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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.

 By weight, more maize is produced each year than any other grain: global production is more than 850 million tonnes. Maize production is increasing at twice the annual rate of rice and three times that of wheat. In 2020, demand for maize in developing countries alone is expected to exceed 500 million tonnes and will surpass the demand for both rice and wheat.  This projected rapid increase in demand is mainly because maize is the grain of choice to feed animals being reared for meet – but it is placing strain on the supply of maize for poor human consumers. Demand for maize as feed for poultry and pigs is growing, particularly in East and Southeast Asia, as an ever-increasing number of people in Asia consume meat. In some areas of Asia, maize is already displacing sorghum and rice. Acreage allocated to maize production in South and Southeast Asia has been expanding by 2.2 percent annually since 2001. In its processed form, maize is also used for biofuel (ethanol), and the starch and sugars from maize end up in beer, ice cream, syrup, shoe polish, glue, fireworks, ink, batteries, mustard, cosmetics, aspirin and paint.

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.

Photo: A Wangalachi/CIMMYT

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.

Photo: X Fonseca/CIMMYT

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.

Photo: N Palmer/CIAT

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 AltSB, 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.

Photo: L Kochian

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 AltSB 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.

Marker-assisted selection helps breeders like Sam Gudu more quickly develop plants that have desirable genes. When two plants are sexually crossed, both positive and negative traits are inherited. The ongoing process of selecting plants with more desirable traits and crossing them with other plants to transfer and combine such traits takes many years using conventional breeding techniques, as each generation of plants must be grown to maturity and phenotyped – that is, the observable characteristics of the plants must be measured to determine which plants might contain genes for valuable traits.   By using molecular markers that are known to be linked to useful genes such as ZmMATE1, breeders can easily test plant materials to see whether or not these genes 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. Marker-assisted selection therefore reduces the number of years it takes to breed plant varieties with desired traits.

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.

Photo: N Palmer/CIAT

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.”

Photo: N Palmer/CIAT

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.

Photo: D Mowbray/CIMMYT

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.

Photo: A Erlangga/CIFOR

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.

Photo: E Phipps/CIMMYT

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.”

Photo: CIMMYT

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.

More links

Photo: N Palmer/CIAT

A farmer displays maize harvested on his farm in Laos.

Jun 192015
 
Photo: N Palmer/CIAT

Bean Market in Kampala, Uganda.

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

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

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

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

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

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

Photo: N Palmer/CIAT

Steve Beebe in the field.

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

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

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

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

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

What makes a plant drought tolerant?

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

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

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

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

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

Photo: N Palmer/CIAT

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

Fat beans indicate plants coping with drought stress

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

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

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

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

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

Photo: N Palmer/CIAT

Bean farmer in Rwanda.

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

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

Photo: J D'Amour/HarvestPlus

Beans from Rwanda.

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

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

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

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

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

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

Photo: W Arinaitwe/CIAT/PABRA

Common bacterial blight on bean.

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

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

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

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

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

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

Photo: ILRI

Malawian farmer Jinny Lemson grows beans to feed her livestock.

Ethiopia’s new bean breeders

Photo: ILRI

Young women sorting beans after a harvest in Ethiopia.

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

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

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

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

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

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

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

Photo: N Palmer/CIAT

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

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

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

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

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

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

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

Photo: O Thiong'o/CIAT/PABRA

Bean trials at KALRO in Kenya.

Kenya chasing higher bean yields

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

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

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

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

Photo: CIMMYT

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

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

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

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

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

Photo: O Thiong'o/CIAT/PABRA

Varieties fare differently in KALRO bean trials in Kenya.

Commercialising beans

Photo: CIAT

Maturing bean pods.

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

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

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

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

Success built on a solid foundation

Photo: N Palmer/CIAT

Field workers tend beans in Rwanda.

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

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

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

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

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

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

Developing physical capacity

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

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

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

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

Delivering the right beans to farmers

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

Photo: N Palmer/CIAT

Diversity at bean market in Masaka, Uganda.

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

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

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

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

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May 292015
 

A little over a decade ago, a PhD student in Brazil was poring over sorghum genes, trying to isolate one that helps plants withstand acidic soils.

Photo: B Nichols/USDA

Sorghum

Scientists at the Brazilian Corporation of Agricultural Research (EMBRAPA) had been researching plants that can grow well in acidic soils since the mid-1970s.

“What we have done within the Generation Challenge Programme,” explains Jurandir Magalhães, now a senior scientist for EMBRAPA, as he reflects back on the past decade, “is speed up maize and sorghum breeding for acidic soil adaptation”.

