Summary

After two decades of declining international interest in the agricultural production of developing nations, it is exciting and hopeful that greater attention is now being paid to the potential of the agricultural sector to foster economic growth and reduce poverty. In sub-Saharan Africa (SSA) and South Asia (SA), international donors and national governments are investing in the agriculture economy and improving the structure of agricultural markets, the availability of financing for farmers, and the supply of inputs, such as seeds and fertilizer. To complement those investments, these organizations are seeking ways to improve crop and animal production, whose yields are far below world averages and too low to support the expanding population in the regions. Whereas much of the developed world takes its food supply for granted, a systematic effort over several decades will be needed to boost agricultural yields in SSA and SA to levels that will eliminate chronic food shortages and support steady economic growth.

How will increases in agricultural productivity in SSA and SA be achieved? Although technology is not the only determining factor in a farmer’s success, having access to improved inputs, methods, and knowledge can make a substantial contribution to better agricultural production. Over the millennia, farmers have used trial and error to find effective methods of converting natural resources (solar energy, atmospheric carbon, water, and nutrients) into biomass. In the last 300 years, agricultural scientists and engineers have improved on those methods and developed technologies to mitigate the effects of stresses, such as diseases, excessive heat, and poor availability of nutrients. The innovations have included better varieties of crops and animal breeds, synthetic nutrients, pest-management tools, and



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Summary After two decades of declining international interest in the agricultural production of developing nations, it is exciting and hopeful that greater attention is now being paid to the potential of the agricultural sector to foster economic growth and reduce poverty. In sub-Saharan Africa (SSA) and South Asia (SA), international donors and national governments are investing in the agriculture economy and improving the structure of agri- cultural markets, the availability of financing for farmers, and the supply of inputs, such as seeds and fertilizer. To complement those investments, these organizations are seeking ways to improve crop and animal produc- tion, whose yields are far below world averages and too low to support the expanding population in the regions. Whereas much of the developed world takes its food supply for granted, a systematic effort over several decades will be needed to boost agricultural yields in SSA and SA to levels that will eliminate chronic food shortages and support steady economic growth. How will increases in agricultural productivity in SSA and SA be achieved? Although technology is not the only determining factor in a farm- er’s success, having access to improved inputs, methods, and knowledge can make a substantial contribution to better agricultural production. Over the millennia, farmers have used trial and error to find effective methods of converting natural resources (solar energy, atmospheric carbon, water, and nutrients) into biomass. In the last 300 years, agricultural scientists and engineers have improved on those methods and developed technologies to mitigate the effects of stresses, such as diseases, excessive heat, and poor availability of nutrients. The innovations have included better varieties of crops and animal breeds, synthetic nutrients, pest-management tools, and 

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emerging technologies benefit farmers  to irrigation equipment. Recent advances in science, including advances in disciplines not ordinarily associated with agriculture, are expanding the breadth and power of innovations to improve agriculture. Although the principles that underpin methods of food production are as valid in SSA and SA as they are in other parts of the world, innovations developed for farming in temperate regions may not always be suitable for farmers in tropical regions, who grow a variety of different crops under different conditions. Those farmers need innovations that can help them to increase productivity and efficiency in the face of some of the world’s most challenging environmental stresses and competing demands for natural resources—conditions that push science and technology to their limits. A STUDY OF EMERGING TECHNOLOGIES At the request of the Bill & Melinda Gates Foundation, the National Research Council’s Board on Agriculture and Natural Resources (BANR) organized a study to examine the innovations in science and technology that are most likely to help farmers in SSA and SA. The goal of the study was to find innovations with the potential to transform food production in the two regions. Eleven experts in the agricultural sciences, including some specifically familiar with the agricultural constraints facing farmers in SSA and SA, were appointed to the study committee and tasked with identifying priori- ties for technologies that, if developed, might substantially boost agricul- tural production and favorably affect the lives of poor farmers in SSA and SA. The study focused on “emerging technologies,” which included existing applications that have not been widely used or adapted in SSA and SA, and innovations in the conceptual or nascent developmental stage that hold promise for improving agriculture. Appendix A of the report contains the formal statement of task for the study. With input from scientists in SSA and SA, the study first explored critical needs for improving agriculture in the regions. Next, a “visioning” exercise and a multidisciplinary brainstorming session were held with scien- tists, engineers, economists, and other innovators to predict constraints that farmers in the regions would face in the future and to suggest conceptual solutions to address them. Finally, in a series of meetings with scientific experts, the committee learned about existing agricultural technologies and innovations at the frontiers of biotechnology, energy science, nanotechnol- ogy, engineering, remote sensing, and other disciplines in which novel ad- vances potentially offer new opportunities and applications for agriculture. Scientists and other experts who contributed their insight and expertise to the study are listed in Appendixes C and D. The committee’s report describes about 60 technological tools (listed at the conclusion of this summary) that could help farmers in SSA and SA

