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Oct 272015
 

 

Photo: N Palmer/CIAT

GCP sowed the seeds of a genetic resources revolution.

“In the last 10 years we have had a revolution in terms of developing the genetic resources of crops.”

So says Pooran Gaur, Principal Scientist for chickpea genetics and breeding at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), and Product Delivery Coordinator for chickpeas for the CGIAR Generation Challenge Programme (GCP).

He attributes this revolution in large part to GCP, saying it “played the role of catalyst. It got things started. It set the foundation. Now we are in a position to do further molecular breeding in chickpeas.”

Led by Pooran, researchers from India, Ethiopia and Kenya worked together not only to develop improved, drought-tolerant chickpeas that would thrive in semiarid conditions, but also to ensure these varieties would be growing in farmers’ fields across Africa within a decade.

The 10-year Generation Challenge Programme, with the goal of improving food security in developing countries, aimed to leave plant genetic assets as an important part of its legacy.

Diagnostic, or informative, molecular markers – which act like ‘tags’ for beneficial genes scientists are looking for – are an increasingly important genetic tool for breeders in developing resilient, improved varieties, and have been a key aspect of GCP’s research.

Photo: ICARDA

Chickpeas, ready to harvest.

What is a diagnostic molecular marker?

Developments in plant genetics over the past 10–15 years have provided breeders with powerful tools to detect beneficial traits of plants much more quickly than ever before.

Scientists can identify individual genes and explore which ones are responsible for, or contribute to, valuable characteristics such as tolerance to drought or poor soils, or resistance to pests or diseases.

Once a favourable gene for a target agronomic trait is discovered and located in the plant’s genome, the next step is to find a molecular marker that will effectively tag it. A molecular marker is simply a variation in the plant’s DNA sequence that can be detected by scientists using any of a range of methods. When one of these genetic variants is found close on the genome to a gene of interest (or even within the gene itself), it can be used to indicate the gene’s presence.

To use an analogy, think of a story as the plant’s genome: its words are the plant’s genes, and a molecular marker works like a text highlighter. Molecular markers are not precise enough to highlight specific words (genes), but they can highlight sentences (genomic regions) that contain these words, making it easier and quicker to identify whether or not they are present.

Once a marker is found to be associated with a gene, or multiple genes, and determined to be significant to a target trait, it is designated an informative marker, diagnostic marker or predictive marker. Some simple traits such as flower colour are controlled by one gene, but more complex traits such as drought tolerance are controlled by multiple genes. Diagnostic markers enable plant breeders to practise molecular breeding.

Breeders use markers to predict plant traits

Photo: N Palmer/CIAT

Hard work: a Ugandan bean farmer’s jembe, or hoe.

In the process known as marker-assisted selection, plant breeders use diagnostic molecular markers early in the breeding process to determine whether plants they are developing will have the desired qualities. By testing only a small amount of seed or seedling tissue, breeders are able to choose the best parent plants for crossing, and easily see which of the progeny have inherited useful genes. This considerably shortens the time it takes to develop new crop varieties.

“We use diagnostic markers to check for favourable genes in plants under selection. If the genes are present, we grow the seed or plant and observe how the genes are expressed as plant characteristics in the field [phenotyping]; if the genes are not present, we throw the seed or plant away,” explains Steve Beebe, a leading bean breeder with the International Center for Tropical Agriculture (CIAT) and GCP’s Product Delivery Coordinator for beans.

“This saves us resources and time, as instead of a growing few thousand plants to maturity, most of which would not possess the gene, by using markers to make our selection we need to grow and phenotype only a few hundred plants which we know have the desired genes.”

GCP supported 25 projects to discover and develop markers for genes that control traits that enable key crops, including bean and chickpea, to tolerate drought and poor soils and resist pests and diseases.

Genomic resources, including genetic maps and genotyping datasets, were developed during GCP’s first phase (2004–2008) and were then used in molecular-breeding projects during the second five years of the Programme (2009–2014).

“GCP’s philosophy was that we have, in breeding programmes, genomic resources that can be utilised. Now we are well placed, and we should be able to continue even after GCP with our molecular-breeding programme,” says Pooran.

Photo: IRRI

A small selection of the rice diversity in the International Rice Research Institute gene bank – raw material for the creation of genomic resources.

Markers developed for drought tolerance

Photo: N Palmer/CIAT

Cracked earth.

With climate change making droughts more frequent and severe, breeding for drought tolerance was a key priority for GCP from its inception.

Different plants may use similar strategies to tolerate drought, for example, having longer roots or reducing water loss from leaves. But drought tolerance is a complex trait to breed, as in each crop a large number of genes are involved.

Wheat, for example, has many traits – each controlled by different genes – that allow the crop to tolerate extreme temperature and/or lack of moisture. Identifying drought tolerance in wheat is therefore a search for many genes. In the particular case of wheat, this search is compounded by its genetic make-up, which is one of the most complex in the plant kingdom.

The difficulty of identifying genes that play a significant role in drought tolerance makes it all the more impressive when researchers successfully collaborate to overcome these challenges. GCP-supported scientists were able to develop and use diagnostic markers in chickpea, rice, sorghum and wheat to breed for drought tolerance. The first new drought-tolerant varieties bred using marker-assisted selection have already been released to farmers in Africa and Asia and are making significant contributions to food and income security.

Photo: ICRISAT

Tanzanian sorghum farmer.

Markers developed for pests and diseases

Photo: IITA

A bumper harvest of cassava roots at the International Institute of Tropical Agriculture (IITA) in Nigeria.

Cassava mosaic disease (CMD) is the biggest threat to cassava production in Africa – where more cassava is grown and eaten than any other crop. A principal source of CMD resistance is CMD2, a dominant gene that confers high levels of resistance.

Nigerian GCP-supported researchers worked on identifying and validating diagnostic markers that are associated with CMD2. These markers are being used in marker-assisted selection work to transfer CMD resistance to locally-adapted, farmer-preferred varieties.

In the common bean, GCP-supported researchers identified genes for resistance to pests such as bean stem maggot in Ethiopia, as well as diseases such as the common mosaic necrosis potyvirus and common bacterial blight, which reduce bean quality and yields and in some cases means total crop losses.

Markers developed for acidic and saline soils

Photo: N Palmer/CIAT

Sifting rice in Nepal.

Aluminium toxicity and phosphorus deficiency, caused by imbalanced nutrient availability in acid soils, are major factors in inhibiting crop productivity throughout the world. Aluminium toxicity also exacerbates the effects of drought by inhibiting root growth.

Diagnostic markers for genes that confer tolerance to high levels of aluminium and improve phosphorus uptake were identified in sorghum, maize and rice. The markers linked to these two sets of similar major genes have been used efficiently in breeding programmes in Africa and Asia.

Salt stress is also a major constraint across many rice-producing areas, partly because modern rice varieties are highly sensitive to salinity. Farmers in salt-affected areas have therefore continued growing their traditional crop varieties, which are more resilient but give low yields with poor grain quality. To address this issue, GCP supported work to develop and use markers to develop popular Bangladeshi varieties with higher tolerance to salt. GCP also funded several PhD students working in this area, one of whom was Armin Bhuiya.

Markers mean information, which means power

Diagnostic molecular markers are, in their most essential form, data. That means they are easily stored and maintained as data in publicly accessible databases and publications. Breeders can now access the molecular markers developed for various crops through the Integrated Breeding Platform – a web-based one-stop shop for integrated breeding information (including genetic resources), tools and support, which was established by GCP and is now continuing independently following GCP’s close – in order to design and carry out breeding projects.

“We could not have done that much in developing genomic resources without GCP support,” says Pooran. “Now the breeding products are coming; the markers are strengthening our work; and you will see in the next five to six years more products coming from molecular breeding.

“For me, GCP has improved the efficiency of the breeding programme – that is the biggest advantage.”

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Photo: N Palmer/CIAT

Beans on sale in Uganda.

Oct 182015
 

C-Egesi_w“You can use any technology in the world, you can develop any product, but you need the products that farmers are willing to grow in their field.”

So says Chiedozie Egesi, a plant breeder and geneticist who has been one of the inspirational leaders and Principal Investigators for the CGIAR Generation Challenge Programme’s (GCP) Cassava Research Initiative in Africa.

It was his commitment to helping farmers that led Chiedozie to forsake his dream of becoming a surgeon, and instead to train as a plant breeder and help smallholder farmers in Nigeria. Having grown up in a small town in south-eastern Nigeria where poverty was a daily reality, he was particularly concerned about food security and nutrition for the people. He dreamt of developing cassava varieties that could beat the pests and diseases that often devastate such crops.

