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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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Sep 282015
 

 

Photo: Agência BrasíliaSorghum is already a drought-hardy crop, and is a critical food source across Africa’s harsh, semi-arid regions where water-intensive crops simply cannot survive. Now, as rainfall patterns become increasingly erratic and variable worldwide, scientists warn of the need to improve sorghum’s broad adaptability to drought.

Crop researchers across the world are now on the verge of doing just that. Through support from the CGIAR Generation Challenge Programme (GCP), advanced breeding methods are enhancing the capacity of African sorghum breeders to deliver more robust varieties that will help struggling farmers and feed millions of poor people across sub-Saharan Africa.

Photo: ICRISAT

A farmer in her sorghum field in Tanzania.

Sorghum at home in Africa

From Sudanese savannah to the Sahara’s desert fringes, sorghum thrives in a diverse range of environments. First domesticated in East Africa some 6000 years ago, it is well adapted to hot, dry climates and low soil fertility, although still depends on receiving some rainfall to grow and is very sensitive to flooding.

In developed countries such as Australia, sorghum is grown almost exclusively to make feed for cattle, pigs and poultry, but in many African countries millions of poor rural people directly depend on the crop in their day-to-day lives.

Photo: ICRISAT

A Malian woman and her child eating sorghum.

In countries like Mali sorghum is an important staple crop. It is eaten in many forms such as couscous or (a kind of thick porridge), it is used for making local beer, and its straw is a vital source of feed for livestock.

While the demand for, and total production of, sorghum has doubled in West Africa in the last 20 years, yields have generally remained low due to a number of causes, from drought and problematic soils, to pests and diseases.

“In Mali, for instance, the average grain yield for traditional varieties of sorghum has been less than one tonne per hectare,” says Eva Weltzein-Rattunde, Principal Scientist for Mali’s sorghum breeding programme at the International Crops Research Institute for the Semi-Arid-Tropics (ICRISAT).

In a continued quest to integrate ways to increase productivity, GCP launched its Sorghum Research Initiative (RI) in 2010. This aimed to investigate and apply the approaches by which genetics and molecular breeding could be used to improve sorghum yields through better adaptability, particularly in the drylands of West Africa where cropping areas are large and rainfall is becoming increasingly rare.

Kick starting the work was a GCP-funded collaboration between project Principal Investigator Niaba Témé, plant breeder at Mali’s Institut d’économie rurale (IER) and the RI’s Product Delivery Coordinator Jean-François Rami of the Centre de coopération internationale en recherche agronomique pour le développement (CIRAD; Agricultural Research for Development), France, with additional support from the Syngenta Foundation for Sustainable Agriculture in Switzerland.

The collaboration aimed to develop ways to improve sorghum’s productivity and adaptation in the Sudano-Sahelian zone, starting with Mali in West Africa, and expanding later across the continent to encompass Burkina Faso, Ethiopia, Kenya, Niger and Sudan.

Photo: F Noy/UN Photo

A farmer harvest sorghum in Sudan.

Sorghum gains from molecular research

Since 2008, with the help of CIRAD and Syngenta, Niaba and his team at IER have been learning how to use molecular markers to develop improved sorghum germplasm through identifying parental lines that are more tolerant and better adapted to the arid and volatile environments of Mali.

The two breeding methods used in the collaboration are known as marker-assisted recurrent selection (MARS) and backcross nested association mapping (BCNAM).

MARS

Photo: N Palmer/CIAT“MARS identifies regions of the genome that control important traits,” explains Jean-François. “It uses molecular markers to explore more combinations in the plant populations, and thus increases breeding efficiency.”

Syngenta, he explains, became involved through its long experience in implementing MARS in maize.

“Syngenta advised the team on how to conduct MARS and ways we could avoid critical pitfalls,” he says. “They gave us access to using the software they have developed for the analysis of data, and this enabled us to start the programme immediately.”

With the help of the IER team, two bi-parental populations from elite local varieties were developed, targeting two different environments found in sorghum cropping areas in Mali. “We were then able to use molecular markers through MARS to identify and monitor key regions of the genome in consecutive breeding generations,” says Jean-François.

“When we have identified the genome regions on which to focus, we cross the progenies and monitor the resulting new progenies,” he says. “The improved varieties subsequently go to plant breeders in Mali’s national research program, which will later release varieties to farmers.”

Jean-François is pleased with the success of the MARS project so far. “The development of MARS addressed a large range of breeding targets for sorghum in Mali, including adaptation to the environment and grain productivity, as well as grain quality, plant morphology and response to diseases,” he says. “It proved to be efficient in elucidating the complex relationships between the large number of traits that the breeder has to deal with, and translating this into target genetic ideotypes that can be constructed using molecular markers.”

Jean-François says several MARS breeding lines have already shown superior and stable performance in farm testing as compared to current elite lines, and these will be available to breeders in Mali in 2015 to develop new varieties.

Photo: ICRISAT

Eva Weltzein-Rattunde examines sorghum plants with farmers in Mali.

BCNAM

Like MARS, the BCNAM approach shows promise for being able to quickly gain improvements in sorghum yield and adaptability to drought, explains Niaba, who is Principal Investigator of the BCNAM project. BCNAM may be particularly effective, he says, in developing varieties that have the grain quality preferences of Malian farmers, as well as the drought tolerance that has until now been unavailable.

“BCNAM involves using an elite recurrent parent that is already adapted to local drought conditions, then crossing it with several different specific or donor parents to build up larger breeding populations,” he explains. “The benefit of this approach is it can lead to detecting elite varieties much faster.”

Eva and her team at ICRISAT have also been collaborating with researchers at IER and CIRAD on the BCNAM project. The approach, she says, has the potential to halve the time it takes to develop local sorghum varieties with improved yield and adaptability to poor soil fertility conditions.

“We don’t have these types of molecular-breeding resources available in Mali, so it’s really exciting to be a part of this project,” she says. “Overall, we feel the experience is enhancing our capacity here, and that we are closer to delivering more robust sorghum varieties which will help farmers and feed the ever-growing population in West Africa.”

Indeed, during field testing in Mali, BCNAM lines derived from the elite parent variety Grinkan have produced more than twice the yields of Grinkan itself. As they are rolled out in the form of new varieties, the team anticipates that they will have a huge positive impact on farmers’ livelihoods.

Photo: E Weltzein-Rattunde/ICRISAT

Malian sorghum farmers.

Mali and Queensland similar problem, different soil

In Mali and the wider Sahel region within West Africa, cropping conditions are ideal for sorghum. The climate is harsh, with daily temperatures on the dry, sun-scorched lower plains rarely falling below 30°C. With no major river system, the threat of drought is ever-present, and communities are entirely dependent on the 500 millimetres of rain that falls during the July and August wet season.

“All the planting and harvesting is done during the rainy season,” says Niaba. “We have lakes that are fed by the rain, but when these lakes start to dry up farmers rely mostly on the moisture remaining in the soil.”

Over 17 thousand kilometres to the east of Mali, in north-eastern Australia’s dryland cropping region, situated mainly in the state of Queensland, sorghum is the main summer crop, and is considered a good rotational crop as it performs well under heat and moisture stress. The environment here is similar to Mali’s, with extreme drought a big problem.

Average yields for sorghum in Queensland are double those in Mali—around two tonnes per hectare—yet growers still consider them low, directly limited by the crop’s predominantly water-stressed production environment in Australia.

One of the differentiating factors is soil. “Queensland has a much deeper and more fertile soil compared to Mali, where the soil is shallow, with no mulch or organic matter,” says Niaba. “Also, there is no management at the farm level in Mali, so when rain comes, if the soil cannot take it, we lose it.”

Photo: Bart Sedgwick/Flickr (Creative Commons)

Sorghum in Queensland, Australia.

Making sorghum stay green, longer

Another key reason for the difference in yields between Queensland and Mali is that growers in Queensland are sowing a sorghum variety of with a genetic trait that makes it more tolerant to drought.

This trait is called ‘stay-green’, and over the last two decades it has proven valuable in increasing sorghum yields, using less water, in north-eastern Australia and the southern United States.

Stay-green allows sorghum plants to stay alive and maintain green leaves for longer during post-flowering drought—that is, drought that occurs after the plant has flowered. This means the plants can keep growing and produce more grain in drier conditions.

“We’ve found that stay-green can improve yields by up to 30 percent in drought conditions with very little downside during a good year,” says Andrew Borrell from the Queensland Alliance for Agriculture and Food Innovation (QAAFI) at the University of Queensland (UQ) in Australia.

“Plant breeders have known about stay-green for some 30 years,” he says. “They’d walk their fields and see that the leaves of certain plants would remain green while others didn’t. They knew it was correlated with high yield under drought conditions, but didn’t know why.”

Stay-green’s potential in Mali

With their almost 20 years working on understanding how stay-green works, Andrew and his colleagues at UQ were invited by GCP in 2012 to take part in the IER/CIRAD collaborative project, to evaluate the potential for introducing stay-green into Mali’s local sorghum varieties and enriching Malian pre-breeding material for the trait.

A pivotal stage in this new alliance was a 12-month visit to Australia by Niaba and his IER colleague Sidi Coulibaly, to work with Andrew and his team to understand how stay-green drought resistance works in tall Malian sorghum varieties.

“African sorghum is very tall and sensitive to variation in day length,” explains Andrew. “We have been looking to investigate if the stay-green mechanism operates in tall African sorghums (around four metres tall) in the same way that it does in short Australian sorghum (one metre tall).”

Having just completed a series of experiments at the end of 2014, the UQ team consider their data as preliminary at this stage. “But it looks like we can get a correlation between stay-green and the size and yield of these Malian lines,” says Andrew. “We think it’s got great potential.”

Photo: S Sridharan/ICRISAT

Sorhum growing in Mozambique.

Sharing knowledge as well as germplasm

Eva Weltzein-Rattunde has played more of an on-the-ground capacity development role in Mali since accepting her position at ICRISAT in 1998. She says “the key challenges have been improving the infrastructure of the national research facilities [in Mali] to do the research as well as increasing the technical training for local agronomists and researchers.”

Photo: ICRISAT

A Malian farmer harvests Sorghum.

A large part of GCP’s focus is building just such capacity among developing country partners to carry out crop research and breeding independently in future, so they can continue developing new varieties with drought adaptation relevant to their own environmental conditions.

A key objective of the IER team’s Australian visit was to receive training in the methods for improving yields and drought resistance in sorghum breeding lines from both Australia and Mali.

“We learnt about association mapping, population genetics and diversity, molecular breeding, crop modelling using climate forecasts, and sorghum physiology, plus a lot more,” says Niaba. This training complemented previous training Niaba and IER researchers had from CIRAD and ICRISAT through the MARS and BCNAM projects.

“We [CIRAD] have a long collaboration in sorghum research in Mali and training young scientists has always been part of our mission,” says Jean-François. “We’ve hosted several IER students here in France and we are always interacting with our colleagues in Mali either over the phone or travelling to Mali to give technical workshops in molecular breeding.”

Photo: Rita Willaert/Flickr (Creative Commons)

Harvested sorghum in Sudan.

Working together to implement MARS in the sorghum breeding program in Mali represented many operational challenges, Jean-François explains. “The approach requires a very tight integration of different and complementary skills, including a strong conventional breeding capacity, accurate breeders’ knowledge, efficient genotyping technologies, and skills for efficient genetic analyses,” he says.

Because of this requirement, he adds, there are very few reported experiences of the successful implementation of MARS.  It is also the reason why these kinds of projects would normally not be undertaken in a developing country like Mali, but for the support of GCP and the dedicated mentorship of Jean-François.

sorghum quote 2“GCP provided the perfect environment to develop the MARS approach,” says Jean-François. “It brought together people with complementary skills, developed the Integrated Breeding Platform (IPB), and provided tools and services to support the programme.”

In addition to developing capacity, Jean-François says one of the great successes of both the MARS and the BCNAM projects was how they brought together Mali’s sorghum research groups working at IER and ICRISAT in a common effort to develop new genetic resources for sorghum breeding.

“This work has strengthened the IER and ICRISAT partnerships around a common resource. The large multiparent populations that have been developed are analysed collectively to decipher the genetic control of important traits for sorghum breeding in Mali,” says Jean-François. “This community development is another major achievement of the Sorghum Research Initiative.” The major challenge, he adds, will be whether this community can be kept together beyond GCP.

Considering the numerous ‘non-GCP’ activities that have already been initiated in Africa as a result of the partnerships forged through GCP research, Jean-François sees a clear indication that these connections will endure well beyond GCP’s time frame.

GCP’s sunset is Mali’s sunrise

Photo: S Sridharan/ICRISAT

Sorghum at sunset in Mozambique.

Among the new activities Jean-François lists are both regional and national projects aimed at building on what has already been achieved through GCP and linking national partners together. These include the West African Agricultural Productivity Program (WAAPP), the West Africa Platform being launched by CIRAD as a continuation of the MARS innovation, and another MARS project in Senegal and Niger through the Feed the Future Innovation Lab for Collaborative Research on Sorghum and Millet at Kansas State University.

“These are all activities which will help maintain the networks we’ve built,” Jean-François says. “I think it is very important that these networks of people with common objectives stick together.”

sorghum quoteFor Niaba, GCP provided the initial boost needed for these networks to emerge and thrive. “We had some contacts before, but we didn’t have the funds to really get into a collaboration. This has been made possible by GCP. Now we’re motivated and are making connections with other people on how we can continue working with the material we have developed.”

“I can’t talk enough of the positive stories from GCP,” he adds. “GCP initiated something, and the benefits for me and my country I cannot measure. Right now, GCP has reached its sunset; but for me it is a sunrise, because what we have been left with is so important.”

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Photo: ICRISAT

A sorghum farmer in her field in Tanzania.

Sep 242015
 

Hei Leung has always been passionate about diversity, especially genetic diversity, and that’s one reason why he leapt at the chance to get involved with the CGIAR Generation Challenge Programme (GCP) right from its inception more than a decade ago.

Photo: IRRIBut GCP’s attraction for Hei wasn’t just about genetic diversity; it was also about working with diverse institutes and researchers. At the time, Hei had been working for the International Rice Research Institute (IRRI) for some 10 years, on and off, including a stint at Washington State University in the USA.

“The whole idea of the Challenge Programme was to bring people together from different places instead of an individual CGIAR Centre doing things,” he says.

Hei also saw the likely spin-offs from rice research to other crops such as wheat, maize and sorghum, which are also crucial to food security.