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summary  to increase agricultural productivity in a wide variety of ways. A technical strategy for developing any of the innovations into specific applications may be considered separately in a future National Research Council study. However, based on its evaluation of the merits of individual technologies described in the report, the committee recommended 18 technologies as most likely to have a significant impact on agricultural productivity in SSA and SA. CONTEXT FOR SELECTING HIGH-PRIORITY TECHNOLOGIES A set of criteria was used to evaluate technologies in the context of several recurring themes that arose during the course of the study. Those themes, described below, shaped the committee’s perspective on how a technology would have the greatest favorable effect on farmers in SSA and SA and provide important context for the technologies ultimately recommended. Technologies Must Be Implemented in a System-wide Approach Technological innovations in agriculture provide fixes for specific problems in production, but they are not comprehensive solutions by themselves. Agricultural production is a complex system, and agricul- tural technologies are interdependent. For example, although elite, locally adapted germplasm is essential for optimal yield potential, the value of such seed is substantially diminished when it is planted in poor-quality soil that is infested with weeds that harbor insect-borne viruses that infect the crop and limit its yield. Many of those conditions are likely to coexist in SSA and SA. The same is true for livestock production: it is difficult to improve livestock reproduction or increase meat or milk production if the animals are chronically infected with pathogens and are fed low-quality, poorly digestible forages. The development of solutions to the problem of poor agricultural productivity requires a multifaceted approach to address deficiencies throughout the farming system. The Development and Success of Innovations Require Local Expertise and Participation It cannot be assumed that agricultural technologies developed and used in industrialized countries will work in SSA and SA. Not all innovations need to be developed locally, but at some point a technology will need to be evaluated with respect to whether it meets local needs and conditions. For example, the development of a vaccine for cattle will need to be tested against regional variants of a pathogen in local breeds of cattle. Crop breeding requires the evaluation of phenotypes under local environmental

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emerging technologies benefit farmers  to conditions. Unique soil conditions need evaluation and remediation plans. Weather prediction algorithms need rainfall data collected at ground level. Those tasks require a trained, local workforce. In addition, the successful implementation of an agricultural technology requires that farmers be con- vinced of its benefits and understand how it works. Agricultural systems in industrialized nations have substantial public and private extension ser- vices, and farmers in SSA and SA need the same support. Although many countries in SSA and SA maintain a large number of agricultural extension agents on government payrolls, they do not have sufficient resources to get into the field or to develop and provide the information they need if they are to support farmers. In addition to local radio, the growing access to the Internet and cellular phones can be used to great advantage in the regions to transform services. The people of SSA and SA can become innovators on behalf of their own farmers; the eradication of rinderpest from cattle in Africa, a pro- cess led by scientists and practitioners from the continent, attests to that. However, generating successful applications of emerging technologies for agriculture in SSA and SA will require long-term human-resource develop- ment at the technical, extension, engineering, and professional levels. As in industrialized countries, building a science base can be achieved through multiple approaches, such as the establishment of the equivalent of the U.S. land-grant institutions that integrate research, teaching, and extension; cre- ating special incentives to engage the world’s top-tier scientists as research leaders; and giving outstanding students in the region both the opportunity to learn abroad and the resources to conduct research on returning home. Lasting solutions to agricultural productivity in the regions will be achieved only with the participation of their citizens. Agricultural Innovations for SSA and SA Do Not Need to Be Based on “Low” Technology Because farmers in SSA and SA are generally resource-poor, there is a need for innovations that are affordable, and these are historically associated with “low” or “appropriate” technologies. But cost and cost- effectiveness are different concepts. For example, although farmer-saved seed will continue to be important for the very poor, it is counterproduc- tive to suggest that it is the only good policy, given the performance of high-quality hybrid seed that has a high germination rate, is pathogen-free, and is clear of weed seed. The challenge to science is to reduce the cost of hybrid seed or to find a way to maintain the performance of seed from one generation to the next. It is generally accepted that advanced technologies will be developed and used in industrialized countries before they are introduced to SSA and

