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Genetic stocks: the secret to more productive and efficient crops

Crop breeding, Genetic resources, Genetics, Themes No Responses »

Oct 192015

Precious sorghum seed diversity.

Humans are a protective species. We like to hoard away our precious items in vaults and safes made of concrete and steel, safe from thieves and catastrophes.

One not-so-obvious precious item, which many people take for granted, is seed. Without seeds, farmers would not be able to grow the grains, legumes, vegetables and fruits we eat.

For centuries, farmers have harvested seeds to store and protect for planting the following year. Most of the time, farmers will only keep seeds harvested from plants that have excelled in their environment – that have produced high yields or have favourable qualities such as larger or tastier grain. This simple iterative process of selecting primarily for high yields means that many crops today are closely related genetically, which can make them more vulnerable to evolving diseases and pests.

Without diversity, a severe epidemic can completely wipe out a farmer’s crop — and even a whole region’s crop. One of the best-known historical examples of just such a disastrous crop failure is the Irish Potato Famine of the 19^th century, when potato blight disease caused extensive death, human suffering and social upheaval. A number of crops around the world are in similar danger today, including wheat, threatened by the Ug99 strain of stem rust disease, to which almost all the world’s wheat is susceptible, and cassava, menaced by African cassava mosaic virus (ACMV).

The solution – genetic diversity

Plant breeders are looking at ways to increase diversity among cultivated crops, mitigating the risks of pests and diseases and introducing genes that help plants thrive in their local environments. To do this they are looking for useful traits in traditional cultivars, related species and wild ancestors. Such traits may include tolerance to drought, heat, and poor soils as well as insect and disease resistance. Breeders cross these donor parents with high-yielding elite breeding lines. The resulting new varieties have all the preferred traits of their parents and none of the deficiencies.

The genetic diversity of crops and their wild relatives is held by gene banks. There are thousands of gene banks worldwide, which collect and store seeds from hundreds of thousands of varieties. Breeders and researchers submit seed and tissue of wild and cultivated varieties as well as of lines of new varieties they are trying to breed.

Staff hard at work in the medium-term storage room of the International Rice Genebank at IRRI.

“For years, gene banks were primarily repositories, but with genetics evolving, and its subsequent application in plant breeding growing over the past 10 years, breeders and geneticists are now mining gene banks for wild and exotic species that might have favourable genes for desired traits,” explains Ruaraidh Sackville Hamilton, evolutionary biologist and head of the International Rice Genebank maintained by the International Rice Research Institute (IRRI) at its headquarters in The Philippines.

Sifting through all these gene-bank collections for plants with desired traits is challenging for breeders, even for traits that are easy to select for through visual screening. For example, Ruaraidh says the rice collection held at the International Rice Genebank contains more than 117,000 different types of rice, or accessions.

In recognition of this challenge, the initial rationale of the CGIAR Generation Challenge Programme’s (GCP) genetic stocks activity was to make the diversity in gene banks more easily accessible and practical for the study – and application – of genetic diversity.

Taking stock of genetic stocks

The first step towards making diversity accessible to breeders was to develop reference sets, representing as much genetic diversity as possible within a small proportion of gene bank accessions, selected through pedigree and molecular marker information.

“Reference sets reduce the number of choices that breeders have to search through, from thousands down to a few hundred,” says Jean Christophe Glaszmann, a plant geneticist at France’s Centre de coopération internationale en recherche agronomique pour le développement (CIRAD; Agricultural Research for Development), who held a managing role at GCP between 2004 and 2010, overseeing much of the reference-set work as GCP’s Subprogramme Leader on Genetic Diversity during GCP’s Phase I.

“A reference set represents the whole diversity found in the collections. Breeders can then use this sample to make crosses with their preferred varieties to try and integrate specific genes from the reference-set lines into those varieties.”

During the first phase of GCP (2004–2008), the Programme focused on identifying and characterising reference sets, each of roughly 300 lines, for banana, barley, cassava, chickpea, coconut, common bean, cowpea, faba bean, finger millet, foxtail millet, groundnut, lentil, maize, pearl millet, pigeonpea, potato, rice, sorghum, sweetpotato, wheat and yam. For most crops phenotyping data – information about physical plant traits – were also being made available for the reference sets, helping researchers to select material of interest for breeding.

A trainee at the International Maize and Wheat Improvement Center (CIMMYT) shows off diverse wheat ears, a small sample of the thousands of different lines found in the centre’s gene bank.

A further aspect of the work was the development of data-kits, which included molecular markers used to genotype and verify the sets. These kits allow plant scientists to assess and compare the diversity of their own collections with that of the reference sets, thus facilitating the introduction of new diversity in their prebreeding programmes.

Jean Christophe says the reference sets and data-kits were pivotal to the success of GCP’s molecular-breeding projects as they allowed researchers in different institutes to simultaneously work on the same genetic materials. “The sets served as consistent reference material that everybody collaborating on the project could analyse,” he explains. “Some of these collaborations involved hundreds of researchers, particularly those projects seeking to map genomes and identify genes.”

During the second phase of GCP (2009–2014), the reference sets for GCP’s Phase II target crops (cassava, chickpea, common bean, cowpea, groundnut, maize, rice, sorghum and wheat) were thoroughly phenotyped under different environments, including biotic and abiotic stresses. Jean Christophe says this work helped to identify new alleles (alternative forms of a gene or genetic locus) associated with desired traits that could be used for breeding purposes. Reference sets have been used successfully to identify and use new plant material in breeding programmes to improve various traits, particularly disease resistance and even more complex traits such as drought tolerance in cassava, chickpea, cowpea, maize, sorghum and wheat.

Broadening groundnut’s genetic base to prevent disease

A farmer in Senegal shows off her groundnut crop, almost ripe for harvest.

Another objective of GCP’s genetic stocks activity was to create new diversity within domesticated cultivated crops that have narrow genetic diversity, such as groundnut.

“The groundnuts we grow today are not too dissimilar to the ones that were first created naturally five to six thousand years ago,” says David Bertioli, a plant geneticist at the University of Brasília, Brazil. “This means that they are genetically very similar and have a narrow genetic base – the narrowest of any cultivated crop.”

This genetic similarity means that all cultivated groundnuts are very susceptible to diseases, particularly leaf spot, requiring expensive agrochemicals, especially fungicides. Without agrochemicals, which smallholder farmers in Africa and Asia often cannot afford, yields can be very low.

David says groundnut breeders always recognised the need to increase diversity, but because cultivated groundnuts have had a narrow base for so long, they became radically different from their wild relatives, making it very difficult to successfully cross wild species with cultivated species.

New genetic diversity is created through recombination, that is, through crossing contrasting varieties to create novel lines. Researchers can study these recombinants to identify genes associated with desired traits or use them in further crosses to develop new varieties.