Photo: IITA

Peeling cassava roots.

“The food people grow should be nutritious, resistant and high-yielding enough to allow them to sell some of it and make money for other things in life, such as building a house, getting a motorbike or sending their kids to school,” Chiedozie says.

Nigeria is the most populous African country, with a population of more than 174 million. The main staple food is cassava, making Nigeria the world’s largest producer and consumer of the crop. But cassava is also important in other African countries. It is grown by nearly every farming family in sub-Saharan Africa. Africa produced nearly 140 million metric tonnes of cassava in 2012 – but most of the production is low-yielding subsistence farming for food by small-scale farmers for food for their own households alone.

After almost eight years working on GCP-supported cassava projects, Chiedozie is proud of what they have managed to accomplish: “That we’ve been able to give African farmers the varieties that they will love to grow is my biggest achievement”.

Meet Chiedozie and hear all about his research and the importance of cassava in the video series below (or watch on YouTube):

Transformation for Chiedozie – and for cassava

Chiedozie’s journey with GCP began after he had gained his PhD in yam breeding from the University of Ibadan, Nigeria. He undertook further studies and training at Cornell University and the University of Washington, both in the USA. He then returned home to Nigeria to lead the cassava breeding team at the National Root Crops Research Institute (NRCRI) and, following a promotion in 2010, was made Assistant Director of NRCRI’s Biotechnology Department. In 2004, a chance find on the Internet of a molecular breeding training programme in South Africa first led to Chiedozie’s involvement in GCP.

In 2010, work by Chiedozie and the NRCRI team, in collaboration with a transnational network of partners, resulted in the official release to Nigerian farmers of Africa’s first cassava variety developed using molecular-breeding techniques. Known as UMUCASS33 (or CR 41-10), it was resistant to cassava mosaic disease (CMD) – a devastating plant disease that can wipe out entire cassava crops – and also highly nutritious. In addition to a stream of further disease-resistant varieties, in 2012 they followed this accomplishment with the release of a high-starch variety bred using molecular techniques.

Photo: IITA

Nigerian women at work processing cassava.

In 2011, the cassava team together with the International Institute of Tropical Agriculture (IITA) and HarvestPlus (another CGIAR Challenge Programme focussed on the nutritional enrichment of crops), released three cassava varieties rich in pro-vitamin A, which hold the potential to provide children under five and women of reproductive age with up to 25 percent of their daily vitamin A requirement – a figure Chiedozie and his team are now ambitiously striving to increase to 50 percent. In 2014, they released three more pro-vitamin A varieties with higher concentrations of beta-carotene.

These new and improved varieties – all generated as a direct or indirect result of his engagement in GCP projects – are, Chiedozie says, worth their weight in gold for the people of Africa.

Research that delivers benefits to poor farmers is what drives Chiedozie. In addition to the direct rewards of new varieties there are other highlights from his involvement with GCP, indicating a long term change in breeding science: “People are now using improved or modern techniques in breeding; people think about database management in cassava breeding across Africa; and African breeders are getting PhDs in molecular breeding.”

Photo: N Palmer/CIAT

Cassava leaves.

Building African capacity

Chiedozie believes a crucial element of GCP’s success in breeding better cassava varieties for smallholder African farmers lies in the capacity building and infrastructure support provided by GCP.

After his initial GCP training at the University of Pretoria, South Africa, Chiedozie engaged in other capacity-building opportunities, including a one-year visiting scientist fellowship at the International Center for Tropical Agriculture (CIAT) in Colombia. The significance of these early GCP opportunities was, Chiedozie says, momentous: “Prior to my GCP work, I was more or less a plant breeder, and a conventional one at that. Whilst I’d been exposed to molecular tools during my early work on yam and other crops, I was not applying them in my work back then.”

Chiedozie quoteChiedozie emphasises that such training opportunities are vital for the future food security of Africa. “We raised up a new crop of cassava breeders in Africa – people who were bold enough to take up a molecular breeding project and pursue it with support from the international centres. And today we are seeing the results of that. Cassava breeding programmes are standing today because of our quality of seeds sown in the past.”

The networking opportunities offered by the Cassava Community of Practice – founded by GCP and now hosted by the Integrated Breeding Platform (IBP) – have meant that Chiedozie and his colleagues could expand their collaboration at the local, national and regional levels: “We now have a network of cassava breeders that you can count on and relate with in different countries. This has really widened our horizons and also made our work more visible,” he says, citing effective links formed with Côte d’Ivoire, Ethiopia, Ghana, Liberia, Malawi, Mozambique, Sierra Leone and South Sudan.

Photo: M Mitchell/IFPRI


Selling fufu, a staple food made with cassava flour, at a market in Nigeria.

A paradigm shift

These opportunities have led to what Chiedozie calls a ‘paradigm shift’ in how national research agencies are viewed by donors and research investors: “GCP helped us to build an image for ourselves in Nigeria and in Africa, and this created a confidence in other global actors, who, on seeing our ability to deliver results, are choosing to invest in us.

“Our work with GCP helped us to gain that capacity that we needed to be able to negotiate or even make a request for funding. And people are able to trust that you can deliver if you have delivered in the past for an organisation like GCP. So it gave us credibility; it gives us a platform to be able to speak to donors directly, and donors can now approach us, which never used to happen in pre GCP days.”

This newly found confidence and profile sees the NRCRI cassava team currently engaging with the Bill & Melinda Gates Foundation and the CGIAR Research Program on Roots, Tubers and Bananas (RTB) on research that will expand on and follow through on what GCP started.

Hear from Chiedozie on the beneficial outcomes of GCP – in terms not only of variety releases but also of attracting further projects, prestige, and enthusiastic young breeders – in the video below (or on YouTube):

For Chiedozie, his dream of helping his country’s struggling farmers and people is coming true. He has no regrets about dropping his dream of becoming a surgeon for one of helping his country as a plant breeder: “Coming from Umuahia, a small town in the southeast of the country, I grew up in an environment where you see people who are struggling, weak from disease, poor, and with no opportunities to send their children to school.

“Despite the social injustice around me, I always thought there was opportunity to improve people’s lives. This is what the GCP-supported research has helped me to do, even faster than I would have believed possible.”

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Oct 132015
 

 

Photo: N Palmer/CIAT

The vibrant colours of a cassava leaf.

Little did some of Ghana’s crop researchers know back in 2007 that they would be cultivating not just their plants but also themselves over the following seven years.

“When you see one person being trained and then another person being trained, it doesn’t mean much. But when you put all the numbers together and they see themselves as a force, as a team, I think that’s where new strength lies for our African researchers,” reflects Elizabeth Parkes on the impacts of the CGIAR Generation Challenge Programme (GCP).

Elizabeth is a cassava breeder in Ghana. She works for the Crops Research Institute (CRI) of Ghana’s Council for Scientific and Industrial Research (CSIR) and is currently on a leave of absence working at the International Institute of Tropical Agriculture (IITA).

“Wherever I go, whatever opportunity I have, I refer back to GCP and its capacity-building work. You see, it’s good to release new plant varieties, but it’s also good to release people,” she says.

The internationally funded GCP set out to enhance the local plant-breeding capabilities of people like Elizabeth, and so help developing nations meet ever-growing demands for food in the face of climate change and worsening drought conditions, the threat of crop disease, and other pressures.

Photo: N Palmer/CIAT

Scientists at the Crops Research Institute (CRI) work to improve crop production in Ghana and so ensure national food security and decent livelihoods for people like this Ghanaian cassava farmer.

This has meant empowering scientists with cutting-edge tools and knowledge, as well as overcoming some surprisingly down-to-earth obstacles.

“One thing that really energises me,” enthuses GCP Consultant Hannibal Muhtar, “is seeing people understand why they need to do the work and being given the chance to do the how.”

Hannibal, under his GCP remit, was asked to visit the research sites of GCP-funded projects at research centres and stations across Africa, to identify those where effective research might be hindered by significant gaps in three fundamental areas: infrastructure, equipment and support services. He selected 19 target research sites, in Burkina Faso, Ethiopia, Ghana, Kenya, Mali, Niger, Nigeria and Tanzania. Two of these were in Ghana, namely the CRI research sites at Kumasi and Tamale.