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summary  SA, but this means that technologies addressing specific needs in SSA and SA will never materialize if they do not fill a niche or need in the industrial- ized world. As a result, important opportunities may be missed, such as the development of state-of-the-art biofuels or of off-the-grid energy sources more suited to SSA and SA than to other regions. The use of biocontrol and biopesticides might be much more successful in SSA, where synthetic pesti- cide use is lower than in industrialized countries. Incentives and support for the development of specific applications could deliver benefits faster than waiting for market forces to propel technological development and letting benefits eventually trickle down to developing countries. Climate Change Has Implications for Technological Applications in SSA and SA Farmers in SSA and SA already face severe environmental constraints, but by all predictions, their livelihoods will be imperiled by the conse- quences of global climate change, especially water scarcity. Comprehensive planning to alleviate the economic and ecological impacts of drought will be needed. In Africa, where only 5 percent of agricultural land is irrigated, compared with more than 60 percent in Asia, small-scale farmers suffer from the vagaries of weather that are inevitable in rain-fed agriculture. In Asia, water use is inefficient, water quality is increasingly poor, and the receding of Himalayan glaciers is an ominous sign. For those reasons, technologies that improve the availability and efficiency of water use— whether by irrigation, by the use of drought-tolerant crops, or by other mechanisms—will be needed. There are many unknowns in the future effects of global climate change on temperature, carbon dioxide concentrations, and the annual rain cycle in SSA and SA. In part, that is because existing models and forecasting tools for determining weather conditions in those regions are underdeveloped. If climate change creates more erratic weather conditions, it will be even more important to provide farmers with forecasts of the onset of the rainy season, the prospect of severe weather events, and the likelihood of droughts. In the context of the themes described above, the committee used a set of criteria to examine the relative merits of different technologies (Box S-1). In general, the criteria placed higher value on technologies that could be clearly aimed at a problem specific to agriculture in SSA and SA and that could provide the greatest overall benefit to farmers. That meant giving high priority to technologies that could help the largest number of farmers or could most completely overcome the most severe problems. The next most important factor was the speed at which a field-testable application could be developed, followed by the ability to easily disseminate the technology or to use it in applications of different scales. Other factors considered

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emerging technologies benefit farmers 0 to BOX S-1 Criteria for Evaluating Technologies • s the technology relevant and applicable to agricultural constraints in sub- I Saharan Africa and South Asia? —Does it address a problem that is specific to these regions? —Would it have a direct effect on agricultural productivity in these regions? • What is the magnitude of the expected benefit? —Will many farmers and the rural poor benefit from the technology? —Will it address a widespread or severe problem? —How complete a solution would it provide? —Would it empower the farmer? —Is it likely to have a direct effect on farmer income? • How long would it take for the technology to become available? • Could the technology be easily disseminated and adapted? Is it scalable? • oes the technology address an issue that cannot be approached in any other D way? • s the technology a gateway to other innovations in agriculture? Will it leverage I the development of other technologies to help farmers in sub-Saharan Africa and South Asia? • s the technology already under consideration, or is the problem already being I addressed? important, although given lesser weight, were the uniqueness of the “fix” provided by the application, the likelihood that development of the tech- nology would lead to other breakthroughs, and whether the contemplated technological application was being developed elsewhere and was directed at a problem already receiving attention by many groups. Although the criteria were useful for evaluating technologies, using them to set priorities had limitations, especially because the magnitude of the benefits expected from a particular technology could not be judged independently—the impacts of a single intervention depend heavily on the overall environmental conditions of farm systems. RECOMMENDATIONS Priority Technologies for Development and Exploration The technologies that have the greatest potential impact on agricultural production in SSA and SA are the ones that address four major components