“One of our first jobs was to make wild-species recombinants to trace out the relatedness of the wild-species genomes,” says David. “Once we could see the relatedness, we could see which wild species we could cross with cultivated lines. We had to do a lot of these crosses, but we eventually started to broaden the genetic diversity of the cultivated lines.”

David says this painstaking work, carried out under GCP, also formed the platform for sequencing the groundnut genome for the first time.

“That gave us an even greater understanding of the genetic structure, which is laying the groundwork for new varieties with traits such as added disease resistance and drought tolerance,” says David.

An additional key outcome of the groundnut aspect of the Legumes Research Initiative was developing ‘wild × domesticated’ synthetic lines, which are being crossed with domesticated groundnut varieties in Malawi, Niger, Senegal and Tanzania to introduce higher drought tolerance.

Like many areas of Africa struck by climate change, this village in Tanzania is suffering the effects of drought, with temperature increases and increasingly unpredictable rainfall.

Genetic gain by exploiting genetic stocks

The genetic stocks activity has generated a large and diverse array of resources across GCP’s target crops, not just for groundnut.

Recombinant inbred lines (RILs) incorporating specific traits of interest – particularly drought tolerance – have been developed for cowpea, maize, rice, sorghum and wheat. RILs are stabilised genetic stocks, created over several years by crossing two inbred lines followed by repeated generations of sibling mating to produce inbred lines that are genetically identical. These can then be used to discover and verify the role of particular genes and groups of genes associated with desired traits.

Near-isogenic lines (NILs) are RILs that possess identical genetic codes, except for differences at a few specific genetic loci. This enables researchers to evaluate particular genes and groups of genes that they may want to incorporate into breeding lines, particularly genes that have come from plants that otherwise do not perform well agronomically, such as wild relatives or older varieties. Sorghum NILs incorporating the Alt_SB locus for aluminium tolerance are being tested in Burkina Faso, Mali and Niger on problematic acid soils.

Multiparent advanced generation intercross (MAGIC) populations are a form of recombinants developed from crossing several parental lines from different genetic origins and, in some cases, exotic backgrounds to maximise the mix of genes from the parental lines in the offspring. MAGIC populations have been developed for chickpea, cowpea, rice and sorghum, and are being developed for common bean. Selected parental lines have been used to combine elite alleles for simple traits such as aluminium tolerance in sorghum and submergence tolerance in rice, as well as for complex traits such as drought or heat tolerance.

The further evaluation and use of the genetic stocks stemming from GCP-supported projects, as well as the generation of new genetic stocks, will continue beyond GCP through CGIAR’s Research Programs as well as through those institutes and national breeding programmes associated with GCP. There will be a continuing and evolving need to identify new genes associated with desired traits to improve cultivated germplasm.

Transplanting rice plants in Myanmar.

Sustaining genetic stocks into the future

Sustainability of genetic stocks has always been an issue, as stocks are generally not managed in a centralised way but are left under the direct responsibility of the scientists who developed them. These resources have therefore usually been handled in a highly ad hoc manner.

Because of high staff turnover in CGIAR Centers and breeding programmes in developing countries, and also because their management is neither centralised nor coordinated, these resources are also often lost as staff move from one organisation to another.

Although different genetic resources require different management protocols and storage timelines, the idea that gene bank curators take on the management of genetic stocks was proposed several years ago. For Centers such as IRRI, this is already a reality – for at least some of the genetic resources developed.

However, with the growing popularity of tapping into the rich diversity in gene banks that GCP’s genetic stocks activity has helped drive, gene bank supervisors such as Ruaraidh Sackville Hamilton are concerned about how genetic stocks will be sustained.

“The more popular molecular breeding and genetic stock become, the more funds we need to help us curate and disseminate them,” says Ruaraidh. He proposes to recover costs for managing genetic resources through a chargeback system on a two-tier scale, with non-profit organisations receiving stock at lower costs than commercial organisations. “Such a system would be sustainable and reduce the burden on gene bank institutes,” he says.

Still, the costs are of concern to institutes, particularly CGIAR Centers, which maintain most of the world’s plant crop gene banks.

CGIAR, a global partnership that unites 15 research Centres, including IRRI, is engaged in research for a food-secure future. CGIAR also created GCP. “CGIAR’s main priority is to conserve genetic resources for all humankind,” says Dave Hoisington, Senior Research Scientist and Program Director at the University of Georgia in the US. He was formerly Director of Research at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and Director of the Genetic Resources Program and of the Applied Biotechnology Center at the International Maize and Wheat Improvement Center (CIMMYT) (both CGIAR Centers) and Chair of the GCP Consortium Committee.

“In both of the CGIAR Centers I worked in,” says Dave, “we always maintained the position that if the Center were to shut down, the last thing we’d do would be to turn out the lights of the gene bank. Even when we had funding cuts, we would never cut the budget for the gene bank.”

At work in the maize active collection in the gene bank at CIMMYT, which keeps maize and wheat diversity in trust for the world.

New programme to fund crop diversity

To alleviate some of the funding burden on CGIAR Centers and free up more money to use in research and development, CGIAR created a new CGIAR Research Program for Managing and Sustaining Crop Collections. The comprehensive five-year programme is managed by the Crop Trust (formerly Global Crop Diversity Trust).

“The Trust is a financial mechanism to raise an endowment, to ensure the conservation and availability of crop diversity,” says Charlotte Lusty, Genebank Programmes Coordinator at the Global Crop Diversity Trust. “The new programme is an extension of the Trust’s work. We aim to raise a USD 500 million endowment by 2016. The interest from this will be divided between the CGIAR Centers to cover all their long-term conservation operations.”

The new programme is also reviewing how gene banks within CGIAR are being managed, with a view to developing a quality management system, which it hopes will make gene banks run more efficiently. Charlotte says it is also encouraging stronger gene banks, such as IRRI and CIMMYT, to lend their expertise and experience to smaller gene banks so they can meet and build on their management quality.

Dave Hoisington believes that the new programme will provide CGIAR’s gene banks with greater capacity and make them even more attractive for researchers wanting to make use of their rich diversity.

A wide diversity of rice seed from the collection of the International Rice Genebank at IRRI.

Looking forward 30 years

Tapping into new diversity was really at the heart of GCP, and was a major, if not the primary, rationale for its establishment. Over its 10-year lifespan, has invested almost USD 28 million, or 18 percent of its budget, in developing genetic stocks, both reference sets and recombinants, for over 20 different crops.

Although these products don’t directly benefit farmers, they do indirectly help by significantly increasing breeding efficiency.

“All this research is fairly new and I am amazed, as a geneticist and plant breeder, by how far we’ve come since GCP started in 2004,” says David Bertioli.

“What we’ve been able to do in groundnut – that is, broaden the genetic base – hasn’t occurred naturally or through conventional breeding for thousands of years. And we’ve been able to do it in less than ten years.”

David recognises that the true value of the research will only be realised when new disease-resistant varieties are available for farmers to grow, which may be in five to seven years. “Only then will we be able to look back and consider the worth of all the hard work and cooperation that went into developing these precious varieties.”

