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SATrends Issue 4

March 2001

NEWS FROM THE SEMI-ARID TROPICS:

  1. Agriculture: an Ally Against Global Warming?
  2. Breaking the Spell of Witchweed
  3. Groundnut Taking Root in Central Asia and the Caucasus
  4. Zimbabwean Smallholders Drive the Research Agenda
  5. Highlights of Previous Issues

1. Agriculture: an Ally Against Global Warming?

Global warming is likely to induce devastating cyclones, floods, and droughts worldwide over the coming decades, according to the recent U.N. report on Climate Change. These events will especially hurt the poor of the developing world, who will have little means to cope.

Fossil fuel combustion, generating massive carbon dioxide emissions into the atmosphere, is thought to be a major cause of global warming. Many suggest that polluting industries should pay the cost of cleaning the carbon back out of the atmosphere again.

Plants can help clean the atmosphere by 'sequestering' carbon as plant tissue through photosynthesis. A new agricultural enterprise can be envisioned in which farmers accept payments from urban industries to scrub their pollutants back out of the atmosphere - so-called 'carbon markets' that balance industrial needs against environmental concerns.

But would these gains be real? Much plant carbon re-enters the atmosphere as soon as the plants die and decay. Some of the more persistent root matter may linger for a longer time in the soil, though (see left), depending on complex processes of soil biology and chemistry. The only way to confirm net carbon sequestration is to track soil carbon patterns over long periods of time in particular agro-ecosystems.

Fortunately, long-term core funding provided by farsighted governments and foundations around the world has made it possible for CGIAR Centers like ICRISAT to carry out multi-decade soil studies that shed light on this critical issue. Experiments ongoing since 1976 at the Institute's Patancheru, India campus (near Hyderabad) on Vertisols (heavy black clay soils) recently revealed that improved management practices have indeed sequestered an average of 335 extra kilograms of carbon per hectare per year over the 24-year period, compared to traditional practices.

“Over a 10-year period, it may be possible to sequester about 0.5 gigatons of atmospheric carbon from 1.49 million km2 Vertisols in the SAT," said ICRISAT Soil Scientist Dr. S. P. Wani. “In an eventual carbon market, this might have a value somewhere between US$ 10-15 billion - funds that could be used to address food security and environmental quality.”

The management practices that helped increase carbon sequestration included multiple cropping, fertilizer application, and the addition of legume crops to complement the traditional cereals. These practices also increased farm productivity and farmer income, creating a win-win situation for both the environment, and for the poor farmer.

Excited by these findings, the Government of India is now funding a 3-year project on 'Identifying systems for carbon sequestration and increased productivity in semi-arid tropical environments', engaging ICRISAT and three member institutions of the Indian Council on Agricultural Research - the Central Research Institute for Dryland Agriculture (CRIDA), the Indian Institute of Soil Science (IISS), and the National Bureau of Soil Survey and Land Use Planning (NBSS&LUP). The project will study carbon stocks in soil profiles at 26 selected locations across the semi-arid tropics of India, seeking a better understanding of why some systems sequester more carbon than others.

For more information, contact: s.wani@cgiar.org

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2. Breaking the Spell of Witchweed

Applying cutting-edge biotechnology, researchers from Germany and ICRISAT are learning how to manipulate genes that can enable sorghum plants to escape the seemingly magical trance of ‘witchweed’.

Invisible to the farmer during its most damaging early stages underground, this parasitic plant, also known as Striga hermonthica or simply ‘striga’ (pink flowers at left), attaches itself to sorghum roots and appears to intoxicate them. In damaging the staple cereal crop that feeds many of the poorest people across the dry tropics of Africa, it causes annual losses that may run as high as US $2.9 billion across the continent.

A number of research organizations including ICRISAT have been searching for lines that can resist witcheed’s spell over the past quarter century. The lines IS 9830 (from Sudan) and N13 (from India) are distinctively resistant, but conventional plant breeding efforts had been frustrated by the complexity of the many genes apparently involved, variability induced by the environment, and the high cost of field trials, which required very precise management.

Scientists wondered if the new tools of biotechnology might provide a breakthrough. Supported by ICRISAT and the German Federal Ministry for Economic Cooperation and Development, scientists from ICRISAT, the national programs in Mali (IER), Burkina Faso (INERA), and Kenya (KARI), Hohenheim University, and the University of Tübingen decided to see if they could reduce the layers of mystery and variability by directly mapping the genes on the plant’s DNA.

After 6 years of hard work, their preliminary analysis has found regions of the sorghum genome (Quantitative Trait Loci, or QTL) that do indeed appear to explain a large proportion of the resistance in these two varieties.

The QTL for witchweed resistance were identified by first crossing these resistant lines with E 36-1, a line that lacks the resistance, to observe the contrasting genetic differences. They self-crossed the offspring for several generations to produce Recombinant Inbred Lines (RILs). Since each RIL is genetically different, some should contain more resistance genes than others.

The RILs were subjected to extensive field tests in East and West Africa to evaluate their degree of resistance or susceptibility to witchweed. In parallel, the same lines were evaluated in the lab by extracting their DNA and assaying for molecular markers.

