Climate-smart perennial systems

Banana-coffee systems in East Africa. Photo by P. van Asten
Banana-coffee systems in East Africa. Photo by P. van Asten

Laurence Jassogne,, Piet van Asten, Peter Laderach, Alessandro Craparo, Ibrahim Wanyama, Anaclet Nibasumba, and Charles Bielders

Coffee is a major cash crop in the East African highland farming systems. It represents a high proportion of export values at the national level (for example >20% for Uganda). It is also crucial for the sustainability of the livelihoods of smallholder farmers.

During a survey in Uganda, smallholder farmers explained that the income generated by coffee had sent their children to school and helped to build permanent houses. Prices of coffee have also been increasing in the past decennia, motivating them to continue growing the crop.

Although coffee is a promising cash crop, smallholder farmers that grow coffee are still vulnerable. Soil fertility is declining, pest and disease pressure is increasing, populations are rising, and land is continuously fragmented. Above all, climate change is starting to take its toll and puts further pressure on the coffee-based farming systems—directly, because temperature and rainfall have an impact on the physiology of Arabica coffee, and indirectly because the incidence and severity of certain pests and diseases such as the coffee berry borer and coffee leaf rust will increase.

Figure 1. Change of suitability for Arabica-growing areas in Uganda using MAXENT approach and based on a ‘business as usual’ climate change scenario.
Figure 1. Change of suitability for Arabica-growing areas in Uganda using MAXENT approach and based on a ‘business as usual’ climate change scenario.

Current and future suitability of coffee growing areas
In collaboration with Dr Peter Laderach (CIAT), the direct effect of climate change on the suitability of coffee-growing areas in Uganda was mapped (Fig. 1).

If the current coffee crop systems do not change (i.e., same coffee varieties and management practices), these areas will move up the slope and the suitable surface area will decrease. In this light, climate-smart coffee- based systems need to be developed to sustain the existing coffee- based systems.

Adaptation strategies in coffee systems
IITA-led field surveys in the region, combined with a literature review, revealed that there is a multitude of coffee systems that exist. This diversity reflects the variability among farmers in terms of their resource availability, objectives, political history, and opportunities (Fig. 2).

Highest yields can be obtained in systems without shade or with low shade levels (Fig. 2). However, these same systems represent higher production risks and a higher use of external inputs. In polyculture systems and forest systems, on the other hand, highest yield quality can be obtained with the minimum use of external inputs. Furthermore, they allow, among others, a better adaptation to climate change, higher carbon stocks, and more ecological services. Quantifying these trade-offs and raising awareness among farmers and other stakeholders along the coffee value chain will help informed and sustainable decisions to be made about the coffee systems.

Figure 2. Trade-offs at a farmer-plot level in coffee systems.
Figure 2. Trade-offs at a farmer-plot level in coffee systems.

The more coffee is shaded, the more it is protected from rising temperatures and extreme weather events. Shade in coffee systems can reduce the average temperature in the lower coffee canopy by a few degrees. Although shade is an interesting technology to make coffee systems “climate smart” and hence, adapted to climate change, it is not the primary reason why farmers add shade to their coffee. Shade plants often produce fruit and/or timber. This diversifies the income of the farmer.

The same happens when farmers intercrop coffee with banana. Adding banana to the system increases food security, diversifies income, and adds shading to coffee. A country-wide survey in Uganda showed that coffee/banana intercropping was a common cropping system except in North and North-West Uganda. The incidence of coffee leaf rust was 50% when coffee was intercropped with banana.

Most farmers have some shade trees in their coffee; many practice intercropping with common beans. The combination of short- and long-term benefits of such shade systems makes them ideal climate-smart candidates. Shade trees also sequester carbon, contributing to the mitigation of the effects of climate change. In the end, few farmers (<5%) have pure full-sun monocropped coffee.

Figure 3. Pie charts depict major nutrient deficiencies based on soil and foliar samples of 10 coffee farms per site (black dots).
Figure 3. Pie charts depict major nutrient deficiencies based on soil and foliar samples of 10 coffee farms per site (black dots).

Constraints in diversified systems
However, shade trees also compete with coffee for light, nutrients, and water. If this competition is not managed well, then the shaded coffee system risks collapse, especially in conditions of poor soil fertility. Due to increasing population pressure and land fragmentation, integrated soil fertility management (ISFM) will help to manage nutrient competition. In a shaded system, the turn-over of biomass contributes to nutrient recycling. Organic matter from shade trees or banana will act as in-situ mulch. However, soils in Uganda are poor and have some major nutrient deficiencies (Fig. 3).

