reduction) of cyanogenic glucoside synthesis. This makes the procedure to find the right lines time-consuming.

The protein content in current elite cassava cultivars is very low partly perhaps because of the continued breeding for high starch yield. In the past, breeding for high protein content would be at least partly in vain because a significant proportion of the protein is lost anyway during processing when the cyanogenic glucosides and their toxic degradation products are removed to provide food safe for consumption.

Using molecular breeding, there are several ways to achieve transgenic lines with enhanced protein levels in the tubers. One way is to identify specific storage proteins from wild cassava varieties that exhibit a high content of essential amino acids, such as methionine and lysine, and then express these nutritionally beneficial proteins in the elite lines. Another way would be to use storage proteins from other known species, such as patatin from potato. We are currently transforming African elite lines with constructs encoding patatin that will be incorporated into the starch grains in the cassava tuber.

Transgenic acyanogenic cassava (TME12) in greenhouse. Photo by K. Jørgensen
Transgenic acyanogenic cassava (TME12) in greenhouse. Photo by K. Jørgensen

The original focus on the molecular breeding of elite cassava cultivars with a controlled and reduced content of cyanogenic glucosides and a higher protein content has recently been expanded to incorporate varieties carrying yellow tubers. These have increased levels of carotenoids that are precursors of vitamin A. IITA provided the cassava lines with high carotenoid content obtained by classical breeding.

The long-term aim of our research is to improve the nutritional value of cassava tubers from African elite cultivars by blocking the accumulation of cyanogenic glucosides, enhancing the protein content, and increasing the pro-vitamin A content. Future goals involve engineering resistance to important pests and diseases in the very same lines.

Climate change has spurred a worldwide demand for drought-tolerant plants, such as cassava. Likewise, as Western industrialized countries move towards a bio-based society less dependent on fossil fuels, starchy plants that can produce very high yields under optimal growth conditions become key targets for research. As part of these efforts, the cassava genome is now being sequenced in the US. When the genome sequence is available research on cassava will be that easier and may be the first step in developing the crop as an efficient environmentally benign “green factory” for producing valuable chemicals and pharmaceuticals.

The cassava group at the University of Copenhagen is headed by Professor Birger Lindberg Møller and principal investigator Associate Professor Kirsten Jørgensen, together with Assistant Professor Rubini Kannangara, Technicians Charlotte Sørensen, Evy Olsen, and Susanne Bidstrup, and gardener Steen Malmmose.


http://www.proactiveplants.life.ku.dk

Ticket out of poverty

Market in Nigeria. Photo by IITA
A market in Nigeria. photo by IITA

The world’s food supply has for the last few decades worked well but now new dynamics, as reflected by the recent food crisis, call for change. The current system, based on large-scale production in the developed world, is efficient and responsive to market dictates though distorted by subsidies. It could be stabilized when complemented with a more significant system from the developing world. Such a two-tiered system would also protect poor regions of the world from extreme food scenarios.

Today’s world food situation has been well aired in the media. But what is not fully appreciated is the opportunity it also brings for Africa. As the most food-deprived region of the world, Africa needs a more robust agricultural growth. This food crisis, albeit temporary, could be used to trigger an agricultural turn-around. African countries are food importers and thus affected by international prices of traded food commodities, but have untapped assets to exploit for the immediate and longer term.

The African food basket is, in many countries, complex and its commodities are affected differently by international food prices. For example, while maize prices in Tanzania were dragged up with the world prices, the effect on sorghum, cassava, and plantain was much less. This allows some immediate substitution and underscores the need for focusing on local production, helps reduce foreign currency needs that limit a country’s purchasing power, and stimulates rural economies to benefit both the rural and urban poor.1

Food commodities also allow for substitution in agroprocessing. If rice is used to produce starch, it can be replaced with other crops such as millet/sorghum or roots and tubers. Bread does not have to be 100% wheat. Tef, banana, sweetpotato, millet, sorghum, and a mix can be used that includes cassava, and yam. This richness needs to be more appreciated and encouraged.2

For the less immediate term Africa just needs to produce more (see Figure 1). Its food output is extremely low. But its diversity of ecologies, altitudes, and cultures, is a powerful asset. Africa can produce more food by expanding acreage, unlike Asia. But other things need to happen before the potential of ample arable lands can be realized. Immediate needs would be rural feeder roads, access to credit and inputs, and a stimulated processing sector. The latter is increasingly important as the growing urban migration means more consumers are far from production zones and food shelf-life and convenience are major concerns.

