â€œThe soil nutrient losses in sub-Saharan Africa are an environmental, social, and political time bomb. Unless we wake up soon and reverse these disastrous trends, the future viability of African food systems will indeed be imperiled.” – Dr Norman Borlaug, 14 March 2003, Muscle Shoals, Alabama, USA
IITA was the first major African link in the integrated network of international agricultural research centers. It was also one of the first centers that engaged inÂ farming systems research. In the 1980s and 1990s, the Institute had a very strong program on natural resource management (NRM), covering aspects of soil fertility management, cropping system diversification, and improved agronomy. This, along with the emphasis on the genetic improvement of the major food crops in the humid tropics, provided an integrated program of research on sustainable agricultural development.
Over the past fifteen years, the focus of research-for-development activities at IITA shifted away from NRM, party driven by changes in the investment portfolios of important donors. With the area of soils and natural resources back on top of the development agenda and recognizing that the potential of improved germplasm can only be realized in the presence of appropriate crop and nutrient management practices, IITA has recently decided to increase its investments on NRM research for development with a particular focus on soils.
The March 2012 issue of R4D Review commemorated IITAâ€™s 45 years. It focused on the successes, challenges, and prospects of the genetic improvement programs; these are key to the Instituteâ€™s success in improving food crop production in sub-Saharan Africa. Innovations in genetic improvement have shown how enhanced crop productivity, along with other ingredients, such as capacity building and policies, has helped to lift millions out of poverty.
This second issue for the year highlights our important work undertaken in partnership with national and international institutions in the area of sustainable NRM in sub-Saharan Africa. It also signals IITA’s renewed focus on this area of research. The articles cover the three main pillars of the NRM research-for-development agenda: (1) Integrated Soil Fertility Management, aiming at enhancing crop productivity following agroecological principles, with a livelihood focus, (2) Sustainable Land Management, aiming at rehabilitating soils for the provision of other essential ecosystem services, with a landscape focus, and (3) Climate Change, aiming at enhancing the resilience of farming systems to climate variability.
Bernard Vanlauwe, email@example.com, Alpha Kamara, Stefan Hauser, and Piet Van Asten
Over the past few years, the CGIAR system has been engaged in a substantial, research-led restructuring of its research agenda through the creation of the CGIAR Research Programs (CRP), supported by a Consortium Office, a Fund for international agricultural research, an Independent Science and Partnership Council, and an Independent Evaluation Arrangement. A total of seven CRPs are now active with several having a crop-specific focus, others a farming system focus, and others addressing themes related to natural resource management (NRM) or the creation of an enabling environment for the uptake of improved options. IITA is leading the Humidtropics CRP and contributing significantly to the CRPs on Water, Land, and Ecosystems (WLE) and the Climate Change, Agriculture, and Food Security (CCAFS), all of these having significant NRM components. This article highlights these components in the context of the overall CGIAR research framework and the specific contributions of IITA towards the success of these CRPs.
The humid tropics is home to 2.9 billion of the world’s poorest people. It is the part of the world with the biggest gap between its ecological and economic potential and human welfare. The Humidtropics CRP aims to realize more of that potential to improve the livelihoods of the majority of the population and protect their environment and natural resources from the usual rapid degradation when used for agriculture or forest (timber) exploitation. Humidtropics seeks intensification pathways and critical points of intervention to design superior crop, livestock, fallow, and perennial (tree) production systems along with improved soil, water, and vegetation management practices, and the identification of investment strategies for sustainable natural resource base management.
Interventions will increase overall farm and system productivity and income while improving the natural resource base, particularly soil quality. Humidtropics will strategically select critical entry points that foster more diverse system components to generate more equitable agricultural growth in which rural communities move beyond commodities, reduce their risks, sustainably manage their natural resources, and effectively reduce rural poverty.
Humidtropics is led by IITA in partnership with the International Center for Tropical Agriculture (CIAT), International Livestock Research Institute (ILRI), World Agroforestry Centre (ICRAF), International Potato Center (CIP), Bioversity International, International Water Management Institute (IWMI), International Centre of Insect Physiology and Ecology (icipe), Forum for Agricultural Research in Africa (FARA), The World Vegetable Center (AVRDC), and Wageningen University. It will operate in various action areas in Africa, Latin America, and Asia with the Western Humid Lowland and the East and Central African Highland Action Areas led by IITA. Humidtropics is a systems research program that covers all lowland humid and subhumid ecologies (between dry land and aquatic), draws on research in commodity CRPs, and integrates technologies and forecasting ability from the CRPs on Policies and Markets, Nutrition and Health, Water and Land, and Climate Change (see diagram).