Rice is a ‘model crop’ because of its small genome. This means researchers in major cereals like wheat and maize, which have much bigger genomes but share genes of similar functions, can benefit from our work with rice.”

Photo: Jeffreyw/Flickr (Creative Commons)

From little pizzas great programmes grow!

It all began in 2003, over pizza, in Rome. Hei remembers that his commitment to GCP started when he met with a small group of people including Robert Zeigler, who was to become the first Director of GCP, and who is currently Director General of IRRI.

“Little did we know that pizza was so inspiring,” Hei says, recalling that it was during that meeting that they agreed on the name: the Generation Challenge Programme.

GCP was formally launched in 2004 in Brisbane, Australia, at the 4th International Crop Science Congress.

Making the Programme ‘pro-poor’

Hei was initially involved with GCP as Subprogramme Leader for Comparative Genomics for Gene Discovery between 2004 and 2007, and later as a Principal Investigator for the Rice Research Initiative. Taking on his leadership role, Hei recognised from the start that many crops important to developing communities in Asia and Africa needed to become more drought-tolerant because of the increasing effects of climate change.

“We wanted to have a programme that is what we call ‘pro-poor’,” he says. “The majority of the world’s people depend on crops such as rice, wheat and maize for food.”

“I always feel that if you can solve eastern India’s problems, you can solve most of the problems in the world,” Hei adds. “If you travel in eastern India, you can see climate change happening day in, day out. You don’t have to wait 10 years or 50 years; it’s happening already. They either have too much or too little water. It’s a high-stress environment.”

Photo: N Palmer/CIAT


Women at work threshing rice near Sangrur, Punjab, India.

Rice is the world’s most widely consumed cereal crop, and is particularly important as the staple food of 2.4 billion people in Asia. GCP recognised rice’s importance and invested almost USD 29.5 million in rice research and development.

Furthermore, the genetic breeding lessons learnt from rice can also be applied to other staple crops such as wheat, maize and sorghum.

Other GCP-supported researchers used comparative genetics to determine if the same or similar genes – for example, the phosphorus starvation tolerance (PSTOL1) protein kinase gene found in rice – was also present and operating in the same manner in sorghum and maize.

They found sorghum and maize varieties that contained genes, similar to rice’s PSTOL1, that also conferred tolerance to phosphorus-deficient soils by enhancing the plant’s root system. They were then able to develop molecular markers to help breeders in Brazil and Africa to identify lines with these genes, which can now be used in breeding and developed as varieties for farmers growing crops, particularly in acidic soils.

Seeing the potential for novel researcher interactions

Hei also recognised that crops that received less scientific attention but remained important as regional staple foods, such as bananas and plantains (of the genus Musa), could benefit from comparative genomics research.

“We had a highly motivated group of researchers willing to devote their efforts to Musa,” remembers Hei, who is currently IRRI Program Leader of Genetic Diversity and Gene Discovery.

“GCP’s community could offer a framework for novel interactions among banana-related actors and players working on other crops, such as rice. So, living up to its name as a Challenge Programme, GCP decided to take the gamble on banana genomics and help it fly.”

Photo:  Asian Development Bank

A banana farmer at work in the Philippines.

However, after four years, Hei found it difficult to maintain his GCP leadership role as well as keep on top of his IRRI work: “They said I was 50 percent with IRRI and 50 percent with GCP, but it is never like that in reality. I was always doing two jobs, or at least one-and-a-half jobs, and I didn’t think I was doing a good enough job for either. I thought it was time for other people to come into GCP.”

While Hei stepped down from a leadership role, he remained active working on GCP projects throughout the life of the Programme.

Hei says that during the last five years of GCP, a lot of technology to characterise genetic diversity evolved “to bring high-quality science to accelerate our mission to help the poor areas of Asia and Africa.”

Streamlining GCP reporting: from three reports a year down to just one One of the things that initially bothered Hei during his GCP time was the reporting requirements: “I remember we used to ask people to submit a mid-year report, end-of-year report and an update. “So I stuck my neck out during the last couple of years, and I said: ‘Guys, stop it. Don’t ask for these reports. They become mechanical. People just fill in the blanks. Ask for just one report before or after our annual meeting: just one report that people are excited to write about. And that was adopted.”

A MAGIC affair

The development of MAGIC (multi-parent advanced generation intercross) populations is the project that Hei gets most excited about. From these populations, created by crossing different combinations of multiple parents, plant lines can be selected that have useful characteristics such as drought tolerance, salinity tolerance and the ability to produce better quality grain.

“Now many crop breeders are calling for MAGIC populations,” says Hei. “I feel proud that at GCP we decided to support this concept and activity. This is one of GCP’s most important legacies and it’s one of my most favourite things.”

Photo: IRRI

Hei Leung looking relaxed in the lab at IRRI.

Honoured as a Fellow of the American Phytopathological Society (APS), Hei is recognised “for his leadership in the international community toward building and distributing rice genetic and genomic resources and creating capacity in plant pathology in the developing countries of Asia.”

Hei’s GCP leadership and research have clearly provided him with an important platform for taking on leadership and champion roles linking many individuals and organisations across Asia and Africa. His ASP profile concludes: “His promotion of collaborative research and his leadership in such programmes in the developing world have contributed to the building of a dynamic research community that promotes both basic knowledge and food security for Asia and the world.”

Making a difference to food security and farmer’s lives in developing countries is what GCP is all about. Such differences have been made possible through collaborative links that connect a diversity of organisations and people with the latest research in genetic diversity and breeding techniques.

Photo: IRRI

A farmer transplants rice in the Philippines.

It’s amore!

hei quoteHei recalls his personal and professional journey with GCP with much affection: “I think that it has been a wonderful scientific journey in terms of knowing the science and opening up my mind to being more receptive to alternative ways of doing things.

“There have been so many friends I have met through networking with GCP. Sometimes you go through bumpy roads, but anything you do will have bumpy times. And it’s very unusual to have a programme so illuminating. We honoured our commitment to finish in 10 years. It is a programme that had a fresh start and a clean ending.

“Most importantly, GCP has enabled plant breeders to embrace cutting-edge science through partnerships that focused on improving crop yields in areas previously deemed unproductive,” he says. “GCP is unique, one-of-a-kind, and I love it!”

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Jun 222015
 
Photo: Joseph Hill/Flickr (Creative Commons)

Groundnut plants growing in Senegal.

Across Africa, governments and scientists alike are heralding groundnuts’ potential to lead resource-poor farmers out of poverty.

Around 5,000 years ago in the north of Argentina, two species of wild groundnuts got together to produce a natural hybrid. The result of this pairing is the groundnut grown today across the globe, particularly in Africa and Asia. Now, scientists are discovering the treasures hidden in the genes of these ancient ancestors.

Nearly half of the world’s groundnut growing area lies within the African continent, yet Africa’s production of the legume has, until recently, accounted for only 25 percent of global yield. Drought, pests, diseases and contamination are all culprits in reducing yields and quality. But through the CGIAR Generation Challenge Programme (GCP), scientists have been developing improved varieties using genes from the plant’s ancient ancestors. These new varieties are destined to make great strides towards alleviating poverty in some of the world’s most resource-poor countries.

Photo: Bill & Melinda Gates Foundation

A Ugandan farmer at work weeding her groundnut field.

A grounding in the history of Africa’s groundnuts

From simple bar snack in the west to staple food in developing countries, groundnuts – also commonly known as peanuts – have a place in the lives of many peoples across the world. First domesticated in the lush valleys of Paraguay, groundnuts have been successfully bred and cultivated for millennia. Today they form a billion-dollar industry in China, India and the USA, while also sustaining the livelihoods of millions of farming families across Africa and Asia.

Groundnut facts and figures •	About one-third of groundnuts produced globally are eaten and two-thirds are crushed for oil  •	The residue from oil processing is used as an animal feed and fertiliser •	Oils and solvents derived from groundnuts are used in medicines, textiles, cosmetics, nitro-glycerine, plastics, dyes, paints, varnishes, lubricating oils, leather dressings, furniture polish, insecticides and soap •	Groundnut shells are used to make plastic, wallboard, abrasives, fuel, cellulose and glue; they can also be converted to biodiesel

“The groundnut is one of the most important income-generating crops for my country and other countries in East Africa,” says Malawian groundnut breeder Patrick Okori, Principal Scientist at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), who was also GCP’s Product Delivery Coordinator for groundnuts.

“It’s like a small bank for many smallholder farmers, one that can be easily converted into cash, fetching the highest prices,” he says.

The situation is similar in West Africa, according to groundnut breeder Issa Faye from the Institut Sénégalais de Recherches Agricoles (ISRA; Senegalese Agricultural Research Institute), who has been involved in GCP since 2008. “It’s very important for Senegal,” he says. “It’s the most important cash crop here – a big source of revenue for farmers around the country. Senegal is one of the largest exporters of peanut in West Africa.”

Groundnuts have good potential for sustaining a strong African export industry in future, while providing a great source of nutrition for Africa’s regional farming families.

“We believe that by using what we have learnt through GCP, we will be able to boost the production and exportation of groundnuts from Senegal to European countries, and even to Asian countries,” says Issa. “So it’s very, very important for us.”

Photo: Joseph Hill/Flickr (Creative Commons)

Harvested groundnuts in Senegal.

How Africa lost its groundnut export market

Photo: V Vadez

Groundnuts in distress under drought conditions.

In Africa, groundnuts have mostly been grown by impoverished smallholder farmers, in infertile soils and dryland areas where rainfall is both low and erratic. Drought and disease cause about USD 500 million worth of losses to groundnut production in Africa every year.

“Because groundnut is self-pollinating, most of the time poor farmers can recycle the seed and keep growing it over and over,” Patrick says. “But for such a crop you need to refresh the seed frequently, and after a certain period you should cull it. So the absence of, or limited access to, improved seed for farmers is one of the big challenges we have. Because of this, productivity is generally less than 50 percent of what would be expected.”

Photo: S Sridharan/ICRISAT

Rosette virus damage to groundnut above and below ground.

Diseases such as the devastating groundnut rosette virus – which is only found in Africa and has been known to completely wipe out crops in some areas – as well as pests and preharvest seed contamination have all limited crop yields and quality and have subsequently shut out Africa’s groundnuts from export markets.

The biggest blow for Africa came in the 1980s from a carcinogenic fungal toxin known as aflatoxin, explains Patrick.

Photo: IITA

Aflatoxin-contaminated groundnut kernels from Mozambique.

Aflatoxin is produced by mould species of the genus Aspergillus, which can naturally occur in the soil in which groundnuts are grown. When the fungus infects the legume it produces a toxin which, if consumed in high enough quantities, can be fatal or cause cancer. Groundnut crops the world over are menaced by aflatoxin, but Africa lost its export market because of high contamination levels.

“That’s why a substantial focus of the GCP research programme has been to develop varieties of groundnuts with resistance to the fungus,” says Patrick.

After a decade of GCP support, a suite of new groundnut varieties representing a broad diversity of characteristics is expected to be rolled out in the next two or three years. This suite will provide a solid genetic base of resistance from which today’s best commercial varieties can be improved, so the levels of aflatoxin contamination in the field can ultimately be reduced.

Ancestral genes could hold the key to drought tolerance and disease resistance

In April 2014, the genomes of the groundnut’s two wild ancestral parents were successfully sequenced by the International Peanut Genome Initiative – a multinational group of crop geneticists, who had been working in collaboration for several years.

The sequencing work has given breeders access to 96 percent of all groundnut genes and provided the molecular map needed to breed drought-tolerant and disease-resistant higher-yielding varieties, faster.

“The wild relatives of a number of crops contain genetic stocks that hold the most promise to overcome drought and disease,” says Vincent Vadez, ICRISAT Principal Scientist and groundnut research leader for GCP’s Legumes Research Initiative. And for groundnut, these stocks have already had a major impact in generating the genetic tools that are key to making more rapid and efficient progress in crop breeding.

“Genetically, the groundnut has always been a really tough nut to crack,” says GCP collaborator David Bertioli, from the University of Brasilia in Brazil. “It has a complex genetic structure, narrow genetic diversity and a reputation for being slow and difficult to breed. Until its genome was sequenced, the groundnut was bred relatively blindly compared to other crops, so it has remained among the less studied crops,” he says.

With the successful genome sequencing, however, researchers can now understand groundnut breeding in ways they could only dream of before.

Photo: N Palmer/CIAT

Groundnut cracked.

“Working with a wild species allows you to bring in new versions of genes that are valuable for the crop, like disease resistance, and also other unexpected things, like improved yield under drought,” David says. “Even things like seed size can be altered this way, which you don’t really expect.”

The sequencing of the groundnut genome was funded by The Peanut Foundation, Mars Inc. and three Chinese academies (the Chinese Academy of Agricultural Sciences, the Henan Academy of Agricultural Sciences, and the Shandong Academy of Agricultural Sciences), but David credits GCP work for paving the way. “GCP research built up the populations and genetic maps that laid the groundwork for the material that then went on to be sequenced.”

Chair of GCP’s Consortium Committee, David Hoisington – formerly ICRISAT’s Director of Research and now Senior Research Scientist and Program Director at the University of Georgia – says the sequencing could be a huge step forward for boosting agriculture in developing countries.

“Researchers and plant breeders now have much better tools available to breed more productive and more resilient groundnut varieties, with improved yields and better nutrition,” he says.

These resilient varieties should be available to farmers across Africa within a few years.

Genetics alone will not lift productivity – farmers’ local knowledge is vital

Improvements in the yield, quality and share of the global market of groundnuts produced by developing countries are already being seen as a result of GCP support, says Vincent Vadez. “But for this trend to continue, the crop’s ability to tolerate drought and resist diseases must be improved without increasing the use of costly chemicals that most resource-poor farmers simply cannot afford,” he says.

While genetic improvements are fundamental to developing the disease resistance and drought tolerance so desperately needed by African farmers, there are other important factors that can influence the overall outcome of a breeding programme, he explains. Understanding the plant itself, the soil and the climate of a region are all vital in creating the kinds of varieties farmers need and can grow in their fields.

Photo: Y Wachira/Bioversity International

Kenyan groundnut farmer Patrick Odima with some of his crop.

“I have grown increasingly convinced that overlooking these aspects in our genetic improvements would be to our peril,” Vincent warns. “There are big gains to be made from looking at very simple sorts of agronomic management changes, like sowing density – the number of seeds you plant per square metre. Groundnuts are often cultivated at seeding rates that are unlikely to achieve the best possible yields, especially when they’re grown in infertile soils.”

