Jun 242014
 

Triumphs and tragedies, pitfalls and potential of the ‘camel crop’Cassava leaf. Photo: N Palmer/CIAT

We travel through space and time, with a pair of researchers who have a pronounced passion for a plant brought to Africa by seafaring Portuguese traders in the 16th century. Fastforwarding to today, half a millennium later, the plant is widespread and deep inland, and is the staple food for Africa’s most populous nation – Nigeria.

Meet cassava, the survivor. After rice and maize, cassava is the third-largest source of carbohydrate in the tropics. Surviving, nay thriving, in poor soils and shaking off the vagaries of weather – including an exceptionally high threshold for drought – little wonder that cassava, the ‘camel’ of crops is naturally the main staple in Nigeria. And with that, it has propelled Nigeria to the very top of the cassava totem pole as the world’s leading cassava producer, and consumer: most Nigerians eat cassava in one form or another practically every day.

Great, huh? But there’s also a darker side to cassava, as we will soon find out from our two cassava experts. For starters, the undisputed global cassava giant, Nigeria, produces just enough to feed herself. Even if there were a surplus for the external demand, farming families, which make up 70 percent of the Nigerian population, have limited access to these lucrative external markets. Secondly, cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are deadly in Africa. Plus, cassava is a late bloomer (up to two years growth cycle, typically one year), so breeding and testing improved varieties takes time. Finally, cassava is most definitely not à la mode at all in modern crop breeding: the crop is an unfashionably late entrant into the world of molecular breeding, owing to its complex genetics which denied cassava the molecular tools that open the door to this glamour world of ‘crop supermodels’.

Emmanuel Okogbenin (left) and Chiedozie Egesi (right) in  a cassava field.

Emmanuel Okogbenin (left) and Chiedozie Egesi (right) in a cassava field.

But all is not doom and gloom, which inexorably dissolve in the face of dogged determination. All the above notwithstanding, cassava’s green revolution seems to be decidedly on the way in Nigeria, ably led by born-and-bred sons of the soil: Chiedozie Egesi and Emmanuel Okogbenin (pictured right) are plant breeders and geneticists at the National Root Crops Research Institute (NRCRI). With 36 years’ collective cassava research experience between them, the two men are passionate about getting the best out of Nigeria’s main staple crop, and getting their hands into the sod while about it: “I’m a plant breeder,” says Chiedozie, with pride. “I don’t just work in a laboratory. I am also in the field to experience the realities.”

Hitting two birds with one stone…two stones are even better!
As Principal Investigators (PIs) leading three different projects in the GCP-funded Cassava Research Initiative, Chiedozie and Emmanuel, together with other colleagues from across Africa, form a formidable team. They also share a vision to enable farmers increase cassava production for cash, beyond subsistence. This means ensuring farmers have new varieties of cassava that guarantee high starch-rich yields in the face of evolving diseases and capricious weather.

Chiedozie is one of cassava’s biggest fans. His affection for, and connection to, cassava is almost personal and definitely paternal. He is determined to deploy the best plant-breeding techniques to not only enhance cassava’s commercial value, but to also protect the crop against future disease outbreaks, including ‘defensive‘ breading. But more on that later…

Emmanuel is equally committed to the cassava cause. As part of his brief, Emmanuel liaises with the Nigerian government, to develop for – and promote to – farmers high-starch cassava varieties. This ensures a carefully crafted multi-pronged strategy to revolutionise cassava: NRCRI develops and releases improved varieties, buttressed by financial incentives and marketing opportunities that encourage farmers to grow and sell more cassava, which spurs production, thereby simultaneously boosting food security while also improving livelihoods.

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Standing tall. Disease resistance and high starch and yield aside, farmers also prefer an upright architecture, which not only significantly increases the number of plants per unit, but also favours intercropping, a perennial favourite   for cassava farmers.

Cross-continental crosses and cousins, magic for making time, and clocking a first for cassava

No one has been able to manufacture time yet, so how can breeders get around cassava’s notoriously long breeding cycle? MAS (marker-assisted selection) is crop breeding’s magic key for making time. And just as humans can benefit from healthy donor organ replacement, so too does cassava, with cross-continental cousins donating genes to rescue the cousin in need. Latin American cassava is nutrient-rich, while African cassava is hardier, being more resilient to pests, disease and harsh environments.

Thanks to marker-assisted breeding, CMD resistance from African cassava can now be rapidly ‘injected’ much faster into Latin American cassava for release in Africa. Consequently, in just a three-year span (2010–2012), Chiedozie, Emmanuel, Martin Fregene of the Donald Danforth Plant Science Center (USA) and the NRCRI team, released two new cassava varieties from Latin American genetic backgrounds (CR41-10 and CR36-5). These varieties, developed with GCP funding, are the first molecular-bred cassava ever to be released, meaning they are a momentous milestone in cassava’s belated but steady march towards its own green revolution.