Figure 1. Index of total agricultural output per capita by region (index 1961-2005). Adapted from FAOSTAT 2006. Source: Hazel and Woods.
Figure 1. Index of total agricultural output per capita by region (index 1961-2005). Adapted from FAOSTAT 2006. Source: Hazel and Woods.

For the medium term, Africa has to increase yields. For most food crops of sub-Saharan Africa3 yields can be increased by 150-300% immediately, because varieties already exist with this potential4.

To benefit more from what it grows, Africa also needs a parallel effort to reduce huge (postharvest) losses, ranging from 18 to 40% depending on the crop. Investments in food processing and transformation, energy, and roads are needed.

This processing and transformation capacity is also critical to address the rural-to-urban migration, which is itself a major challenge. Not long ago, 80-90% of Africans were rural; today most are urban. Wars have accelerated rural-to-urban migration. Africa must increase production even more, because it is not one to one in feeding the urban versus the rural poor. As production systems function today there is tremendous waste at all levels, rural and urban.

A holistic approach to the sector is essential and includes the now well-rehearsed list of needs and problems—infrastructure, finance, taxation, corruption, communication, soils, inputs, productivity, and numerous postharvest technologies and processes. As these elements are developed and constraints cleared away, the approach has to adjust. Underinvestment in infrastructure is costly in many ways. Transport difficulties, for example, give Malawi’s (2007/8) maize surpluses few outlets so that farmers do not fully gain from favorable global prices.

Family eating banana
Family eating banana

It is not uncommon to have food shortages in one part of a country, when another has food surpluses. Poor information and transport systems, plus the short shelf-life of many commodities prevent Africa from benefiting fully from its harvest. In Ethiopia, widespread drought (2003) in some parts of the country put at risk over 12 million people, while in other parts, prices collapsed due to a bumper crop of cereals (Borlaug and Natios). Zambians (2004) were suffering from a shortage of cassava, when Nigeria had abundant surpluses.

Small producers are one group that needs special attention. While they are the key to Africa’s food self-sufficiency, it is hard for them to respond effectively to increased food needs on their own. One way to support them is to encourage the movement of their produce into alternative uses within the food chain.1 Again, this means investments in the agroprocessing sectors and a slew of processed food products. Farmers take all the risks but rarely benefit long from any gains.

Conclusion: The full use of Africa’s assets—arable land, different ecologies, altitudes, cultural differences, and eating habits—gives Africa resources more powerful than oil. Emphasizing and then benefiting from the agricultural sector has positive repercussions that reach far into all segments of an economy, in particular in increasing employment at all levels and with it, purchasing power.

1 Hartmann. 2004. An Approach to Hunger and Poverty. IITA.
2 Cereal imports in the last couple of years have increased by a factor of three to five times.
3 Rice is the exception where the yield gap is around 67%.
4 For example, IITA varieties of these crops already have this potential built into their genetic codes.

30 years R4D in soybean: what’s next?

Forty years ago, only a handful of farmers in Benue State, middle belt of Nigeria were growing soybean. The crop was generally thought more suitable for large-scale commercial growing and industrial processing. But not anymore.

This golden bean is grown in the farms of resource-poor smallholders in the Guinea savannas of Nigeria and other parts of sub-Saharan Africa.

“In the 1970s, there was little interest and effort in Africa to grow and improve soybean because of extremely low yields and seed viability, poor nodulation, high shattering rate, and limited postharvest use,” reported Dr Hailu Tefera, soybean breeder and OIC of IITA-Malawi, on 30 years of IITA soybean breeding work.

Breeding gains

When IITA started improvement research in 1974, the average yield per hectare in Africa was 660 kg/ha. Total production was only 0.2 million tons. Thirty years later, using IITA-developed varieties, the average yield in West African countries increased by more than 50%, and 67% in the whole of Africa, equivalent to 1.1 t/ha over 20 years of breeding effort. That is a genetic gain of more than 2% per year in grain yield.

