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‘Milking’ cowpeas in Mozambique for protein and profit… plus a pox upon pests!

Africa, Capacity building, Cowpeas, Crop breeding, Genomics, Legumes No Responses »

May 302014

Rogério Chiulele

Today, we travel the Milky Way on a voyage to Mozambique. Our man along the Milky Way is Rogério Marcos Chiulele (pictured), a lecturer at Mozambique’s Universidade Eduardo Mondlane’s Crop Science Department. He is also the lead scientist for cowpea research in Mozambique for the Tropical Legumes I (TLI) project. This gives Rogério a crucial tri-focal down-to-earth and away-from-the-clouds perspective on cowpea pedagogy, research and development. It is through this pragmatic triple-lens prism that Rogerio speaks to us today, once he’s captained us safely back from the stars to Planet Earth, Southeast Africa. After the protein and profit, next stop for him and team is ridding cowpeas of pod-sucking pests, among other things slated for the future. But back from the future to the present and its rooted realities…Problems, yes, but also lots of good scores, plus a deft sleight of hand that are bound to have you starry-eyed, we bet.

…cowpeas rank fourth as the most cultivated crop…”

Q: Tell us about Mozambique and cowpeas: are they important?

The devastating effects of nematodes on cowpea roots.

In Mozambique, cowpeas are an important source of food, for both protein and profit, particularly for the resource-poor households that benefit from cowpea income and nutrition. In terms of cultivation, cowpeas rank fourth as the most cultivated crop after maize, cassava and groundnuts, accounting for about 9 percent of the total cultivated area, and estimated at nearly four million hectares of smallholder farms. The crop is produced for grain and leaves, mostly for household consumption but it is becoming increasingly important as a supplement for household income.

But while its potential for food, protein and income is recognised, the realisation of such potential is still limited by drought due to irregular and insufficient rain; affliction by pests such as aphids, flower thrips and nematodes; diseases such as cowpea aphid mosaic virus and cowpea golden mosaic virus; and cultivation of low-yielding and non-improved varieties.

…we backcross to varieties with traits that farmers prefer…”

Q: And on cowpea research and breeding?
Since 2008, Universidade Eduardo Mondlane [UEM] established a cowpea-breeding programme for addressing some of the limiting constraints affecting cowpea production and productivity. This has been possible through collaboration with different funding institutions such as the Generation Challenge Programme.

2008: Screening of the 300 genotypes.

That same year [2008], a UEM research team that I coordinate qualified for a GCP capacity-building à la carte grant. In this project, we screened 300 Mozambican cowpea lines for drought tolerance. From these, we identified 84 genotypes that were either high-yielding or drought-tolerant. We further evaluated the 84 genotypes for another three seasons in two locations. From the 84, we identified six genotypes that not only had the two sought-after traits, but were also adapted to different environments.

In 2010, the UEM team joined the TLI project. For the six pre-identified genotypes, the UEM breeding programme is using marker-assisted recurrent selection [MARS] and marker-assisted backcrossing [MABC], combining drought tolerance and resistance to major biotic stresses occurring in Mozambique. In MABC, we are conducting a backcross to varieties with traits that farmers prefer, which includes aspects such as large seeds, early maturity and high leaf production.

…we conducted a farmers’ participatory varietal selection to glean farmers’ perceptions and preferences on cowpea varieties and traits…”

Q: What is the main focus in your work, and how and when do farmers come in?
The breeding work conducted by UEM is targeting all Mozambican agroecologies, but with particular focus on southern Mozambique which is drought-prone. In addition to drought, the area is plagued by many pests such as aphids, flower thrips, nematodes and pod-sucking pests. So, in addition to drought tolerance, we are conducting screening and selection for resistance to aphids, flower thrips and nematodes. In the near future, we will start screening for resistance to pod-sucking pests.

2009: field screening of the 84 genotypes in diff locations.

2009: Rogério during field screening of the 84 genotypes in different locations.

In 2009, we conducted a farmers’ participatory varietal selection to glean farmers’ perceptions and preferences on cowpea varieties and traits. From the study, six of the lines passed participatory variety selection with farmers, as they were large-seeded with good leaf production which provides additional food.

we hope to release three varieties in 2015…Our involvement with GCP has not only increased our exposure, but also brought along tangible benefits… I firmly believe black-eyed peas can really make a difference.”