GCP’s genetic stock activities have generated a large and diverse array of resources. These resources lay the foundation for further genetic stock development and will aid in researchers’ quests to tap into genetic diversity well into the future.

ICRISAT researchers agree, partnerships can alleviate poverty

Africa, Asia, Chickpeas, Crop breeding, Genetics, Groundnuts, Partnerships, Pearl millet, Phase I crops, Pigeonpeas, Sorghum No Responses »

Oct 162015

Pigeonpea farmers in India.

The tagline of the CGIAR Generation Challenge Programme (GCP) is ‘Partnerships in modern crop breeding for food security’. One of GCP’s many rewarding partnerships was with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).

The Institute was a source of valuable partnerships with highly regarded agricultural scientists and researchers, as well as of germplasm and genetic resources from its gene bank. With assistance from GCP, these resources have enabled scientists and crop breeders throughout Africa, Asia and Latin America to achieve crop improvements for chickpea, groundnut, pearl millet, pigeonpea and sorghum, all of which are staple crops that millions of people depend upon for survival.

“The philosophy of GCP at the start was to tap into and use the genomic recourses we had in our gene banks to develop ICRISAT’s and our partners’ breeding programmes,” says Pooran Gaur, GCP’s Product Delivery Coordinator for chickpeas, and Principal Scientist for chickpea genetics and breeding at ICRISAT.

ICRISAT’s gene bank is a global repository of crop genetic diversity. It contains 123,023 germplasm accessions – in the form of seed samples – assembled from 144 countries, making it one of the largest gene banks in the world.

The collection serves as insurance against genetic loss and as a source of resistance to diseases and pests, tolerance to climatic and other environmental stresses, and improved quality and yield traits for crop breeding.

Pooran says the ultimate goal of the GCP–ICRISAT partnership was to use the resources in the gene bank to develop drought-tolerant varieties that would thrive in semi-arid conditions and to make these varieties available to farmers’ fields within a decade.

Harvesting sorghum in Kenya.

Setting a foundation for higher yielding, drought-tolerant chickpeas

Pooran was involved with GCP from its beginning in 2004 and was instrumental in coordinating chickpea projects.

Chickpea harvest, India.

“GCP got things started; it set a foundation for using genomic resources to breed chickpeas,” says Pooran. During Phase I of GCP (2004–2009), ICRISAT was involved in developing reference sets for chickpeas and developing mapping populations for drought-tolerance traits. It also collaborated with 19 other international research organisations to successfully sequence the chickpea genome in 2013 – a major breakthrough that paved the way for the development of even more superior chickpea varieties to transform production in semi-arid environments.

The International Chickpea Genome Sequencing Consortium, led by ICRISAT and partly funded by GCP, identified more than 28,000 genes and several million genetic markers. Pooran says these are expected to illuminate important genetic traits that may enhance new varieties.

The trait of most interest to many chickpea breeders is drought tolerance. In recent years, droughts in the south of India, the largest producer of chickpeas, have reduced yields to less than one tonne per hectare. Droughts have also diminished chickpea yields in Ethiopia and Kenya, Africa’s largest chickpea producers and exporters to India. While total global production of chickpeas is around 8.6 million tonnes per year, drought causes losses of around 3.7 million tonnes worldwide.

Putting it to the test: Rajeev Varshney (left, see below) and Pooran Gaur (right) inspecting a chickpea field trial.

Pooran says the foundation work supported by GCP was particularly important for identifying drought-tolerance traits. “We had identified plants with early maturing traits. This allowed us to develop chickpea varieties that have more chance of escaping drought when cereal farmers produce a fast-growing crop in between the harvest and planting of their main crops,” he says.

New varieties that grow and develop more quickly are expected to play a key role in expanding the area suitable for chickpeas 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.”

Developing capacity by involving partners in Kenya and Ethiopia

Monitoring the water use of chickpea plants in experiments at Egerton University, Njoro, Kenya.

As part of GCP’s Tropical Legumes I project (TLI), incorporated within its Legume Research Initiative (RI), ICRISAT partnered with Egerton University in Kenya and the Ethiopian Institute of Agricultural Research (EIAR) to share breeding skills and resources to produce higher yielding, drought-tolerant chickpea varieties.

“When we first started working on this project in mid-2007, our breeding programme was very weak,” says Paul Kimurto of the Faculty of Agriculture at Egerton University, who was Lead Scientist for chickpea research in the TLI project. “We have since accumulated a lot of germplasm, a chickpea reference set and a mapping population, all of which have greatly boosted our breeding programme.”

Paul says that with this increased capacity, his team in Kenya had released six new varieties of chickpea in the five years prior to GCP’s close at the end of 2014, and were expecting more to be ready within in the next three years.

In fields across Ethiopia, meanwhile, the introduction of new varieties has already brought a dramatic increase in productivity, with yields doubling in recent years, according to Asnake Fikre, Crop Research Directorate Director for EIAR.

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. This has transformed Ethiopia’s chickpeas from simple subsistence crop to one of great commercial significance.

This chickpea seller in Ethiopia says that kabuli varieties are becoming more popular.

Decoding pigeonpea genome

Two years prior to the decoding of the chickpea genome, GCP’s Director Jean-Marcel Ribaut announced that a six-year, GCP-funded collaboration led by ICRISAT had already sequenced almost three-quarters of the pigeonpea genome.

“This will have significant impact on resource-poor communities in the semi-arid regions, because they will have the opportunity to improve their livelihoods and increase food availability,” Jean-Marcel stated in January 2012.

Pigeonpea, the grains of which make a highly nutritious and protein-rich food, is a hardy and drought-tolerant crop. It is grown in the semi-arid tropics and subtropics of Asia, Africa, the Americas and the Caribbean. This crop’s prolific seed production and tolerance to drought help reduce farmers’ vulnerability to potential food shortages during dry periods.

A pigeonpea farmer in his field in India.

The collaborative project brought together 12 participating institutes operating under the umbrella of the International Initiative for Pigeonpea Genomics. The initiative was led by Rajeev K Varshney, GCP’s Genomics Theme Leader and Director of the Center of Excellence in Genomics at ICRISAT. Other participants included BGI in Shenzhen, China; four universities; and five other advanced research entities, both private and public. The Plant Genome Research Program of the National Science Foundation, USA, also funded part of this research.

“We were able to assemble over 70 percent of the genome. This was sufficient to enable us to change breeding approaches for pigeonpea,” says Rajeev. “That is, we can now combine conventional and molecular breeding methods – something we couldn’t do as well before – and access enough genes to create many new pigeonpea varieties that will effectively help improve the food security and livelihoods of resource-poor communities.”

Pigeonpea breeders are now able to use markers for genetic mapping and trait identification, marker-assisted selection, marker-assisted recurrent selection and genomic selection. These techniques, Rajeev says, “considerably cut breeding time by doing away with several cropping cycles. This means new varieties reach dryland areas of Africa and Asia more quickly, thus improving and increasing the sustainability of food production systems in these regions.”