Water, Land, and Ecosystems (WLE)
The global population in 2050 will be about 9 billion, with most of the increase between now and then taking place in developing countries. To feed the world in 2050 and beyond, we need to intensify agricultural production. Many observers believe that intensification will cause unacceptable harm to the environment, perhaps undercutting the ecosystems that support agriculture. WLE challenges this perspective and examines how we can intensify agriculture while protecting the environment and lifting millions of farm families out of poverty.
To achieve the vision of sustainable intensification, we must redouble our efforts to increase agricultural productivity, while protecting the environment, and we must conduct new and integrative research on agricultural and ecosystem interactions. Consequently the objective of WLE is to learn how to intensify farming activities, expand agricultural areas and restore degraded lands, while using natural resources wisely and minimizing harmful impacts on supporting ecosystems.
Within the broad topic of WLE, we have identified five strategic research portfolios (SRPs): Irrigated Systems, Rainfed Systems, Resource Reuse and Recovery, River Basins, and Information Systems. The Rainfed Systems SRP, to which IITA is contributing, targets 80% of the worldâ€™s farmland that is largely rainfed. Although many farmers in rainfed areas capture and store water for use as supplemental irrigation, millions more entirely depend on rainfall. In many areas, increasing populations have placed substantial pressure on rainfed cropland and on the land and water resources used by livestock. As a result, the land and water resources in many areas are degraded and unproductive. WLE researchers will determine ways to restore degraded resources using multifunctional landscape management approaches, and will develop integrated soil and water management techniques.
In pastoral systems, extensive land degradation and the loss of access to water and land resources threaten the livelihoods of millions of pastoralists, leading to conflicts in some areas. WLE researchers will determine the changes in land and water management and the complementary policies needed to support pastoral livelihoods. The Rainfed System SRP currently works around five problem sets: (1) Recapitalizing African soils and reducing land degradation; (2) Revitalizing productivity on responsive soils; (3) Increasing agricultural production while enhancing biodiversity; (4) Enhancing availability and access to water and land for pastoralists; and (5) Reducing risk by providing farmers with supplemental irrigation.
Climate Change, Agriculture, and Food Security (CCAFS)
Climate change is an immediate and unprecedented threat to the livelihoods and food security of hundreds of millions of people who depend on small-scale agriculture. To overcome these threats, the CGIAR and Earth System Science Partnership have united through CCAFS, a strategic ten-year partnership. Farmers, policymakers, donors, and other stakeholders are strongly involved to integrate end-user knowledge and needs. Synergies and tradeoffs between climate change, agriculture, and food security are studied to promote more adaptable and resilient agriculture and food systems. CCAFS is structured around four thematic research areas: (Theme 1) Adaptation to Progressive Climate Change, (Theme 2) Adaptation through Managing Climate Risk, (Theme 3) Pro-poor Climate Change Mitigation, and (Theme 4) Integration for Decision Making. Place-based research is focused on five regions: East Africa, West Africa, South Asia, Latin America, and Southeast Asia.
IITA is one of the 15 CGIAR centers involved and it particularly contributes to research on:
â€¢Â Â Â Theme 1 on crop G Ã— E interactions. The major focus is on the IITA crops cassava, maize, soybean, yam, cowpea, and banana, but with other crops in the system being investigated as well, including horticultural crops and tree crops such as coffee and cocoa.
â€¢Â Â Â Theme 2 on plant health Ã— climate change: IITA has a strong plant health team that is currently exploring the relationship between climate variables and major pest and disease threats, with the same crop focus as listed under G Ã— E.
â€¢Â Â Â Theme 3 on analyzing trade-offs and synergies in climate change adaptation and mitigation in perennial-based crop systems in the humid tropics: The research focuses particularly on coffee and cocoa-based systems (see page 44 in this issue).
â€¢Â Â Â Theme 4 on communicating the results of the trade-off and carbon-footprinting analysis to the stakeholders, in particular policymakers, certification bodies, and the private sector.