Q: To what would you attribute the successes your team is scoring, and what are your goals for the future, besides screening for pod-sucking pests?
The success of the work that the Eduardo Mondlane team is doing is partly due to the collaboration and partnership with USA’s University of California, Riverside [UCR]. UCR sent us 60 lines from the GCP cowpea reference set* [Editorial note: see explanation at the bottom], which we evaluated for drought tolerance for four seasons in two locations – one with average rainfall and the other drought-prone. As these lines were already drought-tolerant, we tested them for adaptation to the local environment, and for high yield. From the set, we hope to release three varieties in 2015. In addition, for evaluating the different varieties, we also crossed the local varieties with black-eyed peas, which have a huge market appeal: local varieties fetch roughly half a US dollar per kilo, compared to black-eyed peas whose price is in the region of four to five US dollars.

2013: multilocation trials.

Our involvement with GCP has not only increased our exposure, but also brought along tangible benefits. For example, previously, nothing was being done on drought tolerance for cowpeas. But now we receive and exchange material, for example, the black-eyed peas from UCR that we received through GCP, which are set to boost production and markets, thereby improving lives and livelihoods. Amongst the varieties we are proposing to release is one black-eye type. I firmly believe black-eyed peas can really make a difference.

In addition, besides funding a PhD for one of our researchers, Arsenio Ndeve, who is currently at UCR, the Generation Challenge Programme, contributed to improvement on storage and irrigation facilities. We purchased five deep freezers for seed storage and one irrigation pump. Presently, we have adequate storage facilities and we conduct trials even during the off-season, thanks to the irrigation pump provided by GCP.

****

And on that upbeat note even as the challenge ahead is immense, today’s chat with Rogério ends here. To both pod-sucking pests and all manner of plagues on cowpeas, beware, as thy days are numbered: it would seem that Rogério and team firmly say: “A pox on both your houses!”

*A ‘reference set’ is a sub-sample of existing germplasm collections that facilitates and enables access to existing crop diversity for desired traits, such as drought tolerance or resistance to disease or pests

Links

REPORT on Rogério’s groundbreaking cowpea research capacity-building project on pp 130–132 in this PDF. Excerpt: “This project was the first of this nature in the country.”
BLOGPOST: Cowpeas – uncowed and unbowed: believing that what could be can be, in breeding
BLOGPOST: Profile on Jeff Ehlers, previously TLI cowpea research leader, he talks of his past but also his TLI work in this post
Cowpea research | research products | blogposts
Legumes Research initiative | InfoCentre | blogposts
Capacity building

Cowpeas – uncowed and unbowed: believing that what could be can be, in breeding

Africa, Cowpeas, Legumes No Responses »

Apr 042014

Phil Roberts

Like its legume relatives, cowpeas belong to a cluster of crops that are still referred to in some spheres of the crop-breeding world as ‘orphan crops’. This, because they have largely been bypassed by the unprecedented advances that have propelled ‘bigger’ crops into the world of molecular breeding, endowed as they are with the genomic resources necessary. But as we shall hear from Phil Roberts (pictured), of the University of California–Riverside, USA, and also the cowpea research leader for the Tropical Legumes I Project (TLI), despite the prefix in the name, this ‘little kid’ in the ‘breeding block’ called cowpeas is uncowed and unbowed, confidently striding into the world of modern crop breeding, right alongside the ‘big boys’! What more on this new kid on the block of modern molecular breeding? Phil’s at hand to fill us in…

Vigna the VIP that shrinks with the violets
But is no shrinking violet, by any means, as we shall see. Also known as niébé in francophone Africa, and in USA as black-eyed peas (no relation to the musical group, however, hence no capitals!), this drought-tolerant ancient crop (Vigna unguiculata [L] Walp) originated in West Africa. It is highly efficient in fixing nitrogen in the unforgiving and dry sandy soils of the drier tropics. And that is not all. This modest VIP is not addicted to the limelight and is in fact outright lowly and ultra-social: like their fetching African counterpart in the flower family, the African violet, cowpeas will contentedly thrive under the canopy of others, blooming in the shade and growing alongside various cereal and root crops, without going suicidal for lack of limelight and being in the crowd. With such an easy-going personality, added to their adaptability, cowpeas have sprinted ahead to become the most important grain legume in sub-Saharan Africa for both subsistence and cash. But – as always – there are two sides to every story, and sadly, not all about cowpeas is stellar…

Improved varieties are urgently needed to narrow the gap between actual and potential yields… modern breeding techniques… can play a vital role”

A cowpea experimental plot at IITA.