Twenty-one African countries now produce soybean. Nigeria has the highest 6-year (2000-05) average production of 486,000 tons on an area of 553,260 hectares, followed by South Africa with 205,270 tons from 122,870 hectares, and Uganda with 155,500 tons from 139,500 hectares.

Soybean production increased dramatically, Tefera said, as locally adapted tropical germplasm was developed and distributed to other African countries. In Nigeria, the soybean industry quickly advanced. Integrated processing, use, and marketing aspects followed efforts to develop improved cultivars. This is a testament to IITA’s research for development (R4D) in soybean that produced high-yielding and stable varieties, tolerant or resistant to biotic and abiotic constraints, and promoted processing and use.

Community impact

In 1985, to improve nutrition and to create demand, IITA began the development of small-scale and home-level food processing technologies. A study funded by the International Development Research Centre (IDRC) Canada with the Institute for Agricultural Research and Training (IART), Ibadan, Nigeria, after 3 years found that soybean had been successfully used to increase the protein content of traditional foods. New products—flour, milk, baby food—had been developed and introduced. Small-scale processing machines were introduced. Over 25,000 people in the rural areas were trained, with training project sites increasing from 3 to 27. The number of farmers growing soybean in target villages increased by 35%. Sales of grain and flour soybean increased in Nigerian markets.

Phase 2 of the project covered all Nigeria with several national institutions such as IART; National Cereals Research Institute, Badeggi; National Agricultural Extension Research and Liaison Services, Zaria; and the University of Nigeria at Nsukka. An assessment of four states in 1992 showed wide commercialization.

Markets had increased from 2 in 1987 to 42 in 1993. The number of retailers ballooned from 4 in 1987 to 824 in 1993. In Benue State, more women were involved in soybean production. New IITA varieties were widely adopted and grown by 9% of farmers in 1989 to 75% in 1997 on 30% of the area planted to soybean in the state.

So far, Tefera reports, some 17 IITA-bred tropical soybean varieties have been released by national agricultural research and extension systems (NARES) of several West and Central African countries (Nigeria, Benin, Ghana, Democratic Republic of Congo, Togo),  and Uganda. These show considerable increases in grain and fodder yields, improving soil fertility in the savannas and enhancing the yields of subsequent crops such as maize and sorghum. Since 2000, however, support for soybean research among the NARES has declined. On-farm variety testing and releases is at a standstill, except for MAKSOY 1N, an early maturing variety resistant to rust, a destructive foliar disease, in Uganda.

Potential for expansion

Soybean growing suitability map. IITA
Soybean growing suitability map. IITA

IITA recently expanded breeding of its West Africa-bred varieties to Southern Africa, where cultivation by small-scale farmers is rising because of less susceptibility to pests and disease, better grain storage quality compared with other legumes, large leaf biomass, and a secure commercial market. Commercial soybean farms are now found in South Africa, Zimbabwe, and Zambia.

In South Africa, the Agricultural Research Council develops cultivars with better adaptation and seed quality, high yield, resistance to nematodes and rust, and tolerance to low night temperatures. It is also developing genetically modified drought-tolerant soybean—the first soybean GMO in South Africa. Twenty-one members of the South African National Seed Organization produced 2,879 tons of soybean seed in 2006-07.

SeedCo in Zimbabwe breeds varieties for the local market and other countries in the region; these are resistant to red leaf blotch and frogeye disease. It produces inoculants that go with the varieties. The Zambia Seed Company produces, processes, and markets seeds of various crops including soybean and is considering testing IITA-developed varieties under Zambian conditions.

“Soybean improvement efforts in the past focused on helping subsistence farming,” said Tefera. “Currently many African countries are practicing market-oriented agriculture to increase farmers’ income and reduce poverty. Soybean improvement work at IITA should consider technologies for use by farmers of different capacities.”

According to FAO, Africa spent US$1 billion in 2004 to import soybean and soy oil. Of this, US$752 million was for soybean oil and US$254 million was for soybean grain/meal. Countries such as South Africa, Malawi, Zimbabwe, and Zambia in aggregate produce 33.4% of Africa’s total production.