For Omari Mponda, now Director of Tanzania’s Agricultural Research Institute at Naliendele (ARI–Naliendele), previously Zonal Research Coordinator and plant breeder, and country groundnut research leader for GCP’s Tropical Legumes I project (TLI; see box below), combining good genetics with sound agronomic management is a matter of success or failure for any crop-breeding programme, especially in poverty-stricken countries.

“Molecular markers by themselves will not address the productivity on the ground,” he says, agreeing with Vincent. “A new variety of groundnut may have very good resistance, but its pods may be too hard, making shelling very difficult. This does not help the poor people, because they can’t open the shells with their bare hands.”

And helping the poor of Africa is the real issue, Omari says. “We must remind ourselves of that.”

This means listening to the farmers: “It means finding out what they think and experience, and using that local knowledge. Only then should the genetics come in. We need to focus on the connections between local knowledge and scientific knowledge. This is vital.”

The Tropical Legumes I project (TLI) was initiated by GCP in 2007 and subsequently incorporated into the Programme’s Legumes Research Initiative (RI). The goal of the RI was to improve the productivity of four legumes – beans, chickpeas, cowpeas and groundnuts – that are important in food security and poverty reduction in developing countries, by providing solutions to overcome drought, poor soils, pests and diseases. TLI was led by GCP and focussed on Africa. Work on groundnut within TLI was coordinated by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). The partners in the four target countries were Malawi’s Chitedze Research Station, Senegal’s Institut Sénégalais de Recherches Agricoles (ISRA), and Tanzania’sAgricultural Research Institute (ARI). Other partners were France’s Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), the Brazilian Corporation of Agricultural Research (EMBRAPA) and Universidade de Brasil in Brazil, and University of Georgia in the USA. Tropical Legumes II (TLII) was a sister project to TLI, led by ICRISAT on behalf of the International Institute of Tropical Agriculture (IITA) and International Center for Tropical Agriculture (CIAT). It focussed on large-scale breeding, seed multiplication and distribution primarily in sub-Saharan Africa and South Asia, thus applying the ‘upstream’ research results from TLI and translating them into breeding materials for the ultimate benefit of resource-poor farmers. Many partners in TLI also worked on projects in TLII.

Photo: A Diama/ ICRISAT

Participants at a farmer field day in Mali interact with ICRISAT staff and examine different groundnut varieties and books on aflatoxin control and management options.

Local knowledge and high-end genetics working together in Tanzania

Like Malawi, Tanzania has also experienced the full spectrum of constraints to groundnut production – from drought, aflatoxin contamination, poor soil and limited access to new seed, to a lack of government extension officers visiting farmers to ensure they have the knowledge and skills needed to improve their farming practices and productivity.

Although more than one million hectares of Tanzania is groundnut cropping land, the resources supplied by the government have until now been minimal, says Omari, compared to those received for traditional cash crops such as cashews and coffee.

Photo: C Schubert/CCAFS

A farmer and her children near 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.

“But the groundnut is now viewed differently by the government in my country as a result of GCP’s catalytic efforts,” Omari says. “More resources are being put into groundnut research.”

In the realm of infrastructure, for instance, the use of GCP funds to build a new irrigation system at Naliendele has since prompted Tanzania’s government to invest further in irrigation for breeder seed production.

“They saw it was impossible for us to irrigate our crops with only one borehole, for instance, so they injected new funds into our irrigation system. We now have two boreholes and a whole new system, which has helped expand the seed production flow. Without GCP, this probably wouldn’t have happened.”

Irrigation, for Omari, ultimately means being able to get varieties to the farmers much faster: “maybe three times as fast,” he says. “This means we’ll be able to speed up the multiplication of seeds – in the past we were relying on rainfed seed, which took longer to bulk and get to farmers.”

With such practical outcomes from GCP’s research and funding efforts and the new genetic resources becoming available, breeders like Omari see a bright future for groundnut research in Tanzania.

Photo: C Schubert/CCAFS

Groundnut farmer near Dodoma, Tanzania.

The gains being made at Naliendele are not only sustainable, Omari explains, but have given the researchers independence and autonomy. “Before we were only learning – now we have become experts in what we do.”

Prior to GCP, Omari and his colleagues were used to conventional breeding and lacked access to cutting-edge science.

“We used to depend on germplasm supplied to us by ICRISAT, but now we see the value in learning to use molecular markers in groundnut breeding to grow our own crosses, and we are rapidly advancing to a functional breeding programme in Tanzania.”

Omari says he and his team now look forward to the next phase of their research, when they expect to make impact by practically applying their knowledge to groundnut production in Tanzania.

Similar breeding success in Senegal

Photo: C Schubert/CCAFS

Harvesting groundnuts in Senegal.

Issa Faye became involved in GCP in 2008 when the programme partly funded his PhD in fresh seed dormancy in groundnuts. “I was an example of a young scientist who was trained and helped by GCP in groundnut research,” he says.

“I remember when I was just starting my thesis, my supervisor would say, ‘You are very lucky because you will not be limited to using conventional breeding. You are starting at a time when GCP funding is allowing us to use marker-assisted selection [MAS] in our breeding programme’.”

The importance of MAS in groundnut breeding, Issa says, cannot be overstated.

“It is very difficult to distinguish varieties of cultivated groundnut because most of them are morphologically very similar. But if you use molecular markers you can easily distinguish them and know the diversity of the matter you are using, which makes your programme more efficient. It makes it easier to develop varieties, compared to the conventional breeding programme we were using before we started working with GCP.”

By using markers that are known to be linked to useful genes for traits such as drought tolerance, disease resistance, or resistance to aflatoxin-producing fungi, breeders can test plant materials to see whether or not they are present. This helps them to 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, saving time and money.

Photo: S Sridharan/ICRISAT

These women in Salima District, Malawi, boil groundnuts at home and carry their tubs to the Siyasiya roadside market.

Senegal, like other developing countries, does not have enough of its own resources for funding research activities, explains Issa. “We can say we are quite lucky here because we have a well-developed and well-equipped lab, which is a good platform for doing molecular MAS. But we need to keep improving it if we want to be on the top. We need more human resources and more equipment for boosting all the breeding programmes in Senegal and across other regions of West Africa.”

Recently, Issa says, the Senegalese government has demonstrated awareness of the importance of supporting these activities. “We think that we will be receiving more funds from the government because they have seen that it’s a kind of investment. If you want to develop agriculture, you need to support research. Funding from the government will be more important in the coming years,” he says.

“Now that we have resources developed through GCP, we hope that some drought-tolerant varieties will come and will be very useful for farmers in Senegal and even for other countries in West Africa that are facing drought.”

It’s all about poverty

“The achievements of GCP in groundnut research are just the beginning,” says Vincent. The legacy of the new breeding material GCP has provided, he says, is that it is destined to form the basis of new and ongoing research programmes, putting research well ahead of where it would otherwise have been.

“There wasn’t time within the scope of GCP to develop finished varieties because that takes such a long time, but these products will come,” he says.

For Vincent, diverse partnerships facilitated by GCP have been essential for this to happen. “The groundnut work led by ICRISAT and collaborators in the target countries – Malawi, Senegal, and Tanzania – has been continuously moving forward.”

Photo: S Sridharan/ICRISAT

Groundnut harvesting at Chitedze Agriculture Research Station, Malawi.

Issa agrees: “It was fantastic to be involved in this programme. We know each other now and this will ease our collaborations. We hope to keep working with all the community, and that will obviously have a positive impact on our work.”

For Omari, a lack of such community and collaboration can only mean failure when it comes to addressing poverty.

“If we all worked in isolation, a lot of money would be spent developing new varieties but nothing would change on the ground,” he says. “Our work in Tanzania is all about the problem of poverty, and as scientists we want to make sure the new varieties are highly productive for the farmers around our area. This means we need to work closely with members of the agricultural industry, as a team.”

Omari says he and his colleagues see themselves as facilitators between the farmers of Tanzania and the ‘upstream end’ of science represented by ICRISAT and GCP. “We are responsible for bringing these two ends together and making the collaboration work,” he says.

Only from there can we come up with improved technologies that will really succeed at helping to reduce poverty in Africa.”

As climate change threatens to aggravate poverty more and more in the future, the highly nutritious, drought-tolerant groundnut may well be essential to sustain a rapidly expanding global population.

By developing new, robust varieties with improved adaptation to drought, GCP researchers are well on the way to increasing the productivity and profitability of the groundnut in some of the poorest regions of Africa, shifting the identity of the humble nut to potential crop champion for future generations.

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Photo: S Sridharan/ICRISAT

Oswin Madzonga, Scientific Officer at ICRISAT-Lilongwe, visits on-farm trials near Chitala Research Station in Salima, Malawi, where promising disesase-resistant varieties are being tested real life conditions.

Jun 192015
 
Photo: N Palmer/CIAT

Bean Market in Kampala, Uganda.

Common beans are the world’s most important food legume, particularly for subsistence and smallholder farmers in East and Southern Africa. They are a crucial source of protein, are easy to grow, are very adaptable to different cropping systems, and mature quickly.

To some, beans are ‘a near-perfect food’ because of their high protein and fibre content plus their complex carbohydrates and other nutrients. One cup of beans provides at least half the recommended daily allowance of folate, or folic acid – a B vitamin that is especially important for pregnant women to prevent birth defects. One cup also supplies 25–30 percent of the daily requirement of iron, 25 percent of that of magnesium and copper, and 15 percent of the potassium and zinc requirement.

Unfortunately, yields in Africa are well below their potential – between 20 and 30 percent below. The main culprit is drought, which affects 70 percent of Africa’s major bean-producing regions. Drought is especially severe in the mid-altitudes of Ethiopia, Kenya, Malawi and Zimbabwe, as well as across Southern Africa.

“For the past seven or eight years, rains have been very unreliable in central and northern Malawi,” says Virginia Chisale, a bean breeder with Malawi’s Department of Agricultural Research and Technical Services.

“In the past, rains used to be very reliable and people were able to know the right time to plant to meet the rains in critical conditions,” she says. “Now these primary agriculture regions are either not receiving rain for long periods of time, or rains are not falling at the right time.”

Virginia recounts that during the 2011/12 cropping season there were no rains soon after planting, when it is important that beans receive moisture. Such instances can cut bean yields by half.

Photo: N Palmer/CIAT

Steve Beebe in the field.

“Drought is a recurrent problem of rainfed agriculture throughout the world,” says Steve Beebe, a leading bean breeder with the International Center for Tropical Agriculture (CIAT). “Since over 80 percent of the world’s cultivated lands are rainfed, drought stress has major implications for global economy and trade.”

Steve was the Product Delivery Coordinator for the beans component of the Legumes Research Initiative (RI), part of Phase II of the CGIAR Generation Challenge Programme (GCP). The RI incorporated several projects, the biggest of which was Tropical Legumes I (TLI) (see box). The main objective of the work on beans within TLI was to identify and develop drought-tolerant varieties using marker-assisted breeding techniques. The resulting new varieties were then evaluated for their performance in Ethiopia, Kenya, Malawi and Zimbabwe.

“It’s vital that we develop high-yielding drought-tolerant varieties so as to help farmers, particularly in developing countries, adapt to drought and produce sustained yields for their families and local economies,” says Steve.

The Tropical Legumes I project (TLI) was initiated by GCP in 2007 and subsequently incorporated into the Programme’s Legumes Research Initiative (RI). The goal of the RI was to improve the productivity of four legumes – beans, chickpeas, cowpeas and groundnuts – that are important in food security and poverty reduction in developing countries, by providing solutions to overcome drought, poor soils, pests and diseases. TLI was led by GCP and focussed on Africa. Work on beans within TLI was coordinated by the International Center for Tropical Agriculture (CIAT). The partners in the four target countries were Ethiopia’s South Agricultural Research Institute (SARI), the Kenya Agricultural Research Institute (now known as the Kenya Agricultural and Livestock Research Organization, KALRO), Malawi’s Department of Agricultural Research and Technical Services (DARTS) and Zimbabwe’s Crop Breeding Institute (CBI) of the Department of Research and Specialist Services (DR&SS). Cornell University in the USA was also a partner. Tropical Legumes II (TLII) was a sister project to TLI, led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) on behalf of the International Institute of Tropical Agriculture (IITA) and CIAT. It focussed on large-scale breeding, seed multiplication and distribution primarily in sub-Saharan Africa and South Asia, thus applying the ‘upstream’ research results from TLI and translating them into breeding materials for the ultimate benefit of resource-poor farmers. Many partners in TLI also worked on projects in TLII.

For an overview of the work on beans from the perspectives of four different partners, watch our video below, “The ABCs of bean breeding”.

What makes a plant drought tolerant?

The question of what makes a plant drought tolerant is one that breeders have debated for centuries. No single plant characteristic or trait can be fully responsible for protecting the plant from the stress of intense heat and reduced access to water.

“It’s a difficult question to answer for any plant, including beans,” says Steve. “Once you do isolate a trait genetically, it can often be difficult to identify this trait in a plant in the field, for example, identifying the architecture and length of a plant’s roots.”

Phenotyping is an important process in conventional plant breeding. It involves identifying and measuring the presence of physical traits such as seed colour, pod size, stem thickness or root length. Gathering data about a range of such characteristics across a number of different plant lines helps breeders decide which plants to use as parents in crosses and which of the progeny have inherited useful traits.

Root length has long been thought of as a drought-tolerance trait: the longer the root, the more chance it has of tapping into moisture stored deeper in the soil profile.

Given, however, that it is difficult to inspect root length in the field, researchers at CIAT have been exploring other more accessible drought-tolerance traits they can more easily identify and measure. One of these is measuring the weight of the plants’ seeds.

Photo: N Palmer/CIAT

Comparison between varieties in trials of drought tolerant beans at CIAT’s headquarters in Colombia.

Fat beans indicate plants coping with drought stress

“We measure seed weight because we are discovering that under drought stress, drought-tolerant bean varieties will divert sugars from their leaves, stems and pods to their seed,” says Steve. “We call this trait ‘pod filling’, and for us it is the most important drought-tolerance trait to be found over the last several years.”

Finding bean plants with larger, heavier seeds when growing under drought conditions indicates that the plants are coping well, and means farmers’ yields are maintained.

As part of GCP’s Legumes RI, African partners like Virginia have been measuring the seed weight of several advanced breeding lines, which can be used as parents to develop new varieties. These breeding lines have been bred by CIAT and demonstrate this pod-filling process and consequent tolerance of drought.