What could be, and what molecular breeding has to do with it
Yields are low, only reaching a mere 10 to 30 percent of their potential, primarily because of insect- and disease-attack, sometimes further compounded by chronic drought in the desiccated drylands cowpeas generally call home. “Improved varieties are urgently needed to narrow the gap between actual and potential yields,” says Phil. The cowpea project he leads in TLI is implemented through GCP’s Legume Research Initiative. Phil adds, “Such varieties are particularly valuable on small farms, where costly agricultural inputs are not an option. Modern breeding techniques, resulting from the genomics revolution, can play a vital role in improving cowpea materials.”

He and his research team are therefore developing genomic resources that country-based breeding programmes can use. Target-country partners are Institut de l’Environnement et de Recherches Agricoles (INERA) in Burkina Faso; Universidade Eduardo Mondlane in Mozambique; and Institut Sénégalais de Recherches Agricoles (ISRA) in Senegal. Other partners are the International Institute of Tropical Agriculture (IITA) headquartered in Nigeria and USA’s Feed the Future Innovation Labs for Collaborative Research on Grain Legumes and for Climate Resilient Cowpeas.

It’s a lot easier and quicker, and certainly less hit-or-miss than traditional methods!… By eliminating some phenotyping steps and identifying plants carrying positive-trait alleles for use in crossing, they will also shorten the time needed to breed better-adapted cowpea varieties preferred by farmers and markets.”

Cowpea seller at Bodija Market, Ibadan, Nigeria.

On target, and multiplying the score
[First, a rapid lesson on plant-genetics jargon so we can continue our story uninterrupted: ‘QTLs’ stands for quantitative trait loci, a technical term in quantitative genetics to describe the locations where genetic variation is associated with variation in a quantitative trait. QTL analysis estimates how many genes control a particular trait. ‘Allele’ means an alternative form of a the same gene. Continuing with the story…]

The curved shape means that these cowpea pods are mature and ready for harvesting.

Culinary curves and curls: the curved shape means that these cowpea pods are mature and ripe for harvesting.

“We first verified 30 cowpea lines as sources of drought tolerance and pest resistance,” Phil recalls. “Using molecular markers, we can identify the genomic regions of the QTLs that are responsible for the desired target phenotype, and stack those QTLs to improve germplasm resistance to drought or pests. It’s a lot easier and quicker, and certainly less hit-or-miss than traditional methods! However, standing alone, QTLs are not the silver bullet in plant breeding. What happens is that QTL information complements visual selection. Moreover, QTL discovery must be based on accurate phenotyping information, which is the starting point, providing pointers on where to look within the cowpea genome. Molecular breeding can improve varieties for several traits in tandem,” suggests Phil. “Hence, farmers can expect a more rapid delivery of cowpea varieties that are not only higher-yielding, but also resistant to several stresses at once.”

And what are Phil and team doing to contribute to making this happen?

“The genomic resources from Phase I – especially genotyping platforms and QTL knowledge – are being used in Phase II of the TLI Project to establish breeding paradigms, using molecular breeding approaches,” Phil reveals. He adds that these approaches include marker-assisted recurrent selection (MARS) and marker assisted back-crossing (MABC). “These paradigms were tested in the cowpea target countries in Africa,” Phil continues. “By eliminating some phenotyping steps and identifying plants carrying positive-trait alleles for use in crossing, they will also shorten the time needed to breed better-adapted cowpea varieties preferred by farmers and markets.”

… best-yielding lines will be released as improved varieties… others will be used…as elite parents…”

Future work
What of the future? Phil fills us in: “The advanced breeding lines developed in TLI Phase II are now entering multi-location performance testing in the target African countries. It is expected that best-yielding lines will be released as improved varieties, while others will be used in the breeding programmes as elite parents for generating new breeding lines for cowpeas.”