Replenishing soil fertility by adding external inputs is necessary if farming systems need to be sustained. Adding small amounts of fertilizers adapted to site-specific deficiencies increases fertilizer use efficiency and forms part of the ISFM approach. Coffee can be a major driver for the adoption of fertilizers by smallholders since farmers are generally organized for access to output markets. The same organizational lines can then be used to provide access to input markets.

Understanding the farmers’ objectives, perceptions, and constraints is critical in identifying the adoption pathways of production-increasing technologies. To continue this research, IITA will start a case study in Rakai (Uganda) at a site of the CGIAR Research Program on Climate Change, Agriculture, and Food Security (CCAFS). Here, climate-smart coffee scenarios will be developed in a participatory manner with smallholder farmers, based on data from previous projects, interviews with individual farmers and groups, and farm measurements. Greenhouse gas emissions will be quantified to measure the mitigation potential of the existing coffee systems. Furthermore, fertilizer trials throughout Uganda will be set up to test the site-specific recommendations. IITA also plans to further advance its collaborative research efforts on modeling trade-offs and synergies in coffee smallholder systems in East Africa.

ISFM for banana systems

Piet van Asten,, Severine Delstanche, Lydia Wairegi, Tony Muliele, Syldie Bizimana, Godfrey Taulia, Ken Giller, Peter Leffelaar, Laurence Jassogne, Philippe Baret, and Charles Bielders

Banana systems in Rwanda. Photo by Piet van Asten
Banana systems in Rwanda. Photo by Piet van Asten

Banana is the primary food crop in the Great Lakes Region, providing food and income for over 85% of the population. Unfortunately, current banana yields of 5–30 t/ha/year are low compared to potential yields of over 70 t/ha/year. Although between 25% and 70% of this yield gap can be explained by low soil fertility (Fig. 1), the use of external inputs such as fertilizers is virtually nonexistent and soil fertility is mostly managed by recycling local organic residues.

A study done by Severine Delstanche at the Catholic University of Louvain-la-Neuve (UCL) showed that very little nutrients were released from the soil through weathering of the soil minerals (Fig. 2). Hence, soil fertility depended almost entirely on the soil’s organic matter content. In banana-based farming systems, nutrient recycling is very important, as the harvest index is relatively small (<30%). This helps maintain relatively high organic matter content in the soil.

Figure 1. Primary crop constraints identified by use of boundary line approach.
Figure 1. Primary crop constraints identified by use of boundary line approach.

Furthermore, the large and perennial canopy and root system of banana help protect the soil from erosion. Banana therefore plays an important role in protecting the environment in this hilly landscape.

In addition to being an important component in sustaining soil fertility, banana plays an important socioeconomic buffer role for the smallholders. The crop provides food security as bunches are harvested throughout the year and any surplus can be sold to generate a continuous cash flow.

Banana systems particularly occur in areas with high population pressure and small (<2 ha) farm sizes. A study by Lydia Wairegi at Makerere University (Uganda), showed that fertilizer use was very profitable in the peri-urban area close to Kampala with marginal rates of return sometimes exceeding 500%. However, in areas far from the market (>150 km), the intensification process seemed less promising, but banana continues to play an important buffer role to maintain food security and protect the environment. In these remote locations, it seems wiser to invest in improved use of local (nutrient) resources, than to purchase mineral fertilizers.

Figure 2. The proportion of annual K fluxes in banana systems originating from soil mineral weathering (2%), crop<br /> residues (77%), and the crop harvest (21%).
Figure 2. The proportion of annual K fluxes in banana systems originating from soil mineral weathering.

To maintain its buffer role, banana can be integrated with other crops such as coffee and beans. The Ph.D. studies of Tony Muliele and Syldie Bizimana (both UCL) showed that intercropping beans with banana could be improved. Traditionally, farmers in Rwanda, Burundi, and DR Congo would till the banana field at the beginning of the wet season to suppress weeds and prepare the land for bean intercropping. Unfortunately, this practice damages a large proportion of the superficial root system of banana plants. Based on practices observed in Southwest Uganda, a technology of zero-tillage and mulching was tested. Beans are planted in the mulch. The planting holes for the beans were made using a stick. The use of external mulch greatly improved banana performance in eight trials across the region. However, beans did suffer some setback in some instances when the improved banana growth would lead to a more dense canopy, outshading the understory beans. In collaboration with Bioversity International and the Tropical Soil Biology and Fertility Institute of CIAT (TSBF-CIAT), a series of trials was conducted to reduce the banana canopy through leaf pruning. The results are almost ready, but they provide farmers with advice on how to best manage the trade-offs between banana and the understory legumes.

To improve fertilizer use efficiency and profitability, it will be important for farmers to apply the right nutrients at appropriate rates. To enable the identification of the most deficient nutrients (see photo) that need primary attention when applying fertilizers, compositional nutrient diagnosis (CND norms) were developed by Lydia Wairegi in Uganda and by Severine Delstanche in Rwanda. The CND norms are based on foliar analysis and allow a quick assessment of nutrient deficiencies observed within the plant. Contrary to critical norms for single nutrients, the CND allows for an integrated assessment of nutrient imbalances within the plant.