Although this measurement is relatively cheap and easy for breeders all over the world to do, Steve and his team are interested in finding an even more efficient way to spot plants that maintain full pods under drought.

“We are trying to understand which genes control this trait so we can use molecular-assisted breeding techniques to determine when the trait is present,” says Steve. Having identified several regions of genes related to pod filling, he and his team have developed molecular markers to help breeders identify which plants have these desired genes. “The use of molecular markers in selection significantly reduces the time and cost of the breeding process, making it more efficient. This means that we get improved varieties out to farmers more quickly.”

Photo: N Palmer/CIAT

Bean farmer in Rwanda.

Molecular markers (also known as DNA markers) are used by researchers as ‘flags’ to identify particular genes within a plant’s genome (DNA) that control desired traits, such as drought tolerance. These markers are themselves fragments of DNA that highlight particular genes or regions of genes by binding near them.

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 (genes), making it easier and quicker to identify whether or not they are present.

Photo: J D'Amour/HarvestPlus

Beans from Rwanda.

Plant breeders can use molecular markers from early on in the breeding process to choose parents for their crosses and determine whether progeny they have produced have the desired trait, based on testing only a small amount of seed or seedling tissue.

“If the genes are present, we grow the progeny and conduct the appropriate phenotyping; if not, we throw the progeny away,” explains Steve. “This saves us resources and time because we need to grow and phenotype only the few hundred progeny which we know have the desired genes, instead of a few thousand progeny, most of which would not possess the gene.”

Outsourcing genotyping to the UK Steve says a significant contribution made by GCP was facilitating a deal with a private UK company (LGC Genomics, formerly KBioscience) that is able to quickly and cheaply genotype leaf samples sent to them by African breeders. The company then forwards the data to the International Center for Tropical Agriculture (CIAT), who analyse it and let the breeders in Africa know which progeny contain the desired genes and are suitable for breeding, and which ones to throw away.  “The whole process takes roughly four weeks, but saves the breeders the time and effort to grow all progeny,” says Steve. “This system works well for countries that don’t have the capacity or know-how to do the molecular work,” says Darshna Vyas, a plant genetics specialist with LGC Genomics. “Genotyping has advanced to a point where even larger labs around the world choose to outsource their genotyping work, as it is cheaper and quicker than if they were to equip their lab and do it themselves. We do hundreds of thousands of genotyping samples a day – day in, day out. It’s our business.”

GCP has supported this foundation work, building on the extensive bean research already done by CIAT dating back to the 1970s, to develop molecular markers not only for drought-tolerance traits such as pod filling, but also for traits associated with resistance to important insect and disease menaces.

“Under drought conditions, plants become more susceptible to pests and diseases, so it was important that we also try to identify and include resistance traits in the drought-tolerant progeny,” says Steve.

Drought is but one plant stressor – diseases and pests wreak havoc too

Photo: W Arinaitwe/CIAT/PABRA

Common bacterial blight on bean.

The bean diseases that farmers in Ethiopia, Kenya, Malawi and Zimbabwe continually confront are angular leaf spot, bean common mosaic virus, common bacterial blight and rust. Key insect pests are bean stem maggot and aphids.

“We’ve had reports of bean stem maggot and bean common mosaic virus wiping out a whole field of beans,” says Virginia. “Although angular leaf spot and common bacterial blight are not as damaging, they can still reduce yields by over 50 percent.”

Virginia says this is devastating for farmers in Malawi, many of whom only have enough land and money to grow beans to feed their families and sell what little excess there is at market to purchase other necessities.

“This is why we are excited by the prospect of developing not just drought-tolerant varieties, but drought-tolerant varieties with disease and pest resistance as well,” says Virginia.

Virginia’s team in Malawi – along with other breeders in Ethiopia, Kenya and Zimbabwe – are currently using over 200 Mesoamerican and Andean bean breeding lines supplied by CIAT to help breed for drought tolerance and disease and pest resistance. Although many do not yet have the capacity to do molecular breeding in their countries, thanks to advances in plant science it is becoming more feasible and cheaper to outsource molecular breeding stages of the process (see box above).

“With help from GCP and CIAT, we have successfully crossed a line from CIAT with some local varieties to produce plants that are high yielding and resistant to most common bean diseases,” Virginia says.

Photo: ILRI

Malawian farmer Jinny Lemson grows beans to feed her livestock.

Ethiopia’s new bean breeders

Photo: ILRI

Young women sorting beans after a harvest in Ethiopia.

One man who has been helping build this new breeding capacity is Bodo Raatz, a molecular geneticist who joined CIAT and GCP’s Legumes RI in late 2011.

“We’ve [CIAT] hosted several African PhD students here in Colombia and have conducted several workshops in Colombia and Africa too,” says Bodo.

“At the workshops we teach local breeders and technicians how to use genetic tools and markers for advanced breeding methods, phenotyping and data management. The more people there are who can do this work, the quicker new varieties will filter through to farmers.”

Bodo says he has found delivering the training both personally and professionally rewarding, especially “seeing the participants understand the concepts and start using the tools and techniques to develop new lines [of bean varieties] and contribute to the project.”

One national breeder whom Bodo has seen advance from the training is Daniel Ambachew, then a bean breeder at the Southern Agricultural Research Institute (SARI) in Ethiopia.

Daniel started as a GCP-funded Master’s student enrolled at Haramaya University, Ethiopia, evaluating bean varieties with both tolerance to drought and resistance to bean stem maggot. He eventually became the Ethiopian project leader for beans within GCP’s Legumes RI.

“Daniel is currently one of only a handful of bean breeders in Ethiopia who are using molecular-assisted breeding techniques to breed new varieties,” says Bodo. “It’s quite an achievement, especially now that he has taken on the lead role in Ethiopia.”

Photo: N Palmer/CIAT

Buying and selling at a bean market in Kampala, Uganda.

For Daniel, learning about and using the new molecular-breeding techniques has been an exciting new challenge. “The most interesting part of the technology is that it helps us understand what is going on in the plant at a molecular level and lets us know if the crosses we are making are successful and the genes we want are present,” says Daniel. “All this helps improve our efficiency and speeds up the time it takes us to breed and release new varieties for farmers.”

By the end of 2014, Daniel and his team had finished the third year of trials and had several drought-tolerant lines ready for national trials in 2015 and eventual release in 2016.

Between 2012 and 2014, Daniel, and two other breeders from SARI, attended GCP’s three-year Integrated Breeding Multiyear Course, learning how to design molecular-assisted breeding trials; collect, analyse and interpret genotypic and phenotypic data from the trials; and manage data using the GCP’s Integrated Breeding Platform (IBP), particularly its Breeding Management System (BMS).

“The IBP is a really fantastic tool,” says Daniel. “During the course we learnt about the importance of recording clear and consistent phenotypic data, and the IBP helps us to do this as well as store it in a database. It makes it easier to refer to and learn from the past. I’m now trying to pass on the knowledge I’ve learnt as well as create and implement a data-management policy for all plant breeders and technicians in our institute.”

Bodo agrees with Daniel about the importance of IBP and believes it will be a true legacy of GCP beyond the Programme’s end in 2014. “The Platform has been designed to be the main data-management platform for plant breeders. It allows breeders to talk the same language and will reduce the need for learning new systems.”

Daniel says the challenge for his institute now is to build further capacity among staff – and to retain it. “At the moment we only have two bean breeders,” says Daniel. “It’s hard to retain research staff in Ethiopia as salaries are very low, so people move on to new, higher paying positions when they get the chance. It’s not unique to Ethiopia, but true of all Africa.”

Photo: O Thiong'o/CIAT/PABRA

Bean trials at KALRO in Kenya.

Kenya chasing higher bean yields

Across the border, Kenya has also been facing staffing issues.

“We are behind Ethiopia, Malawi and Zimbabwe in terms of our capacity and our trials,” says David Karanja, a bean breeder and project leader at the Kenya Agricultural and Livestock Research Organisation (KALRO, formerly the Kenya Agricultural Research Institute, or KARI). “At the start of the project, we didn’t have a breeder to lead the project for almost two years. However, we are now rapidly catching up with the others.”

And it’s a good thing too, as the country is in need of higher yielding beans to accommodate its population’s insatiable appetite for the crop. Out of the four target African countries, Kenya is the largest bean producer and consumer. As such, the country relies on beans imports from Ethiopia, Malawi, Tanzania and Uganda.

“A lot of families eat beans every day,” says David. “On average, the population eats 14–16 kilograms per person each year, but in western Kenya the average is over 60 kilograms.”

Photo: CIMMYT

Githeri, a Kenyan staple food made with maize and beans.

Kenyans consume an average total of 400,000 tonnes of beans each year, consistently more than the country produces. Projected trends in population growth indicate that this demand for beans will continue to increase by three to four percent annually.

Even though the area planted to beans has been increasing, David says farmers and breeders need to work together to improve productivity, which is well below where it should be. “The national average yield is 100 kilograms per hectare, which can range from 50 kilograms up to 700 kilograms, depending on whether we experience a drought, or a pest or disease epidemic,” explains David. “The minimum target we should be aiming for is 1,200 kilograms per hectare.”

Such a figure may seem impossible, but David believes that new breeding techniques and the varieties KALRO are producing with the help of CIAT are providing hope that farmers can reach these lofty goals.

“We have several bean lines that are showing good potential to produce higher yields under drought conditions and also have resistance to diseases like rust and mosaic virus,” says David. “They are currently under national trials, and we are confident these will be released to farmers in 2015.”

Photo: O Thiong'o/CIAT/PABRA

Varieties fare differently in KALRO bean trials in Kenya.

Commercialising beans

Photo: CIAT

Maturing bean pods.

“Many subsistence farmers have limited access to good quality bean seeds; they lack knowledge of good crop, pest and disease management; and they have poor post-harvest storage facilities,” says Godwill Makunde, who was previously a breeder at Zimbabwe’s Crop Breeding Institute (CBI) and leader of GCP’s Legumes RI bean project in Zimbabwe.

TLI’s sister project, Tropical Legumes II (TLII, see box above), led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), provided the route by which the upstream work of TLI would have impact in helping these farmers, seeking to deliver the new varieties developed under TLI into their hands. As part of TLII, Godwill, his successor Bruce Mutari, and other African partners worked on developing sustainable seed systems.

“Because beans are self-pollinating, which means each crop is capable of producing seed exactly as it was sown, farmers tend to propagate seed on farm,” says Godwill. “While this can be cost effective, it can reduce farmers’ access to higher yielding, tolerant lines, like the ones we are currently producing.”

In none of the partner countries of TLI and TLII are there formal systems for producing and disseminating bean seeds. Godwill and other partners are working with seed companies on developing a sustainable model where both farmers and seed companies can benefit.

Success built on a solid foundation

Photo: N Palmer/CIAT

Field workers tend beans in Rwanda.

A key to the success of the beans component of GCP’s Legumes RI, according to Ndeye Ndack Diop, GCP’s Capacity Building Theme Leader and TLI Project Manager, has been partners’ existing relationships with each other.

“Many of the partners are part of a very strong network of bean breeders: the Bean Coordinated Agricultural Project [BeanCAP],” explains Ndeye Ndack, adding that the TLI and BeanCAP networks benefited each other.

BeanCAP released more than 1,500 molecular markers to TLI researchers, which have helped broaden the genetic tools available to developing-country bean breeders.

TLI was also able to leverage and advance previous BeanCAP work and networks. For example, it was through this collaboration that GCP was introduced to LGC Genomics, a company it then worked with on many other crop projects.

To sustain integrated breeding practices beyond the Programme’s close in 2014, GCP established Communities of Practice (CoPs) that are discipline- and commodity-oriented.

“GCP’s CoP for beans has also helped to broaden both the TLI and BeanCAP networks too,” says Ndeye Ndack. “The ultimate goal of the CoPs is to provide a platform for community problem solving, idea generation and information sharing.”

Developing physical capacity

Besides developing human capacity, GCP has also invested in developing infrastructure in Ethiopia, Kenya and Zimbabwe.

SARI now has an irrigation system to enable them to conduct drought trials year round. “We have 12.5 hectares of irrigation now, which we use to increase our efficiency and secure our research,” says Daniel. “We can also increase seed with this irrigation during the off-season and develop early generation seeds for seed producers.”

In Zimbabwe, CBI received specialised equipment that enables them to extract DNA and send it for genotyping in the UK.

Both SARI and CBI also received automatic weather stations from GCP for high-precision climatic data capture, with automated data loading and sharing with other partners in the network.

Delivering the right beans to farmers

Back in Malawi, Virginia says another important facet of the TLII project is that researchers understand what qualities farmers want in their beans. “It’s no use developing higher yielding beans if the farmer doesn’t like the colour, or they don’t taste nice,” she says. “For example, consumers in central Malawi prefer khaki or ‘sugar beans’, which are tan with brown, black or red speckles. While those in southern Malawi tend to prefer red beans. Farmers know this and will grow beans that they know consumers will want.”

Photo: N Palmer/CIAT

Diversity at bean market in Masaka, Uganda.

Breeders in all four countries have been conducting workshops and small trials with farmers to find out this information. In Kenya, David finds farmer participation a great way to promote the work they are doing and show the impact the new drought-tolerant and disease-resistant lines can have.

“Farmers are excited and want to grow these varieties immediately when they see for themselves the difference in yield these new varieties can produce compared to their regular varieties,” says David. “They understand the pressure on them to produce more yields and are grateful that these varieties are becoming more readily available as well as tailored to their needs.”

For Steve, such anecdotes provide him and his collaborators with incentives to continue their quest to discover more molecular markers associated with drought tolerance, post-GCP.

“It’s a testament to everyone involved that we have been able to develop these advanced lines with pod-filling traits using molecular techniques, and make them available to farmers in six years instead of ten,” says Steve.

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Jun 162015
 
Ripening barley.

Ripening barley.

Barley is thought to have been one of the first crops ever cultivated by humankind. This is largely because it is a tough plant able to withstand dry and salty conditions. Its fortitude is especially important for the small land-holders living on the fringes of deserts in West Asia and North Africa, where it is “the last crop grown before the desert,” says Dr Michael Baum, who led barley research for the CGIAR Generation Challenge Programme (GCP).

Michael, who is Director of the Biodiversity and Integrated Gene Management Programme at the International Center for Agricultural Research in the Dry Areas (ICARDA), says one of the GCP’s first tasks was to find where the useful genes were in wild barley.