Clearly then, the job is not yet done, as the ultimate goal is to deliver better cowpeas to farmers. But while this goal is yet to be attained and – realistically – can only be some more years down the road, it is also equally clear that Phil and his team have already chalked up remarkable achievements in the quest to improve cowpeas. They hope to continue pressing onwards and upwards in the proposed Tropical Legumes III Project, the anticipated successor to TLI and its twin project TLII – Tropical Legumes II.

Links

Cowpea research | research products | blogposts
Legumes Research initiative | InfoCentre | blogposts
BLOGPOST: Profile on Jeff Ehlers, previously TLI cowpea research leader, he talks of his past but also his TLI work in this post
SLIDES: below…

GRM 2013: Improve cowpea productivity for marginal environments in sub-Saharan Africa — P Roberts from CGIAR Generation Challenge Programme

PAG XXII 2014 – Genomic resources applied to marker-assisted breeding in cowpeas – BL Huynh from CGIAR Generation Challenge Programme

California’s ‘Constant Gardener’, cowpea crusader and catapult constructor

Africa, Capacity building, Cowpeas, Genetics, Genomics, Legumes, Researchers 2 Responses »

Mar 202014

Jeff Ehlers

Our guest today is Jeff Ehlers (pictured), Programme Officer at the Bill & Melinda Gates Foundation. Jeff’s an old friend of GCP, most familiar to the GCP community in his immediate past stomping grounds at the University of California, Riverside (UCR), USA, leading our research to improve cowpea production in the tropics, for which sunny California offers a perfect spot for effective phenotyping. Even then, Jeff was not new to CGIAR, as we’ll see from his career crossings. But let’s not get ahead of ourselves in narrating Jeff’s tale. First, what would high-end cowpea research have to do with crusading and catapults? Only Jeff can tell us, so please do read on!

The GCP model was a very important way of doing business for CGIAR and the broader development community, enabling partnerships between international research institutes, country programmes and CGIAR. This is particularly important as the possibilities of genomics-led breeding become even greater…If anything, we need to see more of this collaborative model.”

Growing green, sowing the seed, trading glory for grassroots
Growing up in USA’s Golden State of California, green-fingered Jeff had a passion for cultivating the land rather than laboratory samples, harbouring keen ambitions to become a farmer. This did not change with the years as he transited from childhood to adolescence. The child grew into a youth who was an avid gardener: in his student days, Jeff threw his energy into creating a community garden project ‒ an initiative which promptly caught the eye of his high school counsellor, who suggested Jeff give the Plant Science Department at UCR a go for undergraduate studies.

And thus the seeds of a positively blooming career in crop research were sown. However, remaining true to the mission inspired by his former community-centred stomping grounds, a grassroots focus triumphed over glory-hunting for Jeff, who – no stranger to rolling his sleeves up and getting his fingers into the sod – found himself, when at the University of California, Davis, for his advanced studies, embarking on what was to become a lifelong undertaking, first at the International Institute of Tropical Agriculture (IITA) and then at UCR, dedicated to a then under-invested plant species straggler threatening to fall by the research world’s wayside. With a plethora of potential genomic resources and modern breeding tools yet to be tapped into, Jeff’s cowpea crusade had begun in earnest…

GCP’s TLI was essential in opening that door and putting us on the path to increased capability – both for cowpea research enablement and human capacity”

Straggler no more: stardom beckons, and a place at the table for the ‘orphan’
And waiting in the wings to help Jeff along his chosen path was the Generation Challenge Programme (GCP), which, in 2007, commissioned Jeff’s team to tackle the cowpea component of the flagship Tropical Legumes I (TLI) project, implemented by GCP under the Legumes Research Initiative. TLI is mainly funded by the Bill & Melinda Gates Foundation. The significance of this project, Jeff explains, was considerable: “The investment came at a very opportune time, and demonstrated great foresight on the part of both GCP and the Foundation.” Prior to this initiative, he further explains, “there had been no investment by anyone else to allow these orphan crops to participate in the feast of technologies and tools suddenly available and that other major crops were aggressively getting into. Before GCP and Gates funding for TLI came along, it was impossible to think about doing any kind of modern breeding in the orphan grain legume crops. GCP’s TLI was essential in opening that door and putting us on the path to increased capability – both for cowpea research enablement and human capacity.”

