SATrends Issue 54                                                                                                                 May 2005

1. Hagaz is the first
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Pearl millet ( Pennisetum glaucum ) is grown in Eritrea on a total area of over 80,000 hectares mainly by smallholder farmers in low and mid lands, and is the second most important cereal in the country after sorghum. Farmers grow exclusively traditional landraces, which have many preferred traits and a modest yield potential, but are generally susceptible to downy mildew.

Pearl millet downy mildew disease, caused by the fungus Sclerospora graminicola , is widely distributed in Eritrea. In the years 1999 and 2000, 30-50% of the plants in most pearl millet areas surveyed in Zobas Anseba and Gash Barka were infected with downy mildew. This disease caused yield reductions estimated at 30% in Anseba alone in 2000.

Cumulative grain yield performance of Hagaz and local cultivars

The Eritrean pearl millet variety “Hagaz” , released in 2004, is the first product of a type of partnership that ICRISAT sees as a model for its future work in Africa. The partnership involves the Eritrean National Agricultural Research Institute, a donor agency with a commitment to the improvement of Eritrean agriculture, and ICRISAT. It began in 1998 when Mr Negusse Abraha, now Eritrea's millet breeder, did his dissertation research at ICRISAT for his Masters degree in plant breeding. When Mr Negusse returned to Eritrea, ICRISAT helped him to develop a breeding program designed to improve Eritrean landraces and to breed new varieties from crosses between selected local landraces (which provided local adaptation and farmer-valued traits) and ICRISAT varieties/populations (which provided disease resistance and a higher yield potential). Initially Danida, and since 2002 the Syngenta Foundation, have provided generous funding for the Eritrean Millet Program, including funds for technical support from ICRISAT.

Hagaz, bred from a cross between the Eritrean landrace variety Tokroray and the ICRISAT variety ICMV 221, was identified from the first set of population crosses for its superior grain yield and downy mildew resistance (1% infection vs. 38% for Tokroray). In on-farm trials conducted in 2001 and 2002, the cumulative mean grain yield across all environments in 41 test sites showed that it was clearly superior to the local landrace (see graph). The development of the variety Hagaz (named after the location where the crosses were first made) has proceeded in parallel with the Eritrean millet program itself. It is a genuine tribute to a small, but very effective partnership between three different agencies who share a common objective – to provide Eritrean farmers with the tools to improve their own livelihoods.

For more information contact b.raj@cgiar.org

2. Biotechnology against bollworm
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Cotton bollworm or legume pod borer, Helicoverpa armigera (Hubner), is a major pest of several crops, forest trees, and a range of vegetables and fruit. Pest management strategies require integration of different control tactics based on the relationship between population density and economic loss. H ost plant resistance would be an effective management option, and biotechnology can play a major role in this area. The approaches that can be exploited are:

Transgenic plants with toxin genes: Transgenic crops can control pests that have become resistant to common insecticides. Genes from bacteria such as Bacillus thuringiensis (Bt) have been used to develop crop cultivars that resist insect pests. Protease inhibitors, plant lectins, ribosome inactivating proteins, secondary plant metabolites, vegetative insecticidal proteins from Bt and related species, and small RNA viruses can also be used alone or in combination with Bt genes and conventional host plant resistance.  

Marker-assisted selection. It takes five to six generations to transfer a trait within a species through conventional breeding. Recombinant DNA technologies allow the identification of specific chromosomal regions carrying genes contributing to traits of economic interest. DNA marker technology, molecular markers and quantitative trait loci (QTL) associated with insect resistance, can accelerate the process of transferring insect resistance genes into improved cultivars.  

Alteration of metabolic pathways. Secondary plant metabolites such as flavonoids, terpenoids, and alkaloids have been implicated in host plant resistance to insects. Compounds of the flavonoid biosynthetic pathway accumulate in response to biotic and abiotic stresses. Genetic engineering can be used to change these pathways to increase the amounts of flavonoids, which could play an important role in host-plant resistance.  

Wide hybridization . Wild relatives of crops can be useful sources of genes for marker-assisted selection. Introgression of genes from wild relatives of crops is another strategy to develop crop cultivars with mechanisms of resistance.

Gene switches. Inducible genes have been identified in plants based on endogenous chemical signals such as phytohormones, response to insect attack, or wounding. Chemically induced expression systems or “gene switches” enable the temporal, spatial, and quantitative control of genes introduced into crop plants, or those that are already present in the plants.

Dominant repressible lethal genetic system . Traditionally, the sterile insect technique can control insects. However, this depends on large-scale production of the target insect, and use of irradiation or chemical sterilization. Release of insects carrying a dominant lethal (RIDL) gene has been proposed as an alternative to the conventional techniques. Such insects, produced through genetic transformation, when released in the eco-system to mate with the wild population, will produce self-perpetuating sterile insects.

To sum up, ideal biotechnologies should be commercially viable, environmentally benign, and easy to use in diverse agro-ecosystems, where the risks would be lower than current or alternative technologies, and the benefits would be greater.

      Cotton bollworm damage in transgenic
(right) and non-transgenic (left) plots
of cotton
.