The mission of CRI is to ensure high and sustainable crop productivity and food security in Ghana through the development and dissemination of environmentally sound technologies. Its research areas are broad and include maize, rice, cowpeas, soybeans, groundnuts, cassava, yams, cocoyams, sweetpotatoes, plantains and bananas.

In developing countries like Ghana that the obstacles to achieving research objectives are often quite mundane in nature: a faulty weather station, a lack of irrigation systems, or fields ravaged by weeds or drainage problems and in dire need of rehabilitation. Yet such factors compromise brilliant research.

Even a simple lack of fencing commonly results not only in equipment being stolen, but also in precious experimental crops being stomped on by roaming cattle and wild animals such as boars, monkeys, hippopotamuses and hyenas; this also poses a serious threat to the safety of field staff.

“The real challenge lies not in the science, but rather in the real nuts and bolts of getting the work done in local field conditions,” Hannibal explains.

He says: “If GCP had not invested in research support infrastructure and services, then their investment in research would have been in vain. Tools and services must be in place as and when needed, and in good working order. Tractors must be able to plough when they should plough.”

Photo: N Palmer/CIAT

Cassava chips on sale in a Ghanaian market.

Ghana gains a new centre of excellence

CRI Ghana quote 1Elizabeth is one of more than 10 researchers from Ghana who gained their PhDs via GCP-funded research projects. They were given the opportunity to travel to international research laboratories to learn the latest research methods, train in genotyping and establish contacts with leading scientific minds.

“They [GCP] have made us attractive for others to collaborate with,” says Elizabeth.

“GCP gave you the keys to solving your own problems; it put structures in place so that knowledge learnt abroad could be transferred and applied at home.

“Before GCP we really struggled, but now everybody wants to have training in Ghana. Everybody wants to have something to do with us, and I will always say thank you to GCP for that, for making us attractive as researchers,” Elizabeth says.

At the outset of the Programme, Elizabeth was learning how to breed new cassava varieties suitable for African soils. She worked with scientists from IITA in Nigeria to use genetic resources (germplasm) from South America, where cassava originates, to integrate the CMD2 gene into local germplasm using molecular breeding. CMD2 gives cassava resistance to the devastating cassava mosaic disease, which slowly shrivels and yellows leaves and roots, destroying crop yields.

Photo: IITA

Elizabeth Parkes poses with a sturdy and nutritious harvest of cassava roots.

Cassava is a lifeline for African people, and is a particularly important staple food for poorer farmers. More cassava is produced in Africa than any other crop, according to 2012 figures from the Food and Agriculture Organization of the United Nations. It is grown by nearly every farming family in sub-Saharan Africa, supplying about a third of people’s daily energy intake in the region. This makes cassava mosaic disease a potential disaster, and makes effectively breeding improved varieties an activity with real impact.

“We started out doing low-cost marker-assisted selection, for which we had some grants. Someway, somehow, the government got interested and brought in more resources. So together we started a small biotech lab. Now this lab has become the Centre of Excellence for West African productivity,” says Elizabeth.

“I have attended three GCP Annual Research Meetings, and I have won awards for my posters. This greatly boosted my confidence,” says Elizabeth. She also continues to be an active member of the Cassava Community of Practice – founded by GCP and now hosted by the Integrated Breeding Platform (IBP) – which facilitates and supports the integration of marker-assisted selection into cassava breeding. All this has accelerated Elizabeth’s quest to produce and disseminate farmer-preferred cassava varieties that are resistant to pests and diseases.

“We are all forever grateful to GCP and its funders. GCP has had a huge impact on research in Ghana, especially for cassava, rice, maize and yam. All the agricultural research institutes and individual scientists who came into contact with GCP have been fundamentally transformed.”

Capacity building à la carte a real ‘life changer’

For Allen Oppong, a maize pathologist at CRI, GCP was a life changer too: “Indeed, I am very grateful to GCP for making me what I am today.”

CRI Ghana quote 2Allen’s first experience of GCP was in 2007, when he won a Capacity building à la carte grant for research into characterising locally adapted maize varieties. During the project he travelled to international research meetings and received training in marker-assisted selection in advanced laboratories.

Infrastructure improvements funded by GCP also came at a critical time for Allen. There was a drought, which, without the irrigation systems provided through the Programme, would have meant a much longer research process.

Even without drought, these kinds of improvements can dramatically speed up breeding, as Hannibal explains: “By providing glasshouses or the capacity to irrigate in the dry season, we are enabling breeders to accelerate their breeding cycles, so that they can work all year round rather than having to wait until the rain comes.”

“Through the support of GCP,” Allen recalls, “I was able to characterise maize varieties found in Ghana using the bulk fingerprinting technique. This work has been published and I think it’s useful information for maize breeding in Ghana – and possibly other parts of the world.”

One of the biggest challenges that Allen experienced during his GCP work was getting farmers to try the new varieties that are being developed.

“Most people don’t like change. The new varieties are higher yielding, disease resistant, nutritious – all good qualities. But the challenge is demonstrating to farmers that these materials are better than what they have.

Photo: N Palmer/CIAT

A Ghanaian farmer holds a just-harvested maize ear.

“You can have very good material that has all these attributes, but if the farmer doesn’t have access to it, then how can he know the attributes that you are talking about? How can he see it when it is in your research station?”

Ghanaian farmers generally select maize varieties for their adaptation to specific local environments. But as Allen explains, average maize yields in Ghana, at 1–1.5 tonnes per hectare, are well below the global average of 5.2 tonnes per hectare.

Allen is looking forward optimistically to this next stage. “We have the capacity to more than double what we are producing now. The possibility is there, as long as farmers adopt the good materials.”

A ‘kick-start’ for plant science and for people

The catalytic effect of international funding programmes like GCP on small research laboratories in developing countries is often underestimated.

“We got GCP support to kick-start molecular biology research activities,” says Marian Quain, a senior research scientist at CRI. “It provided us with laboratory chemicals, reagent and equipment. My lab also received funding under the Genotyping Support Service initiative to characterise hundreds of sweetpotato, yam and cassava accessions.

“This support from GCP contributed immensely to transforming the lab.”

Ruth Prempeh – CRI researcher who was able to achieve her PhD with GCP support – hard at work collecting data in the field.

Ruth Prempeh – CRI researcher who was able to achieve her PhD with GCP support – hard at work collecting data in the field.

Funding injections can kick-start careers for young scientists too. In 2009, Ruth Prempeh received funding for her PhD, Genetic analysis of postharvest physiological deterioration in cassava (Manihot esculenta Crantz) storage roots, which was completed in 2013.

“From my thesis, l have prepared three manuscripts for publication. I have also had the opportunity to attend the three-year Integrated Breeding Multiyear Course, during which l acquired knowledge and skills in data analysis, interpretation and management and also in using modern technologies for crop improvement,” says Ruth.

“This has been very useful and has really had an impact on my career, making me what l am today. With this, l know l have a great future and I believe l will achieve great things. I am really proud to have been associated with GCP and very grateful for the opportunity.”

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Photo: William Haun/Flickr (Creative Commons)

Cassava flour on sale in Ghana.

Oct 072015
 

Young Nigerian scientists often leave Africa and look for jobs with international research agencies overseas. But with the CGIAR Generation Challenge Programme (GCP)-funded Cassava Research Initiative (RI), two young nationals have been leading the international collaboration and injecting confidence into Africa’s research capacity.

Leadership is a quality admired and consistently sought after, particularly when overcoming a challenge. Some leaders direct from afar; others rise through the ranks and work with their peers on the ground – winning respect from the people they lead as they get their hands dirty.

Photo: G Norton

Dream team: Emmanuel Okogbenin (left) and Chiedozie Egesi (right), both of Nigeria’s National Root Crops Research Institute.

“If you want to work for the people, you have to walk with the people – that’s an African concept,” says Emmanuel Okogbenin, a plant breeder and geneticist at Nigeria’s National Root Crops Research Institute (NRCRI). “Then when you work with the people, you really understand what they want. When you speak, they know they can trust you.”

This powerful sentiment is one reason why GCP sought the collaboration of NRCRI in overcoming the challenge of sustaining Africa’s, and indeed the world’s, cassava production.

Having started as a small farm in 1923, NRCRI has taken giant strides to become one of Nigeria’s best research institutes, contributing immensely to the country’s economic development and making it the leading producer of cassava in the world. NRCRI Executive Director Julius Chukwuma Okonkwo says, “This would not have been attainable if not for the trust and support that GCP had in us when they made two of our young cassava researchers the leaders of an international collaboration.”