Flashback: UCR cowpea team in 2009. Left to right: Wellington Muchero, Ndeye Ndack Diop (familiar, right?!), Raymond Fenton, Jeff Ehlers, Philip Roberts and Timothy Close in a greenhouse on the UCR campus, with cowpeas in the background. Ndeye Ndack and Jeff seem to love upstaging each other. She came to UCR as a postdoc working under Jeff, then she moved to GCP, with oversight over the TLI project, thereby becoming Jeff’s boss, then he moved to the Foundation with oversight over TLI. So, what do you think might be our Ndeye Ndack’s next stop once GCP winds up in 2014? One can reasonably speculate….!

Of capacity building, genomics and ‘X-ray’ eyes
This capacity-building cornerstone – which, in the case of the TLI project, is mainly funded by the European Commission – is, says Jeff, a crucial key to unlocking the potential of plant science globally. “The next generation of crop scientists ‒ particularly breeders ‒ need to be educated in the area of genomics and genomics-led breeding.”

While stressing the need for robust conventional breeding efforts, Jeff continues: ”Genomics gives the breeder X-ray eyes into the breeding programme, bringing new insights and precision that were previously unavailable.”

In this regard, Jeff has played a leading role in supporting skill development and organising training for his team members and colleagues across sub-Saharan Africa, meaning that partners from Mozambique, Burkina Faso and Senegal, among others, are now, in Phase II of the TLI project, moving full steam ahead with marker-assisted and backcross legume breeding at national level, thanks to the genotyping platform and genetic fingerprints from Phase I of the project. The genotyping platform, which is now publicly available to anyone looking to undertake marker-assisted breeding for cowpeas, is being widely used by research teams not only in Africa but also in China. Thanks in part then to Jeff and his team, the wheels of the genomics revolution for cowpeas are well and truly in motion.

Undergoing the transition from phenotypic old-school plant breeder to modern breeder with all the skills required was a struggle…it was challenging to teach others the tools when I didn’t know them myself!…without GCP, I would not have been able to grow in this way.”

Talking about a revolution, comrades-in-arms, and a master mastering some more
But as would be expected, the road to revolution has not always been entirely smooth. Reflecting on some of the challenges he encountered in the early TLI days, and highlighting the need to invest not only in new students, but also in upgrading the existing skills of older scientists, Jeff tells of a personal frustration that had him battling it out alongside the best of them: “Undergoing the transition from phenotypic old-school plant breeder to modern breeder with all the skills required was a struggle,” he confides, continuing: “It was challenging to teach others the tools when I didn’t know them myself!”

Thus, in collaboration with his cowpea comrades from the global North and South, Jeff braved the steep learning curve before him, and came out on the other side smiling – an accomplishment he is quick to credit to GCP: “It was a very interesting and fruitful experience, and without GCP, I would not have been able to grow in this way,” he reveals. Holding the collaborative efforts facilitated by the broad GCP network particularly dear, Jeff continues: “The GCP model was a very important way of doing business for CGIAR and the broader development community, enabling partnerships between international research institutes, country programmes and CGIAR. This is particularly important as the possibilities of genomics-led breeding become even greater…If anything, we need to see more of this collaborative model.”

GCP’s Integrated Breeding Platform addresses the lack of modern breeding skills in the breeding community as a whole, globally…The Platform provides extremely valuable and much-needed resources for many public peers around the world, especially in Africa…”

One initiative which has proved especially useful in giving researchers a leg up in the mastery of modern breeding tools, Jeff asserts, is GCP’s Integrated Breeding Platform (IBP): “IBP addresses the lack of modern breeding skills in the breeding community as a whole, globally. By providing training in the use of genomic tools that are becoming available, from electronic capture of data through to genotyping, phenotyping, and all the way to selective decision-making and analysis of results, IBP will play a critical role in helping folks to leverage on the genomics revolution that’s currently unfolding,” Jeff enthuses, expanding: “The Platform provides extremely valuable and much-needed resources for many public peers around the world, especially in Africa where such one-off tools that are available commercially would be otherwise out of reach.”

Conqueror caparisoned to catapult: life on the fast lane and aiming higher
Well-versed in conquering the seemingly unobtainable, Jeff shares some pearls of wisdom for young budding crop scientists:”Be motivated by the mission, and the ideas and the science, and not by what’s easy, or by what brings you the most immediate gratification,” he advises, going on to explain: “Cowpeas have been through some really tough times. Yet, my partners and I stuck it out, remained dedicated and kept working.” And the proof of Jeff’s persistence is very much in the pudding, with his team at UCR having become widely acclaimed for their success in catapulting cowpeas into the fast lane of crop research.