“Looking at wild barley is especially important for low-input agriculture, such as is found in developing countries,” he says. “Wild barley grows in, and is very adapted to, the harsh conditions at the edge of the deserts in the Fertile Crescent of West Asia: Iraq, Syria, Jordan and Turkey.”

In some regions, wild barley produces an even higher yield of grain when there is a drought. And this was the kind of useful trait that GCP researchers were looking for in their work on barley during the first phase of GCP, when the internationally funded Programme set out to enhance genetic stocks and plant-breeding skills that will help developing nations cope with increasingly extreme drought conditions.

Signs of barley being domesticated and grown for human use in the Fertile Crescent date back to more than 8,000 BCE. It was a staple cereal of ancient Egypt, where it was used to make bread and beer.  The Fertile Crescent is a crescent-shaped region containing comparatively moist and fertile land within otherwise arid and semiarid West Asia and the Nile Valley and Nile Delta of Northeast Africa. The modern-day countries with significant territory within the Crescent are Cyprus, Egypt, Iraq, Israel, Jordan, Kuwait, Lebanon and Syria; it also includes the southeastern fringe of Turkey and the western fringes of Iran.  Today barley is an important crop for many of these countries, and while production in many other parts of the world is declining it is increasing in this region. Worldwide, barley is grown in more than 100 countries, yielding more than 120 million tonnes a year for food, livestock feed and beer production. This makes it the world’s fourth most important cereal crop, after maize, rice and wheat.

Barley a ‘chosen one’ for research

Photo: Peter Haden/Flickr (Creative Commons)

Preparing barley in Ethiopia.

During its first five years, GCP chose barley as one of its focus crops as advances had already been made in understanding its genetic makeup and in using new molecular plant-breeding technologies to find and incorporate useful genes into barley varieties.

“At the same time, we needed to find the genes or characteristics we did not want in cultivated barley so we could avoid these traits,” says Michael. “This includes the way wild barley disperses its seed when its brittle spikes shatter. Domesticated barley has non-shattering spikes, making it much easier to harvest.”

Resource-poor farmers mostly grow barley in poor environments, where yields of key crops are chronically low, and crop failures are common. Resilient, high-yielding varieties could make a big difference to livelihoods.

Farmers in Central and West Asia and North Africa (CWANA) plant more than five million hectares of barley each year, where it is largely used as feed for the sheep and goats that are the main source of meat, milk and milk products for rural populations. In these environments, barley grain is harvested only two to three times over a five-year period. In years when it is too dry, sheep are sent into the barley field to graze on the straw.

Barley grain is used as animal feed, malt and human food. Barley straw is used as animal feed, for animal bedding and for roofing huts. In many developing countries, livestock graze on the stubble after barley is harvested. Barley is also used for green grazing or is cut before maturity and either directly fed to animals or used for silage. In the highlands of Tibet, Nepal, Ethiopia, Eritrea, in the Andean countries and in North Africa, barley is also an important food source.

Barley-based livestock system on marginal drylands in Morocco.

Barley-based livestock system on marginal drylands in Morocco.

Finding the clues to help breeders select barley’s best DNA

Photo: Dave Shea/Flickr (Creative Commons)

Malted barley.

The quest for better barley varieties – those that yield more, have more protein, can resist pests and diseases and can tolerate drought – means understanding what genes for what characteristics are available to plant breeders.

With 2,692 different barley accessions (or genetically different types of barley) in the ICARDA collection, from 84 different countries, this is no mean feat. GCP-supported researchers selected seed from 1,000 of the most promising accessions and planted single plants, whose seed was then ‘fingerprinted’, or genotyped, according to its DNA composition.

“From this, we selected 300 different barley lines that represented 90 percent of all the different characteristics of barley,” says Michael.

“This [reference set] is really good for someone new to barley. By looking at 300 lines they are seeing the diversity of almost 3,000 lines without any duplication,” he says. “This is much better and quicker for a plant breeder.”

The reference set of 300 barley lines is now available to plant breeders through the ICARDA gene bank.

Morocco researchers use GCP barley reference set to improve food security In Morocco, barley is the second most important cereal after wheat. Farmers produce about 1.3 million tonnes a year from a cultivated area of almost 1.9 million hectares. In this North African country, barley is used as food as well as for animal feed. It plays an important role in food security, as the per capita barley consumption is the highest in the world. However, production is constrained by diseases, pests, and stresses such as drought, and climate change has further aggravated the problem. Morocco imports cereals to meet its domestic demand.  Moroccan varieties of barley have a narrow genetic base, making it difficult to breed better varieties. In this context, the GCP barley reference set was introduced to Morocco from ICARDA and used in the breeding programme. “This has helped my country to develop new varieties,” says Fouad Abbad Andaloussi, Head of the Plant Protection Department at L'Institut National De La Recherche Agronomique (INRA; National Institute for Agricultural Research). “GCP has also greatly enhanced my personal scientific contacts and helped me to explore new developments in plant genetics and biotechnology.”

Photo: ICARDA

Barley growing on experimental fields in Morocco.

Checking out the effects of the environment on gene expression

Photo: World Bank Photo Collection

Harvesting barley in Nepal.

It’s not enough to discover what genes are present in different varieties of barley. It’s also important to understand how these genes express themselves in terms of barley’s yield, quality (especially protein content) and adaptation to stresses such as drought when grown in different environments.

To make this happen, GCP improved collaboration across research centres. This increased the probability of relatively quick advances in identifying new traits and opportunities to improve barley varieties for the poorer farmers of CWANA.

GCP funded a collaborative project between ICARDA and researchers in Australia (the University of Adelaide and the Australian Centre for Plant Functional Genomics), Italy (l’Università degli Studi di Udine) and Syria (Tishreen University) to apply a new method, analysing allele-specific expression (ASE), to understand how genes express themselves in barley, using experimental hybrid plants (cultivated plants crossed with wild barley plants). Over three years, the collaboration tested 30 genes and 10 gene-cross combinations and found that there were changes in genetic expression when plants were grown in drought conditions.

“This is a project we could not have done without the partners in the GCP collaboration,” says Michael. “We gained important insights into how genes are regulated and how gene expression changes under different environmental conditions, such as drought, or during growth stages, such as early plant development or grain filling. We published our results in a high-impact journal [The Plant Journal (2009) 59(1):14–26], which was a great outcome for a project with such a limited timespan.”

This project was designed not so much for the practical plant breeder, but for those using molecular-breeding technologies where it is important to understand that there is a change in the expression of genes over the lifetime of a plant. “This affects the selection of genes for breeding programmes,” says Michael.

Barley: Food of gladiators Barley contains about 75 percent carbohydrate, 9 percent protein and 2 percent fat. Barley grain is rich in zinc (up to 50 ppm), iron (up to 60 ppm) and soluble fibres and has a higher content of Vitamins A and E than other major cereals. Barley has been documented as a high-energy food since the Roman times, when the gladiators were called ‘hordearii’, meaning barley men or barley eaters, because they were fed a barley diet before going to an arena to fight. Some varieties of barley are also remarkably high in protein. For example, some Ethiopian varieties have up to 18 percent protein.

Photo: Peter Haden/Flickr (Creative Commons)

Preparing barley in Ethiopia.

Making the most of wild barley

Photo: Rahel Jaskow/Flickr (Creative Commons)

Wild barley in flower.

Once some of the fundamental research into barley’s building blocks had been done, GCP revisited the potential of wild barley, with the aim to identify specific DNA that increased or decreased drought tolerance.

“Whenever you can’t find the characteristics you are looking for in a cultivated crop, you go back to look again at the wild varieties,” says Michael.

Once again, a collaborative effort – this time between ICARDA, the Scottish Crop Research Institute (since renamed to the James Hutton Institute), the University of California, Riverside, the University of Oregon and Chile’s Instituto de Investigaciones Agropecuarias (INIA; Agricultural Research Institute) – was the key to success.

Joanne Russell from the James Hutton Institute says success came when “we combined the power of genomics with a unique population of 140 barley lines to identify segments of the donor genome that confer drought tolerance”.

The barley lines were composed of an advanced elite genetic background combined with introduced segments of DNA from wild barley that came from the Fertile Crescent.

“We were successful in identifying parts of the DNA from hybrid plants that confer a significant increase in yield under drought,” says Joanne.

Leader of this GCP project from the James Hutton Institute, Professor Robbie Waugh, adds that GCP provided a unique opportunity for their laboratory to interact with international colleagues on a project focussed on improving the plight of some of the world’s poorest subsistence farmers.

“The genetic technologies we had developed prior to the GCP project starting were, at the time, state of the art – even in the more developed world,” says Robbie. “Our ability to then apply these technologies to wild barley genetic material from ICARDA and to varieties derived from wild × cultivated crosses allowed us to learn a lot about patterns of genetic and phenotypic variation in the wider barley gene pool.

“Indeed, we are still working on one of the genetic populations of barley that we studied in the GCP program, now using sophisticated phenotyping tools and approaches to explore how genes in defined segments of the wild barley genome help provide yield stability under drought conditions through architectural variation in the root system.”

Photo: Richard Weil/Flickr (Creative Commons)

Women harvesting barley in India.

GCP builds genetic resources through ongoing collaboration

Photo: Diana Prichard/ONE.org/Flickr (Creative Commons)

Barley in rural Ethiopia.

For Michael, one of the most important outcomes of the GCP work was the ability to meet and work with researchers from other centres across the world.

“Before GCP, I had only visited two other CGIAR centres,” he says. “GCP was the first attempt to develop a programme across the CGIAR centres and to work on a specific topic, which was genetic resources. I would give GCP high marks for stimulating this cross-centre cooperation, particularly through their annual GCP meeting.”

And when the decision came to end barley research after the first phase of GCP, Michael found that he missed the GCP meetings: “I would have found it useful if I could have continued to attend the annual meetings,” he says. “These were much more important to me than getting the project funding out of GCP.”

Despite this and despite dealing with the challenge that some countries, such as China, were unable to provide the barley germplasm (samples of materials) that they initially promised, Michael has continued his relationships with some of the people he first met through GCP. “I’m still collaborating with China through a continuous bilateral effort on barley. Ten years later, the collaborations are still ongoing. Often when a project finishes, the collaboration finishes, but we are still continuing our collaboration on barley.”

Most importantly, Michael believes the GCP-supported and -funded collaborations brought a new approach to providing plant genetic resources to breeders. “The reference sets we assembled for barley and other crops provided a new way to look at large germplasm collections,” he says.

“This was one aim of GCP: about how to have a more rational look at germplasm collections. Now plant breeders don’t have to ask for five to ten thousand accessions of a crop, and then spend several years on evaluation.

“Now they have a higher chance of finding the genetic characteristics they want more quickly from the much smaller reference collection.”

And although the reference-set approach has been further refined since GCP’s first phase of research concluded, Michael believes it builds on what GCP started through its collaborative teams, with barley being just one example.

“GCP helped make it all happen,” he says.

For research and breeding products, see the GCP Product Catalogue and search for barley.

Photo: Oleksii Leonov/Flickr (Creative Commons)

Field of barley.

Jun 122015
 
Photo: IITA

Growing cowpea pods.

Each year, millions of people in Senegal go hungry for several months, many surviving on no more than one meal a day. Locals call this time soudure – the hungry period. It typically lasts from June through to September, when previous winter and spring cereal supplies are exhausted and people wait anxiously for a bountiful autumn cereal harvest.

During this period, a bowl of fresh green cowpea pods once a day is the best that many people can hope for. Cowpeas are the first summer crop to mature, with some varieties ready to harvest in as little as 60 days.

While cowpeas provide valued food security in Africa, yields remain low. In Senegal, average cowpea yields are 450 kilograms per hectare, a mere 10–30 percent of their potential. This poor productivity is primarily because of losses due to insects and diseases, but is sometimes further compounded by chronic drought.

In 2007, the CGIAR Generation Challenge Programme (GCP) brought together a team of plant breeders and geneticists from Burkina Faso, Mozambique, Nigeria, Senegal and the USA to collaborate on cowpea. Their goal was to breed varieties that would be higher yielding, drought tolerant and resistant to pests and diseases, and so help secure and improve local cowpea production in sub-Saharan African countries.

Photo: IITA

A trader selling cowpea at Bodija market, Ibadan, Nigeria.

Cowpea production – almost all of it comes from Africa

A type of legume originating in West Africa, cowpeas are also known as niébé in francophone Africa and as black-eyed peas in the USA.  They are well adapted to drier, warmer regions and grow well in poor soils. In Africa, they are mostly grown in the hot, drought-prone savannas and very arid sub-Saharan regions, often together with pearl millet and sorghum.

Nutritionally, cowpeas are a major source of dietary protein in many developing countries. Young leaves, unripe pods and peas are used as vegetables, and the mature grain is processed for various snacks and main meal dishes. As a cash crop, both for grain and animal fodder, cowpea is highly valued in sub-Saharan Africa.

Worldwide, an estimated 14.5 million hectares of land is planted with cowpea each year. Global production of dried cowpeas in 2010 was 5.5 million tonnes, 94 percent of which was grown in Africa.

“In Senegal, cowpeas cover more than 200,000 hectares,” says Ndiaga Cissé, cowpea breeder at L’institut sénégalais de recherches agricoles (ISRA; Senegalese Agricultural Research Institute). “This makes it the second most grown legume in Senegal, after groundnuts.”

In 2011, Senegal experienced its third drought within a decade. Low and erratic rainfall led to poor harvests in 2011 and 2012: yields of cereal crops (wheat, barley and maize) fell by 36 percent compared to 2010. Consequently, the hungry period in 2012 started three months earlier than usual, making gap-fillers like cowpea even more important. In fact, cereal production in sub-Saharan African countries has not seen substantial growth over the last two decades – total area, yield and production grew by only 4.3 percent, 1.5 percent and 5.8 percent, respectively.

Climate change is expected to further compound this situation across sub-Saharan Africa. Droughts are forecast to occur more frequently, weakening plants and making them more vulnerable to pests and diseases.

“Improved varieties of cowpeas are urgently needed to narrow the gap between actual and potential yields,” says Ndiaga. “They will not only provide security to farmers in the face of climate change, but will also help with food security and overall livelihoods.”

Photo: IITA

Farmers in Northern Nigeria transport their cowpea harvest.

Mapping the cowpea genome

For over 30 years, Phil Roberts, a professor in the Department of Nematology at the University of California, Riverside (UCR), has been breeding new varieties of cowpea. “UCR has a long history of research in cowpea breeding that goes back to the mid-seventies,” explains Phil. “One of the reasons we were commissioned by GCP in 2007 was to use our experience, particularly in using molecular breeding, to help African cowpea-breeding programmes produce higher yielding cowpeas.”