The two researchers to whom Julius refers are Emmanuel and his colleague Chiedozie Egesi, also a plant breeder and geneticist at NRCRI. Their combined 36 years’ of cassava research experience is matched by their passion to get the best out of Nigeria’s main staple crop.

And they are happy to get some dirt under their fingernails. “It’s just as important to work with the farmers in the field and understand what they want, as it is to do the research in the lab,” says Emmanuel. “At the end of the day we need to please the farmers, as they are the ones who will be using the new varieties that we are developing to sustain their livelihoods.”

Photo: IITA

Nigerian farmers display their cassava harvest.

Developing and leading Africa’s cassava research

Between 2010 and 2014, both Emmanuel and Chiedozie led three different projects within GCP’s Cassava RI, working with other colleagues in national breeding programmes in Ghana, Tanzania and Uganda, as well as the International Institute of Tropical Agriculture (IITA), the International Center for Tropical Agriculture (CIAT), the Brazilian Corporation of Agricultural Research (EMBRAPA) and Cornell University in the USA. The aim of the initiative was to use molecular-breeding techniques to accelerate the development of high-starch cassava varieties with resistance to diseases and tolerance to drought – and so ensure both food supplies and income for farmers.

Meet Chiedozie and Emmanuel in the video playlist below, learn more about cassava in Africa, and hear all about their research (or watch on Youtube):

Emmanuel explains that before GCP, “most African national programmes didn’t really have established crop-breeding programmes, and didn’t have the resources” to do the scale of research GCP assisted with. Nor did they have the capacity to use molecular-breeding techniques, which can potentially halve the time it takes to develop new varieties.

With help from GCP and CIAT, NRCRI was able to equip a new molecular-breeding laboratory, and staff were trained to incorporate molecular-breeding techniques into their breeding programme. “GCP was there not only to provide technology, but also to guide us in how to operate that technology,” explains Chiedozie.

Julius points out that both Chiedozie and Emmanuel were also influential in disseminating this knowledge and, in turn, building and sustaining NRCRI’s human capacity. “They both mentored many young scientists who have chosen a career in cassava and molecular breeding because of this.”

Photo: IITA

Transporting a bountiful cassava harvest from farm to market in Nigeria.

With training and infrastructure in place, NRCRI led an international collaboration that in 2010 released Africa’s first cassava variety developed using molecular-breeding techniques. Known as UMUCASS33 (or CR 41-10), it was resistant to cassava mosaic disease (CMD) – a devastating plant disease that can wipe out farmers’ entire cassava crops – and also highly nutritious. This was swiftly followed by a second similar variety, CR 36-5, and supplied to farmers.

Between this landmark release and GCP’s close in 2014, the cassava team had already released nearly 20 higher yielding, more nutritious varieties resistant to diseases and pests, and had begun working on developing drought-tolerant varieties.

These new and improved varieties – all generated as a direct or indirect result of his engagement in GCP projects – are, Chiedozie says, worth their weight in gold: “Through these materials, people’s livelihoods can be improved. The food people grow should be nutritious, resistant and high-yielding enough to allow them to sell some of it and make money for other things in life, such as building a house, getting a motorbike or sending their kids to school.” This social aspect is particularly pertinent in Nigeria, where these cassava varieties will have the greatest impact.

Five years, 20 new varieties for African farmers Between 2010 and 2014, NRCRI and its collaborators developed and released multiple new cassava varieties with a combination of traits. This work has continued after the closure of GCP, with more releases in the pipeline. Disease and pest resistance During 2010-2014 the team released several varieties of cassava resistant to cassava mosaic disease (CMD) for different environments in Nigeria, Ghana, Uganda and Tanzania as well as several varieties resistant to cassava brown streak disease (CBSD) – a similarly devastating disease originating in Tanzania but quickly spreading into Uganda and further west. They have also developed new varieties with combined resistance to CMD and CBSD. These have the potential to double the yield of existing commercial varieties. The team has also worked with Tanzanian breeders to develop cassava varieties that are resistant to bacterial blight and green mites. These new Tanzanian varieties are on their way to commercial breeders and will be available to farmers by 2015–16. High starch content In 2012 the team released a variety with very high starch content – an essential element of good cassava.  Improved nutrition In 2011, the NRCRI team, together with IITA and HarvestPlus (another CGIAR Challenge Programme focussed on the nutritional enrichment of crops), released three cassava varieties rich in pro-vitamin A, which hold the potential to provide children under five and women of reproductive age with up to 25 percent of their daily vitamin A requirement. Since then, the team has aimed to increase this figure to 50 percent. In 2014, they released three more pro-vitamin A varieties with higher concentrations of beta-carotene.

Feeding a giant

Photo: IITA

Nigerian farmer with his bountiful cassava harvest.

Nigeria is often referred to as the ‘Giant of Africa’. It is the most populous African country, with over 174 million inhabitants. The population’s main staple food is cassava, making Nigeria the world’s largest producer and consumer of the crop. At the same time, the country imports almost USD 4 billion of wheat every year – a figure that is expected to quadruple by 2030 if wheat consumption continues to grow at the same rate it is today.

The government is wary of this ‘overreliance’ on imported grain and is working towards making the country less reliant on wheat by imposing a wheat tariff. It also hopes to boost cassava production and commercialisation by promoting 20 percent substitution of cassava flour for wheat in breadmaking.

“The government feels that to quickly change the fortunes of farmers, cassava is the way to go,” explains Emmanuel, who liaises with the Nigerian Government to promote to farmers the benefit of cassava varieties with high starch concentrations. It is the flour from these varieties that is being used to partially replace wheat flour to make bread. GCP support has been crucial here too, in providing vital scientific information to the government. Emmanuel explains: “The tariff from wheat is expected to be ploughed back to support agricultural development – especially in the cassava sector – as the government seeks to increase cassava production to support flour mills.”

Cassava offers a huge opportunity to transform the agricultural economy, stimulate rural development and further improve Nigeria’s gross domestic product. In 2014, Nigeria’s economy surpassed that of South Africa’s to become the largest on the continent. By 2050, Nigeria is expected to rise further and become one of the world’s top 20 economies.

Unfortunately, however, like many growing economies worldwide, Nigeria is still working to address severe inequality, including in the distribution of wealth and in feeding the country’s expanding population.

Photo: IITA

A woman with her children at work in a cassava processing centre in Nigeria.

It’s a problem Chiedozie understands well: “Nigeria is an oil-producing country, but you still see grinding poverty in some cases,” he says. “Coming from a small town in the southeast of the country, I grew up in an environment where you see people who are struggling, weak from disease, poor, and with no opportunities to send their children to school,” he reveals. The poverty challenge, he explains, hits smallholder farmers particularly hard: “Urban development caught up with them in the end: some of them don’t even have access to the land that they inherited, so they’re forced to farm along the street.”

For Chiedozie, the seemingly bleak picture only served to ignite a fierce determination and motivation to act: “Despite the social injustice around me, I always thought there was opportunity to improve people’s lives.” And thus galvanised by the plight of Nigerian farmers, Chiedozie promptly shelved his plans for a career in medical surgery and pursued biological sciences and a PhD in crop genetics, a course he interspersed with training stints in the USA at Cornell University and the University of Washington, before returning to his homeland to accept a job as head of the cassava breeding team, and – following a promotion in 2010 – to become Assistant Director of the Biotechnology Department at NRCRI.

Empowering African researchers

Photo: IITA

Carrying cassava at a processing centre in Nigeria.

Emmanuel, who followed a similar educational route to Chiedozie, says both he and his colleague are exceptions to the norm in Africa, where African researchers tend to look for opportunities at international or private institutes rather than in national breeding programmes.

“It is difficult being a researcher in Africa,” says Emmanuel. “We don’t get paid as much as breeders in more developed countries, and funding is very hard to obtain.”

Emmanuel says his proudest moment was when GCP was looking for Africans to take up leadership roles. “They felt we could change things around and set a precedent to bring people back to the continent,” he says. “They appreciated our values and the need to install African leaders on the ground in Africa rather than in Europe, Asia or the Americas.”

Jean-Marcel Ribaut, GCP’s Director, says that seeking this local leadership was a novel approach for a transnational programme like GCP at the time, and proved to be an imperative feature for all GCP Research Initiatives. “The reasoning behind the approach is two-fold: Firstly, it’s important that our national partners share in feeling ownership of the projects and outcomes; secondly, they are gaining experience in the role so they can continue to do so after the close of the Programme in 2014,” he says. “We feel that most of our leading institutes, NRCRI included, are in a better position now than when they joined the project, and that this, along with their experience, has already gained them more exposure and funding opportunities.”