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summary  of agricultural systems: (1) the management of the natural resource base supporting agriculture; (2) the application of genetic diversity to improve the production characteristics of crops and animals; (3) the reduction or elimination of biotic constraints (disease, pests, and weeds) that reduce yields of crops, meat, and milk; and (4) the availability of affordable, renewable energy for farmers. Technologies effective in addressing those components are listed in Table S-1 and grouped in two tiers. The committee recommends that Tier I tools and technologies, which already exist and are connected to fundamental elements of agricultural production, be given the highest priority for development into specific ap- plications. Applications based on those existing technologies will have the greatest impact on production in the shortest time. From the perspective of SSA and SA, the technologies are emerging in that applications specific to the needs of farmers in the regions have not been developed or widely used. Such applications, which will have a high payoff for farmers in the regions, can be built on technological platforms and knowledge that have, in most cases, proved to be effective, but building them will be a unique and challenging endeavor. Tier II technologies include ideas that are emerging from advances in biology, chemistry, materials, remote sensing, and energy science that have TABLE S-1 Priority Technologies and Applications for Improving Agriculture Tier II Focus of Tier I High Priority for Technology High Priority for Development Additional Exploration Natural • Soil management techniques • Soil-related nanomaterials Resources • Integrated water management • Manipulation of the rhizosphere Management • Climate and weather prediction • Remote sensing of plant physiology Improving • Annotated crop genomes • Site-specific gene integration Genetics of Crops • Genome-based animal breeding • Spermatogonial stem cell and Animals transplantation • Microbial genomics of the rumen Overcoming • Plant-mediated gene silencing Biotic Constraints • Biocontrol and biopesticides • Disease-suppressive soils • Animal vaccines Energy • Solar energy technologies Production • Photosynthetic microbe-based biofuels • Energy storage technology

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emerging technologies benefit farmers  to important implications for agriculture. In concept, applications based on these technologies would have a great deal to offer farmers in the two re- gions. These applications are in various stages of development and some are not conceptually new but are being revitalized by scientific advances. Although these advances will be universally important, farmers in SSA and SA may stand to gain the most from novel capabilities and agricultural applications that could meet their specific needs. The committee recom- mends that Tier II technologies be given high priority for further explora- tion to elucidate their potential for implementation in SSA and SA. Some of them will require long-term research to ascertain their potential value and to determine whether it is possible to develop them into cost-effective applications. Descriptions of Priority Technologies Technologies for Natural Resources Management Soil quality was the number 1 issue identified by scientists from SSA and SA as important for increasing agricultural productivity in these re- gions. The prospect of water scarcity was the most commonly raised issue of greatest concern in the future. The committee attaches high priority to the development of soil-management and water-management applications. Because soils and water are closely related and the climatic and socioeco- nomic conditions in which they exist differ regionally, approaches to their management are highly situational and should be area-specific and integrate natural and social factors. Soil management and water management are integrative technologies—they require multiple methods determined for a particular site. Tier I Technologies Soil management techniques. The physical structure of many soils in SSA and SA is less than ideal for agriculture, and poor agricultural practices (overgrazing, deforestation, intensive row cropping, and removal of crop residue) contribute to the problem both by robbing soil of nutrients and by promoting erosion. If the degraded soils of SSA and SA were remediated, the magnitude of benefits to crop production would be substantial. Because climatic and socioeconomic conditions differ regionally, approaches to soil management are highly situational and require individual planning ef- forts. Techniques to improve soil include controlled grazing, mulching with organic matter, applying manure and biosolids, use of cover crops in the rotation cycle, agroforestry, contour farming, hedgerows, terracing, plastic mulch for erosion control, no-till or conservation tillage, retention of crop residue, appropriate use of water and irrigation, and the use of integrated

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summary  nutrient management, including the judicious use of chemical fertilizers. Land-use planning and land-tenure reform are policy tools to accompany those techniques. Integrated water management. The water-related problems of SSA and SA are two sides of a coin. In SSA, farms are primarily rain-fed; there is too little installed irrigation. In SA, water is used inefficiently, and this use degrades the resource. An array of efficient, on-farm irrigation-water capture, storage, pumping, field application and drainage technologies could be used to address both situations. Water management technologies include tube wells, on-site storage tanks, and effective irrigation methods. The efficiency of traditional surface irrigation (flood and furrow) techniques is 30-50 percent. A major improvement is drip irrigation that distributes water on the surface through inexpensive tubing. However, water can be used most efficiently if it is applied only to the active root zone of plants. Subsurface drip irrigation (SDI), which uses buried plastic tubes that con- tain embedded emitters, is an emerging technology that is very effective in delivering water to the root zone. The widespread use of SDI is limited by the cost and maintenance of the system. If those issues can be overcome, the technology will offer some advantages, such as the possibility of using wastewater for irrigation and longer life than surface tube systems because of lower ultraviolet light exposure. Climate and weather prediction. The ability to more accurately predict the onset of the tropical rainy season or drought would be a transformative development for farmers in SSA and SA and enable them to make pivotal timing and management decisions about their growing operations. In spite of intense international interest in the influence of the large land masses of the regions on global climate and weather, the data and algorithms needed to enhance existing climate models for SSA and SA have not been devel- oped. The types of models, databases, and monitoring devices that enable weather prediction based on climate data are taken for granted in many parts of the world, but these tools need to be built for SSA and SA. Specific attention is needed to ensure the generation of information that farmers can easily receive and use. Tier II Technologies Nanotechnology-based applications for soil. Nanotechnology is an emerging field that is enabling the creation of materials with unique charac- teristics. Naturally occurring minerals, such as zeolites, exist as prototypes for the development of nanotechnology-based soil amendments that could have utility for some specific applications. The utility of zeolites is derived from their unique flexible internal structures, which permit ion exchange