For seven years, Phil and his team at UCR coordinated the cowpea component of the Tropical Legumes I (TLI) project led by GCP (see box below).  The objective of this work was to advance cowpea breeding by applying modern, molecular breeding techniques, tools and knowledge to develop lines and varieties with drought tolerance and resistance to pests and diseases in the sub-Saharan African countries Burkina Faso, Mozambique, Nigeria and Senegal.

The molecular breeding technology that UCR uses for cowpeas is based on finding genes that help cowpea plants tolerate insects and diseases, identifying markers that can indicate the presence of known genes, and using these to incorporate valuable genes into higher yielding varieties.

“Using molecular breeding techniques is a lot easier and quicker, and certainly less hit-or-miss, than conventional breeding techniques,” says Phil. “We can shorten the time needed to breed better adapted cowpea varieties preferred by farmers and markets.”

Phil explains that the first priority of the project was to map the cowpea genome.

“The map helps us locate the genes that play a role in expressing key traits such as drought tolerance, disease resistance or pest resistance,” says Phil. “Once we know where these genes are, we can use molecular marker tools to identify and help select for the traits. This is a lot quicker than growing the plant and observing if the trait is present or not.”

To use an analogy, think of the plant’s genome as a story: its words are the plant’s genes, and a molecular marker works as 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 (genes), making it easier and quicker to identify which plants have them. Traditionally, breeders have needed to grow plants to maturity under appropriately challenging conditions to see which ones are likely to have useful traits, but by using markers to flag valuable genes they are able to largely skip this step, and test large amounts of material to choose the best parents for their crosses, then check which of the progeny have inherited the gene or genes.

Photo: IITA

Diversity of cowpea seed.

Breeding new varieties faster, using modern techniques

Photo: ICRISAT

A farmer pleased with her cowpea plants.

The main focus of the cowpea component in TLI was to optimise marker-assisted recurrent selection (MARS) and marker-assisted backcrossing (MABC) breeding techniques for sub-Saharan African environments and relevant traits.

MARS identifies regions of the genome that control important traits. In the case of cowpeas, these include drought tolerance and insect resistance. It uses molecular markers to explore more combinations in the plant populations, thus increasing breeding efficiency.

MABC is the simplest form of marker-assisted breeding, in which the goal is to incorporate a major gene from an agronomically inferior source (the donor parent) into an elite cultivar or breeding line (the recurrent parent). Major genes by themselves have a significant effect; it’s therefore easier to find a major gene associated with a desired trait, than having to find and clone several minor genes. The aim is to produce a line made up almost entirely of the recurrent parent genotype, with only the selected major gene from the donor parent.

Using the genome map and molecular markers, the UCR team identified 30 cowpea lines with drought tolerance and pest resistance from 5,000 varieties in its collection, providing the raw material for marker-assisted breeding. “Once we knew which lines had the drought-tolerance and pest-resistance genes we were looking for, we crossed them with high-yielding lines to develop 20 advanced cowpea lines, which our African partners field tested,” says Phil.

The lines underwent final field tests in 2014, and the best-yielding drought-tolerant lines will be used locally in Burkina Faso, Mozambique and Senegal to develop new higher yielding varieties that will be available to growers by 2016.

“While we are still some time off from releasing these varieties, we already feel we are two or three years ahead of where we would be if we were doing things using only conventional breeding methods,” says Ndiaga.

Photo: IITA

A parasitic Striga plant, in a cowpea experimental plot.

The genome map and molecular markers have helped cowpea breeders like Ousmane Boukar, cowpea breeder and Kano Station Representative with the International Institute of Tropical Agriculture (IITA), headquartered in Nigeria, to locate the genes in cowpeas that play a role in expressing desirable traits.

Ousmane, who was GCP’s cowpea Product Delivery Coordinator, says, “We have used this technology to develop advanced breeding lines that are producing higher yields in drier conditions and displaying resistance to several pests and diseases like thrips and Striga. We expect these lines to be available to plant breeders by the end of 2015.

“TLI has had a huge impact in Africa in terms of developing capacity to carry out marker-assisted breeding,” he says. “This form of breeding helps us to breed new varieties in three to five years instead of seven to ten years.”

The Tropical Legumes I project (TLI) was initiated by GCP in 2007 and subsequently incorporated into the Programme’s Legumes Research Initiative (RI). The goal of the RI was to improve the productivity of four legumes – beans, chickpeas, cowpeas and groundnuts – that are important in food security and poverty reduction in developing countries, by providing solutions to overcome drought, poor soils, pests and diseases. TLI was led by GCP and focussed on Africa. Work on cowpea within TLI was coordinated by the University of California, Riverside in the USA. Target-country partners were Institut de l’Environnement et de Recherches Agricoles (INERA) in Burkina Faso, Universidade Eduardo Mondlane in Mozambique and Institut Sénégalais de Recherches Agricoles (ISRA; Senegalese Agricultural Research Institute) in Senegal. Other partners were the International Institute of Tropical Agriculture (IITA) and USA’s Feed the Future Innovation Labs for Collaborative Research on Grain Legumes and for Climate-Resilient Cowpea. Tropical Legumes II (TLII) was a sister project to TLI, led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) on behalf of IITA and the International Centre for Tropical Agriculture (CIAT). It focussed on large-scale breeding, seed multiplication and distribution primarily in sub-Saharan Africa and South Asia, thus applying the ‘upstream’ research results from TLI and translating them into breeding materials for the ultimate benefit of resource-poor farmers. Many partners in TLI also worked on projects in TLII.

Burkina Faso – evaluating new lines to improve the country’s economy

Cowpea is an important crop for the people of Burkina Faso. Over 10 million farmers produce on average 800,000 tonnes of cowpeas each year, making the country the third largest producer in the world, behind neighbours Nigeria and Niger.

Much of Burkina Faso’s cowpea crop is consumed domestically, but the government sees potential in increasing productivity for export to Côte d’Ivoire and Ghana in the south. This new venture would improve the country’s gross domestic product (GDP), which is the third lowest in the world.

“The government is very interested in our research to improve cowpea yields and secure them against drought and disease,” says Issa Drabo, lead cowpea breeder with the Institut de l’Environnement et de Recherches Agricoles (INERA) in Burkina Faso.

“We’ve been working closely with UCR to evaluate advanced breeding lines that we can use in our own breeding programme. So far we have several promising lines, some of which breeders are using to create varieties for release to farmers – some as early as this year.”

Photo: IITA

Farmers in Burkina Faso discuss cowpea varieties during participatory varietal selection activities.

Outsourcing the molecular work

Issa says his team has mainly been using conventional breeding techniques and outsourcing the molecular breeding work to the UK and USA. “We send leaf samples to the UK to be genotyped by a private company [LGC Genomics], who then forward the data to UCR, who analyse it and tell us which plants contain the desired genes and would be suitable for crossing.”

The whole process takes four to six weeks, from taking the samples to making a decision on which plants to cross.

“This system works well for countries that don’t have the capacity or know-how to do the molecular work,” says Darshna Vyas, a plant genetics specialist with LGC Genomics. “Genotyping has advanced to a point where even larger labs around the world choose to outsource their genotyping work, as it is cheaper and quicker than if they were to equip their lab and do it themselves. We do hundreds of thousands of genotyping samples a day – day in, day out. It’s our business.”

Darshna says LGC Genomics have also developed plant kits, as a result of working more with GCP partners from developing countries. “We would receive plant tissue that was not properly packaged and had become mouldy on the journey. The plant kits help researchers package their tissue correctly. The genotyping data you get from undamaged tissue compared to damaged tissue is a thousand times better.”

Getting the genotyping expertise on the ground

Photo: IITA

A trader bagging cowpeas at Bodija market, Ibadan, Nigeria.

To reduce their African partners’ reliance on UCR, researchers from the university, including Phil, have been training young plant breeders and PhD students from collaborating institutes. Independent of the cowpea project, they have also been joining GCP’s Integrated Breeding Platform (IBP) training events in Africa to help breeders understand the new technologies.

“All this capacity building we do really gets at the issue of leaving expertise on the ground when the project ends,” says Phil. “If these breeders don’t have the expertise to use the modern breeding technologies, then we won’t make much progress.”

GCP Capacity Building Theme Leader and TLI Project Manager Ndeye Ndack Diop has been impressed by UCR’s enthusiasm to build capacity in its partner countries. “Capacity building is a core objective for GCP and the TLI project,” says Ndeye Ndack. “While it is built into almost all GCP projects, UCR have gone over and above what was expected of them and contributed towards building capacity not only among its partner institutions, but in many other African national breeding institutes as well.”

Issa Drabo reports that in 2014 two of his young researchers from Burkina Faso completed their training in GCP’s Integrated Breeding Multiyear Course, conducted by UCR and the IBP team.

One of Issa’s researchers at INERA, Jean-Baptiste de la Salle Tignegré, says the course helped him understand more about the background genetics, statistical analysis and data management involved in the process of molecular breeding. “Because of the course, we are now able to analyse the genotype data from LGC,” he says.

Mozambique – insects and drought are the problem

In 2010, the Universidade Eduardo Mondlane (UEM) joined the cowpea component of TLI, three years after the project started. “We were a little late to the party because we were busy setting up Mozambique’s first cowpea breeding programme, which only began in 2008,” recalls Rogerio Chiulele, a lecturer at the university’s Faculty of Agronomy and Forestry Engineering and lead scientist for cowpea research in Mozambique for TLI.

That year (2008), UEM received a GCP Capacity building à la carte grant to establish a cowpea-breeding programme for addressing some of the constraints limiting cowpea production and productivity, particularly drought, pests and diseases.

As in Burkina Faso and Senegal, in Mozambique cowpeas are an important source of food, for both protein and profit, particularly for the poor. Cowpeas rank as the fourth most cultivated crop in Mozambique, accounting for about nine percent of the total cultivated area, or an estimated four million hectares of smallholder farms.

Photo: IITA

Cowpea plants infested by aphids.

Rogerio says that farmers in his country, just as in other parts of Africa, struggle to reach their full yield potential because of climate, pests and diseases. “Several insect pests – such as aphids, flower thrips, nematodes and pod-sucking pests – can substantially reduce cowpea yield and productivity in Mozambique,” he says.

“Cowpea aphids can cause problems at any time in the growing season, but are most damaging during dry weather when they infest seedlings that are stressed from lack of water. In wetter parts of the country, flower thrips – which feed on floral buds – are the most damaging insect pest.” These insects are also major pests in Burkina Faso and Senegal, along with hairy caterpillar (Amsacta moloneyi), which can completely destroy swaths of cowpea seedlings.

Rogerio says breeding for insect resistance and drought tolerance, using marker-assisted techniques, improves breeders’ chances of increased cowpea productivity. “Productivity is key to increasing rural incomes, and new resources can then be invested in other activities that help boost total family income,” says Rogerio. “These new breeding techniques will help us achieve this quicker.”

Three high-yielding varieties to hit the Mozambique market in 2015

Photo: IITA

Mature cowpea pods ready for harvesting.

Since 2010, Rogerio’s team have quickly caught up to Burkina Faso and Senegal and plan to release three higher yielding new lines with drought tolerance in 2015. One of these lines, CB46, is based on a local cowpea variety crossed with a UCR-sourced American black-eyed pea variety that displays drought tolerance, which potentially has huge market appeal.

“Local varieties fetch, on average, half a US dollar per kilogram, compared to black-eyed pea varieties, whose price is in the region of four to five US dollars,” says Rogerio. “Obviously this is beneficial to the growers, but the benefits for consumers are just as appealing. The peas are better quality and tastier, and they take half as long to cook compared to local varieties.”

All these extra qualities are important to consider in any breeding programme and are a key objective of the Tropical Legume II (TLII) project (see box above). TLII activities, led by ICRISAT, seek to apply products from TLI to make an impact among farmers.

“TLII focuses on translating research outputs from TLI into tangible products, including new varieties,” says Ousmane Boukar, who works closely with Ndiaga, Issa and Rogerio in TLI and TLII.

Building a community of breeders to sustain success

Photo: C Peacock/IITA

Cowpea flower with developing pods.

Part of Ousmane’s GCP role as Product Delivery Coordinator for cowpeas was to lead a network of African cowpea and soybean breeders, and he champions the need for breeders to share information and materials as well as collaborating in other ways so as to sustain their breeding programmes post-GCP.

“To sustain integrated breeding practices post-2014, GCP has established Communities of Practice (CoP) that are discipline- and commodity-oriented,” says Ndeye Ndack. “The ultimate goal is to provide a platform for community problem solving, idea generation and information sharing.”

Ousmane says the core of this community was already alive and well before the CoP. “Ndiaga, Issa and I have over 80 years combined experience working on cowpea. We have continually crossed paths and have even been working together on other non-GCP projects over the past seven years.”

One such project the trio worked together on was to release a new drought-tolerant cowpea breeding line, IT97K-499-35, in Nigeria. “The performance of this variety impressed farmers in Mali, who named it jiffigui, which means ‘hope’,” says Ousmane. “We shared these new lines with our partners in Mali and Niger so they could conduct adaptation trials in their own countries.”

For young breeders like Rogerio, the CoP has provided an opportunity to meet and learn from these older partners. “I’ve really enjoyed our annual project meetings and feeling more a part of the world of cowpea breeding, particularly since we in Mozambique are isolated geographically from larger cowpea-producing countries in West Africa.”

For Phil Roberts, instances where more-established researchers mentor younger researchers in different countries give him hope that all the work UCR has done to install new breeding techniques will pay off. “Young researchers represent the future. If they can establish a foothold in breeding programmes in their national programmes, they can make an impact. Beyond having the know-how, it is vital to have the support of the national programme to develop modern breeding effort in cowpea – or any crop.”

Setting up breeders for the next 20 years

Photo: IITA

Farmer harvesting mature cowpea pods.

In Senegal, Ndiaga is hopeful that the work that the GCP project has accomplished has set up cowpea breeders in his country and others for the next 20 years.

“Both GCP’s and UCR’s commitment to build capacity in developing countries like Senegal cannot be valued less than the new higher yielding, drought-tolerant varieties that we are breeding,” says Ndiaga. “They have provided us with the tools and skills now to continue this research well into the future.

“We are close to releasing several new drought-tolerant and pest- and disease-resistant lines, which is our ultimate goal towards securing Senegal’s food and helping minimise the impact of the hungry period.”