Several genes, unique to pigeonpea, were also identified for drought tolerance by the project. Future research may find ways of transferring these genes to other legumes in the same family – such as soybean, cowpea and common bean – helping these crops also become more drought tolerant. This would be a significant asset in view of the increasingly drier climates in these crops’ production areas.

“We cannot help but agree with William Dar, Director General of ICRISAT, who observed that the ‘mapping of the pigeonpea genome is a breakthrough that could not have come at a better time’,” says Jean-Marcel.

East African farmers inspect pigeonpea at flowering time.

Securing income-generating groundnut crops in Africa

Groundnut, otherwise known as peanut, is one of ICRISAT’s mandate crops. Groundnuts provide a key source of nutrition for Africa’s farming families and have the potential to sustain a strong African export industry in future.

“The groundnut is one of the most important income-generating crops for my country and other countries in East Africa,” says Patrick Okori, who is a groundnut breeder and Principal Scientist with ICRISAT in Malawi and who was 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

It is the same in West Africa, according to groundnut breeder Issa Faye from the Institut Sénégalais de Recherches Agricoles (ISRA), 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 groundnut in West Africa.”

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, including those from ICRISAT, 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.

Drying groundnut harvest, Mozambique.

“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 science

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.

Supporting key crops in West Africa

Harvested pearl millet and sorghum in Ghana.

With a focus on the semi-arid tropics, ICRISAT has been working closely with partners for 30 years to improve rainfed farming systems in West Africa. One sorghum researcher who has been working on the ground with local partners in Mali since 1998 is Eva Weltzien-Rattunde. She is an ICRISAT Principal Scientist in sorghum breeding and genetic resources, based in Mali, and was Principal Investigator for GCP’s Sorghum Research Initiative.

Eva and her team collaborated with local researchers at Mali’s Institut d’Economie Rurale (IER) and France’s Centre de coopération internationale en recherche agronomique pour le développement (CIRAD; Agricultural Research for Development) on a project to test a novel molecular-breeding approach: backcross nested association mapping (BCNAM). Eva says this method has the potential to halve the time it takes to develop local sorghum varieties with improved yield and adaptability to poor soil fertility conditions.

In another project, under GCP’s Comparative Genomics Research Initiative, Eva and her team are using molecular markers developed through the RI to select for aluminium-tolerant and phosphorus-efficient varieties and validating their performance in field trials across 29 environments in three countries in West Africa.

“Low phosphorus availability is a key problem for farmers on the coast of West Africa, and breeding phosphorus-efficient crops to cope with these conditions has been a main objective of ICRISAT in West Africa for some time,” says Eva.

“We’ve had good results in terms of field trials. We have at least 20 lines we are field testing at the moment, which we selected from 1,100 lines that we tested under high and low phosphorous conditions.” Eva says that some of these lines could be released as new varieties as early as 2015.

Ibrahima Sissoko, a data curator working with Eva’s team at ICRISAT in Mali, also adds that the collaborations and involvement with GCP have increased his and other developing country partners’ capacity in data management and statistical analysis, as well as helping to expand their network. “I can get help from other members of my sorghum community,” he says.

In summing up, Eva says: “Overall, we feel the GCP partnerships are enhancing our capacity here in Mali, and that we are closer to delivering more robust sorghum varieties that will help farmers and feed the ever-growing population in West Africa.”

Enjoying a tasty dish of sorghum.

Tom Hash, millet breeder and Principal Scientist at ICRISAT and GCP Principal Investigator for millet, shares Eva’s sentiments on GCP and the impact it is having in West Africa.

Between 2005 and 2007, GCP invested in genetic research for millet, which is the sixth most important cereal crop globally and a staple food (along with sorghum) in Burkina Faso, Chad, Eritrea, Mali, Niger, northern Nigeria, Senegal and Sudan.

With financial support from GCP, and drawing on lessons learnt from parallel GCP genetic research, including in sorghum and chickpea, ICRISAT was able to mine its considerable pearl millet genetic resources for desirable traits.

Hari D Upadhyaya, Principal Scientist and Head of Genebank at ICRISAT in India, led this task to develop and genotype a ‘composite collection’ of pearl millet. The team created a selection that strategically reduced the 21,594 accessions in the gene bank down to just 1,021. This collection includes lines developed at ICRISAT and material from other sources, with a range of valuable traits including tolerance to drought, heat and soil salinity and resistance to blast, downy mildew, ergot, rust and smut, and even resistance to multiple diseases.

The team then used molecular markers to fingerprint the DNA of plants grown from the collection.

“GCP supported collaboration with CIRAD, and our pearl millet breeding teams learnt how to do marker-based genetic diversity analysis,” says Tom. “This work, combined with the genomic resources work, did make some significant contributions to pearl millet research.”

Over 100 new varieties of pearl millet have recently been developed and released in Africa by the African Centre for Crop Improvement in South Africa, another developing country partner of ICRISAT and GCP. Tom says the initial genetic research was pivotal to this happening.

A Ghanaian farmer examines his pearl millet harvest.

From poverty to prosperity through partnerships

Patrick Okori says that GCP has enabled his organisation to make a much stronger contribution to the quality of science.

“Prior to GCP, ICRISAT was already one of the big investors in legume research, because that was its mandate. The arrival of GCP, however, expanded the number of partners that ICRISAT had, both locally and globally, through the resources, strategic meetings and partnership arrangements that GCP provided as a broad platform for engaging in genomic research and the life sciences.”

This expansion of ICRISAT, facilitated by GCP, also enabled researchers from across the world and in diverse fields to interact in ways they had never had the opportunity to before, says Vincent Vadez.

“GCP has allowed me to make contact with people working on other legumes, for example,” he says. “It has allowed us to test hypotheses in other related crops, and we’ve generated quite a bit of good science from that.”

Pooran Gaur has had a similar experience with his chickpea research at ICRISAT.

“GCP provided the first opportunity for us to work with the bean and cowpea groups, learning from each other. That cross-learning from other crops really helped us. You learn many things working together, and I think we have developed a good relationship, a good community for legumes now.”

This community environment has made the best use of an unusual variety of skills, knowledge and resources, agrees Rajeev Varshney.

“It brought together people from all kinds of scientific disciplines – from genomics, bioinformatics, biology, molecular biology and so on,” he says. “Such a pooling of complementary expertise and resources made great achievements possible.”

Scientists paint a rainbow over maize research

Africa, Asia, Comparative genomics in cereals, Crop breeding, Genomics, Latin America, Maize No Responses »

Oct 122015

Photo: One Acre Fund/Flickr (Creative Commons)

A Kenyan farmer harvesting her maize.

“The map of Kenya’s maize-growing regions mirrors the map of the nation’s acid soils.”

