Prof Felix Nweke: Staying true to the course

Prof Felix Nweke about himself: I was born in Eastern Nigeria as an Igbo man but I consider myself an African right now. My training background is agricultural economics. I am a professor by occupation, retired some years back. Just call me “Prof.”

How did you get into root and tuber crops research & development?
I like that question because yam and cassava are the rhythm of my life from the beginning; I was born growing and eating them. When I was born where I was born we woke up in the morning, ate cassava fufu, then went to the field. Later in the afternoon we ate yam and continued to work in the field until dusk. We went home and ate cassava again for dinner; we did this day in, day out and it was good at that time.

As I grew up and went to school I was attracted to agriculture by the then Government of Eastern Nigeria which offered scholarships. My interest was in mathematics but my parents could not pay my university education costs from growing yam and cassava. At the University of Nigeria, Nsukka, which is in the yam belt of the world, what was taught was not called yam and cassava but those crops were still part of everyday life.

When I completed the undergraduate program and after my Biafran experience, I went to Michigan State University (MSU) for postgraduate studies. There, I was spared working on and eating cassava and yam but on return to the University of Nigeria, Nsukka, as a teacher I got immersed in the influence of those crops once again. The first research program I conducted was a project titled “Yam-Based Cropping System of Eastern Nigeria”; it was as if I had no choice but work on yam.

Can you explain the benefit and value of yam to you.
I envy my parent’s generation and rhythm of life for its routine and stable life pattern. That is the positive side. But there is a negative side to the life of that generation; I told you we ate cassava in the morning, yam in the afternoon, and cassava again at night. That story is true but yam was not always available, especially during the hungry season (after planting yam). During the hungry season we ate cassava morning, afternoon, and night. At the time, it meant nothing to me; but today if I have to worry about what my grandchildren would eat the next day, I would probably go what some people of the Caribbean describe as “separat”, i.e., mind and body going separate ways.

My parents worried about what we would eat the next day. Today, not everybody can afford even to eat cassava three times a day. I know families that live under leaking roofs, if you can call it a roof at all; I know families that cannot afford painkillers when a member is sick. When I walk in the streets I see beggars all the time. I do not give to them because private charity does not solve the social inequality problem. I pursue social justice by doing my work with honesty, courage, and commitment; in that way everybody can benefit from my work. If successful, my work on yam and cassava research will benefit everybody. That is what I got from my childhood experience of poverty and deprivation, which are still the experience of many people today.

What make yam and cassava so interesting?
Cassava and yam are interesting to me because they are rooted in my blood; if you cut me, I shall bleed cassava and yam. I could have migrated to the US and worked on wheat or corn but that will be a betrayal; by working on yam and cassava I am staying true to the course; I am giving back to what made me what I am and I feel good doing that.

Those crops are important to people of sub-Saharan Africa as a whole. There is a lot of value in these crops; we know that about cassava in Africa because that is a crop that is now well studied. It is clear that cassava has a lot of food and monetary values while its value as feed and industrial raw material remains potentials as far as Africa is concerned.

On the other hand, yam is not studied and people do not understand the crop. The monetary value to farmers who produce yam is quite high; when farmers grow yam they can sell all of it because they cannot afford their own yam. The money they get from it is more valuable to them than the yam; they use that money to buy cheaper foods like cassava.

It is often said that yam has cultural values, but people have a superficial understanding of that value. When a farmer distinguishes himself in yam production, he becomes a reference point in his community; when he speaks, people listen. He plays a key role in community mobilization and leadership. Rites of thanksgiving, passage, appeasement, and petition that are performed with yam as a ritual object among several yam-producing people of West Africa sustain the traditional social values in which the existence of the people, individually and communally, is rooted.

What does the future of yam look like to you?
The future of yam looks bright to me. Today, yam is costly to produce because of Stone Age technologies that dominate the yam crop sector. Yam production, harvesting, and storage technologies are primitive. Why? The answer is that there has not been significant investment in yam research and development. Yam is produced and consumed in West Africa, mostly, that is. West African governments do not care and in that case the Western world does not bother.

But the situation is beginning to change with the funding of YIIFSWA by the Bill & Melinda Gates Foundation. In a regional agricultural research on a crop produced and consumed with rudimentary technology, US$12 million over five years is seed money. But it is an important seed money because it is the first of its kind and it will grow to help break the low technology bottleneck in the yam crop sector.

People have talked about the extinction of yam because of its primitive production and handling technologies. Such people should understand that as long as there are yam eaters, yam would be produced. Yam has a bright future because in spite of high costs, West Africans have continued to produce and eat yam. More importantly, with the US$12 million funding for YIIFSWA, the international donor community is beginning to appreciate the various values of yam.