More links

Jun 052015
 
Photo: Bill & Melinda Gates Foundation

Farmer Maria Mtele holds recently harvested orange-fleshed sweetpotatoes in a field in Mwasonge, Tanzania.

Sweetpotato has a long history as a lifesaver. The Japanese used it when typhoons demolished their rice fields. It kept millions from starvation in famine-plagued China in the early 1960s and came to the rescue in Uganda in the 1990s, when a virus ravaged the cassava crop.

In sub-Saharan Africa, sweetpotato is proving crucial in the fight against blindness, disease and premature death among children under five. And, as agriculture becomes more market-oriented across the continent, sweetpotato has some significant advantages: it requires fewer inputs and less labour than other crops such as maize, tolerates marginal growing areas and can mature within four months.

On these fertile grounds, researchers across the globe are not underestimating the importance of sweetpotato as a staple crop.

“Yields achieved by resource-poor farmers in sub-Saharan Africa are typically low,” says Roland Schafleitner of the International Potato Center (CIP), based in Peru.

“Improved and well-adapted sweetpotato varieties with increased tolerance to drought, pests and diseases will have a positive impact on food and income security in sub-Saharan Africa and can significantly contribute to increasing productivity,” he says.

Roland was Principal Investigator of two research projects funded by the CGIAR Generation Challenge Programme (GCP), which developed genetic and genomic resources for breeding improved sweetpotato.

At the outset of the work, Roland says: “Breeding efforts were limited by the crop’s genetic complexity and the lack of information available about its genetic resources.

“It was clear that if we could develop genetic tools and make concerted efforts towards understanding the gene pool of sweetpotato, the breeding potential of the crop would improve.”

Photo: Bill & Melinda Gates Foundation

Farmer Mwanaidi Rhamdani at work in an orange-fleshed sweetpotato field in Mwasonge, Tanzania.

Sub-Saharan Africans getting their vitamin A from sweetpotato

Photo: CIP

Sweetpotato diversity.

Malnutrition does not always mean a simple lack of calories; research suggests that nutrient shortfalls are an even bigger killer. Vitamin A deficiency is a leading cause of blindness, infectious disease and premature death among children under five and pregnant women in sub-Saharan Africa and Asia.

Sweetpotato comes in a wide range of colours. Varieties with dark orange flesh are naturally very rich in the pigment beta-carotene, which the body converts into vitamin A. However, the sweetpotatoes traditionally grown in Africa are pale-fleshed and low in beta-carotene. African consumers were not used to eating colourful sweetpotato – and these orange-fleshed varieties were in any case not well adapted African growing conditions.

Recent years have therefore seen a collaborative effort by researchers across the world to breed orange-fleshed sweetpotato varieties fortified with high levels of beta-carotene, and even enriched with other nutrients, that have also been crossed with local varieties and so are adapted to local conditions and tastes. A crucial part of these efforts has also been to create public awareness and encourage people to grow, eat and buy these new varieties.

Photo: HarvestPlus

Two cheeky young chappies from Mozambique enjoy the sweet taste of orange-fleshed sweetpotato rich in beta-carotene, or pro-vitamin A.

All of this adds to the growing momentum behind sweetpotato. The growing awareness of sweetpotato’s potential nutritional benefits for the poor and food insecure, as well as its value for subsistence farmers as a reliable crop that withstands drought and requires minimal inputs, mean that it is growing in significance.

Photo: HarvestPlus

Orange-fleshed sweetpotato can be used to make a variety of tasty products from doughnuts to chapati.

More than 95% of the world’s sweetpotato crop is grown in developing countries, where it is the fifth most important staple food crop. It is particularly important in many African countries: Madagascar in Southern Africa; Nigeria in West Africa; and those surrounding the Great Lakes in East and Central Africa – Uganda, Malawi, Angola and Mozambique.

According to 2013 figures from the Food and Agriculture Organization of the United Nations, 3.6 million hectares of sweetpotato were harvested in Africa. While the average global yield of sweetpotato per hectare was 14.8 tonnes, across all East African countries in 2013 it was only half this, at 7.1 tonnes per hectare. In West African nations the average yield was even worse, at 3.7 tonnes per hectare.

Farmers are unable to make the most of their crops because the varieties available to them, including traditional varieties (or landraces) have low resistance to viral diseases and insect pests, and poor tolerance to drought. It is therefore crucial that when developing new varieties breeders are able to efficiently incorporate pest and disease resistance and drought tolerance traits.

Sweetpotato, in spite of its name, is only distantly related to the potato. Unlike the potato – which is a tuber, or thickened stem – the sweetpotato is a root. Sweetpotato is not related to the yam either, despite the physical similarity between the two. Sweetpotato can grow at altitudes ranging from sea level to 2,500 metres. It requires fewer inputs and less labour than other crops such as maize, and, in contrast to the potato, it can tolerate heat.

New DNA markers identified for sweetpotato disease

The sweetpotato virus disease (SPVD) is the most serious disease affecting sweetpotato in sub-Saharan Africa. It often causes serious yield losses of up to 80–90 percent.

The disease is the result of joint infection by two viruses: the sweetpotato feathery mottle virus and the sweetpotato chlorotic stunt virus. Of the two, the stunt virus is the more problematic.

Wolfgang Grüneberg, also from CIP, says that, in the years 2006–2008, 52 new DNA markers were developed as part of GCP-funded research to improve marker-assisted selection for resistance to the disease.

“The results,” says Wolfgang, Principal Investigator for the research, “looked promising for developing a large number of orange-fleshed sweetpotatoes with resistance to SPVD.”

Immediately following the development of the markers, two varieties of sweetpotato were developed using a cloned gene, Resistan, known to confer resistance to the virus. The first variety was used to improve an SPVD test system so that the disease could be diagnosed earlier if a crop was affected. The second variety underwent field tests in regions in Uganda that were highly affected by the disease.

Photo: HarvestPlus

Sweetpotato vines and roots.

Mobilising the genetic diversity of sweetpotato for breeding

The goals of the GCP-supported work were to develop a diverse genetic resource base for sweetpotato and stimulate the use of new tools in ongoing breeding programmes.

To help transfer this work from high-end laboratories to resource-poor research labs in developing countries, GCP promoted collaboration across institutions and borders. Researchers from Brazil, Mozambique, Uganda and Uruguay worked together on sweetpotato genetic research projects.

As Roland explains, the basic first steps needed to begin to ‘mobilise’ the genetic diversity of sweetpotato were developing a reference set of varieties and improving genomics tools to work with polyploid crops, i.e. those possessing multiple sets of chromosomes, such as sweetpotato.

GCP-supported researchers in Peru and sub-Saharan Africa defined a reference set of 472 varieties of sweetpotato, carefully selected and honed to represent both the diversity of the crop and its most important agronomical and nutritional traits.

“Based on a reference set, genetic markers can be developed that are associated with important characteristics of the crop and can help breeders to select favourable genotypes,” says Roland.

The gene sequences developed during the Programme are now available as a Sweetpotato Gene Index.

“Based on these sequences,” says Roland, “molecular markers have been designed that can help breeders and gene-bank curators to assess the genetic diversity of their accessions and to perform genetic mapping studies.

“Today, techniques that yield a much larger number of markers for genetic studies and selection are accessible for sweetpotato,” he says.

Photo: Bill & Melinda Gates Foundation

Mwanaidi Rhamdani (left) works with Maria Mtele in an orange-fleshed sweetpotato field in rural Tanzania.

The genetic lifelines reach Africa

Sweetpotato is one of the most important staple crops in Mozambique, ranking in third position after cassava and maize. The areas harvested in Mozambique in 2013 were 1.7 million hectares of maize, 780,000 hectares of cassava and 120,000 hectares of sweetpotato.

Photo: CIP

A child eats cooked orange-fleshed sweetpotato in Uganda.

GCP funded breeders in Mozambique and Uganda to learn how to identify genetic markers that would prove useful for future sweetpotato breeding.

“Our African partners visited us at CIP and helped us complete the work on identifying markers,” recalls Roland. “This provided the opportunity for direct ‘technology transfer’ to breeders in the target region.”

The collaboration had, for the first time, created a critical amount of genetic and genomics resources for sweetpotato. The resulting Sweetpotato Gene Index and the new markers were published in a peer-reviewed journal, BMC Genomics (2010) 11:604.

The new genetic resources are in use at CIP in Peru and in breeding programmes in Burkina Faso, Mozambique, Uganda, Uruguay and the USA for the assessment of the genetic diversity of germplasm collections.

“The markers have been used for diversity analysis, especially at the CIP gene bank, and also in Africa,” says Roland, who says the markers will help future research.

“Such analysis guides germplasm conservation decisions, and diversity studies are a great tool to develop core collections and composite genotype sets – subsets of the whole collection – which allow for more practical screening for specific traits than large collections.”

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Photo: P Casier/CGIAR

Kenyan farmer Emily Marigu with her sweetpotatoes.

Jun 012015
 

Crop science and collaboration help African farmers feed India’s appetite for chickpeas

Photo: ICRISAT

Indian chickpea farmer with her harvest.

India loves chickpeas. With its largely vegetarian population, it has long been the world’s biggest producer and consumer of the nutritious legume. In recent years, however, India’s appetite for chickpea has outstripped production, and the country is also now the world’s biggest importer. With a ready market and new drought-tolerant varieties of chickpea, millions of smallholder African farmers are ready to make up India’s shortfall, improving livelihoods along the way and ensuring food security for some of the world’s most resource-poor countries.

GCP achieved real impacts in chickpea by catalysing and facilitating the deployment of advanced crop science, particularly molecular breeding, in the development of drought-tolerant varieties for both Africa and Asia. Over the course of its research, it also contributed to major advances in chickpea science and genomic knowledge.

Although India boasts the world’s biggest total chickpea harvest, productivity has been low in recent years with yields of less than one tonne per hectare, largely due to drought in the south of the country where much chickpea is grown. The country is relying increasingly on exports from producers in sub-Saharan Africa to supplement its domestic supply.

Drought has been hindering chickpea yields in Africa too, however, and this is a major concern not only for Africa but also for India. Ethiopia and Kenya are Africa’s largest chickpea producers, and both countries have been producing chickpea for export. However, their productivity has been limited, mainly because of heat stress and moisture loss, as well as by a lack of access to basic infrastructure and resources.

Indeed, drought has been the main constraint to chickpea productivity worldwide, and in countries such as Ethiopia and Kenya this is often made worse by crop disease, poor soil quality and limited farmer resources. While total global production of chickpea is around 8.6 million tonnes per year, drought causes losses of around 3.7 million tonnes worldwide.

A decade ago, chickpea researchers, supported by the CGIAR Generation Challenge Programme (GCP), started to consider the potential for developing new drought-tolerant varieties that could help boost the world’s production.

They posed this question: If struggling African farmers were armed with adequate resources, could they make up India’s shortfall by growing improved chickpea varieties for export? Empowering farmers to stimulate and sustain their own food production, it was proposed, would not only offer food security to millions of farmers, but could ultimately secure future chickpea exports to India.

Photo: S Sridharan/ ICRISAT

An Ethiopian farmer harvests her chickpea crop.

In 2007, GCP kicked off a plan for a multiphased, multithemed Tropical Legumes I (TLI) project, which later became part of, and the largest project within, the GCP Legumes Research Initiative (RI; see box below) – the chickpea component of which would involve collaboration between researchers from India, Ethiopia and Kenya. The scope was not only to develop improved, drought-tolerant chickpeas that would thrive in semiarid conditions, but also to ensure that these varieties would be growing in farmers’ fields across Africa and South Asia within a decade.

“We knew our task would not be complete until we had improved varieties in the hands of farmers,” says GCP researcher Paul Kimurto from the Faculty of Agriculture, Egerton University, Kenya.

The success of GCP research in achieving these goals has opened up great opportunities for East African countries such as Ethiopia and Kenya, which are primed and ready to take advantage of a guaranteed chickpea market.

The Tropical Legumes I project (TLI) was initiated by GCP in 2007 and subsequently incorporated into the Programme’s Legumes Research Initiative (RI). The goal of the RI was to improve the productivity of four legumes – beans, chickpeas, cowpeas and groundnuts – that are important in food security and poverty reduction in developing countries, by providing solutions to overcome drought, poor soils, pests and diseases. TLI was led by GCP and focussed on Africa. Work on chickpea within TLI was coordinated by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). Target-country partners were the Ethiopian Institute of Agricultural Research (EIAR), Egerton University in Kenya and the Indian Institute of Pulses Research. The National Center for Genome Resources in the USA was also a partner. Tropical Legumes II (TLII) was a sister project to TLI, led by ICRISAT on behalf of the International Institute of Tropical Agriculture (IITA) and the International Center for Tropical Agriculture (CIAT). It focussed on large-scale breeding, seed multiplication and distribution primarily in sub-Saharan Africa and South Asia, thus applying the ‘upstream’ research results from TLI and filtering them downstream into breeding materials for the ultimate benefit of resource-poor farmers. Many partners in TLI also worked on projects in TLII.

How drought affects chickpea

Chickpea is a pretty tough customer overall, being able to withstand and thrive on the most rugged and dry terrains, surviving with no irrigation – only the moisture left deep in the soil at the end of the rainy season.

Yet the legume does have one chink in its armour: if no rain falls at its critical maturing or ripening stage (otherwise known as the grain-filling period), crop yields will be seriously affected. The size and weight of chickpea legumes is determined by how successful this maturing stage is. Any stress, such as drought or disease, that occurs at this time will reduce the crop’s yield dramatically.

In India, this has been a particular problem for the past 40 years or so, as chickpea cropping areas have shifted from the cooler north to the warmer south.

“In the 1960s and 1970s when the agricultural Green Revolution introduced grain crops to northern India, chickpeas began to be replaced there by wheat or rice, and grown more in the south,” says Pooran Gaur from the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), headquartered in India. Pooran was an Activity Leader for the first phase of TLI and Product Delivery Coordinator for the chickpea component of the Legumes RI.

This shift meant the crop was no longer being grown in cooler, long-season environments, but in warmer, short-season environments where drought and diseases like Fusarium wilt have inhibited productivity.

“We have lost about four or five million hectares of chickpea growing area in northern India in the decades since that time,” says Pooran. “In the central and southern states, however, chickpea area more than doubled to nearly five million hectares.”

Escaping drought in India

“The solution we came up with was to develop varieties that were not only high yielding, but could also mature earlier and therefore have more chance of escaping terminal drought,” Pooran explains.