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emerging technologies benefit farmers 4 to and reversible dehydration. Because they absorb and slowly release water, zeolites can improve water retention in sandy and low-clay soils and im- prove the porosity of impermeable soils. When pretreated with nutrients, zeolite molecules can be used as agents for the slow release of nitrogen and phosphorus and can confer greater control over the conditions for or timing of fertilizer release. They can also be used to enhance the availability of mi- cronutrients or to absorb metal cations and reduce local concentrations of toxic substances that inhibit plant growth and nitrogen-fixing soil microbes. The potential diversity and multiple uses of these nanotechnology-based substances make them ripe for further research and development. Manipulation of the rhizosphere. The rhizosphere is a diverse and complex ecological environment that encompasses intracellular root tissue, root surfaces, and the surrounding soil that is influenced by the root. Cur- rent research suggests that it is possible to optimize root structure for vari- ous purposes, including increases in carbon sequestration, grain yields, and water and nutrient uptake. In addition, understanding of how root exudates and leachates influence microbial community structure is growing. Those effects create a functionally complex community with a high level of com- petition for colonization by bacteria and fungi that may be beneficial, neu- tral, or pathogenic to plants. In the last 10 years, research has increasingly indicated the feasibility of manipulating soil microorganisms to reduce the need for off-farm inputs and to stimulate plant growth. To develop those strategies as technologies, it is imperative to have a better basic understand- ing of microbial ecology in major crop systems of SSA and SA. Remote sensing of plant physiological status. Optical sensing of plant physiological characteristics is an emerging tool for nutrient management and for determining the state of plant health and growth. Current technol- ogy gives us the ability to predict yield potential midway through the grow- ing season and to suggest future fertilizer requirements according to the amount of nitrogen being removed from the soil by plants. Hyperspectral information (information on the full electromagnetic spectrum) collected remotely could be connected to satellite-based, information-gathering sys- tems that would be used by both farmers and scientists. Farmers could use it for decision-making, and scientists could use it for many purposes, including documenting changes in the landscape and the collection of phe- notypic information from plants that is important for breeding programs. At first glance, that might seem to be an unlikely tool for poor farmers, but the power of remote sensing to obtain indicators of diverse changes on the landscape (from the conditions of crops to the spread of plant and animal diseases) is increasingly sophisticated and has the potential to become a practical and valuable decision-making tool.

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summary  Technologies for Using Genetic Diversity for Crop and Animal Improvement Plant and animal improvement involves bringing together new combi- nations of genes that perform well in specific environments, and genomics is transforming that capability. In order for farmers in SSA and SA to ben- efit from genomics, information about the local genetic diversity of crops (including forages) and animals needs to be established. A key scientific goal is to more rapidly establish the relationship between genetic diversity and phenotype (the expression of the genes that make up a trait in a given environment) to speed up breeding. That knowledge is the key to a future revolution in plant and animal trait improvement. Tier I Technologies Annotated plant genomes. High-quality annotated reference sequences do not exist for the genomes of many of the crops that are important to farmers in SSA and SA, but given the advances in the rate of DNA se- quencing, some of these sequences could be built very quickly by using the existing Arabidopsis, rice, and sorghum genomes and the emerging maize genome sequence. That information will speed crop improvement, par- ticularly if plant breeders in SSA and SA are given the sequencing tools to explore variability in local germplasm. Plant genomes and the various tools to analyze them are essential for the creation of a modern plant improve- ment program for both regions. Genome-based animal breeding. The use of well-established quanti- tative genetic tools for identifying genetically meritorious individuals is thwarted by the absence of systematic information on the genotype and phenotypes of Bubalus bubalis, the Asian water buffalo, or any farm ani- mals (such as goats and hair sheep) raised by subsistence farmers in SSA and SA. However, it may be possible to “reverse engineer” family pedigrees by using a reference genome of the breed of interest and DNA and phenotype samples from several thousand animals in geographic regions that have common environmental stresses. Single nucleotide polymorphisms (SNPs) would be generated from the DNA samples by sequencing regions of the genome that have proved to be informative in related species. The database of tag SNPs generated from the sequencing data would be aligned with the reference sequence to build family pedigrees. With pedigrees in hand, tra- ditional quantitative tools could be applied to identify animals of superior genetic merit.