What is yam’s added value?
It is not easy to think clearly of those added values with the present high cost of yam production. Converting yam to starch, liquor, ethanol, etc., will be irrational behavior because there are cheaper sources of those products. If yam is discovered to possess some high medicinal value, which no other plant has, such as a substance that can cure common diseases that have so far defied cure such as diabetes, various cancers, HIV/AIDS, etc., then the crop can be rationally diverted to such use.

How would you then describe the yam of the future?
This is a good question but the answer is not direct because of the different purposes that yam serves which may be conflicting in terms of the nature of yam that serves each purpose. Long ago, I think it was in 1980, the future of yam was the subject of a panel discussion at the Triennial Conference of the ISTRB-African Branch at IITA. The answer to the question ought to consider the different requirements for the various uses for yam. But there is a bottom line and that is cost; the yam of the future must be delivered for the various uses at reduced cost. Yam has no rival as a ritual object in cultural rites in producing communities, but that use alone cannot sustain yam in the future. Yam as food has a wide range of competitors some of which are produced at very low costs following high levels of investments in research and development in the Western countries. As those alternative foods become cheaper, people will switch to them.

You have been associated with IITA for so many years. What do you see as its strengths and what areas need more focus?
I have been associated with IITA since 1977. When I returned to Nigeria from graduate school at Michigan State University, the first place I had a job was the University of Nigeria, Nsukka, as a teacher. A university teacher in agriculture has responsibility for teaching, research, and extension. But the university did not have money for research and I did not want my research responsibility to suffer.

I had a senior colleague in graduate school who was a scientist at IITA, his name was Fred Winch. Fred passed away a few years ago; I do want to remember him. I used Fred’s facilities to carry out the study of “Yam-Based Cropping Systems of Eastern Nigeria” which I referred to earlier. Kun Tekail, who was Director of the Farming Systems Program at IITA, asked me to come to IITA as a full Scientist. I declined because I was enjoying what I was doing in Eastern Nigeria. He then appointed me as a Honoris Causa Scientist at IITA. I continued to work with IITA resources as an honorary scientist until 1987 when I caved in to pressure from Larry Stiffel to join IITA as a full scientist.

I was employed at IITA as a yam economist to work with yam agronomists. Dunstan Spencer was the director of the Resource and Crops Management Program in which I was based. A few months after I came to IITA Dunstan assigned the COSCA project leadership to me and I moved from working on yam to working on cassava. I left IITA in 1997 but I have continued to work on cassava.

There is an agricultural problem that IITA needs to address. That problem is neglected perhaps because of the assumption that Africa’s agricultural development will necessarily follow the path of other regions’ agriculture. For example, in Africa R and D effort is focused on achieving a Green Revolution because of the success of Green Revolution in Asia and South America. But are Africa’s needs and circumstances the same as those of Asia and South America? In Africa, a different kind of revolution is needed to pave the way for a Green Revolution; that is Mechanical Revolution. In the 21st century African agriculture based on the hand hoe cannot compete with the rest-of-the-world agriculture. I am not talking of tractor mechanization but improved farm tools that are designed by engineers working in Africa and maintainable by local artisans.

How do you perceive the impact of IITA’s work on roots and tubers for farmers in Africa?
Whoa! Tremendous! In Nigeria, scientifically determined yield of cassava was 15 tons per hectare in the 1990s following wide adoption of IITA’s high-yielding mosaic resistant TMS varieties. There was an estimate that in Nigeria alone, the additional value in terms of gari from these high-yielding mosaic resistant TMS varieties was enough to feed 29 million people annually. We have information which shows that the price of cassava products relative to the price of other commodities dropped in the 1990s, which meant increased income to consumers who paid less for cassava food products such as gari. At the same time, because of reduced cost, farmers are making more money. IITA’s effort on cassava including the biological control, mosaic disease control, and the high-yielding varieties produced tremendous value in terms of income to millions of cassava producers and consumers.

How do you picture Africa in the next 50 years?
Income will improve in Africa and people will be better off materially. The meaningfulness of that in terms of improved welfare depends on how much the measures that create the wealth interfere with the fundamental values of the African people. I wish to see a significant decline in the present high levels of poverty, deprivation, and inequality in Africa. Retaining African social values while improving the economic conditions of the masses of the people will be the better of two worlds.

How will agriculture play a role in doing that?
Improved agricultural productivity will mean improved income for farmers through reduced production costs and for consumers through reduced food prices. Improved productivity in agriculture will generate feed and industrial raw materials and help expand employment opportunities in the industrial sector. Large farms could be depended on to improve agricultural productivity but they can convert small farmers into farm laborers. Measures to improve agricultural productivity should protect small farms to allow even distribution of increased farm income from improved productivity.