This is indeed true of the NRCRI cassava team, which is engaging with the Bill & Melinda Gates Foundation, Cornell University, IITA and Uganda’s National Crop Resources Research Institute in an initiative that Chiedozie promises will be at the front of cutting-edge technology. “We are still working out specifics, but it will see us continuing to use marker-assisted breeding techniques to develop higher yielding, stress-tolerant cassava varieties.”

Chiedozie adds this would not have been possible without GCP, which helped them to develop their capacity in Nigeria and in Africa, and this has “created a confidence in other global actors, who, on seeing our ability to deliver results, are choosing to invest in us.”

Photo: IITA

Before GCP came along, cassava was something of an orphan crop in agricultural research. Among the challenges to efficient breeding of cassava are that it is slow to grow and is propagated, not by seed, but using cut sections of stem like those shown. But with investment and capacity building from GCP, particularly in molecular breeding tools, African cassava scientists have gained a new confidence and prestige.

Continuing the momentum

One organisation that has been impressed by the work done at NRCRI is the CGIAR Research Program on Roots, Tubers and Bananas (RTB). RTB Director Graham Thiele has been following the work done at NRCRI since 2010 with great interest. “We have been really impressed to see a national programme like NRCRI playing a leading role in these successful GCP projects, and grow as a result of this,” he says.

One area of research that has particularly impressed Graham is Chiedozie and Emmanuel’s pre-emptive breeding for cassava brown streak disease (CBSD) resistance. “CBSD isn’t currently an issue in Nigeria but it has the potential to wipe out all crops, as it has in Uganda and Tanzania, if it continues to spread west from these countries,” he explains.

“What Chiedozie and Emmanuel are doing is using molecular markers, developed in collaboration with IITA, to search for genes in their varieties that confer resistance to brown streak virus. They can then use these when breeding for CBSD resistance without exposing cassava to the virus. It’s very exciting and forward thinking, as normally people breed for resistance only when the disasters happen.”

As GCP approached its sunset in December 2014, Chiedozie and Emmanuel were reaching out to RTB to seek funding to continue this and other projects they are currently working on. “They’ve already created some great varieties but have plenty more in the pipeline, so we want to help them finish this work and, most importantly, keep the momentum going,” says Graham.

Chiedozie looks forward to the next steps with optimism, confirming that the new collaboration will continue in the quest to “give African farmers varieties of cassava that they will love to grow.”

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Photo: IITA


Healthy improved cassava varieties growing in the field.

 

Oct 052015
 

Cassava brings life to African people

Photo: N Palmer/CIATBeyond the glittering coastline of what was once known as the Gold Coast, Ghana’s shrublands and rich forested hills are split by forking rivers that reach inland through the country’s lush tropics, into drier western Africa. In the past 40 years, seven major droughts have battered the people of Africa – with the most significant and devastating occurring in the Sahel region and the Horn of Africa in the early 1970s and 1980s.

Photo: Y Wachira/Bioversity International

This little girl in Kenya already seems to know that cassava roots are precious.

But despite the massive social disruption and human suffering that these droughts cause, life goes on. In south-eastern Ghana and in Togo, the three-million-plus people who speak the Ewe language have a word for this. It is agbeli: ‘There is life’. It is no coincidence that this word is also their name for a tropical and subtropical crop that survives through the worst times to feed Africa’s families: cassava.

Cassava is a lifeline for African people, and is a particularly important staple food for poorer farmers. More cassava is produced in Africa than any other crop, and it is grown by nearly every farming family in sub-Saharan Africa, supplying about a third of the region’s daily energy intake. In the centuries since Portuguese traders introduced this Amazonian plant to Africa, cassava has flourished, yielding up to 40 tonnes per hectare.

Hear more on just why cassava is so important to food security from Emmanuel Okogbenin, of Nigeria’s National Root Crops Research Institute, in the video below (or watch on Youtube):

 

African countries produced nearly 140 million tonnes of cassava in 2012 – but most of the production is subsistence farming by small-scale farmers. Even the undisputed global cassava giant, Nigeria, currently produces only just enough to feed its population – and although the country is increasingly moving towards production of cassava for export as an industrial raw material, the poorest farmers often do not produce enough to sell, or have access to these markets.

Because cassava does so well on poor soils, on marginal land and with little rainfall, it can outlast its more sophisticated crop competitors: wheat, rice and maize. In fact, under harsh conditions such as drought, the amount of energy a given area of cassava plants can produce in the form of starchy carbohydrates outstrips all other crops. Chiedozie Egesi, a plant breeder and geneticist at Nigeria’s National Root Crops Research Institute (NRCRI), describes cassava as “the crop you can bet on when every other thing is failing”.

Benefits of cassava to African farmers and families Most cassava grown is consumed as food – for instance, as starchy, fine powder called tapioca or the fermented, flaky garri. The tubers can also be eaten boiled or fried in chunks, and are used in many other local dishes.  If cassava is grown in favourable conditions, its firm, white flesh can be rich in calcium and vitamin C and contain other vitamins such as B1, B2 and niacin. Some improved varieties are fortified with increased vitamin A levels, giving them a golden hue.   As well as being eaten directly, cassava can also be processed into ingredients for animal feed, alcohol production, confectionery, sweeteners, glues, plywood, textiles, paper and drugs.  Cassava tubers are easy to save for a rainy day – unlike other crops, they can be left in the ground for up to two years, so harvesting can be delayed until extra food is needed, or to await more optimal processing or marketing conditions.

Despite cassava’s superhero cape, however, there’s no denying that its production is not at its highest when faced with diseases, pests, low-nutrient soils and drought. How plants deal with problems like low nutrients or dry conditions is called ‘stress tolerance’ by scientists. Improving this tolerance – plus resistance to diseases and pests – is the long-term goal for staple crops around the world so that they have higher yields in the face of capricious weather and evolving threats.

In the 1980s, catastrophe struck cassava production in East and Central Africa. A serious outbreak of cassava mosaic disease (CMD) – which first slowly shrivels and yellows cassava leaves, then its roots – lasted for almost 15 years and nearly halved cassava yields in that time. Food shortages led to localised famines in 1993 and 1997.

Other diseases affecting cassava include cassava brown streak disease (CBSD), cassava bacterial blight, cassava anthracnose disease and root rot. CBSD is impossible to detect above ground. Its damage is revealed only after harvest, when it can be seen that the creeping brown lesions have spoilt the white flesh of the tubers, rendering them inedible. Many cassava diseases are transmitted through infected cuttings, affecting the next generation in the next season. Pests that also prey on cassava include the cassava green mite and the variegated grasshopper.

Between the effects of drought, diseases, pests and low soil nutrients, cassava yields vary widely – losses can total between 50 and 100 percent in the worst times.

Photo: IITA

Symptoms of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), both of which can cripple cassava yields.

GCP takes the first steps to kick start cassava research

The next step forward for cassava appeared to be research towards breeding stronger and more resilient cassava varieties. However, cassava research had long been neglected – scientists say it’s a tricky crop that has garnered far less policy, scientific and monetary interest than the comparatively glamorous crops of maize, rice and wheat.

Watch as Emmanuel tells us more about the complexities and challenges of cassava breeding in the video below (or on YouTube):

 

Cassava is a plant which ‘drags its feet’: creating new plants has to be done from cuttings, which are costly to cut and handle and don’t store well; the plant takes up to two years to grow to maturity; and it is onerous to harvest. Elizabeth Parkes, of Ghana’s Crops Research Institute (CRI) (currently on secondment at the International Institute of Tropical Agriculture, IITA), says the long wait can be difficult.

This is where the work of scientists funded by the CGIAR Generation Challenge Programme (GCP) came in. Plant breeder and molecular geneticist Emmanuel Okogbenin of NRCRI led the cassava research push launched in 2010. He explains that before GCP, “most national programmes didn’t really have established crop breeding programmes, and didn’t have the manpower” to do the scale of research GCP supported.

Usually, researchers looking to breed crops that are more resistant to drought, diseases and pests would use conventional breeding methods that could take considerable time to deliver any results, especially given cassava’s slow path to maturity. Researchers would be trying to select disease- and pest-resistant plants by looking at how they’re growing in the field, without any way to see the different genetic strengths each plant has.