Farmers can use pictures to diagnose nutrient deficiencies for nitrogen, phosphorus, potassium, and magnesium.
Farmers can use pictures to diagnose nutrient deficiencies for nitrogen, phosphorus, potassium, and magnesium.

Besides developing fertilizer recommendations based on foliar analysis, IITA conducted a series of large nutrient omission trials in central and southwest Uganda. Based on the quantification of nutrient uptake, soil nutrient supply, and crop response, a QUEFTS model was developed to predict fertilizer requirements in collaboration with Wageningen University (WUR). This work was led by Ph.D. student Kenneth Nyombi and is currently being carried forward by Ph.D. student Godfrey Taulya. He observed that potassium nutrition was particularly important for banana to alleviate drought stress. The result from the ongoing research effort clearly shows that strong synergies can be achieved when integrating soil fertility, agronomic, and economic research approaches at the plot, farm, and regional levels.

Breeding superior banana/plantain hybrids

Jim Lorenzen (
Banana Breeder, IITA, Tanzania

Banana (the term includes plantain in this article, Musa species), is a major staple crop in Africa. Although it originated in Asia and was introduced to Africa long ago, it has become more important as a food security crop in its new home in Africa than in its region of origin. From its early domestication in Southeast Asia and the islands extending toward Australia, banana spread to Africa before recorded history. Archaeological evidence suggests that it reached Central Africa several millennia ago.

Pollination of banana flowers. Photo by L. Kumar.
Pollination of banana flowers. Photo by L. Kumar.
The main types of cooking banana in Africa include plantain (AAB genome), East African Highland Banana (EAHB, AAA genome), and a wide range of other types including sweet dessert banana (AAA or AAB genome), starchy but sweet roasting or brewing banana (ABB genome), and a number of other types. The “genome” refers to the portion of the chromosomes that come from one of the progenitor species of banana, Musa acuminata (A genome) or Musa balbisiana (B genome). However, most banana production in sub-Saharan Africa (SSA) consists of the East Africa Highland type or plantains, two sets of varieties with very limited genetic diversity in either. This lack of genetic diversity is a serious concern. About 60% of African production occurs in Uganda and its immediate neighbor countries (Tanzania, Rwanda, Kenya, D.R. Congo; also including Burundi).

Since banana production is year-round, it serves as a buffering bridge crop to provide food in times of scarcity between cereal harvests. As a long-lived clonal crop, it (like cassava) also can serve as a famine-avoidance crop because it is less susceptible than annual crops to catastrophic failure in the event of unseasonable drought and can act as a survival crop during cereal crop failure. Banana also provides important ecological functions for sustainable agriculture by reducing erosion in sloping highland agriculture, and recycling nutrients through the crop residue returned to the soil in each production cycle. In some locations banana leaves and cut stems are an important fodder component in the livestock sector, providing some fodder even during the dry season.

Production constraints
While precolonial banana production may have been relatively stable, pests and diseases introduced into Africa in the last century have destabilized production in some areas. Some important introduced diseases and pests include black leaf streak (also known as Black Sigatoka), Banana bunchy top virus (BBTV), burrowing nematode, banana weevil, and Fusarium wilt. More recently, banana Xanthomonas wilt (BXW) has emerged as an important bacterial disease that apparently originated in Ethiopia and caused a major disease epidemic in much of East Africa in the last decade. Breeding for resistance to these diseases and pests provided the initial motivation for IITA and partners to initiate breeding in Africa.

Manual pollination of banana flowers. Photo by IITA.
Manual pollination of banana flowers. Photo by IITA.
Banana breeding history
Although early efforts to breed banana using modern breeding concepts were initiated by British scientists in the Caribbean about 80 years ago, even today the world has only about seven significant banana breeding programs. IITA initiated a plantain breeding program at the Onne High Rainfall research station in southeast Nigeria in the 1980s as a new epidemic disease, Black leaf streak, arrived in the region. This program made relatively rapid progress, identified fertile plantain varieties to cross to wild sources of resistance, optimized and implemented embryo rescue as a means of boosting germination from <1% to 5─30%, and produced resistant high-yielding hybrids by the early 1990s. Realizing that the bigger portion of African banana production was in highland East Africa and also threatened by black leaf streak, in 1995, IITA initiated a banana breeding program in Uganda in collaboration with the National Agricultural Research Organization (NARO). Working together, scientists identified fertile EAHB varieties, produced resistant high-yielding tetraploid hybrids to serve as parents, and initiated a program to produce resistant high-yielding triploid hybrids that were more likely to remain seedless.