In the ISTRB symposium 2 years ago, you were given the Lifetime Achievement award. What does that award mean to you?
The Award for Lifetime Achievement in research on roots and tuber crops was given to me by peers in the ISTRC and that makes it satisfying. One of the reasons I was given the award is the pan-African cassava research project in which I served as Project Leader while I was a scientist at IITA, i.e., the Collaborative Study of Cassava in Africa or COSCA study. I do not claim the award for myself alone even though it was given in my name.

The COSCA study involved 63 scientists from all over the world not just Africa. The study was the idea of Dunstan Spencer, John Lynam, and others whom I do not even know. Soon after I came to IITA in 1987 as a Yam-Based Systems Economist, the new COSCA study was assigned to me to execute. CIAT, NRI, International Child Health Institute, and MSU are among collaborating institutions from outside Africa. National agricultural research centers of Cote d’Ivoire, Ghana, Nigeria, Democratic Republic of the Congo, Tanzania, and Uganda played critical roles.

What is the value of a medal like this award? Igbo wisdom says that “if you say thank you to somebody, the person will do more.” Saying thank you is inexpensive but it is an inspirer. Besides, awards such as this one can open doors; Prof Felix Nweke, winner of Lifetime Achievement Award, is at the door, please let him in. I am going to make effective use of this effect to do more work on cassava and yam in Africa. That is what the award means to me.

What would you say is the highlight of your career?
This question can hardly be answered with dispassion; self-assessment is more often than not underrated or overrated depending on one’s level of humility. Nevertheless, I consider that the highlight of my career is demonstrated in the accomplishments of the people with whom I have grown up professionally. These are not only students whom I taught in the classrooms or those whose higher degree dissertations I supervised; there are several of those. But having worked closely with Prof Carl Eicher of Michigan State University for the past 50 years beginning in 1963 at the University of Nigeria, Nsukka, I assimilated what I consider his finest professional value. Carl Eicher is like a magnet that draws young professionals to him and he grows with them, in some cases for life. Many of the people I have grown with that way are highly accomplished professionally and they are all over the world, not just in Africa. That is the highlight of my career and it could not have been better.

Nigeria releases improved cassava varieties

Nigeria has released two new improved cassava varieties developed through a collaborative effort between IITA and the Nigerian Root Crops Research Institute (NRCRI), Umudike. The two varieties are originally recognized as IITA-developed genotypes IITA-TMS-I982132 and IITA-TMS-I011206, now known as UMUCASS 42 and UMUCASS 43, respectively.

Both varieties performed well in different cassava production regions of Nigeria with high yield, high dry matter, and good disease resistance. The roots of these varieties are yellow and contain moderate levels of provitamin A.

The potential maximum yield of the two varieties is between 49 and 53 t/ha, according to pre-varietal release trials that were conducted between 2008 and 2010. Local varieties produce less than 10 t/ha. The varieties are also resistant to major pests and diseases that affect cassava in the country including cassava mosaic disease, cassava bacterial blight, cassava anthracnose, cassava mealybug, and cassava green mite.

The varieties are good for high quality cassava flour—a trait sought after by researchers for the cassava transformation agenda in Nigeria; have high dry matter which is positively related to starch and important for cassava value chain development; have high leaf retention which is positively related to drought tolerance and is crucial for cassava production in the drier regions and in mitigating the impact of climate change, with moderate levels of betacarotene for enhancing nutrition.

Cassava project launches database

Cassavabase, a database that promotes open access data sharing, was launched recently.

IITA is a major contributor of data to www.cassavabase.org and will host this information resource through the NEXTGEN Cassava project.

Cassavabase features phenotypic and genotypic data generated by cassava breeding programs involved in the NEXTGEN Cassava project at Cornell University supported by a US$25.2 million grant from the Bill & Melinda Gates Foundation and the Department for International Development of the United Kingdom.

The database makes the data immediately and openly accessible to the whole cassava community prior to publication. It is being developed by Lukas Mueller, adjunct professor of plant breeding and genetics at Cornell, at the Boyce Thompson Institute in Ithaca, New York.

Cassavabase provides a “one-stop shop” for cassava researchers and breeders worldwide. In addition to phenotypic and genotypic data, Cassavabase offers access to all genomic selection analysis tools and phenotyping tools developed by the NEXTGEN Cassava project, and links to auxiliary genome browsers, ontology tools and social networking tools, for the cassava community.