So says Dickson Ligeyo, senior research officer at the Kenya Agricultural and Livestock Research Organisation (KALRO; formerly the Kenya Agricultural Research Institute, or KARI), who believes this paints a sombre picture for his country’s maize farmers.

Maize is a staple crop for Kenyans, with 90 percent of the population depending on it for food. However, acid soils cause yield losses of 17–50 percent across the nation.

Soil acidity is a major environmental and economic concern in many more countries around the world. The availability of nutrients in soil is affected by pH, so acid conditions make it harder for plants to get a balanced diet. High acidity causes two major problems: perilously low levels of phosphorus and toxically high levels of aluminium. Aluminium toxicity affects 38 percent of farmland in Southeast Asia, 31 percent in Latin America and 20 percent in East Asia, sub-Saharan Africa and North America.

Aluminium toxicity in soil comes close to rivalling drought as a food-security threat in critical tropical food-producing regions. By damaging roots, acid soils deprive plants of the nutrients and water they need to grow – a particularly bitter effect when water is scarce.

Maize, meanwhile, is one of the most economically important food crops worldwide. It is grown in virtually every country in the world, and it is a staple food for more than 1.2 billion people in developing countries across sub-Saharan Africa and Latin America. In many cultures it is consumed primarily as porridge: polenta in Italy; angu in Brazil; and isitshwala, nshima, pap, posho,sadza or ugali in Africa.

Photo: Allison Mickel/Flickr (Creative Commons)

Ugali, a stiff maize porridge that is a staple dish across East Africa, being prepared in Tanzania.

Maize is also a staple food for animals reared for meat, eggs and dairy products. Around 60 percent of global maize production is used for animal feed.

The world demand for maize is increasing at the same time as global populations burgeon and climate changes. Therefore, improving the ability of maize to withstand acid soils and produce higher yields with less reliable rainfall is paramount. This is why the CGIAR Generation Challenge Programme (GCP) invested almost USD 12.5 million into maize research between 2004 and 2014.

GCP’s goal was to facilitate the use of genetic diversity and advanced plant science to improve food security in developing countries through the breeding of ‘super’ crops – including maize – able to tolerate drought and poor soils and resist diseases.

Researchers take on the double whammy of acid soils and drought

Part of successfully breeding higher-yielding drought-tolerant maize varieties involves improving plant genetics for acid soils. In these soils, aluminium toxicity inhibits root growth, reducing the amount of water and nutrients that the plant can absorb and compounding the effects of drought.

Improving plant root development for aluminium tolerance and phosphorous efficiency can therefore have the positive side effect of higher plant yield when water is limited.

A farmer in Tanzania shows the effects of drought on her maize crop. The maize ears are undersized with few grains.

Although plant breeders have exploited the considerable variation in aluminium tolerance between different maize varieties for many years, aluminium toxicity has been a significant but poorly understood component of plant genetics. It is a particularly complex trait in maize that involves multiple genes and physiological mechanisms.

The solution is to take stock of what maize germplasm is available worldwide, characterise it, clone the sought-after genes and implement new breeding methods to increase diversity and genetic stocks.

Scientists join hands to unravel maize complexity

Scientists from the International Maize and Wheat Improvement Center (CIMMYT) and the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) got their heads together between 2005 and 2008 to itemise what maize stocks were available.

Marilyn Warburton, then a molecular geneticist at CIMMYT, led this GCP-funded project. Her goal was to discover how all the genetic diversity in maize gene-bank collections around the globe might be used for practical plant improvement. She first gathered samples from gene banks all over the world, including those of CIMMYT and the International Institute of Tropical Agriculture (IITA). Scientists from developing country research centres in China, India, Indonesia, Kenya, Nigeria, Thailand and Vietnam also contributed by supplying DNA from their local varieties.

Maize diversity.

Researchers then used molecular markers and a bulk fingerprinting method – which Marilyn was instrumental in developing – for three purposes: to characterise the structure of maize populations, to better understand how maize migrated across the world, and to complete the global picture of maize biodiversity. Scientists were also using markers to search for new genes associated with desirable traits.

Allen Oppong, a maize pathologist and breeder from Ghana’s Crops Research Institute (CRI), of the Council for Scientific and Industrial Research, was supported by GCP from 2007 to 2010 to characterise Ghana’s maize germplasm. Trained in using the fingerprinting technique, Allen was able to identify distinctly different maize germplasm in the north of Ghana (with its dry savanna landscape) and in the south (with its high rainfall). He also identified mixed germplasm, which he says demonstrates that plant germplasm often finds its way to places where it is not suitable for optimal yield and productivity. Maize yields across the country are low.

Stocktaking a world’s worth of maize for GCP was a challenge, but not the only one, according to Marilyn. “In the first year it was hard to see how all the different partners would work together. Data analysis and storage was the hardest; everyone seemed to have their own idea about how the data could be stored, accessed and analysed best.

“The science was also evolving, even as we were working, so you could choose one way to sequence or genotype your data, and before you were even done with the project, a better way would be available,” she recalls.

Maize ears drying in Ghana.

Comparing genes: sorghum gene paves way for maize aluminium tolerance

In parallel to Marilyn’s work, scientists at the Brazilian Corporation of Agricultural Research (EMBRAPA) had already been advancing research on plant genetics for acid soils and the effects of aluminium toxicity on sorghum – spurred on by the fact that almost 70 percent of Brazil’s arable land is made up of acid soils.

What was of particular interest to GCP in 2004 was that the Brazilians, together with researchers at Cornell University in the USA, had recently mapped and identified the major sorghum aluminium tolerance locus Alt_SB, and were working on isolating the major gene within it with a view to cloning it. Major genes were known to control aluminium tolerance in sorghum, wheat and barley and produce good yields in soils that had high levels of aluminium. The gene had also been found in rape and rye.

GCP embraced the opportunity to fund more of this work with a view to speeding up the development of maize – as well as sorghum and rice – germplasm that can withstand the double whammy of acid soils and drought.

Maize trials in the field at EMBRAPA. The maize plants on the left are aluminium-tolerant and so able to withstand acid soils, while those on the right are not.

Leon Kochian, Director of the Robert W Holley Center for Agriculture and Health, United States Department of Agriculture – Agricultural Research Service and Professor at Cornell University, was a Principal Investigator for various GCP research projects investigating how to improve grain yields of crops grown in acid soils. “GCP was interested in our work because we were working with such critical crops,” he says.

“The idea was to use discoveries made in the first half of the GCP’s 10-year programme – use comparative genomics to look into genes of rice and maize to see if we can see relations in those genes – and once you’ve cloned a gene, it is easier to find a gene that can work for other crops.”

The intensity of GCP-supported maize research shifted up a gear in 2007, after the team led by Jurandir Magalhães, research scientist in molecular genetics and genomics of maize and sorghum at EMBRAPA, used positional cloning to identify the major sorghum aluminium tolerance gene SbMATE responsible for the Alt_SB aluminium tolerance locus. The team comprised researchers from EMBRAPA, Cornell, the Japan International Research Center for Agricultural Sciences (JIRCAS) and Moi University in Kenya.