Banana breeding process
Although most of the world eats banana, few realize that wild banana are full of hard seeds and domestication resulted in the seedless fruits that we now eat. Most varieties are triploids (have 3 sets of each chromosome), which are both more productive and more likely to remain sterile and seedless. However, some edible varieties retain a bit of residual fertility and will set a few seeds if pollinated with a strong source of viable pollen. Banana breeders serve as surrogates to natural pollinators (bats), climb ladders in the early morning to collect male flowers, and carry them and the ladders over to the intended female plants to hand-pollinate female flowers. The flowers open sequentially each day, so each floral bunch is pollinated daily for a week. While many pollinations produce no seeds, some produce a few and a very few produce many seeds. Unfortunately, due to the complex background of domesticated banana, most seeds will not germinate on their own. Therefore breeding programs extract embryos from surface-sterilized seeds and germinate them in test tubes in nutritious media, from which they can later be transplanted to sterile soil, hardened, and eventually planted in the field. Triploid hybrids are evaluated as potential new varieties, while diploid (2 sets of chromosomes) and tetraploid (4 sets) hybrids are evaluated as potential improved parents.

The original plantain hybrids, as well as superior hybrids developed later, are currently being tested for agronomic performance, yield, and consumer acceptability in a number of countries in West and Central Africa, including Nigeria, Cameroon, Ghana, and Coté d’Ivoire. In the meantime, IITA’s original East African partner in banana breeding, NARO, has grown to be one of the largest banana research programs in the world, with internationally recognized capacity in several disciplines.

Fittingly, in 2010 NARO became the first national program in Africa to officially release a banana variety bred in Africa. Kabana6 (nicknamed Kiwangaazi) is a high-yielding variety with resistance to black leaf streak and partial resistance to nematodes and weevils. More encouragingly, newer selections likely to be more acceptable to Ugandan consumers are “in the pipeline,” and procedures are now in place to move some jointly developed NARO-IITA hybrids to countries where their cooked texture and appearance fit the traditional variety “type” better than they do the “matooke” variety type of Uganda. A couple of promising hybrids are finding acceptability in Burundi and eastern D.R. Congo, and hopefully will also be released as varieties. IITA recently opened a second East African breeding site near Arusha, Tanzania, a country with a broader range of environments and irrigation opportunities, potentially better to breed widely adapted varieties and providing the opportunity to screen more systematically for drought tolerance.

Physical measurements of banana fruits. Photo by IITA.
Physical measurements of banana fruits. Photo by IITA.
Other aspects
To support the breeding program, other genetics studies are being conducted, including development of populations for molecular mapping studies, mapping genes controlling important traits, manipulating ploidy to try to create fertility in “sterile” lines, developing molecular “tools” to make breeding more efficient, and investigating gene expression in response to drought. IITA has excellent capacity for screening for resistance to pests and diseases.

The entire banana improvement program depends on collaborative relationships, both within IITA and from a range of partners within Africa and in other continents. The pending release of the reference genome sequence from La recherche agronomique pour le développement (CIRAD)/Genoscope in France should greatly accelerate genetics research on banana and its relatives. In light of the challenges of breeding and the lack of good sources of resistance for two important pathogens (BXW and BBTV), IITA is also investing in biotechnology approaches to banana improvement, with promising signs of resistance in early laboratory, screenhouse, and confined field trials (companion article by Tripathi).

While encouraging progress is being made, banana breeding is challenging, slow, and expensive. Low fertility, poor seed set, and low germination rates mean that it is difficult to produce large numbers of progeny to evaluate. Banana plants are large, so evaluation plots are likewise large and expensive, and plants require up to 3 years to progress through two fruiting cycles. Much of the background genetics underlying key traits have yet to be properly investigated, so the list of research opportunities to make breeding more efficient and productive is long.

Musa is one of the major crops in the world for which wild relatives have yet to be systematically collected, so access to wild species for breeding for more resistant or more nutritious hybrids is problematic. Unfortunately, the global gene pool with the resistance and quality genes for future breeders remains at risk. Hopefully arrangements can be made for collection expeditions in the center of origin (Southeast Asia) in the near future while wild Musa still remain.

Although banana has been a neglected crop in terms of research investment and scientists’ effort in many countries, key decision makers are beginning to realize the essential role of banana/plantain in food security, enhanced livelihoods, and resilient agricultural systems for Africa. The potential to breed superior hybrids has been demonstrated, and there are numerous opportunities for improving both the process and the product, and for realizing impact from already developed hybrids. The future for banana crop improvement looks promising.

A 10-year strategy for the banana sector in Africa

Banana is an important staple food in sub-Saharan Africa. Photo by IITA.
Banana is an important staple food in sub-Saharan Africa. Photo by IITA.