Photo: M Mitchell/IFPRI

An IITA researcher exams cassava roots in the field.

This is where new ‘molecular breeding’ tools are particularly useful, given that – genetically – cassava presents more of a challenge to breeders than its cereal counterparts. Like many other vegetatively propagated crops, cassava is highly heterozygous, meaning that the counterpart genes on paired chromosomes tend to be different versions, or alleles, rather than the same. This makes it difficult to identify good parent plants for breeding and, after these are crossed, to accurately select progeny with desired traits. Useful – or detrimental – genes can be present in a cassava plant’s genetic code but not reflected in the plant itself, making breeding more unpredictable – and adding extra obstacles to the hunt for the exact genes that code for better varieties of cassava.

Although late to the world of molecular breeding, cassava had not missed its chance. Guided by GCP’s ambitious remit to increase food security through modern crop breeding, GCP-supported scientists have applied and developed molecular breeding methods that shorten the breeding process by identifying which plants have good genes, even before starting on that long cassava growth cycle. Increasing the capacity of local plant breeders to apply these methods has great potential for delivering better varieties to farmers much faster than has traditionally been the case.

Charting cassava’s genetic material was the first step in the researchers’ molecular quest. Part of the challenge for African and South American researchers was to create a genetic map of the cassava genome. Emmanuel describes the strong foundation that these early researchers built for those coming after: “It was significant when the first draft of the cassava genome sequence was released. It enabled rapid progress in cassava research activities and outcomes, both for GCP and cassava researchers worldwide.”

Photo: N Palmer/CIAT

Cassava on sale in Kampala, Uganda.

Once cassava’s genome had been mapped, the pace picked up. In just one year, GCP-supported scientists phenotyped and genotyped more than 1000 genetically different cassava plants – that is, measured and collected a large amount of information about both their physical and their genetic traits – searching for ‘superstar’ plants with resistance to more than one crop threat. During this process, scientists compare plant’s physical characteristics with their genetic makeup, looking for correlations that reveal regions of the DNA that seem to contain genes that confer traits they are looking for, such as resistance to a particular disease. Within these, scientists then identify sequences of DNA, or ‘molecular markers’, associated with these valuable genes or genetic regions.

Plant breeders can use this knowledge to apply an approach known as marker-assisted selection, choosing their breeding crosses based directly on which plants contain useful genes, using markers like tags. This makes producing better plant varieties dramatically faster and more efficient. “It narrowed the search at an early stage,” explains Emmanuel, “so we could select only material that displayed markers for the genetic traits we’re looking for. There is no longer any need to ship in tonnes of plant material to Africa.”

Like breadcrumbs leading to a clue, breeders use markers to lead to identifying actual genes (rather than just a site on the genome) that give certain plants desirable characteristics. However, this is a particularly difficult process in cassava. Genes are often obscured, partly due to cassava’s highly heterozygous nature. In trials in Africa, where CMD is widespread, resistant types were hard to spot when challenged with the disease, and reliably resistant parents were hard to pin down.

This meant that two decades of screening cassava varieties from South America – where CMD does not yet exist yet – had identified no CMD-resistance genes. But screening of cassava from Nigeria eventually yielded markers for a CMD-resistance gene – a great success for the international collaborative team led by Martin Fregene, who was based in Colombia at the International Center for Tropical Agriculture (CIAT).

This finding was a win for African plant breeders, as it meant they could use molecular breeding to combine the genes producing high-quality and high-yielding cassava from South America with the CMD-resistance gene found in cassava growing in Nigeria.

Chiedozie Egesi, who led the work on biotic trait markers, explains the importance of combining varieties from South America with varieties from Africa: “Because cassava is not native to Africa, those varieties are not as genetically diverse, so we needed to bring genetic diversity from the centre of origin: South America. Coupling resistance genes from African varieties with genes for very high yields from South America was critical.”

Cassava research leaps forward with new varieties to benefit farmers

GCP’s first investment phase into cassava research stimulated a sturdy injection of people, passion, knowledge and funds into the second phase of research. From the genome maps created during the first phase, some of the world’s best geneticists would now apply genomic tools and molecular breeding approaches to increase and accelerate the genetic gains during breeding, combining farmers’ favourite characteristics with strong resistances and tolerances to abiotic and biotic constraints.

In the sprawling, tropical city of Accra on Ghana’s coast, the second phase of the research was officially launched at the end of the wet season in mid-2010. NRCRI’s Emmanuel Okogbenin coordinated product delivery from the projects, but the roles of Principal Investigator for the different projects were shared between another four individuals.

These were breeder and geneticist Chiedozie Egesi (NRCRI, Nigeria), molecular geneticist Morag Ferguson (IITA), genomic scientist Pablo Rabinowicz (University of Maryland, USA) and physiologist and geneticist Alfredo Alves (Brazilian Corporation of Agricultural Research, EMBRAPA). The team shared the vision of enabling farmers to increase cassava production for cash, well beyond subsistence levels.

Photo: A Hoel/World Bank

Garri, or gari, a kind of granular cassava flour used to prepare a range of foods.

If the Accra launch set the stage for the next five years of cassava collaboration, a breakthrough in Nigeria at the end of 2010 set the pace, with the release of Africa’s first cassava variety developed using molecular-breeding techniques. “It was both disease-resistant and highly nutritious – a world-first,” recalls Emmanuel proudly.

Known as UMUCASS33 (or CR41-10), it took its high yield and nutritional value from its South American background, and incorporated Nigerian resistance to devastating CMD attacks thanks to marker-assisted selection. It was also resistant to several other pests and diseases. UMUCASS33 was swiftly followed by a stream of similar disease-busting varieties, released and supplied to farmers.

Never before had cassava research been granted such a boost of recognition, scientific might and organisational will. And never before had there been so much farmer consultation or so many on-farm trials.

“Cassava was an orphan crop and with the help of GCP it is becoming more prominent,” says Chiedozie. “GCP highlighted and enhanced cassava’s role as a major and reliable staple that is important to millions of poor Africans.”

Another important challenge for scientists was to develop a higher-yielding cassava for water-limited environments. The aim was to keep mapping genes for resistance to other diseases and pests and then combine them with favourable genetics that increase yield in drought conditions – no easy feat. Drought’s wicked effect on cassava is to limit the bulk of the tuber, or sometimes to stop the tuber forming altogether. Emmanuel led the work on marker-assisted recurrent selection for drought.

Hear from Chiedozie on the beneficial outcomes of GCP – in terms not only of variety releases but also of attracting further projects, prestige, and enthusiastic young breeders – in the video below (or on YouTube):

Many traits and many varieties

As closely as the cassava teams in Africa were working together, Chiedozie recalls that each country’s environment demanded different cassava characteristics: “We had to select for what worked best in each country, then continue with the research from there. What works fine for East Africa may not be so successful in Nigeria or Ghana”. A core reference set representing most of the diversity of cassava in Africa was improved with the addition of over 564 varieties. Improving the reference set, says project leader Morag Ferguson, “enables the capture of many diverse features of cassava” within a relatively small collection, providing a pathway for more efficient trait and gene discovery.

While mapping of cassava’s genetic makeup carried on, with a focus on drought tolerance, researchers continued to develop a suite of new varieties. They mapped out further genes that provided CMD resistance. In Tanzania, four new varieties were released that combined resistance to both CMD and CBSD – two for the coastal belt and two for the semi-arid areas of central Tanzania. These new varieties had the potential to double the yield of existing commercial varieties. In Ghana too, disease-resistant varieties were being developed.

Photo: IITA

Built-in disease resistance can make a huge difference to the health of cassava crops. This photo shows a cassava variety resistant to African cassava mosaic virus (ACMV), which causes cassava mosaic disease (CMD), growing on the left, alongside a susceptible variety on the right.

Meanwhile in Nigeria, another variety was released in 2012 with very high starch content – an essential factor in good cassava. This is a critical element to breeding any crop, explains Chiedozie: “A variety may be scientifically perfect, based on a researcher’s perspective, but farmers will not grow it if it fails the test in terms of taste, texture, colour or starchiness.”

Geoffrey Mkamilo, cassava research leader at Tanzania’s Agricultural Research Institute, Naliendele, says that farmer awareness and adoption go hand in hand. Once they had the awareness, he says, “the farmers were knocking on our doors for improved varieties. They and NGOs were knocking and calling.”