For more information contact h.Sharma@cgiar.org

3. Volition in the Volta Basin
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Project 5 of the CGIAR Challenge Program on Water and Food (CPWF) is making great progress. The goal is to reduce poverty and improve food security, income and livelihoods of small-scale resource poor farmers in the Volta Basin. The overall research hypothesis is that using a systems approach that integrates water use efficiency, nutrient, soil and crop management, and improved germplasm together with market opportunity identification rural agro-enterprise development, and the empowerment of rural communities will result in significant benefits to the rural poor and the environment, which can be scaled out to wider geographic areas.

The benchmark sites of this project are located in Burkina Faso and Ghana. Participating institutions include the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) (lead Institution); TSBF-CIAT, Kenya; the International Center for Tropical Agriculture (CIAT), Colombia; Savanna Agricultural Research Institute (SARI), Ghana; Centre National de la Recherché Scientifique et Technologique (CNRST), Burkina Faso; the United Nations University-Institute for Natural Resources in Africa (UNU-INRA),Ghana; the Semi-Arid Food Grain Research and Development (SAFGRAD), Burkina Faso; and Zentrum für Entwicklungsforschung (the Center for Development Research) (ZEF), Germany.

ICRISAT and SARI Project teams at a field trial on Integrated Production Systems in Navrongo, Ghana, October 2004 .

 The major project activities included:

  • Biophysical and socio-economic characterization of benchmark sites in Burkina Faso and Ghana
  • Selection of experimental sites and participating farmers
  • Development of experimental protocols in consultation with partners
  • Collection and compilation of relevant weather data for modelling purposes
  • Determination of nutrient status of soils under various land use and management systems
  • Establishment of field trials on integrated agricultural production systems (integrated soil-water-plant-nutrient management); on fertilizer micro-dosing (strategic application of fertilizers); combination of rainwater and nutrient management and soil degradation
  • Purchase of a QuickBird 8 x 8 km satellite image to characterize initial conditions for the Navrongo site in Ghana
  • Training course on land degradation organized by UNU-INRA in Accra Ghana Training course on DSSAT (Decision Support System for Agro-technology Transfer) in August 2004, in Arusha, Tanzania. A web page for this workshop is being developed by our collaborator from the University of Georgia at http://www.engr.uga.edu/~gerrit/workshop/WorkshopTanzania2004.html  

Visits were made to project sites in Burkina Faso and Ghana by ICRISAT, TSBF-CIAT and other project partners to provide technical backstopping and for monitoring and evaluation purposes. Japan International Research Center for Agricultural Sciences (JIRCAS) scientists also visited benchmark sites in these countries and interacted with partners, developed mechanisms for strengthening collaboration and for future joint project development. The project has participated in conferences and training courses, and has made considerable progress since its launch in March 2004.

For more information contact r.tabo@cgiar.org

4. Soil fertility research: How and why
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What methods have been used (currently and in the past) for developing and disseminating new technologies to improve soil fertility? How have these different methods evolved? Which method is best and why? What lessons can we learn? This is the subject of a new study coordinated by ICRISAT, funded by the Rockefeller Foundation. It focuses on four countries – Malawi, Mozambique, Zambia and Zimbabwe. Partners include Malawi's Bunda College of Agriculture, the Mozambican extension service, the University of Zimbabwe, and the Zambian Agricultural Research Institute.

Broadly, research and extension methods form a continuum from ‘top-down' to ‘bottom-up' approaches. The linear model (strictly top-down) was common from the early 1900s until recently. Researchers conducted on-station experiments; technology recommendations were passed on to extension departments, and thence to farmers. This worked well for large-scale commercial agriculture, but not for smallholder farmers, because the technologies did not address their particular needs and circumstances.

The next stage to evolve, in the late 1970s, was on-farm or farming systems research. Emphasis shifted from the research station to farmers' fields. Experiments were conducted mostly on smallholder farms, aiming to produce more relevant technologies with higher adoption rates. Researchers still controlled the R&D process, but farmers were also involved, especially in helping scientists identify what problems to study.

In the 1990s came participatory methods. Farmers and other stakeholders were closely involved at every stage – problem identification, planning and designing experiments, even dissemination.

Which approach is best? It depends. The linear model is the only practical option in situations where research is just beginning, and large knowledge gaps exist. Once the science is sufficiently advanced and ‘first-generation' technologies have been developed, other approaches may work better.

On-farm or farming systems research is ideal in situations where technologies exist and have been adopted by large-scale farmers – where the aim now is to adapt these technologies for smallholder conditions. The process is sufficiently flexible to create solutions tailored to a specific area or a particular class of farmer.

Village trader repacks fertilizer into small, affordable bags.
These small packs are selling well, even in poor smallholder communities.

Farmer-participatory research is the best choice in situations where the sheer range of diversity (in climate, socio-economic conditions, infrastructure etc) makes it hard for scientists, on their own, to service each group of users – or even to identify the key problems in an area. They must work with the farm community, and with others (NGOs, extension, the private sector) who have local expertise. Such partnerships ensure that research produces solutions to meet local needs. And because farmers have a sense of ‘owning' the new technologies, adoption and dissemination to neighbouring communities proceeds rapidly and efficiently.

For more information contact j.rusike@cgiar.org