Marker-assisted selection is much cheaper, and more focused.” 

On the cusp of a collaborative cassava revolution: on your marks…
With GCP funding, Chiedozie and Emmanuel have been able to use the latest molecular-breeding techniques to speed up CMD resistance. Using marker-assisted selection (MAS) which is much more efficient, the scientists identified plants combining CMD resistance with desirable genetic traits.

“MAS for CMD resistance from Latin American germplasm is much cheaper, and more focused,” explains Emmanuel. “There is no longer any need to ship in tonnes of plant material to Africa. We can narrow down our search at an early stage by selecting only material that displays markers for the genetic traits we’re looking for.” Using markers, combining traits (known as ‘gene pyramiding’) for CMD resistance is faster and more efficient, as it is difficult to distinguish phenotypes with multiple resistance in the field by just observing with the naked eye. This is what makes marker-assisted breeding so effective and desirable in Africa.

GCP’s mode of doing business coupled with its community spirit has spurred the NRCRI scientists to cast their eyes further out to the wider horizon beyond their own borders.

By collaborating with research centres in other parts of the world, Emmanuel and Chiedozie have made remarkable strides in cassava breeding. According to Emmanuel, “GCP helped us make links with advanced laboratories and service providers like LGC Genomics. The outsourcing of genotyping activities for molecular breeding initiatives is very significant, as it enables us to carry out analyses not otherwise possible.”

We can’t afford to sit idle until it comes – we need to be armed and on the ready.”

‘Defensive’ breeding: partnerships to pre-empt catastrophe and combat disease
Closer home in Africa, as PI of the corollary African breeders community of practice (CoP) project, Emmanuel co-organises regular workshops with plant breeders from a dozen other countries (Côte d’Ivoire, DR Congo, Ethiopia, Ghana, Kenya,  Liberia, Malawi, Mozambique, Sierra Leone, Tanzania, Uganda and South Sudan). These events are an opportunity to share knowledge on molecular breeding and compare notes.

Of the diseases that afflict cassava, CBSD is the most devastating. Mercifully, in Nigeria, the disease is non-existent, but Chiedozie is emphatic that this is by no means cause for complacency. “If CBSD gets to Nigeria, it would be a monumental catastrophe!” he cautions. “We can’t afford to sit idle until it comes – we need to be armed and on the ready.”

Putting words to action, though this work on CBSD resistance is still in its early stages, more than 1,000 cassava genotypes (different genetic combinations) have already have been screened in the course of just one year. Chiedozie hopes that the team will be able to identify key genetic markers, and validate these in field trials in Tanzania, where CBSD is widespread. This East African stopover, Chiedozie emphasises, is a crucial checkpoint in the West African process. So the cassava CoP not only provides moral but also material support.

And Africa is not the limit. GCP-funded work on CMD resistance is more advanced than the CBSD work, though the real breakthrough in CMD only happened recently, on the international arena within which the African breeders now operate. According to Chiedozie, two entire decades of screening cassava genotypes from Latin America yielded no resistance to CMD. The reason for this is that although it is widespread in Africa, CMD is non-existent in Latin America.

Through international collaborative efforts, cassava scientists, led by Martin Fregene (now based in USA), screened plants from Nigeria and discovered markers for the CMD2 gene, indicating resistance to CMD. Once they had found these markers, the scientists were off and away! By taking the best of the Latin American material and crossing it with Nigerian genotypes that have CMD resistance, promising lines were developed from which the Nigerian team produced two new varieties. These varieties, CR41-10 and CR36-5, have already been released to farmers, and that is not all. More varieties bred using these two as parents are in the pipeline.

“GCP funding has given us the opportunity to show that a national organisation can do the job and deliver.” 

 

Delivery attracts
The success of the CGP-funded cassava research in Nigeria lies in its in-country leadership. Chiedozie, Emmanuel and Martin are native Nigerian scientists and as such are – in many ways – best placed to drive a research collaboration to benefit the country’s farmers and boost food security. “GCP funding has given us the opportunity to show that a national organisation can do the job and deliver,” says Chiedozie.

This proven expertise has helped NRCRI forge other partnerships and attract more financial support, for example from the Bill & Melinda Gates Foundation for a project on genomic selection. GCP support has also bolstered communications with the Nigerian government, which has launched financial instruments, such as a wheat tariff,* to boost cassava production and use.

[Editors note: * wheat tariff: The Nigerian government is trying to reduce wheat import bills and also boost cassava commercialisation by promoting 20 percent wheat substitution in bread-making. Tariffs are being imposed on wheat to dissuade heavy imports and encourage utilisation of high-quality cassava flour for bread.]