After groundwork in Ghana and Nigeria to find potential sources of resistance, cassava varieties that are resistant to bacterial blight and green mites were also developed in Tanzania and then tested. By the time GCP closed in December 2014, these varieties were on their way to commercial breeders for farmers to take up.

Scientists seeking to resolve the bigger challenge of drought resistance have achieved significant answers as well. Researchers have been able to map genetic regions that largely account for how well the crops deal with drought.

Developing new varieties takes people, and time The numbers of new cassava varieties so far released through GCP-supported research do not tell the full story.   They certainly do not illustrate the patience and skill required from many different people to get to that end-stage of having a new cassava variety. In the first step, after the plants that seem to have resistance to CMD are identified, those plants are cloned and grown.   The DNA of these plantlets is then exposed to markers specific to valuable resistance genes, or regions of the genome known as quantitative trait loci (QTLs), in order to confirm the presence of the gene or QTL in question. Confirmed plants can be used as parents in breeding crosses after growing out and flowering – although sometimes plants don’t flower, another hurdle for the cassava breeder.  This parental selection using genetic information is a powerful way to make cassava breeding more efficient. Breeders also use markers to identify which of the progeny from each cross have inherited the genes they are interested in. Over several generations of crosses, scientists can combine genes and QTLs for useful traits from different plant lines, to eventually develop a new variety for cultivation.  In cassava, this complex process can take seven years – although it takes even longer using only conventional breeding techniques. While fruition is slow, the research aided by GCP has sown the seeds for many more new varieties and bumper harvests for farmers into the future.

Hunt for ‘super powered’ cassava

The hunt was on for drought-tolerance genes in African cassava plants. The end goal was to find as many different drought-related genes as possible, then to put them all together with the applicable disease and pest resistance genes, to make a ‘super powered’ set of cassava lines. Molecular breeders call this process ‘pyramiding’, and in Ghana, Elizabeth Parkes led these projects.

With the help of Cornell University scientists, the researchers compared plants according to their starch content, how they endured a dry season, how they used sunlight and how they dealt with pests and diseases.

Fourteen gene regions or quantitative trait loci (QTLs) were identified for 10 favourable traits from the genetic material in Ghana, while nine were found for the plants in Nigeria – with two shared between the plants from both Ghana and Nigeria. After that success, the identified genes were used in breeding programmes to develop a new generation of cassava with improved productivity.

Pyramiding is important in effective disease resistance; Chiedozie explains in the video below (or on YouTube):

Photo: HarvestPlus

New cassava varieties rich in pro-vitamin A have a telltale golden hue.

The research has also delivered results in terms of Vitamin A levels in cassava. In 2011, the NRCRI team, together with IITA and HarvestPlus (another CGIAR Challenge Programme focussed on the nutritional enrichment of crops), released three cassava varieties rich in pro-vitamin A, which hold the potential to provide children under five and women of reproductive age with up to 25 percent of their daily vitamin A requirement. Since then, the team has aimed to increase this figure to 50 percent. In 2014, they released three more pro-vitamin A varieties with even higher concentrations of beta-carotene.

Photo: IITA

A field worker at IITA proudly displays a high-yielding, pro-vitamin A-rich cassava variety (right), compared with a traditional variety (left).

The new varieties developed with GCP support are worth their weight in gold, says Chiedozie: “Through these varieties, people’s livelihoods can be improved. The food people grow should be nutritious, resistant and high-yielding enough to allow them to sell some of it and make money for other things in life, such as building a house, getting a motorbike or sending their kids to school.”

Turning from Nigeria to Tanzania, Geoffrey has some remarkable numbers. He says that the national average cassava yield is 10.5 tonnes per hectare. He adds that a new cassava variety, PWANI, developed with GCP support and released in 2012, has the potential to increase yields to 51 tonnes per hectare. And they don’t stop there: the Tanzanian researchers want to produce three million cuttings and directly reach over 2,000 farmers with these new varieties, then scale up further.

Photo: N Palmer/CIAT

A farmer tends her cassava field in northern Tanzania.

Cassava grows up: looking ahead to supporting African families

Emmanuel reflects on how the first release of a new disease-resistant high-yielding cassava variety took fundamental science towards tangible realities for the world’s farmers: “It was a great example of a practical application of marker technology for selecting important new traits, and it bodes well for the future as markers get fully integrated into cassava breeding.”

Emmanuel further believes that GCP’s Cassava Research Initiative has given research communities “a framework for international support from other investors to do research and development in modern breeding using genomic resources.” Evaluations have demonstrated that molecular-assisted breeding can slash between three and five years from the timeline of developing better crops.

Photo: M Perret/UN Photo

Women tend to bear most of the burden of cassava cultivation and preparation. Here a Congolese woman pounds cassava leaves – eaten in many regions in addition to cassava roots – prior to cooking a meal for her family.

But, like cassava’s long growth cycle underground, Emmanuel knows there is still a long road to maturity for cassava as a crop for Africa and in research. “Breeding is just playing with genetics, but when you’re done with that, there is still a lot to do in economics and agronomics,” he says. Revolutionising cassava is about releasing improved varieties carefully buttressed by financial incentives and marketing opportunities.

Rural women in particular stand to benefit from improved varieties – they carry most of the responsibility for producing, processing and marketing cassava. So far, Elizabeth explains: “Most women reported an increase in their household income as a result of the improved cassava, but that is still dependent on extra time spent on cassava-related tasks” – a burden which she aims to diminish.

Elizabeth emphasises that future improvement research has to take a bottom-up approach, first talking to female farmers to ensure that improved crops retain characteristics they already value in addition to the new traits. “Rural families are held together by women, so if you are able to change their lot, you can make a real mark,” she says. Morag echoes this hope: “We are just starting to implement this now in Uganda; it’s a more farmer-centric approach to breeding”. The cassava teams emphasise the importance of supporting women in science too; the Tanzanians teams are aiming for a target of 40 percent women in their training courses.

Meet Elizabeth in the podcast below (or on PodOmatic), and be inspired by her passion when it comed to women in agriculture and in science:

 

This direct impact goes much further than individuals, says Chiedozie. “GCP’s daring has enabled many national programmes to be self-empowered, where new avenues are unfolding for enhanced collaboration at the local, national and regional level. We’re seeing a paradigm shift.” And Chiedozie’s objectives reach in a circle back to his compatriots: “Through GCP, I’ve been able to achieve my aims of using the tools of science and technology to make the lives of poor Africans better by providing them with improved crops.”

GCP has been crucial for developing the capacity of countries to keep doing this level of research, says Chiedozie: “The developing-country programmes were never taken seriously,” he says. “But when the GCP opportunity to change this came up we seized it, and now the developing-country programmes have the boldness, capacity and visibility to do this for themselves.”

Emmanuel says his proudest moment was when GCP was looking for Africans to take up leadership roles. “They felt we could change things around and set a precedent to bring people back to the continent,” he says. “They appreciated our values and the need to install African leaders on the ground in Africa rather than in Europe, Asia or the Americas.”

“If you want to work for the people, you have to walk with the people – that’s an African concept. Then when you work with the people, you really understand what they want. When you speak, they know they can trust you.” GCP trusted and trod where others had not before, Chiedozie says.

Elizabeth agrees: “In the past, the assumption was always that ‘Africa can’t do this.’ Now, people see that when given a chance to get around circumstances – as GCP has done for us through the provision of resources, motivation, encouragement and training – Africa can achieve so much!”

More links

Photo: A Hoel/World Bank

Walking into the future: farmer Felicienne Soton in her cassava field in Benin.

Oct 012015
 

 

Photo: C. Schubert/CCAFS

A farmer from Dodoma, Tanzania, an area where climate change is causing increasing heat and drought. Groundnut is an important crop for local famers, forming the basis of their livelihood together with maize and livestock.

If you don’t live with poor people, then your science is of no use to poor people. This is the very clear sentiment of Omari Mponda, one of Tanzania’s top groundnut researchers.

“Sometimes people do rocket science. But that’s not going to help the poor,” says Omari. “Scientists in labs are very good at molecular markers, but markers by themselves will not address the productivity on the ground. You cannot remove poverty through that alone.”

Omari is the Zonal Research Coordinator and plant breeder at Tanzania’s Agricultural Research Institute at Naliendele (ARI–Naliendele).