The Banana 2008 Conference held in Mombasa, Kenya, provided the opportunity for developing a strategy to help propel the banana industry as an important engine of growth in Africa.

It was attended by more than 300 participants from the research and development arena, the private sector, and the business development, production and processing, policymaking, and marketing sectors.

Identifying priorities
The week-long conference focused on the themes markets and trade, production, and innovation systems. Within each theme, subthemes were identified along the whole commodity chain.

The participants identified priorities under the themes that cover the three banana types (dessert banana, plantain, and East African highland banana or EAHB) at three market levels: local, regional, and international.

The table shows the priorities identified by participants for each banana type and market level.

From priorities to action
Priority setting was the first step in strategy development. The next step was identifying who needs to do what to achieve these priorities.

Improving linkages
Improving linkages across the value chain is urgent if the banana sector is to be transformed. Better linkages, which depend on improved information provision and communication between actors, are important in achieving many of the identified priorities. Within markets and trade, for example, the successful matching of supply and demand depends to a large extent on an information flow through effective linkages.
Similarly for production, improved linkages are critical to solve the current gap between science and practice, and allow farmers to have access to knowledge so that they can address production constraints.

All stakeholders must recognize their responsibility to nurture synergistic relationships along the commodity chain. Principal actors (growers, traders, agribusiness, processors, retailers, and consumers) must be open to sharing information with other stakeholders. Supporting actors (those who provide services, inputs, and technologies) and those determining the operating environment (Governments and subregional trade organizations) have a key role to play in initiating and promoting new ways of working that encourage stronger linkages. Extension services provide a particularly important link in the banana chain and need to be strengthened—a role and responsibility of Governments.

To improve linkages across regions, participants suggested creating “knowledge platforms” to share current knowledge and to facilitate multisite testing, training, and education with farmers’ groups. Regional systems would feed into a pan-African system for consultative priority setting that is charged with exchanging information, strengthening capacity, forging partnerships, and developing policy to support banana production and trade across the continent.

Empowering farmers
The banana sector will be successfully transformed only if infrastructure is improved and the position of producers is strengthened. Farmers are greatly empowered by working together in cooperatives or farmers’ associations. Such farmers are in a much better position to address production constraints and to respond to markets. Information sharing and training are greatly facilitated, and effective innovation systems can develop more easily as the economy of scale is increased from individuals to organizations. Supporting actors, such as NGOs and community based organizations, have a crucial role in promoting the development of farmers’ groups. It is also in the interest of agribusinesses to support their creation and operation as it is more efficient and therefore financially viable for them to work with groups for example, in the supply of inputs and purchase of greater volumes of products.

Better linkages and farmers’ organizations will greatly facilitate the optimization of production practices, and also help to guide research priorities. Key actors who work with farmers in addressing production priorities are those providing technical services, particularly the extension services, and those working to develop new technologies and stimulate innovation, particularly NARS and the international research community. Actors determining the policy and operating environments also have a role in facilitating access to technologies and services. Banana genetic resources support production systems. Collecting, characterizing, and sharing banana germplasm will require the continuing efforts of the international agricultural research centers, NARS, advanced research institutes, and regional research organizations and networks.

Markets and trade
Again, effective linkages and participation in farmers’ organizations are needed to enhance farmers’ abilities to understand and respond to markets at all levels. However, markets are rapidly changing, and responding effectively and appropriately will be a major challenge across the banana chain.

At the local and regional level, expanding urban markets and the flourishing supermarket sector will offer many opportunities for banana growers and traders. Improved transport and market infrastructure, provided by local and national governments, is critical to stimulating growth in this area. Processing into innovative and durable new products will become more important to reach more distant regional markets and to smooth out seasonal discrepancies in supply and demand. Agribusinesses and regional trade organizations can guide interventions, with support from governments. Market information will be critical; the need to share this information will bring in actors in the communications field, such as the providers of mobile phone networks.

At the international level the dessert banana will continue to dominate trade, but changes in European trade tariffs will mean that production and freight systems in Africa will need to become far more competitive. There may be opportunities for well-organized farmers’ groups, for example, in supplying “fair trade” and similarly certified bananas. The main actors include international traders, airlines and shipping companies, supermarkets, standard-setting and certification organizations, governments, and regional and international trade organizations. Inland production areas are seriously disadvantaged with regard to transport costs and will require creative market opportunities, such as value-added processing.

Banana being transported by truck to city centers, Uganda. Photo by Piet van Asten, IITA.
Banana being transported by truck to city centers, Uganda. Photo by Piet van Asten, IITA.

Promoting innovation
Effective linkages are at the heart of successful innovation systems.

The Agricultural Science, Technology and Innovation (ASTI) system was adopted as the take-off point for promoting innovation.