By combing the maize genome searching for a similar gene to sorghum’s SbMATE, Jurandir’s EMBRAPA colleague Claudia Guimarães and a team of GCP-supported scientists discovered the maize aluminium tolerance gene ZmMATE1. High expression of this gene, first observed in maize lines with three copies of ZmMATE1, has been shown to increase aluminium tolerance. ZmMATE1 improves grain yields in acid soil by up to one tonne per hectare when introgressed in an aluminium-sensitive line.

Photos: 1 – V Alves ; 2 – F Mendes; both edited by C Guimarães

The genetic region, or locus, containing the ZmMATE1 aluminium tolerance gene is known as qALT6. Photo 1 shows a rhyzobox containing two layers of soil: a corrected top-soil and lower soils with 15 percent aluminium saturation. On the right, near-isogenic lines (NILs) introgressed with qALT6 show deeper roots and longer secondary roots in the acidic lower soil, whereas on the left the maize line without qALT6, L53, shows roots mainly confined to the corrected top soil. Photo 2 shows maize ears from lines without qALT6 (above) and with qALT6 (below); the lines with qALT6 maintain their size and quality even under high aluminium levels of 40 percent aluminium saturation.

The outcomes of these GCP-supported research projects provided the basic materials, such as molecular markers and donor sources of the positive alleles, for molecular-breeding programmes focusing on improving maize production and stability on acid soils in Latin America, Africa and other developing regions.

Kenya deploys powerful maize genes

One of those researchers crucial to achieving impact in GCP’s work in maize was Samuel (Sam) Gudu of Moi University, Kenya. From 2010 he was the Principal Investigator for GCP’s project on using marker-assisted backcrossing (MABC) to improve aluminium tolerance and phosphorous efficiency in maize in Kenya. This project combined molecular and conventional breeding approaches to speed up the development of maize varieties adapted to the acid soils of Africa, and was closely connected to the other GCP comparative genomics projects in maize and sorghum.

MABC is a type of marker-assisted selection (see box), which Sam’s team – including Dickson Ligeyo of KALRO – used to combine new molecular materials developed through GCP with Kenyan varieties. They have thus been able to significantly advance the breeding of maize varieties suitable for soils in Kenya and other African countries.

Maize and Comparative Genomics were two of seven Research Initiatives (RIs) where GCP concentrated on advancing researchers’ and breeders’ skills and resources in developing countries. Through this work, scientists have been able to characterise maize germplasm using improved trait observation and characterisation methods (phenotyping), implement molecular-breeding programmes, enhance strategic data management and build local human and infrastructure capacity.

The ultimate goal of the international research collaboration on comparative genomics in maize was to improve maize yields grown on acidic soils under drought conditions in Kenya and other African countries, as well as in Latin America. Seven institutes partnered up to for the comparative genomics research: Moi University, KALRO, EMBRAPA, Cornell University, the United States Department of Agriculture (USDA), JIRCAS and the International Rice Research Institute (IRRI).

“Before funding by GCP, we were mainly working on maize to develop breeding products resistant to disease and with increased yield,” says Sam. “At that time we had not known that soil acidity was a major problem in the parts of Kenya where we grow maize and sorghum. GCP knew that soil acidity could limit yields, so in the work with GCP we managed to characterise most of our acid soils. We now know that it was one of the major problems for limiting the yield of maize and sorghum.

“The relationship to EMBRAPA and Cornell University is one of the most important links we have. We developed material much faster through our collaboration with our colleagues in the advanced labs. I can see that post-GCP we will still want to communicate and interact with our colleagues in Brazil and the USA to enable us to continue to identify molecular materials that we discover,” he says. Sam and other maize researchers across Kenya, including Dickson, have since developed inbred, hybrid and synthetic varieties with improved aluminium tolerance for acid soils, which are now available for African farmers.

A Kenyan maize farmer.

“We crossed them [the new genes identified to have aluminium tolerance] with our local material to produce the materials we required for our conditions,” says Sam.

“The potential for aluminium-tolerant and phosphorous-efficient material across Africa is great. I know that in Ethiopia, aluminium toxicity from acid soil is a problem. It is also a major problem in Tanzania. It is a major problem in South Africa and a major problem in Kenya. So our breeding work, which is starting now to produce genetic materials that can be used directly, or could be developed even further in these other countries, is laying the foundation for maize improvement in acid soils.”

Sam is very proud of the work: “Several times I have felt accomplishment, because we identified material for Kenya for the first time. No one else was working on phosphorous efficiency or aluminium tolerance, and we have come up with materials that have been tested and have become varieties. It made me feel that we’re contributing to food security in Kenya.”

Maize grain for sale.

Maize for meat: GCP’s advances in maize genetics help feed Asia’s new appetites

Reaping from the substantial advances in maize genetics and breeding, researchers in Asia were also able to enhance Asian maize genetic resources.

A pig roots among maize ears on a small farm in Nepal.

Bindiganavile Vivek, a senior maize breeder for CIMMYT based in India, has been working with GCP since 2008 on improving drought tolerance in maize, especially for Asia, for two reasons: unrelenting droughts and a staggering growth the importance of maize as a feedstock. This work was funded by GCP as part of its Maize Research Initiative.

“People’s diets across Asia changed after government policies changed in the 1990s. We had a more free market economy, and along with that came more money that people could spend. That prompted a shift towards a non vegetarian diet,” Vivek recounts.

“Maize, being the number one feed crop of the world, started to come into demand. From the year 2000 up to now, the growing area of maize across Asia has been increasing by about two percent every year. That’s a phenomenal increase. It’s been replacing other crops – sorghum and rice. There’s more and more demand.

“Seventy percent of the maize that is produced in Asia is used as feed. And 70 percent of that feed is poultry feed.”

In Vietnam, for example, the government is actively promoting the expansion of maize acreage, again displacing rice. Other Asian nations involved in the push for maize include China, Indonesia and The Philippines.

A farmer in Indonesia transports his maize harvest by motorcycle.

The problem with this growth is that 80 percent of the 19 million hectares of maize in South and Southeast Asia relies on rain as its only source of water, so is prone to drought: “Wherever you are, you cannot escape drought,” says Vivek. And resource-poor farmers have limited access to improved maize products or hybrids appropriate for their situation.

Vivek’s research for GCP focused on the development – using marker-assisted breeding methods, specifically marker-assisted recurrent selection (MARS) – of new drought-tolerant maize adapted to many countries in Asia. His goal was to transfer the highest expression of drought tolerance in maize into elite well-adapted Asian lines targeted at drought-prone or water-constrained environments.

Asia’s existing maize varieties had no history of breeding for drought tolerance, only for disease resistance. To make a plant drought tolerant, many genes have to be incorporated into a new variety. So Vivek asked: “How do you address the increasing demand for maize that meets the drought-tolerance issue?”