The passion and dedication of Omari and his colleagues at this East African research centre were the reason why, between 2008 and 2014, the CGIAR Generation Challenge Programme (GCP) provided funding for legumes research at ARI–Naliendele that especially targeted drought, as part of the Tropical Legumes I project. This project supplied national institutes across Africa, Asia and Latin America with training and infrastructure improvements that enabled local researchers to do more advanced plant science that could make a real difference to farmers.

Researchers like Omari, who are working on the ground in developing countries, are a crucial part of the global quest to develop solutions for future food security and improved livelihoods in these countries.

GCP set out to enhance the plant-breeding skills and capacity of researchers in developing nations, such as Tanzania, so that they can develop their own crop varieties that will cope with increasingly extreme drought conditions.

Photo: C Schubert/CCAFS

A farmer in dryland Tanzania shows off his groundnut crop.

“One thing that really energises me,” enthuses GCP Consultant Hannibal Muhtar, “is seeing people understand why they need to do the work and being given the chance to do the how.”

Hannibal, under his GCP remit, was asked to visit the research sites of GCP-funded projects at research centres and stations across Africa, to identify those where effective research might be hindered by significant gaps in three fundamental areas: infrastructure, equipment and support services. He selected 19 target research sites – in Burkina Faso, Ethiopia, Ghana, Kenya, Mali, Niger, Nigeria and Tanzania.

Photo: AgCommons

Hannibal Muhtar (left) and Omari Mponda at ARI–Naliendele.

Two of the locations chosen for some practical empowerment were in Tanzania, namely the ARI research sites at Naliendele and Mtwara, where simple infrastructure improvements like irrigation tubing and portable weather stations have made a surprising difference to the capacity of local researchers.

In developing countries like Tanzania, the obstacles to achieving research objectives are often quite mundane in nature: a faulty weather station, the lack of irrigation systems, or fields ravaged by weeds and in dire need of rehabilitation. Yet such factors compromise brilliant research.

Even a simple lack of fencing commonly results not only in equipment being stolen, but also in precious experimental crops being stomped on by roaming cattle and wild animals such as boars, monkeys, hippopotamuses and hyenas; this also poses a serious threat to the safety of field staff.

“The real challenge lies not in the science, but rather in the real nuts and bolts of getting the work done in local field conditions,” Hannibal explains.

He says: “If GCP had not invested in research support infrastructure and services, then their investment in research would have been in vain. Tools and services must be in place as and when needed, and in good working order. Tractors must be able to plough when they should plough.”

Bridging the gap between the lab and farmers

Since 2008, researchers at ARI–Naliendele in Tanzania have been working together with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) to identify suitable groundnut breeding materials to help the country’s farmers improve crop yields. Currently, yields are at less than one-third of their potential.

“We are bridging the big science to the poor people, to see the real issues we should be addressing. You can have a very good resistant variety, but maybe that variety is not liked by farmers,” Omari says.

He recalls a case where one farmer who helped with variety selection for international research had identified a groundnut variety that was resistant to disease, but the shells were too difficult to crack.

“So that variety won’t help the poor, because he [the farmer] is not able to open the shell. So the breeder had to rethink, what trait could loosen, or make it easier to shell?” recounts Omari.

Photo: N Palmer/CIAT

Shelled groundnuts on sale in Ghana.

The mission of the 10-year GCP was to use genetic diversity and advanced plant science to improve crops in developing countries. More than 200 partners were involved in the programme, including members of the international CGIAR group plus academia and regional and national research programmes.

National institutes like Tanzania’s ARI–Naliendele, established in 1970, are essential linchpins between advanced research centres in developed countries and poor farmers around the world facing the day-to-day realities of climate change and plant pests and diseases.

“If each organisation works in isolation, they will spend a lot of money developing new varieties but nothing will change on the ground. So in actually working together through programmes like the GCP, we can see some change happening,” says Omari.

Through the GCP project, Tanzania’s groundnut researchers received 300 reference-set lines from ICRISAT, which were then phenotyped over three years (2008–2010) for both drought tolerance and disease resistance in order to select the most useful lines under local conditions. To help with this process, Tanzanian scientists and technicians travelled to ICRISAT headquarters in India, where they were trained in phenotyping: that is, how to identify and measure observable characteristics – in this case, traits relating to the plants’ abilities to cope with drought and disease.

After the researchers identified the best varieties, these were provided to participating farmers so they could trial them in their fields for selection in 2011–2012. Five new varieties have since been released to Tanzanian farmers based on this collaboration between ARI and ICRISAT.

Photo: A Masciarelli/FAO

A young groundnut plant.

Things are speeding up in Tanzania

For ARI–Naliendele, the laboratory and field infrastructure provided by GCP funding has helped accelerate the work of local researchers and breeders. It has been transformative for Tanzanian scientists, according to Omari.

“For example, irrigation is very costly, but with the GCP support for an irrigation system, we can fast track our work – we can come up with new varieties in a much shorter period. That is something that will change our lives,” says Omari.

“Groundnut has a very low multiplication ratio, so if you plant one kilogram, you will get only 10 kilograms next year,” he explains. “Ten kilograms in 12 months is not enough. With irrigation, it means that we can have at least two or three crops within a season. Some of the varieties we are developing can be fast tracked to the end users. The speed of getting varieties from the research to the farmers has increased by maybe three times.”

Photo: D Brazier/IWMI

Washing harvested groundnuts, Zimbabwe.

GCP also funded computers, measuring scales, laboratory equipment and a portable weather station, which all help to assure good, reliable information on phenotyping.

Scientists too have become quicker and better at their work from having more advanced skills, according to Omari: “We now have more competent groundnut breeders in Tanzania.

“Initially, we depended on germplasm being brought over by ICRISAT and somebody selecting varieties for us. But they have been training us to do our own crosses, so we can now decide what grows in our breeding programme,” he says.

“For us, it is a big achievement to be able to do national crosses. We are advancing toward being a functional breeding programme in Tanzania.

“These gains made are not only sustainable, but also give us independence and autonomy to operate. We developing-country scientists are used to conventional breeding, but we now see the value and the need for adjusting ourselves to understand the use of molecular markers in groundnut breeding.”

Tanzania’s new zest for advanced plant breeding

Photo: N Palmer/CIAT

A farmer at work in her cassava field in northern Tanzania.

According to cassava breeder Geoffrey Mkamilo, a Principal Agricultural Research Officer at ARI: “There are some things that you just cannot do by conventional breeding.”

Usually researchers looking to breed better drought-tolerant and disease- and pest-resistant crops would use conventional breeding methods. This means researchers would be trying to pick out resilient plants by phenotyping alone, looking at how they are growing in the field under different conditions, which can take considerable time to deliver results – especially for crops that are slow to mature, like cassava.

Molecular breeding, on the other hand, involves using molecular markers to make the breeding process faster and more effective. These markers are genetic sequences known to be linked to useful genes that confer plant traits such as drought tolerance or disease resistance. Breeders can easily test small amounts of plant material for these markers, so they act like genetic ‘tags’, flagging up whether or not particular genes are present.

This knowledge helps breeders to efficiently select the best parent plants to use in their crosses, and accurately identify which of the progeny have inherited the gene or genes in question without having to grow them all to maturity. Phenotyping is still needed in discovering markers, linking genetic information with physical traits, and in testing the performance of materials in the field, but overall the time taken produce a new variety can be reduced by years.

“Before I started working with GCP, molecular breeding for me was very, very difficult… I wasn’t trained to become a molecular breeder. Now, with GCP, I can speak the same language,” Geoffrey says.

Photo: Kanju/IITA

A farmer carefully packs harvested cassava tubers for transportation to the market in Bungu, Tanzania.

Via GCP, Geoffrey had the opportunity to work with scientists based in Colombia at the International Center for Tropical Agriculture (CIAT) and in Nigeria at the International Institute of Tropical Agriculture (IITA), among other experts in research institutes across the world.

The team first began to release new cassava varieties developed using marker-assisted selection in 2011, with four varieties for two different Tanzanian environments. These varieties had manifold benefits: dual resistance to cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), and productivity potential of up to double the yield of existing commercial varieties.

The research continues to produce ever better cassava varieties, and in this endeavour Geoffrey cannot overemphasise the power of integrating conventional breeding practices with molecular breeding.

“I have received so many phone calls from farmers; they even call in the night. They say, ‘Geoffrey, we have heard that you have very good materials. Where do we get these materials?’ So many, many farmers are calling,” says Geoffrey. “Many, many organisations – even NGOs, they also call. They want these materials. And even the private sector calls. GCP has contributed tremendously to this.”

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