“Such varieties could also allow cereal farmers to produce a fast-growing crop in between the harvest and planting of their main higher yielding crops,” he says.

New short-duration varieties are expected to play a key role in expanding chickpea area into new niches where the available crop-growing seasons are shorter.

“In southern India now we are already seeing these varieties growing well, and their yield is very high,” says Pooran. “In fact, productivity has increased in the south by about seven to eight times in the last 10–12 years.”

The southern state of Andhra Pradesh, once considered unfavourable for chickpea cultivation, today has the highest chickpea yields (averaging 1.4 tonnes/hectare) in India, producing almost as much chickpea as Australia, Canada, Mexico and Myanmar combined.

Photo: ICRISAT

Indian chickpea farmer with her harvest.

Developing new varieties: Tropical Legumes I in action

GCP-supported drought-tolerance breeding activities in chickpea created hugely valuable breeding materials and tools during the Programme’s decade of existence, focussing not only in India but African partner countries of Ethiopia and Kenya too. A key first step in Phase I of TLI was to create and phenotype – i.e. measure and record the observable characteristics of – a chickpea reference set. This provided the raw information on physical traits needed to make connections between phenotype and genotype, and allowed breeders to identify materials likely to contain drought tolerance genes. This enabled the creation in Phase II of breeding populations with superior genotypes, and so the development of new drought-tolerant prebreeding lines to feed into TLII.

A significant number of markers and other genomic resources were identified and made available during this time, including simple sequence repeats (SSRs), single nucleotide polymorphisms (SNPs) and Diversity Array Technologies (DArT) arrays. The combination of genetic maps with phenotypic information led to the identification of an important ‘hot spot’ region containing quantitative trait loci (QTLs) for several drought-related traits.

Two of the most important molecular-breeding approaches, marker-assisted backcrossing (MABC) and marker-assisted recurrent selection (MARS), were then employed extensively in the selection of breeding materials and introgression of these drought-tolerance QTLs and other desired traits into elite chickpea varieties.

Photo: L Vidyasagar/ ICRISAT

Developing chickpea pods

Markers – DNA sequences with known locations on a chromosome – are like flags on the genetic code. Using them in molecular breeding involves several steps. Scientists must first discover a large number of markers, of which only a small number are likely to be polymorphic, i.e. to have different variants. These are then mapped and compared with phenotypic information, in the hope that just one or two might be associated with a useful trait. When this is the case, breeders can test large quantities of breeding materials to find out which have genes for, say, drought tolerance without having to grow plants to maturity.

The implementation of techniques such as MABC and MARS has become ever more effective over the course of GCP’s work in chickpea, thanks to the emergence and development of increasingly cost-effective types of markers such as SNPs, which can be discovered and explored in large numbers relatively cheaply. The integration of SNPs into chickpea genetic maps significantly accelerated molecular breeding.

The outcome of all these molecular-breeding efforts has been the development and release of locally adapted, drought-tolerant chickpea varieties in each of the target countries – Ethiopia, Kenya and India – where they are already changing lives with their significantly higher yields. Further varieties are in the pipeline and due for imminent release, and it is anticipated that, with partner organisations adopting the use of molecular markers as a routine part of their breeding programmes, many more will be developed over the coming years.

Molecular breeding in TLI was done in conjunction with target-country partners, with at least one cross carried out in each country. ICRISAT also backed up MABC activities with additional crosses. The elite lines that were developed underwent multilocation phenotyping in the three target countries and the best-adapted, most drought-tolerant lines were promoted in TLII.

The project placed heavy emphasis on capacity building for the target-country partners. Efforts were made, for instance, to help researchers and breeders at Egerton University in Kenya and the Ethiopian Institute of Agricultural Research (EIAR) in Ethiopia to undertake molecular breeding activities. At least one PhD and two Master’s students each from Kenya, Ethiopia and India were supported throughout this capacity-building process.

The magic of genetic diversity

One of the important advances in chickpea science supported by GCP, as part of TLI and its mission to develop drought-tolerant chickpea genotypes, was the development of the first ever chickpea multiparent advanced generation intercross (MAGIC) population.

It was created using eight well-adapted and drought-tolerant desi chickpea cultivars and elite lines from different genetic origins and backgrounds, including material from Ethiopia, Kenya, India and Tanzania. These were drawn from the chickpea reference set that GCP had previously developed and phenotyped, allowing an effective strategic selection of parental lines. The population was created by crossing these over several generations in such a way as to maximise the mix of genes in the offspring and ensure varied combinations.

MAGIC populations like these are a valuable genetic resource that makes trait mapping and gene discovery much easier, helping scientists identify useful genes and create varieties with enhanced genetic diversity. They can also be directly used as source material in breeding programmes; already, phenotyping a subset of the chickpea MAGIC population has led to the identification of valuable chickpea breeding lines that had favourable alleles for drought tolerance.

Through links with future molecular-breeding projects, it is expected that the investment in the development of MAGIC populations will benefit both African and South Asian chickpea production. GCP was also involved in developing MAGIC populations for cowpea, rice and sorghum, which were used to combine elite alleles for both simple traits, such as aluminium tolerance in sorghum and submergence tolerance in rice, and complex traits, such as drought or heat tolerance.

Decoding the chickpea genome

Photo: ICRISAT

Chickpea seed

In 2013, GCP scientists, working with other research organisations around the world, announced the successful sequencing of the chickpea genome. This major breakthrough is expected to lead to the development of even more superior varieties that will transform chickpea production in semiarid environments.

A collaboration of 20 international research organisations under the banner of the International Chickpea Genome Sequencing Consortium (ICGSC), led by ICRISAT, identified more than 28,000 genes and several million genetic markers. These are expected to illuminate important genetic traits that may enhance new varieties.

“The value of this new resource for chickpea improvement cannot be overstated,” says Doug Cook from the University of California, Davis (UC Davis), United States. “It will provide the basis for a wide range of studies, from accelerated breeding, to identifying the molecular basis of a range of key agronomic traits, to basic studies of chickpea biology.”

Doug was one of three lead authors on the publication of the chickpea genome, along with Rajeev Varshney of ICRISAT, who was Principal Investigator for the chickpea work in GCP’s Legumes RI, and Jun Wang, Director of the Beijing Genomics Institute (BGI) of China.

“Making the chickpea genome available to the global research community is an important milestone in bringing chickpea improvement into the 21st century, to address the nutritional security of the poor – especially the rural poor in South Asia and Africa,” he says.

Increased food security will mean higher incomes and a better standard of living for farmers across sub-Saharan Africa.

For Pooran Gaur, GCP played the role of catalyst in this revolution in genomic resource development. “GCP got things started; it set the foundation. Now we are in a position to do further molecular breeding in chickpea.”

The chickpea genome-sequencing project was partly funded by GCP. Other collaborators included UC Davis and BGI-Shenzhen, with key involvement of national partners in India, Canada, Spain, Australia, Germany and the Czech Republic.

In September 2014, ICRISAT received a grant from the Indian Government for a three-year project to further develop chickpea genomic resources, by utilising the genome-sequence information to improve chickpea.

 Photo: L Vidyasagar/ICRISAT

Indian women roast fresh green chickpeas for an evening snack in Andhra Pradesh, India.

Chickpea success in Africa: new varieties already changing lives

With high-yielding, drought tolerant chickpea varieties emerging from the research efforts in molecular breeding, GCP’s partners also needed to reach out to farmers. Teaching African farmers about the advantages of growing chickpeas, either as a main crop or a rotation crop between cereals, has brought about a great uptake in chickpea production in recent years.

A key focus during the second phase of TLI, and onward into TLII, was on enhancing the knowledge, skills and resources of local breeders who have direct links to farmers, especially in Ethiopia and Kenya, and so also build the capacity of farmers themselves.

“We’ve held open days where farmers can interact with and learn from breeders,” says Asnake Fikre, Crop Research Director for EIAR and former TLI country coordinator of the chickpea work in Ethiopia.

“Farmers are now enrolled in farmer training schools at agricultural training centres, and there are also farmer participatory trials.

“This has given them the opportunity to participate in varietal selection with breeders, share their own knowledge and have their say in which varieties they prefer and know will give better harvest, in the conditions they know best.”

EIAR has also been helping train farmers to improve their farm practices to boost production and to become seed producers of these high-yielding chickpea varieties.

“Our goal was to have varieties that would go to farmers’ fields and make a clearly discernible difference,” says Asnake. “Now we are starting to make that kind of impact in my country.”

In fields across Ethiopia, the introduction of new, drought-tolerant varieties has already brought a dramatic increase in productivity, with yields doubling in recent years. This has transformed Ethiopia’s chickpea from simple subsistence crop to one of great commercial significance.

“Targeted farmers are now planting up to half their land with chickpea,” Asnake says. “This has not only improved the fertility of their soil but has had direct benefits for their income and diets.”

Varieties like the large-seeded and high-valued kabuli have presented new opportunities for farmers to earn extra income through the export industry, and indeed chickpea exports from eastern Africa have substantially increased since 2001.

Photo: A Paul-Bossuet/ICRISAT

“The high yields of the drought-tolerant and pest-resistant chickpea, and the market value, meant that I am no longer seen as a poor widow but a successful farmer,” says Ethiopian farmer Temegnush Dabi.

“Ultimately, by making wealth out of chickpea and chickpea technologies in this country, people are starting to change their lives,” says Asnake. “They are educating their children to the university level and constructing better houses, even in towns. This will have a massive impact on the next generation.”

A similar success story is unfolding in Kenya, where GCP efforts during TLI led to the release of six new varieties of chickpea in the five years prior to GCP’s close at the end of 2014; more are expected to be ready within the next three years.

While chickpea is a relatively new crop in Kenya it has been steadily gaining popularity, especially in the drylands, which make up over 80 percent of Kenya’s total land surface and support nearly 10 million Kenyans – about 34 percent of the country’s population.

Photo: GCP

Drought tolerance experiments in chickpea at Egerton University, Njoro, Kenya.

“It wasn’t until my university went into close collaboration with ICRISAT during TLII and gained more resources and training options – facilitated by GCP – that chickpea research gained leverage in Kenya,” Paul Kimurto explains. “Through GCP and ICRISAT, we had more opportunities to promote the crop in Kenya. It is still on a small scale here, but it is spreading into more and more areas.”

Kenyan farmers are now discovering the benefits of chickpea as a rotational or ‘relay’ crop, he says, due to its ability to enhance soil fertility. In the highlands where fields are normally left dry and nothing is planted from around November to February, chickpea is a very good option to plant instead of letting fields stay fallow until the next season.

“By fixing nitrogen and adding organic matter to the soil, chickpeas can minimise, even eliminate, the need for costly fertilisers,” says Paul. “This is certainly enough incentive for cereal farmers to switch to pulse crops such as chickpea that can be managed without such costs.”

Households in the drylands have often been faced with hunger due to frequent crop failure of main staples, such as maize and beans, on account of climate change, Paul explains. With access to improved varieties, however, farmers can now produce a fast-growing chickpea crop between the harvest and planting of their main cereals. In the drylands they are now growing chickpeas after wheat and maize harvests during the short rains, when the land would otherwise lie fallow.

“Already, improved chickpeas have increased the food security and nutritional status of more than 27,000 households across the Baringo, Koibatek, Kerio Valley and Bomet areas of Kenya,” Paul says.

It is a trend he hopes will continue right across sub-Saharan Africa in the years to come, attracting more and more resource-poor farmers to grow chickpea.

Chickpea’s promise meeting future challenges

Beyond the end of GCP and the funding it provided, chickpea researchers are hopeful they will be able to continue working directly with farmers in the field, to ensure that their interests and needs are being addressed.

“To sustain integrated breeding practices post-2014, GCP has established Communities of Practice (CoPs) that are discipline- and commodity-oriented,” says Ndeye Ndack Diop, GCP’s Capacity Building Leader and TLI Project Manager. “The ultimate goal of the CoPs is to provide a platform for community problem solving, idea generation and information sharing.”

Ndeye Ndack has been impressed with the way the chickpea community has embraced the CoP concept, noting that Pooran has played an important part in this and the TLI projects. “Pooran was able to bring developing-country partners outside of TLI into the CoP and have them work on TLI-related activities. Being part of the community means they have been able to source breeding material and learn from others. In so doing, we are seeing these partners in Kenya and Ethiopia develop their own germplasm.

“Furthermore, much of this new germplasm has been developed by Master’s and PhD students, which is great for the future of these breeding programmes.”

“GCP played a catalytic role in this regard,” explains Rajeev Varshney. “GCP provided a community environment in ways that very few other organisations can, and in ways that made the best use of resources,” he says. “It brought together people from all kinds of scientific disciplines: from genomics, bioinformatics, biology, molecular biology and so on. Such a pooling of complementary expertise and resources made great achievements possible.”

Photo: A Paul-Bossuet/ ICRISAT

An Ethiopian farmer loads his bounteous chickpea harvest onto his donkey.

For Rajeev, the challenge facing chickpea research beyond GCP’s sunset is whether an adequate framework will be there to continue bringing this kind of community together.

“But that’s what we’re trying to do in the next phase of the Tropical Legumes Project (Tropical Legumes III, or TLIII), which kicks off in 2015,” explains Rajeev, who will be TLIII’s Principal Investigator. TLIII is to be led by ICRISAT.

“We will continue to work with the major partners as we did during GCP, which will involve, first of all, upscaling the activities we are doing now,” he says. “India currently has the capacity, the resources, to do this.”

Rajeev is hopeful that the relatively smaller national partners from Ethiopia and Kenya, and associated partners such as Egerton University, EIAR and maybe others, will have similar opportunities. “We hope they can also start working with their governments, or with agencies like USAID, and be successful at convincing them to fund these projects into the future, as GCP has been doing,” he says.

“The process is like a jigsaw puzzle: we have the borders done, and a good idea of what the picture is and where the rest of the pieces will fit,” he says.

Certainly for Paul Kimurto, the picture is clear for the future of chickpea breeding in Kenya.

“Improvements in chickpea resources cannot end now that new varieties have started entering farmers’ fields,” he says. “We’ve managed to develop a good, solid breeding programme here at Egerton University. The infrastructure is in place, the facilities are here – we are indeed equipped to maintain the life and legacy of GCP well beyond 2015.”

This can only be good news for lovers of the legume in India. With millions of smallholder farmers in Kenya and Ethiopia poised to exploit a ready market for new varieties that will change their families’ lives, chickpea’s potential for ensuring food security across the developing world seems more promising than ever.

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