In this model, effective linkages and empowered farmers were recognized as holding the key to innovation in the banana sector. Information and communication pathways are also fundamental. There is potential for innovation in all relationships across the banana chain, with all principal actors involved. Those who focus on supplying new technologies and promoting innovation are particularly important, specifically research organizations at all levels (national, regional, and international). The private sector also has a crucial role in facilitating innovation as a source of new technologies and also as a conduit for transferring technologies that may be familiar in a different context to a new set of banana producers or marketers.

Implementing the strategy
The Forum for Agricultural Research in Africa (FARA) and its various elements will be pivotal to transforming Africa’s banana sector. The framework of FARA is the Comprehensive Africa Agriculture Development Programme (CAADP) which has four pillars. Pillar IV aims to enhance agricultural research, technology dissemination and adoption, and its implementation is governed by the Framework for African Agricultural Productivity. The goals are to integrate natural resource management, encourage adoption of appropriate germplasm, develop sustainable market chains, and stimulate policies for sustainable agriculture. The banana strategy addresses these goals specifically for the banana sector, and thus fits squarely into the mandate of FARA.

Implementation of the strategy will begin by building an informed knowledge base organized around innovation platforms that both involve stakeholders and encourage ownership. Implementation of the strategy can happen under existing institutional arrangements. For research issues, NARS join into the subregional organizations such as West and Central African Council for Agricultural Research and Development (WECARD), Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA), and the Southern African Development Community. For trade issues the key bodies are the Economic Community of West African States (ECOWAS) and the Common Market for Eastern and Southern Africa (COMESA). All of these, in turn, feed into FARA. Technical backstopping and technology validation at the regional level will be facilitated by the research centers of the CGIAR and their numerous and diverse research partners, both within Africa and outside the continent. Additional support in specific areas will come from the Technical Centre for Agricultural and Rural Cooperation and the African Agricultural Technology Foundation.

Banana fruit. Photo by IITA.
Banana fruit. Photo by IITA.

Banana researchers in Africa have been accustomed to collaborating within regional networks: Réseau Musa pour l’Afrique Centrale et Occidentale is a part of WECARD and the Banana Research Network for Eastern and Southern Africa is under the auspices of ASARECA. These networks have recently been widened to include NGOs and private sector participants. Links to banana researchers in other regions, for the exchange of information and technologies and for collaborative problem-solving research, are promoted through the global ProMusa network, which also constitutes the Banana and Plantain Section of the International Society for Horticultural Sciences.

Innovation platforms are now envisaged that will unite researchers, extension agents, farmers and farmers’ organizations, agribusiness staff, traders, policymakers, and development partners. Research priorities and technology dissemination strategies will need to be market-oriented and participatory, and use approaches such as collective action by farmers, farmer-to-farmer learning, market-led technology adoption, and mutual learning in the market chain.

The strategy for transforming the banana sector in Africa fits precisely in the FARA model for agricultural innovation and economic development, and can be implemented under existing institutional arrangements. Participants believe that this would facilitate increased visibility and the mobilization of the breadth of expertise and depth of resources needed for its successful implementation. Such an outcome could indeed help banana to realize its full potential as a major economic driver for sustainable and equitable development in Africa.

Towards a healthy banana TC industry

Thomas Dubois,

Tissue culture banana
Banana in smallholder farmer systems is traditionally propagated by means of suckers. These contain soil-borne pests and diseases, and by using them, farmers unknowingly distribute and perpetuate pest and disease problems.

Plants produced by tissue culture (TC), because they are produced axenically in the laboratory, are material that is free from pests and diseases with the exception of fastidious bacteria and viruses.

Young tissue culture plantation in Nairobi, Kenya. Photo by T. Dubois, IITA.
Young tissue culture plantation in Nairobi, Kenya. Photo by T. Dubois, IITA.

There are many added benefits to using TC plants: (1) they are more vigorous, allowing for faster and superior yields; (2) more uniform, allowing for better marketing; and (3) can be produced in huge quantities in short periods of time, allowing for faster and better distribution of existing and new cultivars, including genetically modified banana. In other words, the TC technology can help banana farmers to make the transition from subsistence to income generation.

However, TC plantlets are relatively fragile and require appropriate management practices to fully harness their potential, especially during the initial growth stages shortly after being transplanted to the field. In East Africa, TC plantlets are often planted in fields burdened with biotic pest pressures and abiotic constraints.

A SWOT analysis
The importance of the private sector
The adoption of TC technology is still relatively low in East Africa. In Kenya, coverage of TC banana is estimated at 5–7% of the total banana acreage; adoption rates are significantly lower in countries such as Uganda, Burundi, and Tanzania, although reliable data do not exist.