Producing enough in the region and adding value can save millions spent on imports for other development activities, he further added. There are also export possibilities to Europe and Japan as soybean grown in Africa is mostly non-GMO.
Favorable government policies are needed to develop the soybean industry in Africa. In Brazil and Argentina in the 1990s, economic reforms created favorable conditions for agricultural investment, production, and exports. Research alone was not the driving force for the soybean industry’s impressive growth there.

Market-oriented policy changes included elimination of export taxes, lifted restrictions on import of agricultural inputs, privatization of marketing and transportation infrastructure including state-owned grain elevators, port facilities, and railroads. Farmers also invested heavily in new technologies that improve yields, accelerate planting and harvesting, and facilitate delivery.

“Achieving these targets requires the efforts of various players in research, production, and marketing,” Tefera concluded, “and should consider technological, institutional, and organizational interventions in both the supply and demand sides.”

Transforming livelihoods in Borno State

In Borno State in the extreme northeast of Nigeria, 30 farming communities are reaping the benefits of adopting new and improved soybean and Striga-resistant maize and rice varieties and management practices. They also benefit from knowledge sharing, new products, availability of new markets, and investment in improved and sustainable agricultural practices.

These communities participate in an IITA project funded by the Canadian International Development Agency. The project, Promoting Sustainable Agriculture Project in Borno State or PROSAB, was launched in 2004, to improve the livelihoods of the rural communities in the State through improved food security, reduced environmental degradation, improved sustainable production using transfer of gender-responsive agricultural technologies and management practices, easier access to input and commodity markets, an enabling policy environment, and enhanced capacity of project stakeholders.

Threshing maize in Miringa, Biu, Borno State. Photo by IITA
Threshing maize in Miringa, Biu, Borno State. Photo by IITA

The project operates within a sustainable livelihoods framework, which emphasizes increasing livelihood assets and improving the capabilities of the rural poor. Partners include Borno State Agricultural Development Program (BOSADP), University of Maiduguri (UNIMAID), the State government, IITA’s sister center—the International Livestock Research Institute (ILRI), and Community Research for Empowerment and Development (CRED).

“The project aims to increase farmer productivity through adoption of improved crop varieties and better management practices that ensure improved and viable agriculture-based economic livelihoods.” says Dr Amare Tegbaru, PROSAB Project Manager. “Small farmers form 80% of the population, and agriculture and trading are their only major activities.”

Problems for farmers include erratic rainfall, marginal soil fertility, and an underdeveloped market. Agriculture can no longer cope with the increasing population and greater demand for food. As in many other parts of Nigeria, farmers are diversifying their sources of livelihood outside agriculture, once the backbone of the country’s economy. Subsistence farming is based on growing crops and livestock keeping.

A socioeconomic survey was conducted in 2004 in the target communities to gather benchmark data on demographics, socioeconomic conditions, resource use patterns, market opportunities, and their effects on land degradation and agricultural productivity. Major crops grown are maize, sorghum, cowpea, groundnut, and vegetables, mostly grown for home use; any surplus is sold locally. Cattle, sheep, goats, pigs, and poultry are the animals reared.

According to Tegbaru, the participatory research and extension approach used by the project was effective in undertaking the community analysis to identify livelihood opportunities, constraints, entry points, and plan interventions; participatory action planning to address priority problems; and deployment of best-bet technologies through male/female farmer-led participatory research and trials in pilot communities. More than 300 producer groups in 130 cluster villages, of which 50% comprise women, have also been targeted.

The 2004 survey identified Striga hermonthica, a parasitic weed, as the single biggest agronomic constraint in cereal production. Then 228 farmers from 193 farmer groups across the 30 communities tested integrated Striga control (ISC) options in 2004 and 2005. Soybean was planted as a trap crop in the first year followed by Striga-resistant or tolerant maize in the second year with the standard farmers’ practice. These reduced numbers of emerged Striga by 12% and increased maize productivity by 41%. Partial budget analysis showed a 200% higher profitability for ISC over traditional practices.

Male and female farmers selected the technologies that suited their circumstances and environment from a basket of options. These included maize tolerant to Striga and drought-, dual-purpose soybean and cowpea, early maturing groundnut, dwarf sorghum, and new rice for Africa (NERICA). Improved crop management practices included maize-soybean rotation to reduce Striga and improve fertility, proper and timely application of fertilizer, environmentally friendly agrochemicals, and appropriate planting densities.