“The government feels that to quickly change the fortunes of farmers, cassava is the way to go,” explains Emmanuel. He clarifies, “The tariff from wheat is expected to be ploughed back to support agricultural development – especially 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 and stimulate rural development, including rapid creation of employment for youth.”

The Nigerian government is right in step aiding cassava’s march towards the crop’s own green revolution, as is evident in the the Minister of Agriculture’s tweet earlier this year, and in his video interview below. See also related media story, ‘Long wait for cassava bread’.

Clearly, the ‘camel’ crop – once considered an ‘orphan’ in research  –  has travelled as far in science as in geography, and it is a precious asset to deploy for food production in a climate-change-prone world. As Emmanuel observes, cassava’s future can only be brighter!

Slides by Chiedozie and Emmanuel

 

More links

 

Nov 202013
 
Chiedozie Egesi

Chiedozie Egesi

Despite the social injustice around me, I always thought there was opportunity to improve people’s lives…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.”
 
– Chiedozie Egesi, a would-have-been surgeon who switched sides to biology and crop genetics, and who got acquainted with GCP through the Internet.

Backdrop: A booming economy and a wealth of natural resources may be among some of the common preconceptions of the average Jane and Joe regarding Africa’s most populous nation. Lamentably, however, Nigeria, like numerous robust economies worldwide, is still finding its feet in addressing severe inequality and ensuring that the nation’s wealth also flows to the poorest and most marginalised communities.

It’s a problem Chiedozie Egesi (pictured above), a molecular plant breeder at Nigeria’s National Root Crops Research Institute (NRCRI), understands well: “Nigeria is an oil-producing country, but you still see grinding poverty in some cases. 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.”

Maturing cassava fruits.

Food first! A man with a mission and fire in his belly, determined to make a difference
For this gifted and socially conscious young man, however, 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 the Nigerian smallholder, plans for a career in medical surgery were promptly shelved, and traded for biological sciences and a PhD in crop genetics, a course he interspersed with training stints at USA’s Cornell University and the University of Washington, Seattle, along the way, before returning to the motherland to accept a job as head of the cassava breeding team, and – following a promotion in 2010 – Assistant Director of the Biotechnology Department, at NRCRI.

As evident from the burgeoning treasure chest of research gems to his name, it was a professional detour which paid off, and which continues to bear fruit today.

Making a marked difference, cultivating new partnerships, and looking beyond subsistence
In 2010, work by Chiedozie and his NRCRI team resulted in the official release of Africa’s first molecular-bred cassava variety which was both disease-resistant and highly nutritious – an act they followed in 2012 with the release of a high-starch molecular-bred variety. The team’s astute navigation of molecular markers resulted in breeding Latin American cassava varieties resistant to cassava mosaic disease (CMD), leading to the release of CMD-resistant cassava varieties in the African continent for the first time. Genetic maps intended to enhance breeding accuracy for cassava – the first of their kind for the crop in Africa – have been produced, and quantitative trait loci (QTLs) for cassava breeding are in the making. In 2011, the team, together with their partners at the International Institute of Tropical Agriculture (IITA) and HarvestPlus (a CGIAR Challenge Programme), released three pro-vitamin A-rich varieties of cassava, which hold the potential to provide children under five and women of reproductive age with up to 25 percent of their daily vitamin A allowance – a figure Chiedozie and his team are now ambitiously striving to increase to 50 percent.

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 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.”

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…GCP was not only there to provide technology but also to guide you in how to operate that technology… Now all our staff understand what is meant by good breeding, data analysis or applying genotypic data. My whole team benefitted.”

A chance ‘meeting’, with momentous manifold connections
Having first stumbled across the GCP website by chance when casually surfing the internet one day in a cyber café back in 2004, Chiedozie’s attention was caught by an announcement for a plant breeders’ training course in South Africa, an opportunity which he applied for on the off chance…and for which, hey presto!, he was accepted! Thus, his GCP ‘adventure’ began!

Chiedozie Egesi (left) and Emmanuel Okogbenin (right) in a cassava field.

Chiedozie Egesi (left) and Emmanuel Okogbenin (right) in a cassava field.

Promptly revealing an exceptional craftsmanship for all things cassava, Chiedozie soon became engaged in subsequent opportunities, including a one-year GCP fellowship at the International Centre for Tropical Agriculture (CIAT) in Colombia, a number of GCP Capacity building à la carte-facilitated projects, and, more recently, a major role as a Principal Investigator in the GCP Cassava Research Initiative (RI), teaming up with NRCRI colleague and Cassava RI Product Delivery Coordinator, Emmanuel Okogbenin. The Cassava RI is where Chiedozie’s energies are primarily invested at present, with improving and deploying markers for biotic stresses in cassava being the name of the game.