EMBRAPA partnered with the CGIAR Generation Challenge Programme (GCP) to advance plant genetics so as to breed aluminium-tolerant crops that will improve yields in harsh environments, in turn improving the quality of life for farmers.

Almost 70 percent of Brazil’s arable land is made up of acidic soils. That means the soil has toxic levels of aluminium and low levels of phosphorous – a lethal combination that makes crop production unsustainable. Aluminium toxicity in soil comes close to rivalling drought as a food-security threat in critical tropical food-producing regions. This is because acidic soils reduce root growth and deprive plants of the nutrients and water they need to grow.

Robert Schaffert – EMBRAPA’s longest-serving sorghum breeder – had developed mapping populations for aluminium tolerance in sorghum; these populations were the basis for the work supported by GCP.

During the first four years of the 10-year Programme, Jurandir was able to identify and clone the major aluminium-tolerance gene in sorghum – AltSB – using these mapping populations. The cloned gene has since enabled researchers across Africa and Asia to quickly and efficiently breed improved sorghum and maize plants that can withstand acidic soils.

Jurandir, speaking today about the work to advance sorghum genetic resources, says: “Wherever there are acidic soils with aluminium toxicity and low phosphorous availability, our results should be applicable.”

His story with EMBRAPA is one of many where GCP-supported projects have been instrumental in helping global research centres achieve their goals, which ultimately will help farmers worldwide.

Common objectives

Jurandir is now a research scientist in molecular genetics and genomics at the EMBRAPA Maize & Sorghum research centre. He and colleagues at the centre partnered with scientists in Africa, Asia and the US to identify and clone genes in sorghum, maize and rice that confer resistance or tolerance to stresses such as soil acidity, phosphorus efficiency, drought, pests and diseases.

Photo: R Silva/EMBRAPA

Maize growing in Brazil.

“One important focus of GCP was linking basic research to applied crop breeding,” Jurandir says. “This is also the general orientation of our programme at EMBRAPA. We develop projects and research to produce, adapt and diffuse knowledge and technologies in maize and sorghum production by the efficient and rational use of natural resources.

“GCP provided both financial support and a rich scientific community that were useful to help us attain our common objectives.”

EMBRAPA’s work on cloning the AltSB gene would prove to be one of the first steps in GCP’s foundation sorghum and maize projects, both of which sought to provide farmers in the developing world with crops that will not only survive but thrive in the acidic soils where aluminium toxicity reduces crop production.

Leon Kochian of Cornell University in the US was Jurandir’s supervisor at the time when they applied for GCP funding. Leon was a Principal Investigator for various GCP research projects, researching how to improve grain yields of crops grown in acidic soils.

“The breeders are so important,” says Leon about the importance of supporting institutes such as EMBRAPA to advance plant genetics. “Ultimately, they are the cliché of ‘the rubber hits the road’. They’re the ones who translate what we’re trying to figure out into the actual crop improvements. That’s really what it’s all about.”

“That’s why EMBRAPA is a unique institution. Their mission is to get improved seed out, new germplasm out, for the farmers. They have the researchers in sorghum and maize breeding [Robert Schaffert and Sidney Parentoni] and molecular biology [Jurandir Magalhães and Claudia Guimarães].”

Photo: CIFOR

Maize farmers in Brazil.

Great minds think alike

Jurandir’s EMBRAPA colleague Claudia Guimarães, a plant molecular geneticist focusing on maize, says GCP promoted ‘products’, which also echoed the mission statement of EMBRAPA’s Maize & Sorghum research centre.

The centre’s mission is to: ‘Generate, adapt and transfer knowledge and technology that allows for the efficient production and use of maize, sorghum, and natural resources as well as promotes competitiveness in the agriculture sector, sustainable development, and the well-being of society.’

GCP, says Claudia, “wanted to extract something else from the science – products – the idea of a real, touchable product. You have to have progress: germplasm, lines, markers; they are quite practical things.

“The major goal of GCP is to deliver products that can improve people’s lives worldwide. So it needs to be readily available and useful for other scientists and for the whole community.”

GCP wanted to ensure that research products could and would be adopted, adapted and applied for the ultimate benefit of resource-poor farmers. The Programme therefore set out to catalyse interactions between the various players who are needed to bridge the gap between strategic research in advanced labs and resource-poor farmers.

GCP and EMBRAPA were both working towards tangible applied outcomes, says Claudia: “GCP was not only giving you money, they are really serious about what are you doing: ‘Did you deliver everything you promised?’”

Claudia delivered. She and her team at EMBRAPA were able to find an important aluminium-tolerance gene in maize similar to the sorghum gene. This outcome provided the basic materials for molecular-breeding programmes focusing on improving maize production and stability on acidic soils in Africa and other developing regions.