The future of NRM
Most CRPs have moved into an implementation phase and all facilitating structures have been put in place, which is probably the most exciting change in the way of doing business within the CGIAR since its inception. From the foregoing summary, the crucial role of IITA as a whole and the NRM research areas more specifically is clear, especially for the African continent. Although IITA may have lost some of its NRM capacity over the past decade, as shown in some of the articles in this publication, much NRM innovation, strategic thinking, and practical solution development is still happening at IITA and will only be strengthened over the coming decade with the renewed investment of IITA in NRM.
IITA is promoting greater access to R4D knowledge by making use of knowledge resource access, video-sharing, and online social networking services.
Last year, in partnership with Google Books, IITA started digitizing and uploading more than 200 publications, which are now available via Google Book Search (GBS). It also uploaded videos in SciVee and YouTube. Now, IITA has accounts with Twitter and Facebook too.
Increasing its online presence is an initiative aimed at “getting the word out” to a wider audience and driving more traffic to the Instituteâ€™s Web sites. With these free and popular online services, IITA is potentially tapping into a 300 million-plus combined user-base. Even with just a 1% bite, potentially some 3 million people will get to know more about IITA and what we do.
Bananas are an important crop for global trade and nutrition where they are intensively cultivated, but few efforts exist to breed superior bananas. One of the reasons for this is that humans have intensively â€œselectedâ€ against seeded bananas and it is difficult or impossible to pollinate many banana varieties and successfully produce seeds.
Many of the most important banana varieties are triploid, which means that they carry an extra copy of each chromosome compared to the normal diploid. Being a triploid means that it is difficult for normal chromosome pairing and segregation to make fertile eggs or pollen, which results in most triploids being nearly sterile. Sterile bananas are great for people who donâ€™t like to crack their teeth on banana seeds, but mean that bananas have to be multiplied via vegetative propagation, similar to propagation of potatoes, sweet potatoes, cassava, and selected varieties of other fruit trees or ornamental species.
Gardeners are familiar with â€œseed potatoes,â€ small potato tubers that are planted to produce a potato crop. Bananas do not form tubers; new plants derive from â€œsuckersâ€ that emerge from the lower banana stem (corm). These suckers can be uprooted and used to plant new banana plants. Similar to potato tubers, these suckers were a part of the original mother plant, which means that they potentially carry whatever disease pathogens or pests had infested the mother plant. Therefore, banana suckers are one of the main means of transport and spread of certain disease-causing agents, including important fungi, bacteria, and viruses.
Nematodes and pests can also hitchhike on banana suckers to infest the new crop. Not only does such hitchhiking result in early infection/infestation of new banana plants in a farmerâ€™s field, but transporting long distances may help introduce a new disease or pest problem in a new location. This dual hazard of reduced yield potential of already infected planting material that may introduce new pests and diseases emphasizes the need for superior disease-free planting material produced through a â€œseed systemâ€ designed to minimize the risks of spreading pathogens and pests.
The traditional means of obtaining banana planting material (â€œseedâ€) is to acquire suckers from oneâ€™s own banana garden, from a neighbor, or from a more distant source. This method served to spread common varieties around the world and to multiply them in their new locations. This system can be modified to produce more banana suckers or shoots by manipulating banana corms to allow more buds to sprout. One such method that is described here is called macropropagation. A higher tech procedure to rapidly produce many plants in just a few generations of propagation is called tissue culture. In tissue culture, plants are first surface sterilized and then grown in aseptic culture in test tubes using an artificial growth medium based on a gelling agent like agar. The tender tissue-cultured plants can then be planted in the field after rooting and hardening under protected conditions.
Seed systems for producing clean planting material can be operated at various levels of technology and efficiency. In some cases, plant health could be improved by merely raising the awareness of the negative impact of planting â€œsickâ€ suckers. Where infected plants look visibly different from healthy plants, either because of reduced vigor or visual disease symptoms in infected plants, the propagator could practice negative selection against â€œsickâ€ plants or positive selection for â€œhealthyâ€ plants (or both). Such plants could be multiplied faster by applying a rapid propagation method such as macropropagation. However, while low-tech and affordable for farmers, such a system does not eliminate problems that cannot be detected by visual observation. Unfortunately, many diseases and pests fall into this category for at least part of their infection cycle.
For crops such as cereals, seed certification systems were developed to assure varietal purity, and later expanded to include freedom from weed seeds and seed-transmitted pathogens. Since most pathogens are seed-transmissible for vegetatively-propagated crops like potato or banana, disease management is the major focus of most seed potato certification programs and banana multiplication programs. Modern technology has provided diagnostic tests to detect significant pathogens. These tests are similar to those used in modern laboratories to diagnose human diseases, and can be expensive. For this reason, it is more efficient to test a small number of plants and multiply those that were negative for all pathogens tested in the battery of diagnostic tests.