The significance of his GCP engagements was, Chiedozie affirms, 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.”

Collaboration in a GCP-funded project with CIAT led to the development of a new laboratory space for NRCRI, bolstered by support for basic materials as well as training. “GCP was not only there to provide technology but also to guide you in how to operate that technology,” Chiedozie comments. (For more on how it all began, see At home and to go and Molecular bonds in pp 26–29 in this e-book)

GCP’s Integrated Breeding Platform (IBP), he says, has played a vital role in this regard: “By opening the door to training, generation of data, analysis of data, and by giving support in making decisions, GCP’s IBP serves as a one-stop shop for cassava breeding.” It’s a sentiment shared by his NRCRI colleagues, he says: “GCP is providing a comprehensive full-package deal. Besides myself, several colleagues have been trained at NRCRI. Now all our staff understand what is meant by good breeding, data analysis or applying genotypic data. My whole team benefitted.”

A real deal-breaker is the facilitation of self-empowerment amongst national programmes, and the new avenues unfolding for enhanced collaboration at the local, national and regional level…What we’re seeing is a paradigm shift. In the past there was a general belief that this kind of advanced molecular science was only feasible in the hands of CGIAR Centres or developed-country research institutes – the developing-country programmes were never taken seriously. When the GCP opportunity to change this came up we seized it, and now the developing-country programmes have the boldness and capacity to do molecular breeding and accurate phenotyping for themselves.”

Growth in numbers, capital, capacity, collaboration, reach and impact
Strength in numbers, Chiedozie says, is a vital lifeline for cassava, a crop which has suffered years of financial neglect. As such, a real deal-breaker in Chiedozie’s eyes is the facilitation of self-empowerment amongst national programmes, and the new avenues unfolding, thanks to his involvement in the GCP cassava breeding Community of Practice (CoP), for enhanced collaboration at the local, national and regional level: “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 work more visible,” he offers, citing effective links formed with Ghana, Sierra Leone, Liberia, Mozambique, Malawi and Côte d’Ivoire, amongst several other cassava-breeding neighbours near and far.

Cassava leaf

Cassava leaf

The achievements amongst this mushrooming community are, he stresses, unprecedented: “Participation in the CoP means many countries can now create their own hybrids and carry out their own selection, which they could not do before,” he affirms.

And it’s a milestone Chiedozie and colleagues are justifiably proud of: “What we’re seeing is a paradigm shift. In the past there was a general belief that this kind of advanced molecular science was only feasible in the hands of CGIAR Centres or developed-country research institutes – the developing-country programmes were never taken seriously. When the GCP opportunity to change this came up we seized it, and now the developing-country programmes have the boldness and capacity to do molecular breeding and accurate phenotyping for themselves,” Chiedozie confirms.

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.” 

Building on success, going from strength to strength as the sands shift

With internal capacity now blossoming of its own accord – in no small measure due to the leading role played by NRCRI in the sensitisation of cassava plant breeders throughout Nigeria and beyond – the sands are certainly shifting: “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.”

Anthony Pariyo (left) of NaCRRI, Uganda

Visitors with working clothes on: NaCRRI Uganda’s Anthony Pariyo (left) and Williams Esuma (right) visiting NRCRI Umudike on a breeder-to-breeder visit in July 2012. Williams’ postgraduate studies were funded by GCP through the cassava CoP.

And the beauty of it, Chiedozie continues, is that the cassava crew is going from strength to strength: “Nigeria is seen as a really strong cassava-breeding team, not only within Africa but also globally. And we have not yet realised all the benefits and potential – these are still unfolding,” he enthuses.

Also yet to unfold are Chiedozie’s upcoming professional plans, which, he reveals, will soon see him engaging with the USA’s Cornell University, the Bill & Melinda Gates Foundation, the International Institute of Tropical Agriculture (IITA) and Uganda’s National Crop Resources Research Institute (NaCRRI) in an initiative which, through its focus on genomic selection in cassava breeding, promises to be, Chiedozie reveals, “at the frontier of cutting-edge technology.” Genomic selection for this initiative is already underway.

Readers intrigued by this tantalising taster of what to expect in Chiedozie’s next professional chapter are encouraged to watch this space over the coming years…Judging by his remarkable research record to date, we feel confident that future installments will not disappoint!

Meantime, here’s Chiedozie’s presentation at the GCP General Research Meeting in September 2013. We are also working on videos of Chiedozie and his work. Yet more reason to watch this space!

Links
  • For a picture of Chiedozie’s work near the beginning in 2006, see pp 26–29 here (At home and to go and Molecular bonds)
  • More recent updates are on the Cassava InfoCentre

 

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