Community-based seed multiplication operations were established to provide improved crop seeds. A market information system and links to major food processors provided ready markets.

Results in 2007 from farmers’ test plots showed that new varieties of maize, sorghum, cowpeas, and groundnut yielded well even under poor weather conditions. The project has more than doubled agricultural productivity with the use of new crop varieties and management practices. Yields have increased, compared with baseline data (2004), by 220% (maize), 100% (cowpea), 50% (sorghum), and 70% (groundnuts).

Fifty percent of the farmers adopted cereal and legume rotation and made better use of agrochemicals. Adoption rates of maize (77%) and soybean (53%) by male and female farmers were high. Improved Striga-resistant maize produced, on average, 3 t/ha (against 1 t/ha in 2004). Soybean was popular among women because of their good processing opportunities. Adoption of new sorghum and groundnut showed mixed results. Training increased cowpea yields by over 50%.

Animal fodder demo plots showed how fodder production has been integrated into crop production. Two years of crop and livestock integration have improved land preparation, animal nutrition, and health care. Farmers’ access to genuine veterinary drugs has been ensured.

On the whole, 76% of the farmers’ groups that used some or all of the improved PROSAB recommendations reported yield increases of over 100%, better food availability (94%), improved nutrition among children (86%), improved livelihoods through increased sales, and additional income (86%). Other benefits included better household nutrition through soybean processing and use, improved health care through affordable medicines, and more money for housing and children’s education.

During the review period, 291 seed producers were linked to seed markets, including Premier Seeds, a big seed producer; 21 processors sold 49 tons of improved seeds, yielding N2.4 million (US$18,462). Through improved market linkages, 485 farmers sold 811 tons of soybean, earning N46.8 million (US$414,159). Improved demand by industrial processors and attractive prices helped to motivate the farmers to grow the crop. “This development in the soybean market is likely to be sustained,” said Tegbaru.

The conduct of policy workshops, gender awareness and mainstreaming in technology development and dissemination, and field days have increased awareness among community leaders, policymakers, farmers, and market agents about the benefits of PROSAB’s technologies and management practices. Adoption rates among farmers continue to rise.

Outlying communities and neighboring states not directly involved in the project have started to benefit through the scaling out of technologies by project participants and others.

This shows how IITA R4D technologies—combined with farmers’ endeavors—add greater value to research products.

Success stories

Farmer James Buba and wife
Farmer James Buba and wife

Mrs. Bata Joshua is one of the leading members of the women’s group in a community called Vinadam located in the Hawul Local Government area of Borno State. When asked how PROSAB has contributed to their livelihoods, she stated: “In the past, prior to the introduction of PROSAB in our community, our harvests couldn’t feed us for the whole year. We had to supplement by buying grains from the market. Presently, our harvests are sufficient to feed our families and we even have surplus for sale in the market”. She further said, pointing to a new building under construction. ”This new building is being built from revenues realized from selling soybeans. The project is making a remarkable contribution to improving our livelihoods.” (a translation from Hausa)

Similarly in 2007, James Buba and his wife, who are promising soybean farmers in Nggabu Village had a similar success story with soybeans. Narrating his story, James said “We harvested 4.2 tons of soybeans from my 2-ha farm last year and made a profit of Nigerian N184,000 (about US$1,500) on soybean sales….This year, we have doubled the soybean farm and we expect about 6 tons to make more money.”

Banana + Coffee = More

Banana systems in Rwanda. Photo by IITA
Banana systems in Rwanda. Photo by IITA
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What happens when banana and coffee are grown together? Farmers earn more, say IITA scientists and partners.

Growing coffee and banana forms the economic base for most of the small-scale farmers in much of Uganda and the surrounding highlands of Rwanda, Burundi, northwest Tanzania, and eastern Democratic Republic of Congo.

Banana is an important food staple in Uganda produced all year round; farmers sell surplus yield on a daily basis. Coffee, on the other hand, is a pure cash crop, cultivated on over half a million coffee farms, 98% owned by smallholders. It is a major foreign exchange earner for the Great Lakes countries. In Uganda, for example, it generates some 20% of the country’s foreign exchange revenues. Robusta coffee is dominant below 1400 meters altitude, Arabica at higher altitudes.