It was a success that led him to the hallways of the Bill & Melinda Gates Foundation, where, after two decades at UCR, Jeff is currently broadening his legume love affair to also embrace beans, groundnuts, chickpeas, pigeonpeas and soya beans.

February 2014: Jeff donning his new Gates hat (albeit with a literal ICRISAT cap on). Behind him is a field of early maturing pigeonpea experiment at ICRISAT India.

February 2014: Jeff donning his (now-not-so-)new Gates hat and on the road, visiting ICRISAT in India. Behind him is an ICRISAT experimental field of early-maturing pigeonpeas. Here, our conquering crusader is ‘helmeted’ in an ICRISAT cap, even if not horsed and caparisoned for this ‘peacetime’ pigeonpea mission!

On his future professional aspirations, he says: “The funding cut-backs for agriculture which started before 1990 or so gutted a lot of the capacity in the public sector, both in the national programmes in Africa but also beyond. I hope to play a role in rebuilding some of the capacity to ensure that people take full advantage of the technical resources available, and to enable breeding programmes to function at a higher level than they do now.”

Jeff (foreground) inspecting soya bean trials in Kakamega, Kenya, in January 2013. Next to Jeff is Emmanuel Monyo, the coordinator of the Tropical Legumes II (TLII) project – TLI’s twin – whose brief is seed multiplication. TLII is therefore responsible for translating research outputs from TLI into tangible products in the form of improved legume varieties.

Whilst it’s been several years since he donned his wellington boots for the gardening project of his youth, what’s clear in this closing statement is an unremitting and deeply ingrained sense of community spirit – albeit with a global outlook – and a fight for the greater good that remain at the core of Jeff’s professional philosophy today.

No doubt, our cowpea champion and his colleagues have come a long way, with foundations now firmly laid for modern breeding in the crop on a global scale, and – thanks to channels now being established to achieve the same for close relatives of the species – all signs indicate that the best is yet to come!

Links

Cowpea research
Cowpea research products
Legume Research Initiative
Legumes InfoCentre
At the time we published this post, this is where Jeff was
Check out Jeff’s new perch: see more of what he’s been up to – and with whom he’s been hobnobbing – through these thousand-words-worth photos.

Rooting for the key to more phosphorus for rice

Comparative genomics in cereals, Crop breeding, Genetics, Genomics, Rice 3 Responses »

Sep 072012

ALL IN THE ROOTS: A plant’s roots are a marvellously multitalented organ. They act as fingers and mouths helping plants forage and absorb water and nutrients. They act like arms and legs offering a sturdy base of support so a plant doesn’t keel over. They help store food and water, like our stomach and fat cells. And in some plants, can spawn new life – we leave that to your imagination!

That is why it is of little surprise that this multitalented organ was the key to discovering why some rice lines yield better in phosphorus-poor soils, a puzzle whose answer has eluded farmers and researchers… until now. And even better, the findings hold promise for sorghum, maize and wheat too. Please read on!

In search of the key – The Gene Trackers
In 1999, Dr Matthias Wissuwa, now with the Japan International Research Centre for Agricultural Sciences (JIRCAS), deduced that Kasalath, a northern Indian rice variety, contained one or more genes that allowed it to grow successfully in low-phosphorus conditions.

For years, Matthias made it his mission to find these genes, only to find it was as easy as finding a needle in a genetic haystack. He teamed up with the International Rice Research Institute (IRRI), and with GCP’s support, the gene trackers were able to narrow the search down to five genes of interest.

“We had started with 68 genes and within three years, we had narrowed in on these five candidate genes. And then, one-by-one, we checked whether they were related to phosphorous uptake,” recollects Dr Sigrid Heuer, senior scientist at IRRI and leader of the team that published the discovery in Nature in August 2012.

Sigrid Heuer at a rice phosphorus uptake demonstration field in The Philippines.

“In the end we found that if a certain protein kinase gene was turned on in tolerant plants like Kasalath, then those plants would perform better in phosphorus-deficient soils.”