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emerging technologies benefit farmers  to Tier II Technologies Site-specific gene integration. The ultimate dream of breeders is to be able to replace one allele of a gene with another allele that performs better for the trait that it controls under the conditions desired without carrying along other genes that have no relevance and may even be deleterious. Current transgenic approaches make possible the introduction of specific new genes or better alleles of existing genes, but the site at which they integrate is usually random. Whereas homologous recombination (the pre- cise exchange of one allele for another) has become fairly routine in many animal systems, it has not been possible until recently to achieve in plant systems with any useful frequency. However, emerging new technologies for optimizing site-specific integration in plants are now at hand and should be pursued with vigor with an emphasis on exploring its potential for crops that are important to the poor. Having such a technology available should transform breeding and ease the path to the use of safer and more precisely controlled transgenic approaches to crop improvement. Spermatogonial stem cell transplantation. Spermatogonial stem cell (SSC) transplantation is a way of distributing superior germplasm widely; because resources are inadequate and refrigeration requirements are dif- ficult to meet, this capability does not now exist in developing countries. SSCs (which give rise to sperm cells) could be harvested from genetically superior males and transplanted into sires with less genetic potential. The transplanted SSCs would grow and multiply, and the sires could then be distributed to villages or small farmers. Alternatively, the transplantation procedure could be performed on the farm with the farmer’s males as re- cipients. The recipients would serve as the distribution mechanism for the sperm, mating with many females and siring genetically superior offspring. That is a practical and portable alternative to the current approach of arti- ficially inseminating many females to spread superior germplasm. Microbial genomics of the rumen. A major constraint for livestock of SSA and SA is their poor nutrition; they feed mainly on grasses that are dif- ficult to digest because of high lignocellulose content. If the animals could get more nutrition from grasses, their meat and milk production would im- prove. Digestion of grasses depends on the microbial ecology of the bovine rumen, which is a subject of great interest to animal nutritionists and those interested in ways to break down lignocellulose for biofuels. The function of microbial communities in the rumen and the complex enzymology of fiber digestion are slowly being understood, but the information is insuffi- cient to improve animal nutrition. Because of the global interest in cellulose conversion to glucose as a feedstock for biofuels, this is an opportune time to capitalize on the research to study and improve fiber digestion.

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summary  Technologies for Overcoming Biotic Constraints Diseases and insect pests rob the world of more than 40 percent of the attainable yield of the eight most important food crops, and inva- sive species threaten both crops and native biodiversity. The lives of small farmers in SSA and SA would be transformed if technologies were focused on mitigating the most damaging biotic constraints on their crops. They include Striga (witchweed) in grain and legume crops in SSA; Echinochloa and feral/weedy rice, intractable weeds in rice; Phalaris minor, the major weed of wheat in SA; viruses such as Cassava Brown Streak, Cucumber Mosaic Virus, African Cassava Mosaic Virus, and Cotton Leaf Curl; insect pests such as weevils and stem, fruit, and grain borers; and insects that serve as vectors for disease transmission, such as the whitefly, leaf hopper, and aphid. Tier I Technologies Plant-mediated gene silencing. One of the most exciting developments in plant biology in recent years was the discovery of various types of small RNA molecules that play key roles in plant development and resistance to stresses. The discovery enables researchers to design and overexpress genes encoding RNAs that can target and silence critical genes that are unique to pests or pathogens; pests and pathogens receive gene-silencing RNAs by interacting with the host plant. Research strongly suggests that plant-medi- ated delivery of RNAs can be used to control viruses, nematodes, and some insects, and it may also find applications for use against parasitic plants and fungi. If this natural molecular tool can be harnessed, it has the potential to tackle some of the most recalcitrant pests and diseases facing agriculture in SSA and SA. Biocontrol and biopesticides. Biocontrol involves the release of an insect pest’s specific natural enemies to control its population. With for- eign insect species invading Africa at an increasing rate and threatening agriculture and conservation, biological control has become increasingly relevant because a pest’s enemies can keep its population in check. Africa has seen some of the most successful examples of classical biological con- trol because the insects introduced to control an invading species have not been exposed to pesticides, given the low application rates commonly used by subsistence farmers. Biopesticides that make use of the toxins that some organisms (such as fungi) produce as a substitute for chemical insecticides or herbicides also show promise. Both approaches require systematic plan- ning to be successful.