The recent work on advancing maize genetics for acid soils in the African and Brazilian GCP projects meant it was a golden opportunity for Vivek to reap some of the new genetic resources.

“This was a good opportunity to use African germplasm, bring it into India and cross it to some Asia-adapted material,” he says.

Stored maize ears hanging in long bunches outside a house in China.

A key issue Vivek faced, however, was that most African maize varieties are white, and most Asian maize varieties are yellow. “You cannot directly deploy what you breed in Africa into Asia,” Vivek says. “Plus, there’s so much difference in the environments [between Africa and Asia] and maize is very responsive to its environment.”

The advances in marker-assisted breeding since the inception of GCP contributed significantly towards the success of Vivek’s team.

“In collaboration with GCP, IITA, Cornell University and Monsanto, CIMMYT has initiated the largest public sector MARS breeding approach in the world,” says Vivek.

The outcome is good: “We now have some early-generation, yellow, drought-tolerant inbred germplasm and lines suitable for Asia.

“GCP gave us a good start. We now need to expand and build on this,” says Vivek.

GCP’s supported work laid the foundation for other CIMMYT projects, such as the Affordable, Accessible, Asian Drought-Tolerant Maize project funded by the Syngenta Foundation for Sustainable Agriculture. This project is developing yet more germplasm with drought tolerance.

A better picture: GCP brightens maize research

Dickson Ligeyo’s worries of a stormy future for Kenya’s maize production have lifted over the 10 years of GCP. At the end of 2014, Kenya had two new varieties that were in the final stage of testing in the national performance trials before being released to farmers.

“There is a brighter picture for Kenya’s maize production since we have acquired acid-tolerant germplasm from Brazil, which we are using in our breeding programmes,” Dickson says.

In West Africa, researchers are also revelling in the opportunity they have been given to help enhance local yields in the face of a changing climate. “My institute benefited from GCP not only in terms of human resource development, but also in provision of some basic equipment for field phenotyping and some laboratory equipment,” says Allen Oppong in Ghana.

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

The main challenge now for breeders, according to Allen, is getting the new varieties out to farmers: “Most people don’t like change. The new varieties are higher yielding, disease resistant, nutritious – all good qualities. But the challenge is demonstrating to farmers that these materials are better than what they have.”

This Kenyan farmer is very happy with his healthy maize crop, grown using an improved variety during a period of drought.

Certainly GCP has strengthened the capacity of researchers across Africa, Asia and Latin America, training researchers in maize breeding, data management, statistics, trial evaluations and phenotyping. The training has been geared so that scientists in developed countries can use genetic diversity and advanced plant science to improve crops for greater food security in the developing world.

Elliot Tembo, a maize breeder with the private sector in sub-Saharan Africa says: “As a breeder and a student, I have been exposed to new breeding tools through GCP. Before my involvement, I was literally blind in the use of molecular tools. Now, I am no longer relying only on pedigree data – which is not always reliable – to classify germplasm.”

Allen agrees: “GCP has had tremendous impact on my life as a researcher. The capacity-building programme supported my training in marker-assisted selection training at CIMMYT in Mexico. This training exposed me to modern techniques in plant breeding and genomics. Similarly, it built my confidence and work efficiency.”

There is no doubt that GCP research has brightened the picture for maize research and development where it is most needed: with researchers in developing countries where poor farmers and communities rely on maize as their staple food and main crop.

Cassava: ‘there is life’ for African farmers

Africa, Cassava, Crop breeding No Responses »

Oct 052015

Cassava brings life to African people

Beyond 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”.

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.

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.

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.”

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.

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.

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.

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):

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.

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.

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.

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!”

Groundnut boom may help crack poverty in Africa

Africa, Capacity building, Crop breeding, Genetics, Genomics, Groundnuts, Legumes No Responses »

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.

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.

“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.”

Harvested groundnuts in Senegal.

How Africa lost its groundnut export market

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.”

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.

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.

“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.

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.”

“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.

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.”

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.

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.

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

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.

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.”

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.

Barley: the ‘last crop grown before the desert’

Africa, Asia, Barley, Genetics, Genomics, Phase I crops No Responses »

Jun 162015

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.

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-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.

Barley growing on experimental fields in Morocco.

Checking out the effects of the environment on gene expression

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.

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.

Collective ‘intelligence’ cracks banana’s genetic code, clearing way for breeders

Africa, Asia, Bananas, Genetics, Genomics, Latin America, Phase I crops No Responses »

Jun 022015

A farmer transports bananas to market by bicycle in Uganda.

At whatever time of the day or night you are reading this, somewhere in the world there are sure to be farmers trekking many kilometres to take their bananas to local markets. These small-scale farmers produce almost 90 percent of the world’s bananas, and make up a significant portion of the 400 million people around the globe’s tropical girdle – Africa, Asia and Latin America – who rely on bananas for food and a source of income.

Bananas are often called the world’s most popular fruit, and global production in 2012 was almost 140 million tonnes. India is the largest producer, while South and Central American farmers supply the most to international supermarket shelves, exporting 80 percent of their bananas.

The importance of the banana as a food crop in tropical areas cannot be underestimated. More than a simple snack, plantain-type bananas in particular are a key component in savoury dishes. In Central and East African countries – like Cameroon, Gabon, Rwanda and Uganda – one person will eat an average of between 100 kg and 250 kg of banana each year. That equates to somewhere between 800 and 2000 average-sized bananas. In those four countries, bananas account for up to a quarter of people’s daily calorie intake.

Photo: A Vezina/Bioversity International

A stallholder offers bananas for sale at a fruit market in Nairobi, Kenya.

Banana’s asexuality inhibits its resilience

Bananas growing in Rwanda.

Banana propagates though asexual reproduction. This means that all the bananas of each variety are genetically identical, or nearly so, and therefore susceptible to the same diseases. Indeed, the world has already lost almost its entire banana crop once: before the 1950s, the Gros Michel cultivar dominated banana exports, but it was gradually wiped out in most regions by Panama disease, caused by the fungus Fusarium oxysporum. Furthermore, with reproduction being asexual, it is difficult to develop new, resistant varieties through conventional breeding.

At the turn of the twenty-first century, pests and diseases were once again becoming a real threat to global banana production. Little genetic research had been done on the fruit, and only a small portion of its genes had been used in breeding new varieties in its 7,000-year history as a cultivated crop.

“Several research groups had developed genetic markers for bananas [‘flags’ on the genome that can be linked to physical traits], but there was no coordination and only sketchy germplasm studies,” recalls Jean Christophe Glaszmann from CIRAD (Centre de coopération internationale en recherche agronomique pour le développement; Agricultural Research for Development) in France.

A plantain farmer walks through a plantation in Quindió, Colombia.