It is possible to use tissue culture to efficiently and rapidly multiply plants that tested â€œcleanâ€ in the pathogen testing. Most potatoes eaten in the Western world are just a few field generations removed from tissue-cultured plants used to produce â€œseed potatoesâ€ in screened glasshouses to start the seed production cycle. Similarly, most dessert bananas in the global export trade are from plants originally propagated in tissue culture from plants that tested clean for known banana diseases. A modified form of tissue culture can also be used to eliminate pathogens from plants that did not test clean, after which they can be propagated to produce â€œseedâ€ planting material. There is great potential to improve the health of banana plantations in the developing world through increased use of this technology.
Tissue culture is the process of growing plants that have been surface sterilized and planted in test tubes or similar containers in sterile medium that contains all the nutrients they need to grow. This is almost always done in indoor laboratory facilities and the medium also contains the sugars needed to grow, since there isnâ€™t enough light for photosynthesis.
Sanitation is extremely important, since a single mold spore is enough to contaminate a test tube. Tissue-cultured plants are generally tested for pathogens before commencing the multiplication cycle so that infected plants are not multiplied. The small banana plantlets produce small suckers that can be detached and planted as new plants, or an experienced technician can cut sections that contain buds that will grow. Extra shoots can sometimes be induced by cutting through the growing points so that multiple plants develop from single buds. This process can be repeated every 5-8 weeks so that a single plant can produce many new plantlets in a relatively short period of time.Bananas are sometimes unstable in tissue culture and mutant versions can develop. For this reason, most multiplication labs try to limit the number of multiplication cycles before renewing their cultures from field plants observed to have all the correct traits for that variety.
When tissue-cultured plants are rooted in soil, hardened, and then planted back in the field, they can be more susceptible to some pests and diseases than the original plant was. To restore natural levels of resistance, these plants can be reinfected with the endophyte microorganisms that normally coexist with bananas, similar to the gut bacteria that are important for human intestinal health (see related article on endophytes).
Macropropagation falls somewhere between tissue culture and traditional systems of distributing suckers. In macropropagation, large suckers from healthy banana plants are removed and the roots and soft stem portion (pseudostem) of the sucker are cut away to expose the buds of the corm (the hard stem portion at the base of the sucker). The bare corms are briefly dipped in boiling water to kill any nematodes (micro-worms) that were not removed when cutting off roots. Small cuts are made through the buds to encourage development of multiple sprouts from each bud. The apical (top) bud is often removed because it can suppress development of lower buds. The corm is then covered with moist wood shavings and incubated in a small plastic-covered chamber for a few weeks to encourage shoot development.
Primary shoots can be rooted and used as planting material, or cut off and the growing point again cut to promote additional shooting. Shoots that develop are broken off with a bit of hard stem and roots attached, placed in small nursery bags in a similar high humidity chamber for a few days to allow root development, and finally moved to a nursery for hardening. Hardened plants can be planted in the field, similar to suckers or hardened plants from tissue culture.
A major drawback of macropropagation is that rustic or low-tech methods of detecting pathogens have not been developed, so this method can propagate infected plants if they were chosen as mother plants. Both macropropagated plants and tissue-cultured plants have less food reserves than suckers and require more care (compost/manure, watering) after planting than suckers. Careful siting of â€œmother gardensâ€ established from tissue-cultured plants in clean areas may be the best way to produce suckers for macropropagation.
Traditional seed systems have produced most of the nearly 6 billion banana and plantain plants in Africa currently spread over nearly 4 million hectares of farm and gardens. Many of these are in excellent condition; others have become infected with one or more banana diseases and need to be replaced. Since new banana diseases have been introduced to Africa in the last century, and many diseases have increased in distribution and prevalence, greater care needs to be practiced to multiply â€œhealthy seedâ€.
Breeding programs are nearly ready to release new varieties with resistance to some of the disease problems.
A combination of new and old seed systems can improve the overall health of new plantings by providing healthy plants of both preferred older varieties and resistant new varieties.
IITA’s research on macropropagation is supported by the Directorate General for Development Cooperation (Belgium) and Agricultural Productivity Enhancement Program (APEP-USAID) Uganda Agricultural Productivity Enhancement Project.