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emerging technologies benefit farmers  to Disease-suppressive soils. Soils in which crop-associated microbial communities are actively managed have been shown to reduce the inci- dence of plant disease and pests, but our use of this knowledge as a tool is only now emerging. One approach to developing disease-suppressive soil is to manipulate carbon inputs (such as mulches and cover crops). A second approach involves crop sequencing to increase the presence of beneficial or- ganisms; for example, repeated planting of wheat in the same field enhances growth of the rhizobacterium Pseudomonas fluorescens, which produces an antibiotic that inhibits a soil-based fungal pathogen of wheat. A third approach is to inoculate the soil with or enhance disease-suppressive micro- organisms. Molecular tools now allow us to identify suppressive microbes in situ and recover them in a directed fashion; they can then be developed into inoculants for commercial use in SSA and SA. Animal vaccines. Estimates of losses due to disease in SSA and SA are not well quantified, although one estimate of the annual economic loss due to animal diseases in SSA is around US$40 billion, or 25 percent of the total value of livestock production. There are constraints on the use of existing vaccines, but the control of brucellosis, leptospirosis, bovine virus diarrhea, and other respiratory and intestinal diseases in young, preweaning animals could reduce mortality and improve long-term productivity. The potential exists to support a variety of approaches to vaccine development for ani- mals (from attenuated bacteria to DNA vaccines). Vector-borne parasitic diseases present the greatest challenge to vaccine developers because the discovery of antigens that will result in a protective immune response in the host is elusive. Such a discovery will be assisted by the mapping in the last 2 years of the complete genome sequences of all six major vector-borne pathogens: Anaplasma marginale, Babesia bovis, Ehrlichia ruminantium, Theileria parva, Theileria annulata, and Trypanosoma bruci. Technologies for Opportunities for Energy Production The largest concentrations of the world’s energy-poor live in SSA and SA. In most of the poorer countries, less than 25 percent of rural house- holds have access to electricity, and only 5 percent of the rural population is connected to the electric power grid. Agriculture in these regions is therefore energy-limited, and releasing this constraint would change life dramatically. However, it is critical that cost-effective, clean, renewable en- ergy sources replace the fuels now used. This is an opportune time to take advantage of global interest in the development of distributed renewable energy production. Moreover, the climates of parts of the two regions make them good locations for systems such as solar power and microbe-based oil production. The technologies in question are listed as Tier II.