“It was not a priority,” says Jean Christophe, who was Subprogramme Leader for Genetic Diversity for the CGIAR Generation Challenge Programme (GCP), an international initiative established in 2004 to encourage the use of genetic diversity and advanced plant science to improve crops.

But between 2004 and 2012, under GCP, a wealth of research work was undertaken that culminated in the complete genetic sequencing of banana. It was a long process, says Jean Christophe, but the GCP-funded work on banana made a significant contribution to important results.

The extensive data on the genetics of banana are now available to scientists worldwide, who can use it to delve deeper into banana’s genes to breed varieties that can sustain the poorer populations in developing countries.

Once finally sequenced, the banana genome was published in one of the most prestigious scientific journals, Nature, in July 2012: “The reference Musa [banana and plantains] genome sequence represents a major advance in the quest to unravel the complex genetics of this vital crop, whose breeding is particularly challenging. Having access to the entire Musa gene repertoire is a key to identifying genes responsible for important agronomic characters, such as fruit quality and pest resistance.”

Passionate people pooled for the work

A banana seller in Hanoi, Vietnam.

Plans to sequence the banana genome started taking shape in 2001 at Bioversity International (a CGIAR centre), where a group of scientists formed the Global Musa Genomics Consortium. At that time, the only plant whose genome had been sequenced was Arabidopsis thaliana (a small flowering plant related to cabbage and mustard, used as a model organism in plant science), with rice close behind.

CGIAR established GCP in 2004 “to tap into the rich genetic diversity of crops via a global network of partnerships and breeding programmes,” according to Hei Leung, who was instrumental to GCP’s foundation and a Subprogramme Leader for Comparative Genomics. (During its first phase GCP was organised by Subprogramme; these were later replaced by Research Themes and Research Initiatives.)

Hei acknowledges that banana was ‘somewhat on the fringe’ of GCP’s main focus on improving drought tolerance in crops. However, he says, it was still relevant for GCP to support the emergence of improved genetics for banana.

“The work we did in genetic diversity is about future generations. We wanted a programme that is pro-poor, meaning that the majority of the people in the world are depending on [the crop].

A typical banana and plantain market at Ikire in Osun State, Nigeria.

“Drought tolerance is a good candidate because drought affects a lot of poor areas, but you really cannot just take one trait as pro-poor. We had a highly motivated group of researchers willing to devote their efforts to Musa,” says Hei.

“Nicolas Roux at Bioversity International was a passionate advocate for the partnership,” notes Hei. “The GCP community offered a framework for novel interactions among banana-related actors and players working on other crops, such as rice.”

Nicolas concurs on the potential for a little banana research to have great value: “Even though banana is among the most important basic food crops for 400 million people, and 100 million tonnes are grown annually on over 10 million hectares in 120 countries, it’s still under-researched and underfunded.”

The resultant research team was led by Japan’s National Institute of Agrobiological Sciences, which had vast experience in rice genome sequencing.

“So, living up to its name as a Challenge Programme, GCP decided to take the gamble on banana genomics and help it fly,” says Hei.

To advance genetics, you first need the intelligence

Banana bunches on an experimental plot at IITA.

Three global research agencies were charged with working together to develop a reference set for banana: Bioversity International, CIRAD, and the International Institute of Tropical Agriculture (IITA).

Creating a reference set – a careful, tactical selection representing the genetic diversity of a crop – is an invaluable first step in enabling scientists to work together to develop more ‘intelligent’ genetic data.

“Initially, we put together a community of institutions that have collections [of banana germplasm],” explains Jean Christophe. “And then we put together these initial materials that we sample in order to develop representative subsamples – this is called a ‘composite’ set because it comes from different institutions.

“Then we genotype this composite collection, and the genotyping allows us to understand how all this [genetic material] is structured. Based on how it is structured, we can re sample a smaller representation – this is what becomes a reference set.”

So, in the case of crops with an extensive genetic resource base, such as rice, there may be more than 100,000 different plant samples, or accessions, that are reduced to a few thousand. For banana, which has a smaller genetic resource base, a few hundred thousand accessions can be reduced to a few dozen.

“A couple of hundred accessions or fewer become manageable for plant breeders or crop specialists. And we want this to serve as a reference, shared among people, so that everybody works on the same reference material,” says Jean Christophe.

“If you work on the same reference material, you can compile information that is more intelligent – you can have the crop specialist who says ‘this is resistant; this is tolerant; this is susceptible’, and you can also have the biochemist, you can have the physiologist; in the end, you can compile the information.”

“We analysed about 500 accessions and narrowed it down to 50,” says Jean Christophe. This reference collection is currently stored at the University of Leuven in Belgium.

The refined data collected on the banana reference set enabled the researchers to unravel the origin and genealogy of the most important dessert banana: the Cavendish, the cultivar subgroup that dominates banana exports worldwide. Thanks to the early GCP work, they were able to show that Cavendish bananas evolved from three markedly different subspecies.

65-year-old Cambodian farmer, Khout Sorn, stands in front of his banana trees in Aphiwat Village, Tipo commune, Cambodia.

Malaysian wild subspecies fully sequenced

During these preliminary years of GCP-supported research on banana, the Programme funded several other smaller projects to consolidate genomic resources available for banana. Scientists developed libraries of artificial chromosomes that can be used in sequencing the DNA of banana, as well as genetic maps, which according to Jean Christophe are essential for improving the quality of the sequence.

These projects contributed to the full genome sequencing of a wild banana from Malaysia’s Pahang province in 2008. The ‘Pahang’ subspecies is one of the Cavendish variety’s three ancestors, and has also been shown to have had a role in the origin of many other banana cultivars, including those that are most important for food and economic security.

“GCP did not fund the sequence [of the Pahang banana], but it funded several things that made it possible to undertake full-scale sequencing,” Jean Christophe says. “It supported the development of particular resources and tools, and this made it possible for researchers to start the full-length sequencing.”

A farmer at work on a banana plantation, Mindanao, the Philippines.

Breeders now need to set to work

The more that is known about the genes responsible for disease resistance and other desirable traits in banana, the more researchers will be able to help farmers in developing countries to improve their yields.

“The road remains long, but now we have a good understanding of genetic diversity,” says Jean Christophe. “We have done a range of studies aimed at unravelling the genes that could control sterility in the species.

“This is undoubtedly an inspiring challenge towards unlocking the genetic diversity in this crop.

“If we have more money in the future, we are going to sequence others of the subspecies so that we can have the full coverage of the current Cavendish genome. But that was a good start,” says Jean Christophe.

“What we have to do now is to create the right populations [of banana] in the field so that we can separate out the characteristics we want to breed for.”

The new intelligence on banana genetics has given breeders the material they need that will ultimately help 400 million people in the tropics sustain food supplies and livelihoods.

Chickpea’s promise: to be win-win for Africa and India

Africa, Asia, Capacity building, Chickpeas, Crop breeding, Genetics, Legumes No Responses »

Jun 012015

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

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.

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.

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.

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.

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

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.

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.

“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.

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.”

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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