Cumulative yield (t/ha/cycle) of a plantation derived from tissue culture (orange bars) compared to one derived from conventional planting material (blue bars), over 5 cropping cycles under two management regimes (low input and high input). Every little block represents one crop cycle. Data based on 1,600 plants total.
Cumulative yield (t/ha/cycle) of a plantation derived from tissue culture (orange bars) compared to one derived from conventional planting material (blue bars), over 5 cropping cycles under two management regimes (low input and high input). Every little block represents one crop cycle. Data based on 1,600 plants total.

In East Africa, the technology is booming under the impetus from the private sector. At least 10 commercial private laboratories have sprung up in the last decade in Burundi, Kenya, Uganda, and Tanzania. Collectively, they produce at least 2 million plants/year, although exact numbers seem to fluctuate widely and are hard to come by. Most of these companies manage the entire production chain, from sourcing the mother plants to weaning the TC plantlets. Despite the steep entry barrier, the TC business is very lucrative for the entrepreneur who engages in plantlet production. In some countries, universities and research organizations are also involved in the commercial production of TC banana.

Lack of quality standards and virus indexing
One of the biggest dangers for sustainable commercial production of TC plants is the lack of several essentials: (1) standards for quality management during the production process, (2) plant health certification, and (3) regulatory procedures. Such conditions are especially important to avoid spread of viruses, which are easily transmitted through TC plantlets.

For instance, Banana bunchy top virus (BBTV) is on the list of the 100 most dangerous invasive species worldwide. It is widely distributed in Central Africa and also in Burundi and Rwanda in East Africa, yet implementation of virus indexing schemes is largely absent in East Africa. It is important to put in place standard procedures for ensuring the production and distribution of high-quality, virus-free planting material, and to establish independent agencies that set and implement standards and improve the skills of personnel. In East Africa, certification schemes need to be regionally harmonized, especially with the transnational movement of plants between the countries, so that there is no weak link in the region.

Unregulation—a potential danger to the spread of diseases
At present, the commercial production of TC banana plantlets is largely unregulated. Not only are TC banana plantlets being moved in very large quantities across borders; uncertified mother material is also crossing borders. This practice is potentially risky, and could perpetuate infected sources and cause new outbreaks of disease.

In the ideal situation, there need to be certification standards for the quality and health of TC plants and the monitoring of TC producer operations. These are largely ignored because of poor awareness, and the lack of capacity and regulations required for the implementation of such standards. To transform the system, governments and/or the TC industry could consider common facilities to implement certification schemes. For instance, an accredited governmental or independent virus indexing laboratory, established as a commercial service for TC operators, would leverage costs and improve TC standards.

Another important requirement for TC producers is sustainable access to virus-free and true-to-type mother plants and this is currently lacking. The establishment of certified mother plant gardens as a common resource, either by governmental agencies or a consortium of commercial TC producers, would provide this essential requirement.


Contrary to a general perception, especially among donors, it is not merely the standards themselves that are a constraint, but also a lack of knowledge on how procedures are actually implemented along the value chain, through certification schemes. The equipment for virus indexing has become relatively cheap and technical skills are quite easily acquired. Their costs can be offset, e.g., through a service-based fee to private sector stakeholders.

Also, emphasis could equally be placed on certifying general operational procedures in a private TC laboratory. Currently, the quality of TC plantlets varies significantly, and several producers are struggling with off-types and accidental mixtures of varieties that become apparent only after being planted in the field, resulting in negative perceptions about TC.

Certification schemes need to be implemented in such a way that they do not become burdensome to producers or create bureaucratic barriers. Several quality certification schemes used for clonal crops, including banana, from other regions can be considered to develop an appropriate scheme for East Africa. Ultimately, it is not only the commercial sector that should self-regulate; governmental bodies need to take responsibility.

Nurseries for TC plants are essential, as they act as a distribution hub connecting producers to the farmers. They also act as focus centers for farmers and farmers’ groups, and are therefore an easily approachable venue for training and other interventions. The survey by IITA and University of Hohenheim of all TC nurseries in Burundi, Kenya, and Uganda, found that nurseries in East Africa face an array of problems. Relationships between producers and nurseries, especially those related to timing, quality, and quantity of plantlet supply, are often suboptimal.

At the nursery level, there are three main operational issues: access to water, credit, and the transport of plantlets. The location of the nurseries is also crucial. Nurseries need to be close to the producer and to the market, otherwise they might fail. Clear drivers for the success of a nursery are good agricultural practices and, interestingly, a diversification into crops outside banana.

Plantain for sale in market. Photo by IITA.
Plantain for sale in market. Photo by IITA.