NRM in cassava and yam production systems

Stefan Hauser, s.hauser@cgiar.org

Cassava has the potential to produce roots even under poor soil conditions. Photo by IITA
Cassava has the potential to produce roots even under poor soil conditions. Photo by IITA

Why are yields of cassava in Thailand and India three times higher than in Africa and production costs in Brazil only one-third of those here? Although Africa suffered from the Cassava Mosaic Disease pandemic and currently faces the threat of Cassava Brown Streak Disease, breeding tolerant and resistant germplasm has contributed to yield gains over the last three decades. Thailand, India, and Brazil have been successful in commercial cassava production with yields between 25 and 40 t/ha. The question arises: how can African farmers realize more of the >80 t/ha yield potential of cassava?

Natural resource management (NRM), agronomy, and crop husbandry have hardly ever been credited with “breakthrough” solutions to hunger and poverty. However, when more than 50-75% of the cassava yield potential is not being realized, major improvements are clearly possible through NRM, agronomy, and appropriate crop husbandry.

Agronomy and crop husbandry
For West Africa there is still a dearth of agronomic information on cassava. Currently a density of 10,000 plants/ha is the standard, while further increases are being recommended without concrete data on the yield responses to increased density by different growth types. Cassava varieties vary widely in their branching height and level of ramification, leading to different levels of ground cover by single plants and of the start and intensity of intra-specific competition. Cassava yield distribution within the same variety is highly biased (Fig. 1), raising questions on the optimum plant density and issues such as genetic uniformity and crop responses to edaphic (soil) factors.

Figure 1. Relative contribution to yield of individual plants of cassava variety Zizila in DRC.
Figure 1. Relative contribution to yield of individual plants of cassava variety Zizila in DRC.

One future effort will be to determine optimum plant densities for monocrops by major cassava growth types.

Intercropping cassava with maize or grain legumes is still widely practiced and needs to be improved. The short-term intercrops are cleared from the field, leaving space unused that can be invaded by weeds, thus there needs to be a follow-up either with weed control or a second crop to occupy the open space. Various crops will be tested for their capacity to perform between developed cassava plants and their contribution to total system productivity.

Weed control remains a problem as there are no postemergence herbicides that cassava would tolerate. Combinations of preemergence herbicides with appropriate planting techniques have the potential to reduce weed competition and labor. For instance, a preemergence herbicide can be applied before planting cassava. The herbicide kills germinating seeds as they break through the herbicide-sealed soil surface. The cassava stakes need to be planted in a vertical position and the orientation needs to be correct so that no emerging cassava leaves touch the soil surface. Such technologies combined with the follow-up use of postemergence herbicides with shields can drastically reduce labor and increase productivity as weeding can be done at the most efficient time.

Fertilizer
Fertilizer use is low in Africa yet it appears certain that fertilizer or other forms of soil nutrient replenishment can contribute to yield increases, higher farm incomes, possibly to lower consumer prices, and thus to better livelihoods. Using average nutrient uptake into all cassava plant parts (dry matter basis) of 6.2 kg N/t, 1 kg P/t, and 5.3 kg K/t, a total supply of 165–25–145 kg N-P-K/ha is required to attain 50% of the current potential yield (45 t/ha fresh roots). Such amounts are unlikely to be supplied by the soil and thus nutrient supply is a crucial factor in achieving higher cassava yields.

There are no recent fertilizer response curves for cassava and yam in West Africa, hence, farmers do not know the composition and amounts of fertilizer to apply. The nutrient(s) most limiting to cassava production have not been quantitatively determined. The replenishment of any most limiting nutrient would lead to substantial yield increases. Depending on the limiting nutrient, productivity and profitability increases may be possible at a very low cost and risk. IITA uses a stepwise approach, first determining the most limiting nutrient(s) followed by elaborating the optimum quantity required and the construction of recommendations for optimal nutrient composition and quantities. IITA is currently working with the International Fertilizer Development Center on testing special fertilizer blends for cassava, addressing the augmentation of neglected nutrients such as sulfur, magnesium, zinc, and boron.

Use of other nutrient sources
Compost, manure, mulch, and rock phosphate have all been proposed as means to improve soil nutrient status and crop production. However, none of these sources has had a major impact as farmers need land to produce biomass or else infrastructure is required to mine, process, and distribute rock phosphate. Although the biological sources are important, constraints in biomass production need to be overcome first.

Figure 2. Crop yield response to planted herbaceous fallow in West and Central Africa.
Figure 2. Crop yield response to planted herbaceous fallow in West and Central Africa.

Mineral fertilizers alone cannot sustain crop production on degraded land. Soil organic matter and  soil micro-, meso-, and macro-fauna are important in maintaining soil quality and health. Traditionally, fallow phases between crops were replenishing the soils’ production capacity. With increased population densities, fallow phases have been shortened or no longer exist. Thus, soils do not recover but continue to lose their production potential. Farmers do not seem to invest in soil fertility but look for ways of coping with ever less fertile soils, thereby degrading them to a stage where cropping becomes unprofitable.