Once these preliminary findings are confirmed, these markers should enable breeders to use lab tests to routinely and accurately identify the lines in their breeding programs that carry the largest number of witchweed resistance genes. This marker-assisted selection could shave years off the breeding process while elevating the level of resistance in new varieties.

For more information, contact: d.e.hess@cgiar.org

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3. Groundnut Taking Root in Central Asia and the Caucasus

Once a part of the legendary Silk Route that connected the Orient to Europe, the Central Asia and Caucasus (CAC) region is now opening up to the world as it moves through a period of political, social, and economic transition.

Despite the massive gas and oil deposits found in this region, most of the inhabitants are poor and many areas are threatened by desertification. The nascent countries of the region are seeking international help to reduce poverty through increased agricultural productivity.

The CGIAR System responded by jointly formulating a 3-year project on ‘Germplasm Conservation, Adaptation, and Enhancement for Diversification and Intensification of Agriculture' with the countries of the region. Five CGIAR institutes - CIMMYT, CIP, ICARDA, ICRISAT, and IPGRI - plan to work in concert with the national agricultural research systems. The Project is seeking financial support from development investors interested in reducing poverty and enhancing peace and stability in the region.

Groundnut has been in decline in the area, along with many agricultural activities. In the first review and planning workshop on groundnut in the CAC region held at Tashkent in November 1999, six CAC countries - Armenia, Azerbaijan, Kyrgyzstan, Tadjikistan, Turkemenistan, and Uzbekistan - participated with ICRISAT and its sister CGIAR Centers and the Program Facilitation Unit (PFU) to review the status of the crop, and to identify opportunities to revitalize it.

“Most of the countries in the region import edible oil, which strains their national economy,” said ICRISAT Groundnut Breeder Dr. S.N.Nigam. “Groundnut can play an important role not only in providing high quality edible oil locally, but also in enriching the soil and breaking cereal pest cycles to increase the overall sustainability of agricultural production.”

“The potential for groundnut expansion in some of the CAC countries is significant and we are now implementing the collaborative work plan that we developed,” Dr. Nigam said.

 

For more information, contact: s.nigam@cgiar.org

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4. Zimbabwean Smallholders Drive the Research Agenda

In the Tsholotsho region of Zimbabwe, a role reversal is underway. Poor smallholder farmers are telling researchers what they want, instead of being lectured about what researchers think they need. The result? Farmers are becoming technology innovators and evangelists, and spreading new farming methods to their neighbors.

One group of farmers decided to improve their water conservation and crop management techniques. In discussion with research scientists, Mr. and Mrs. Simeon Moyo chose the treatments they wanted to test, and focused on the results that interested them most. Mrs. Moyo became especially excited about a method called modified tied ridges - raising the soil around the plants to retain water longer so it could be absorbed into the soil, rather than washing it away. The enthusiastic Moyos are expanding their experimentation, studying the effect of pre-soaking the seed the night before planting so that the seeds get a quicker start when they are sown in the field.

Yet another group of farmers set up their own trials as part of a new Farmer Field School project to try out new soil and water management methods. ICRISAT convenes this project in partnership with the national agricultural extension program (AGRITEX), the University of Zimbabwe, and with nongovernmental organizations, through support from the Rockefeller Foundation.

Improved crop varieties have long been available, but adoption has been slow in Africa. Spreading the new seeds has been difficult because subsistence crops attract little attention from the commercial seed industry. Seeking a solution, a cross-sector consortium began talking with farmers in Kulumusenza village to gain their insights and ideas. The ICRISAT-convened consortium engaged Zimbabwe's national research system, a nongovernmental organization (Commutech), and a private seed company (SeedCo), through special project support generously provided by USAID.

These farmers had never been seed producers before. Once they realized that seed fetches twice the price of grain, some even turned their home gardens into seed production plots! Now, 45 of these farmers, led by Mrs. A. Nkomo, have organized a millet seed producers’ association. The institutional partners are providing technical advice as well as marketing outlets to help the farmers gain the most from their new enterprise.

Tsholotsho farmers now face a problem their neighbors might envy - difficulty in harvesting all the increased grain they've been able to grow! To help them manage this fortunate dilemma, ICRISAT's Director General Dr. William Dar gladly donated a new threshing machine during a recent visit.

For more information, contact: r.myers@cgiar.org

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5.Highlights of Previous Issues:s

February 2001: Somalia: Seeds Deliver Hope Amidst Chaos The CGIAR Fights Desertification in Africa Creating the World's First Molecular Marker Map of Chickpea Aflatoxin and Cancer: Cracking a Hard Nut in Developing Countries

January 2001: Things Grow Better with Coke®: Micro-fertilizer System Sparks 50-100 Percent Millet Yield Increases in the Sahel Groundnut (Peanut) Production Accelerates in Vietnam   Pigeonpea Broadens Farmer's Options in Sudan   Private Sector Invests in Public Plant Breeding Research at ICRISAT.

December 2000: International Symposium on SAT Futures Centers Team Up to Help East Timor Spatial Variability in Watersheds World's First Cytoplasmic Male-Sterile Hybrid Pigeonpea Groundnut (Peanut) Variety Boosts Malawian Agriculture National Researchers Persevere in El Salvador ICRISAT Celebrates India-ICRISAT Day ICRISAT and World Vision International Work Together in Southern Africa.

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