They named this protein kinase gene PSTOL1, which stands for Phosphorus Starvation Tolerance. “When we put this gene into intolerant rice varieties that did not have this gene, they performed better in phosphorus-deficient soils.”

The importance of phosphorus
Rice, like all plants, needs phosphorus to survive and thrive. It’s a key element in plant metabolism, root growth, maturity and yield. Plants deficient in phosphorus are often stunted.

Sigrid explains that whereas phosphorus is abundant in most soils, it is however not always easily accessible by plants. “Many soil types bond tightly to phosphorus, surrendering only a tiny amount to plant roots. This is why more than half of the world’s rice lands are phosphorus-deficient.”

Farmers can get around this by applying phosphate fertilisers. However this is a very expensive exercise and is not an option for the majority of the world’s rice growers, especially the poorer ones –the price of rock phosphate has more than doubled since 2007. The practice is also not sustainable since it is a finite resource.

By selecting for rice varieties with PSTOL1, growers will be less reliant on phosphate fertilisers.

How it works: unravelling PSTOL1 mechanics
In phosphorus-poor soils, PSTOL1 switches on during the early stage of root development. The gene tells the plant to grow larger longer roots, which are able to forage through more soil to absorb and store more nutrients.

“By having a larger root surface area, plants can explore a greater area in the soil and find more phosphorus than usual,” says Sigrid. “It’s like having a larger sponge to absorb more water.”

A rice variety — IR-74 — with Pup1 (left) and without Pup1 (right).

Although the researchers focussed on this one key nutrient, they found the extra root growth helped with other vital elements like nitrogen and potassium.

Another by-chance discovery was that phosphorus uptake 1 (Pup1), the collection of genes (locus) where PSTOL1 is found, is present within a large group of rice varieties.

“We found that in upland rice varieties – those bred for drought-prone environments – most have Pup1,” says Sigrid. “So the breeders in these regions have, without knowing it, been selecting for phosphorus tolerance.”

“When thinking about it, it makes sense as phosphorus is very immobile in dry soils, therefore these plants would have had to adapt to grow longer roots to reach water deeper in the soil and this, at the same time, helps to access more reservoirs of phosphorous .”

Breeding for phosphorus tolerance, and going beyond rice
Using conventional breeding methods, Sigrid says that her team introduced PSTOL1 into two irrigated rice varieties and three Indonesian upland varieties, and found that this increased yields by up to 20 percent.

“In our pot experiments,” she added, “when we use soil that is really low in phosphorus, we see yield increases of 60 percent and more. This will mean growers of upland rice varieties will probably benefit the most from these new lines, which is pleasing given they are among the poorest rice growers in the world.”

Read how Indonesian researchers are developing their own breeds of upland rice with the PSTOL1 gene

Sigrid also sheds light on broadening the research to other crop varieties: “The project team is currently looking at Pup1 in sorghum and maize and we are just about to start on wheat.”

Building capacity and ensuring impact
Like all GCP projects, this one invests as much time in building capacity for country breeding programmes as on research.

Sigrid and her team are currently conducting the first Pup1 workshop to train researchers from Bangladesh, India, Indonesia, Nepal, Philippines, Thailand and Vietnam. They will share molecular markers that indicate the presence of PSTOL1, techniques to select for the gene, as well as for new phosphorus-efficient varieties.

Breeding for phosphorus-efficient rice in the Philippines.

“The aim of these workshops is to take these important tools to where they are most needed and allow them to evolve according to the needs and requirements of each country,” says Dr Rajeev Varshney, GCP’s Comparative and Applied Genomics Leader. “Breeders will be able to breed new rice varieties faster and more easily, and with 100 percent certainty that their rice plants will have the gene. Within three to five years, each country will be able to breed varieties identical to those that growers know and trust except that they will now have the Pup1 gene and an improved ability to unlock and take up soil phosphorus.”

Joining hands in collaboration
This IRRI-led project was conducted in collaboration with JIRCAS and the Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development (ICABIOGRAD) working with the Indonesian Centre for Rice Research. Other partners included: Italy’s University of Milano, Germany’s Max Planck Institute in Golm, the University of The Philippines at Los Baños, USA’s Cornell University and University of California (Davis and Riverside), Brazil’s EMBRAPA, Africa Rice Center, Iran’s Agricultural Biotechnology Research Institute, Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and University of Dhaka in Bangladesh.

Links