Such situations have been encountered in southern Bénin. Soil fertility and quality management techniques, such as cover crops, manure application, or any other form of organic matter and nutrient recycling have not been adopted at larger scales. In retrospect, there have been constraints to the adoption that were not considered in the process of technological development. Today, with more options available and a stronger and earlier involvement of farmers in research for development, such approaches are worth reconsidering. One such technology, using leguminous cover crops, had little if any success in cassava (Fig. 2).

Controlling the cover crop was a major problem. Consequently IITA works today on efficient and effective control methods. Pueraria phaseoloides was introduced to smallholders in southern Cameroon but it was not readily accepted as farmers immediately identified it as an aggressive weed, able to destroy crops. However, two years into the use of Pueraria, fallow farmers noticed that the weeds most difficult to control had disappeared and that it was easier to clear Pueraria than the natural fallow. Some farmers burned the Pueraria only to find the land ready to crop without major labor input. Yields of cassava, maize, and groundnut were generally higher after Pueraria, whereby the labor-saving burning produced the highest yields (Fig. 3).

Figure 3. Cassava fresh root yield in burned and mulched maize-cassava and burned maize-cassava-groundnut intercrop.
Figure 3. Cassava fresh root yield in burned and mulched maize-cassava and burned maize-cassava-groundnut intercrop.

Considering farmers’ needs
Pueraria was introduced for soil fertility replenishment but was adopted for its labor-saving effects. Soil fertility was not perceived as a problem and thus positive effects on the soil could be compromised (by burning) without compromising yields. Effects such as weed suppression and the reduction of soil-borne pests and diseases may contribute to the yield increases after Pueraria.

Livestock integration and the search for synergies
Few farmers adopted the use of green manures for soil fertility improvement because they have no direct benefits from it. Herbaceous legumes have rarely been used to feed livestock, although there is (anecdotal) evidence that livestock feed on them and that they are beneficial to growth and reproduction. In the IITA-led CRP on Humidtropics, livestock integration will be a major aspect. It will add value to green manure species when these are used to feed livestock that will also benefit from the canopies of root and tuber crops (cassava leaves) remaining at root harvest. Thus, there will be an increase in returns of animal manure to fields, and to crop yields through the combined use of green and animal manures for improved food security and farm incomes.

Outlook
Efficient combinations of agronomic practices, nutrient supply, and soil management practices will be developed to increase the productivity of cassava and yam while improving the status of the natural resource base. Synergistic effects between these measures and the integration of livestock or fish farming will increase resource use efficiency and income generation as well as the quality of the farm food supplies. Due consideration of social and gender aspects in farm household operations will identify the entry point best suited for IITA’s interventions. Farmers’ feedback and innovations will be integrated into approaches on sustainable intensification to increase food production and improve rural livelihoods while enhancing the capacity of the agroecosystems to deliver essential services.

References
Hauser, S. and C. Nolte. 2002. Biomass production and N fixation of five Mucuna pruriens varieties and their effect on maize yields in the forest zone of Cameroon. Journal of Plant Nutrition and Soil Science 165: 101–109.
Hauser, S., C. Nolte, and R.J. Carsky. 2006. What role can planted fallows play in humid and sub-humid West Africa? Nutrient Cycling in Agroecosystems 76: 297–318.

Tanzania and partners tackle cassava disease

Tanzania’s Ministry of Agriculture, Food Security and Cooperatives (MAFC) and the Bill & Melinda Gates Foundation have launched three new projects to support efforts to develop cassava varieties with resistance to Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD) and to establish more sustainable seed systems to provide smallholder farmers better access to such varieties.

The projects were launched during a cassava value chain event in Dar es Salaam that brought together representatives from the government, donor community, private sector and development partners.

Farmers in Tanzania and the region need access to planting materials of new improved varieties released in the country. Cassava is a very important crop not only for food security but it also has great potential as a cash crop through processing. The two diseases, especially CBSD, are a major problem and need to be urgently addressed.

The Cassava Varieties and Clean Seed to Combat CBSD and CMD (5CP) project will facilitate sharing of five of the best varieties from Tanzania, Kenya, Malawi, Mozambique, and Uganda for regional testing across the countries to speed up the development of varieties with dual resistance to the two diseases.

Pro-vitamin A cassava released

Three pro-vitamin A cassava varieties released in December 2011 were launched recently by the Nigerian government. IITA, in partnership with the National Root Crops Research Institute, Nigeria, developed these varieties using traditional breeding methods in a HarvestPlus-funded project.