In some densely populated areas, banana-coffee intercropping is practiced, but it is not common. Some countries even recommend that coffee be grown as a sole crop. Some farmers, however, report on the advantages of growing coffee under bananas, such as providing shade, mulch, nutrients, and moisture. For instance, farmers use coffee husks to replenish nutrients in banana and coffee fields, although this is discouraged by Robusta coffee growers to prevent the spread of coffee wilt disease. Meanwhile, some researchers also cite advantages such as reduced erosion in the highlands.

The crops complement one another in terms of socioeconomic benefits to growers and farm families. Bananas provide permanent food and income security, doubling as a primary food and cash crop, and providing a modest but continuous cash flow throughout the year. Coffee gives a cash boom twice a year, helping farmers acquire funds for more expensive items such as infrastructure, farm inputs, transport equipment, and large social events.

Drying coffee beans in Uganda. Photo by IITA
Drying coffee beans in Uganda. Photo by IITA

So how effective is intercropping? R4D Review editors asked IITA agronomist Piet van Asten who works on banana-based systems in IITA-Uganda.

“Despite farmers’ beliefs and practices, perceived benefits, and some positive indications, there are no official recommendations or advice about intercropping,” he said. “There has been no research about this until now.”

“Banana and coffee intercropping is much more profitable than either banana or coffee monocropping,” reports van Asten and the team of scientists who conducted a diagnostic survey in seven districts in Uganda.

IITA collaborated with the Agricultural Productivity Enhancement Program (APEP-USAID) to study some 150 APEP demo plots of banana and coffee monocrop and intercrop fields, and 150 farmer control fields in the major banana-coffee growing areas from southwest to east Uganda. The demo plots were farmers’ fields where APEP extension officers provided fertilizer and stimulated the adoption of best crop management practices, such as mulching, pruning (coffee), or desuckering (bananas).

Information on resource use, including external inputs, labor, land, and farmgate prices were obtained through structured farmer interviews in 2006-2007; data on crop production, soil fertility, pest and disease pressure, and management practices were quantified through field visits.

“Study results were beyond our expectations,” van Asten pointed out. “In the Arabica-growing area around Mt. Elgon, coffee yields were similar in monocropped and intercropped coffee—even when the demo plots were fertilized. The number of coffee trees per hectare decreased slightly when intercropped, but yields per tree were higher.”

In the Robusta-growing areas, intercropping reduced coffee yields slightly (by 13%) when the fields were not fertilized, but when they were fertilized coffee yields were the same in monocropped and intercropped fields. In general, banana yields suffered when intercropped with Robusta coffee but not from intercropping with Arabica coffee, (Table 1).


Because the coffee yields were not affected, the additional banana production increased the revenue of banana-coffee intercropped fields by 50-60% compared to monocropped coffee fields (Table 2). These figures show that banana-coffee intercropping is much more profitable than sole planting of either crop, van Asten and IITA and APEP colleagues concluded.

“For instance, in the Arabica coffee-growing region around Mt. Elgon, annual returns per hectare averaged US$4,441 for intercrop, $1,728 for banana monocrop, and $2,364 for coffee monocrop. In Robusta-growing areas in South and Southwest Uganda, annual returns per hectare averaged $1,827 (intercropping), $1,177 (banana monocrop), and $1,286 (coffee monocrop). These results are for the nondemo plots,” he said.

Why did this happen? Coffee plants are shade loving and bananas are taller, so there is not much light competition. Potassium is an important nutrient for both crops, and the intercropped coffee seemed, on average, to be less potassium deficient than sole coffee. This may be due to the very high biomass turnover in the banana system. The mulch may reduce the need for soil tillage, thereby keeping the shallow banana and coffee rooting systems intact. The high biomass turnover may also bring nutrients into forms more easily available for the plants. “There could be other reasons, but the findings thus far at least indicate that the intercrop system does have some strong advantages,” van Asten said.

“More research is needed. We have to understand how this works so we can apply the findings to other banana and coffee-growing areas.”

“We also need to come up with recommendations to help farmers exploit this opportunity to improve productivity and revenues, without purchasing additional inputs or increasing the area under cultivation. Land pressure and lack of credit or capital are two major constraints for African smallholder farmers.”