Photo: L Kochian

Maize trials in the field at EMBRAPA. The maize plants on the left are aluminium-tolerant while those on the right are not.

Multifaceted and tangible results

Through further GCP funding, EMBRAPA researchers Robert Schaffert and Sidney Parentoni were able to work together with two researchers from Kenya, Dickson Ligeyo and Samuel Gudu, to develop a breeding programme to combine the improved Brazilian germplasm with locally adapted Kenyan materials. A new base of improved germplasm was established for Kenyan breeders, which allowed the development of varieties adapted to acidic soils in Kenya.

Sidney, a maize breeder for GCP projects and now the deputy head of research and development for EMBRAPA Maize & Sorghum, says that the benefits of being part of GCP are multifaceted: “It was very important, not only for EMBRAPA as an institute, but also individually for each of the participants that had the opportunity to interact with partners in different parts of the word,” says Sidney.

Photo: Bioversity International

A Kenyan farmer with her sorghum crop.

“Each of them adds a piece to build the results achieved by GCP, which from my perspective promoted a number of advances in the areas of genetics and breeding.

“Technologies such as root image scanning developed at Cornell [University] were transferred to EMBRAPA and allowed us to do large-scale screening in a number of maize and sorghum genotypes with large impacts in phosphorous-efficiency studies.

“Scientists from Africa were trained in breeding and screening techniques at EMBRAPA, and Brazilian scientists had the opportunity to go to Africa and interact with African researchers to jointly develop strategies for breeding maize and sorghum for low-phosphorous and acidic soils.

“These trainings and exchanges of experiences were very important for the people and for the institutions involved,” says Sidney.

Sustainable partnerships to break ground for groundnut

Photo: N Palmer/CIAT

Groundnut

Soraya Leal-Bertioli is a researcher in the EMBRAPA Genetic Resources & Biotechnology centre. She works on groundnut (also known as peanut), and formed part of the GCP team working on groundnut with tolerance to drought and resistance to diseases and fungal contamination. She concurs that GCP united researchers from all over the globe in a common goal.

“GCP not only identified groups, but it went out, searched for people and invited contributions, offered resources to get them together. GCP brought partnerships to a whole new level,” Soraya says.

“Last time I checked there were 200 partners in 50 countries. No one is able to do that. It required a lot of money, a lot of resources, but the way it was dealt with in GCP was: ‘Let’s reach out for the main players, the ones who have the technology, and also the ones who can use the technology’.

“GCP used the resources for the benefit of the community and brought everybody together.”

Soraya says the traditional way of funding research often had ‘no structure’.

“Sometimes a university or funding body receives a large amount of money and decides to build something, a new institute in the middle of the jungle somewhere, but they don’t have anybody to run it; it is not sustainable.

“What GCP did was help to provide the structure and the agents for the whole system. They helped train the people to run the whole system. This is a very sustainable model, which is very likely to give good results in a much shorter time frame than other programmes.”

Watch Soraya – and other members of the team – discuss the complex personality of groundnut and groundnut research in our video series:

Genetic stocks AND people are products

The products and outcomes of the collaboration with GCP have included both the tangible and the not-so-tangible. Sidney says that a large quantity of Brazilian improved maize and sorghum lines tolerant to acidic soils has been developed over the years at EMBRAPA.

“These materials were shared with partners in Africa, and this was a major contribution to Kenyan farmers, as part of this collaborative work done in the scope of GCP.

“To be part of the programme has been very important for EMBRAPA’s research team. It has given us the opportunity to interact with a diversity of institutes.”

Sidney mentions institutes they gave worked with through GCP, including Cornell University and Texas A&M University in the US, the Japan International Research Center for Agricultural Sciences (JIRCAS), the International Rice Research Institute (IRRI), the International Maize and Wheat Improvement Center (CIMMYT), and various institutes in Africa, such as Moi University, Kenya, and the Kenya Agricultural and Livestock Research Organisation (KALRO).

Sidney concludes: “In this large network of partnerships, EMBRAPA was able to learn and to share information in a highly productive way.

“From my perspective, the involvement with GCP projects allowed me to grow as a researcher and as a person, and also at the same time to share and to acquire new knowledge in a number of areas. I think it was a ‘win-win’ interaction for all the participants.”

Many of the products generated within the scope of GCP, such as markers and germplasm, are already available within EMBRAPA’s breeding programmes. Avenues for further research have been paved based on the GCP achievements, and these new research lines will be continued within new projects.

As Claudia says: “The strong partnerships built along the way with GCP will be maintained by us joining with new research teams from other institutes and countries to work on new projects.”

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