The varieties were released by the National Variety Release Committee of Nigeria as UMUCASS 36, UMUCASS 37, and UMUCASS 38; and are recognized as IITA genotypes TMS 01/1368, TMS 01/1412, and TMS 01/1371.

The project works with national partners and the private sector to ensure that the pro-vitamin A-rich varieties reach resource-poor farmers. The consumption of pro-vitamin A cassava could help Nigeria reduce economic losses in gross domestic product estimated at about $1.5 billion. Most importantly, it will also improve the nutrition of women and children who are the most vulnerable.

In developing countries, vitamin A deficiency remains a major bottleneck to improved nutrition with approximately 250,000 to 500,000 malnourished children going blind each year, half of whom die within a year of becoming blind. The prevalence of night blindness due to vitamin A deficiency is also high among pregnant women in many developing countries.

The yellow root color of the vitamin A-rich varieties is the product of over 20 years of breeding efforts for improved nutritional quality. Other partners in this biofortification work include the International Center for Tropical Agriculture (CIAT) and the Brazilian Agricultural Research Corporation (Embrapa).

Combating the threat of CBSD

Cassava brown streak disease (CBSD) is a virus disease that has emerged as a serious threat to production in Eastern and Southern Africa.

Brown streak-affected cassava. Photos by L. Kumar, IITA.
Brown streak-affected cassava. Photos by L. Kumar, IITA.

Two virus species, Cassava brown streak virus and Cassava brown streak Uganda virus, the cassava brown streak viruses or CBSVs, have been recognized to cause CBSD. The infection results in mosaic symptoms on leaves, brown streaks on stems, and a corky necrosis in tuberous roots.

Root necrosis has the most damaging effects on the use and marketability of the tubers and thus affects the livelihoods of cassava farmers. It can make susceptible varieties unusable if the roots are left in the ground for over 9 months.

CBSVs are spread through the planting of infected stem cuttings and also by a vector, a whitefly, Bemisia tabaci. The foliar symptoms of CBSD are less conspicuous and farmers are often unaware of the problem until they harvest the roots and the corky, yellow-brown necrotic rot becomes evident.
There is no cure for the disease. Once plants become infected, the only option for growers is to uproot and destroy them. The use of virus-free planting material and the cultivation of resistant varieties are the only options for the control of CBSD.

Where is it and where is it heading?
CBSD is endemic in Kenya, Malawi, Mozambique, Tanzania, and Uganda and its occurrence is suspected in Burundi, Gabon, Madagascar, DRC, and Rwanda. Available evidence suggests a westward spread of the disease.

What is IITA doing about it?
IITA has adopted a multipronged strategy to tackle CBSD, to reduce the effects on cassava in epidemic areas, and prevent a further spread of the disease. Its efforts begin with informing governments about the threat. The four technical pillars of this strategy are as follows.

-Monitor disease spread and assess its impact: Key outputs include (a) the development of disease distribution maps, (b) estimates of yield loss, and (c) identification of targets for development.

-Understand disease etiology and epidemiology; develop tools for monitoring and forewarning: Key outputs include (a) understanding the effects of the viruses in cassava, (b) examining the characteristics of virus spread, (c) creating diagnostic tools for CBSVs, and (d) using digital-enabled field surveillance tools for real time reporting and a monitoring network.

-Develop and disseminate durable CBSD-resistant cassava cultivars: Key outputs include (a) screening and selecting over 40 elite cassava cultivars with dual resistance/tolerance to CBSD and cassava mosaic disease (CMD) appropriate for various countries, (b) deploying tolerant varieties for farmers to cultivate in East Africa, (c) developing molecular markers and modern molecular breeding tools for the accelerated development of CBSD-resistant varieties, (d) pre-breeding in areas currently not affected by the viruses, and (e) developing clean seed systems for the multiplication and dissemination of virus-free planting material.

-Capacity building through the transfer of knowledge, technology, and products to stakeholders: IITA has (a) built a coalition of international teams to combat CBSD, (b) trained scientists, extension workers, and plant quarantine officials in disease recognition, monitoring, and diagnostics, (c) established regional diagnostic labs, (d) created awareness through the use of the mass media, and (e) provided technical backstopping to national efforts in combating CBSD.

A suite of knowledge, technologies, and products derived so far from IITA’s R4D efforts is playing a vital role in checking the spread of the disease and has contributed to reviving cassava production in areas affected by the epidemic. However, complete recovery and the prevention of any further spread of CBSD are still a long way off. They require a strong commitment from national and international communities to sustain the ongoing and emerging research and development efforts that are devising effective and eco-friendly technologies for sub-Saharan Africa.