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summary  Tier II Technologies Solar energy. Over the next decade, “third-generation” nanomaterials and multijunction solar photovoltaic (PV) cells are expected to realize their potential for cost reduction and improved performance. PV cells are already sold in SSA and SA; expanding existing markets and capturing innovations for rural applications would allow these regions to be at the forefront of technology adoption. Concentrating solar power uses mirrors to convert the sun’s energy into high-temperature heat and thus has particular relevance to arid and semiarid regions. The energy can be used to generate electricity by making steam or in conjunction with a Stirling engine. Large projects of this sort are being contemplated in industrialized countries, where climate conditions are not as conducive as in SSA and SA. The technologies are potentially scalable and inexpensive to operate and would produce a source of off-the-grid energy for rural communities. Photosynthetic microbes. Algae and cyanobacteria efficiently use the sun’s energy to convert water and carbon dioxide into biomass, which can then be made into biofuels. Several algal species can be induced to accu- mulate substantial quantities of lipid, sometimes to more than 60 percent of their biomass, and they can grow in saline waters that are not suitable for agriculture or drinking. The requirements for growth are simple: solar radiation, carbon dioxide, water, and nutrients (primarily nitrogen and phosphorus). Furthermore, up to 90 percent of the water used in algae pro- duction can be recycled, in contrast with conventional biodiesel production from oilseeds. A byproduct of microbial biomass production can be used as animal feed after the oils are removed. Photosynthetic microbes produce much larger quantities of biodiesel than palm oil, Jatropha, and soybean. Energy storage. Pumping water to the top of a hill is a classic means of storing potential energy for future use and, although it is a simple concept, remains relevant where energy sources such as wind and solar power are intermittent. Another type of energy-storage device is the supercapacitor. Such devices have several advantages over batteries, including very high rates of charge and discharge and low rates of degradation over thousands of cycles. Unlike batteries, they are made of materials with low toxicity. Supercapacitors are expected to replace batteries in the future and could be used to power rechargeable, small-scale mechanical devices used for agricultural production and processing. Locally produced energy, such as solar energy, could be used to recharge village-level capacitor systems. Recent advances in supercapacitors have been realized because of the use of carbon nanotubes, which are currently expensive to produce. Replacing

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emerging technologies benefit farmers 0 to BOX S-2 Technologies Examined in the Study • Annotated sequences of crop and model species for comparative genomics • DNA marker development • Mutation breeding and mutant analysis • Rapid sequencing and annotation of crops of SSA and SA • Information technology and computational biology • Proteomics • Systems biology • Analysis of gene-trait associations • Hyperspectral imaging and digital capture • Bt toxin • Herbicide resistance • Engineering transgenes in metabolic pathways • Plant-based gene silencing • S ite-specific gene insertion systems—zinc fingers, other nucleases, site-specific recombination systems • Meiotic recombination • Artificial chromosomes • Apomixis • Bt alternatives • Transgenic sentinels of plant physiology • Chemical-induced switching • Classical biological control • Biopesticides • Genetically engineered biocontrol—suicide-inducing genes • On-farm integrated water management • Water storage • Wastewater reclamation • Desalination • Cloud seeding batteries in the developing world would be a major step toward providing power for small-scale agriculture. CONCLUSION Together with improvements in the structure of agricultural markets, the use of scientific knowledge and technology to increase agricultural

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summary  • Weather and climate forecasting—data capture and modeling • Soil management practices —Increasing carbon in soil for productivity and carbon sequestration —Improving soil-nutrient budget —Soil-water conservation practices • R emote sensing of plant physiology for nutrient management and soil quality • Zeolites and synthesized nanomaterials • Root improvement through breeding and biotechnology • Transgenic nitrogen fixation in non-legumes • Rhizosphere manipulation —Phytostimulators —Disease-suppressive soil —Biological nitrogen fixation —Microbial enhancement of phosphorus uptake by crops • Microbe-enhanced drought tolerance • Improving grass and legume forage • Rumen metagenomics • Molecular breeding for animal improvement • Engineering animals for disease resistance —Use of transgenes —Use of RNAi to target animal viruses • Spermatogonial stem cell transplantation • Improving neonatal passive immunity • Animal vaccines (bacteria-, plant-, DNA-based) • Rapid diagnosis and surveillance of disease • Hydro, wind, geothermal, wave, and tidal power • Solar photovoltaic • Concentrated solar (solar-thermal) energy • Energy storage (supercapacitors) • Hydrogen and fuel cells • Biofuels (cellulosic, halophytes, oilseeds, photosynthetic microorganisms) production may offer hope to nearly 70 percent of the world’s poor whose livelihood is connected to the land on which they live and toil. If farmers can reliably produce greater quantities of staple crops, they can ensure their own food supply. If they can sell what they do not consume, they can improve their income while meeting the needs of a growing regional popu- lation. If they can produce diverse high-value products, they can capitalize on the demand for a greater variety of food on the part of urban dwellers

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emerging technologies benefit farmers  to whose incomes are rising. Increased agricultural productivity is a major stepping stone on the path out of poverty. The potential of new scientific capabilities to address agricultural con- straints in sub-Saharan Africa and South Asia is substantial, provided that they will be pursued with the specific problems of farmers in these regions in mind. Scientists from all backgrounds have an opportunity to become in- volved in bringing the 60 technologies described in this report (see Box S-2) and other technologies to fruition.