Prof Mike Thresh, Scientist Emeritus, Natural Resources Institute, UK (right), during his visit to IITA-Ibadan. Photo by L. Kumar, IITA.
Prof Mike Thresh, Scientist Emeritus, Natural Resources Institute, UK (right), during his visit to IITA-Ibadan. Photo by L. Kumar, IITA.

Advice to stakeholders
In countries where CBSD is already established, IITA recommends that governments require the use of available CBSD control programs, including the adoption of promising CBSD-resistant cultivars, and the production and distribution of clean cassava planting material.

Countries not yet affected need to increase their vigilance and develop the capacity to recognize CBSD and deploy eradication programs; establish plans for preemptive action to reduce the risk of CBSD spreading from affected regions; and put in place programs to produce and distribute clean planting material.

All the cassava-producing countries in Africa should:

-Organize large-scale awareness creation programs to inform farmers, extension workers, CSOs, and national research entities about CBSD, the eradication of infected plants, and the steps for disease control.
-Strengthen the monitoring capacity of the national quarantine authorities and other relevant bodies including the establishment of communication systems for a rapid response to prevent disease and eradicate infections where they are identified.
-Develop resistant varieties most urgently, through breeding, using both conventional and transgenic approaches.
-Put in place a strategy for the production and distribution of clean cassava planting material, and adopt improved varieties with resistance to CBSD and CMD.
-Affirm financial and political support for collaboration, cooperation, and coordination to prevent the further spread of CBSD in tropical Africa.

UPoCA gives farmers a lifeline

Cassava value addition is helping African farmers increase their income, and improve livelihoods and food security through a USAID-funded project called Unleashing the Power of Cassava (UPoCA).

Implemented in seven African countries—Nigeria, DR Congo, Ghana, Malawi, Mozambique, Tanzania, and Sierra Leone—by IITA, the project has benefited thousands of farmers in these countries.

In Sierra Leone, the Tongea Women farmers in Sandeyalu community formed the Tongea women’s development association comprised of 54 women and 4 men.

Through the IITA-UPoCA project, a cassava microprocessing center was subsequently inaugurated, providing farmers with a financial window of opportunity. Incomes from USAID projects such as UPoCA have helped the people of Sandeyalu in rebuilding their community after years of civil unrest.

This success story echoes across other countries such as Nigeria, DR Congo, Ghana, Malawi, Mozambique, and Tanzania where UPoCA is being implemented.

In Malawi, UPoCA helped revive a moribund starch factory—the first in that country. Thousands of farmers benefited from improved cassava cuttings, training, and capacity building for processors.

In Nigeria the project linked up processors to farmers for steady production/supply of cassava roots, provided improved cuttings and training, and also helped build the capacities of farmers and processors.

Farmers in Ido community, Oyo State, Nigeria, have more than doubled the yield of cassava from an average of 10 t/ha to more than 20 t/ha. Other states that benefited from the UPoCA project were Osun, Ondo, Ekiti, Kogi, Nasarawa, and Benue states.

Farmers say the project has increased the production of cassava with the availability of improved cassava stems, making food more secure and generating wealth.

Apart from boosting the productivity of cassava in the project areas and maximizing the use of the root crop, the project is also promoting food security and improving the incomes of women farmers and processors in particular, and African farmers in general.

Nigeria gets improved cassava

The Nigerian government has released four improved cassava varieties that are a product of about a decade-old conventional breeding research. These include NR 01/0004, CR 41-10, TMS 00/0203, and TMS 01/0040.

TMS 00/0203 and TMS 01/0040 were bred by IITA scientists, while NR 01/0004 was bred by the Umudike, Nigeria-based National Root Crops Research Institute, and CR 41-10 by the Colombia-based International Center for Tropical Agriculture (CIAT).

On-farm prerelease trials involving local farmers in eight states of the country show that the improved varieties outperformed local checks with an average yield of about 31 t/ha compared with 26 t/ha recorded by the local varieties.

Farmers love the varieties for their excellent culinary qualities, high yield, and resistance to pests and diseases.

The new varieties seek to strengthen Nigeria’s lead in cassava production, increase farmers’ incomes, and guarantee food security.

DEWN: a novel surveillance system

Innocent Ndyetabula*, indyetabura@yahoo.com and James Legg, j.legg@cgiar.org
*Maruku Agricultural Research Institute, PO Box 127, Bukoba, Tanzania

Researchers inspect cassava plants for disease incidence. Photo by IITA.
Researchers inspect cassava plants for disease incidence. Photo by IITA.

Pandemics of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are the most important biotic constraints to cassava production in East and Central Africa.

For several years, researchers have tracked these two diseases and monitored patterns of pandemic expansion. However, costs have been high, and the visits made once a year have barely kept pace with the rate of disease spread.

Hence, researchers working to control these problems resolved to explore other monitoring options. During early discussions, two themes were frequently highlighted: community participation and new technology. Could both of these be incorporated into an alternative approach to monitoring disease spread in such a way that the system would provide an early warning of new outbreaks?

The result was the Digital Early Warning Network or DEWN. After extensive consultation, a plan was developed for its pilot-level implementation. This system works with six farmers’ groups in each of 10 disease-threatened districts of northwestern Tanzania, and provides them with a system based on the use of the mobile phone for reporting incidences of CMD and CBSD in their farms. By communicating monthly with farmers’ groups, it was expected that new outbreaks would be identified quickly, allowing the timely implementation of control measures.

Partnerships
The pilot phase of DEWN has been primarily implemented by the Lake Zone Agricultural Research Institute (LZARDI), under the IITA-coordinated Disease Objective of the Great Lakes Cassava Initiative (GLCI). GLCI is funded by the Bill and Melinda Gates Foundation (BMGF) and is led by the Catholic Relief Services (CRS). The partners of GLCI in the DEWN target districts included several local NGOs (TAHEA, MRHP, KUMKUMAKA, RUDDO, and TCRS) as well as the local government agricultural advisory system.

Training
At the outset, it was essential to train all participating farmers’ groups to recognize the symptoms of the two virus diseases, and introduce the SMS-based communication system. A total of 1281 farmers were trained in the 60 groups, and district partners were provided with a GPS unit and digital camera to record field locations and any unusual disease symptoms.

Each of the farmers’ groups was provided with a basic GSM phone and SIM card and introduced to the simple texting system for sending monthly disease reports. A straightforward text format was used for the farmers’ groups to provide information on how many farmers had observed each of the two diseases in their fields that month, and for how many farmers each disease had become more severe, less severe, or stayed the same. Once reports had been compiled at the farmers’ group level, they were sent as a single text to the LZARDI modem.

Outcomes
Validation visit. A follow-up visit was made after 6 months to validate farmers’ reports. A refresher course was provided, but the farmers generally indicated a good knowledge of the main symptoms of both diseases. Partly as a consequence of their new understanding of the significance of CMD and CBSD, there was a strong demand from participating farmers for improved varieties.

Voice of the Farmer reports. Participating farmers were linked to the Voice of the Farmer project (VOF). This is a project that is executed by Synovate and financed by BMGF. It aims to use a network of call centers to provide monitoring and evaluation support to existing BMGF programs.

Map based on farmers and researchers' report of CMD occurrence in Lake Zone districts of Tanzania.
Map based on farmers and researchers' report of CMD occurrence in Lake Zone districts of Tanzania.

DEWN provided a means for VOF to communicate directly with many of the participating farmers. This enabled VOF to conduct two surveys to assess the effectiveness of DEWN’s training program on the identification and management of cassava pests and diseases. Participating farmers were called directly by VOF call center staff and were asked a series of short questions in Swahili. Although farmers’ responses indicated a good general knowledge of CMD and CBSD, some confusion about symptoms was evident, highlighting the need for further training support. The VOF–DEWN reports are available online at www.vof.synovate.co.ke.

Mapping new disease outbreaks. Information obtained from the DEWN reports received from farmers’ groups was used to generate maps. One of the most significant findings was that CBSD, reported by farmers via SMS, was then confirmed by researchers’ visits in two districts (Bukombe and Urambo) in which CBSD had not previously been reported. This has allowed project teams to focus extra disease mitigation efforts on these areas.

Extending DEWN. Recognizing the potential value of DEWN for providing communities with a means of doing their own monitoring of crop disease, the GLCI cassava team in Rwanda decided to start a similar scheme. Farmers’ representatives from Rwanda visited DEWN partners in Tanzania in October 2010 and were introduced to the approach and given training in recognizing CBSD and CMD. The Rwanda team will initiate its own DEWN program in 2011.

Map based on farmers and researchers' report of CBSD occurrence in Lake Zone districts of Tanzania.
Map based on farmers and researchers' report of CBSD occurrence in Lake Zone districts of Tanzania.

DEWN has provided an innovative, informative, and relatively cheap means for involving communities in monitoring the health of their own crops. Farmers’ participation has been enthusiastic, and some important practical outcomes have been achieved. Two of the greatest challenges which remain, however, are the accurate diagnosis of CBSD, which has cryptic or unrecognized symptoms and the regular provision of feedback to participating communities.

Plans are already being developed to address these problems. As these difficulties are overcome and as connectivity in rural areas continues to expand, it seems certain that there is great potential for the more widespread use of digital networks such as DEWN for the community-based monitoring of crop diseases.