In TC banana value chains, nurseries have different roles across countries in East Africa. In Uganda, nurseries are run as businesses independent of the TC operators and of the farmers. In Burundi, the nurseries are owned and managed by the producers. In Kenya, nurseries are run as entities separate from the producers, and most of them are owned by farmers’ groups that act as the customers for these nurseries. The business model in Kenya seems to hold the secret for a sustainable and vigorous link between producers and farmers.

Distorted value chains
One danger for a healthy commercial TC sector is the lack of sustainable market pathways to deliver the plants to the farmers. Especially in Burundi and Uganda, outlet markets for TC plantlets are mainly governmental and nongovernmental organizations, a situation which seems unsustainable in the long term.

The sustainability of the banana TC industry is especially worrisome in Burundi, where the entire value chain is subsidized. Virtually all TC plantlets are being bought by developmental agencies, which then pass on these plantlets to often untrained farmers, free of charge, and without embedding this transfer in an encompassing training program or input package (e.g., fertilizers).

Empowerment of farmers in the value chain through farmers’ groups
Organizing banana farmers into groups has long been considered advantageous, because of increased buying and selling power, reduced economic and social risk, increased economies of scale, and improved access to credit and inputs by formally certified groups.

The study by IITA and the University of Hohenheim of the farmer-to-market linkage in Uganda demonstrated that farmers in marketing groups obtain higher prices than their ungrouped colleagues. The certification of farmers’ groups implemented by IITA’s national partners, ISABU (L’Institut des Sciences Agronomiques du Burundi) in Burundi and VEDCO (Volunteer Efforts and Development Concerns) in Uganda, has made them eligible for savings and credit schemes. Some have even engaged in other commercial activities, such as the start-up of a catering service.

The importance of a training package
In East Africa, the distribution of superior planting material alone will not ensure a good crop. Commercial farmers are skilled in juggling the inputs and effort needed to produce crops and make a profit but smallholder farmers are constrained by factors such as a lack of land and capital, access to technology, and a good marketing infrastructure. Therefore, efficient distribution systems will be needed to deliver the TC plants as part of a package, including training and access to microcredit.

Training of farmers' group on business skills in Uganda. Photo by M. Lule.
Training of farmers' group on business skills in Uganda. Photo by M. Lule.

IITA and its national partners, ISABU, JKUAT (Jomo Kenyatta University of Agriculture and Technology), and VEDCO, have been implementing hands-on, comprehensive training schemes for farmers as well as the operators of TC banana nurseries. Training schemes encompass modules in agronomy, marketing, business and financing, and for farmers, group formation and group dynamics. Participants were followed for over a year, and their ability to implement the skills learned during the training program was monitored. So far, a total of 851 separate training events have been implemented in Burundi, Kenya, and Uganda, and through the partnership, 10 new farmers’ groups and 5 new nurseries have been established.

Location, location, location
TC banana plantlets come at a cost, and might not be economically beneficial throughout all banana-producing areas in East Africa. Location is everything.

IITA, in collaboration with Makerere University, conducted a cost-benefit analysis of the technology based on a comprehensive quantitative questionnaire with 240 farmers across four districts in Uganda, and compared it with the use of conventional planting material.

Gross margins (in Ugandan shillings)/ha/year of banana plantations derived from tissue culture (yellow bars) compared to conventional planting material (orange bars) in Uganda, the further away from the main banana market.
Gross margins (in Ugandan shillings)/ha/year of banana plantations derived from tissue culture (yellow bars) compared to conventional planting material (orange bars) in Uganda, the further away from the main banana market.

Both production costs and revenues were consistently higher for TC-derived material than for suckers. However, banana prices varied greatly with district and declined significantly with increasing distance from the main market (see graph). Also, production costs decreased significantly the further away the farms were from Kampala due to better agroecological conditions and the much reduced pressure from pests and diseases. As a result, although both TC plantlets and suckers were profitable to the farmer, TC material was more profitable than suckers closer to the main banana market.

In districts with low banana prices and at a greater distance from the main banana market, farmers could receive similar gains by planting suckers rather than TC plants. For a farmer in Uganda, it makes economical sense to grow TC banana close to the main urban market.

An objective ex-post assessment
Despite a booming commercial sector, there is only anecdotal evidence that farmers who have adopted TC banana benefit tremendously in terms of higher yields and household incomes. Sound socioeconomic analyses are crucial to guide policy strategies, learn from successes already achieved, and identify important constraints for a wider dissemination of TC banana in the region.

Earlier studies on the impacts of TC banana in the region have either employed ex ante methods before any meaningful adoption was actually observable, or they have used relatively simple and ad hoc qualitative methodological tools, which do not allow robust and representative statements. The large body of subjective ‘gray’ literature, sometimes unconditionally and unilaterally promoting the benefits of TC banana, without considering the quality of the plant material, input package, and market access, risks having an adverse effect on the adoption of the technology in the long term.

Banana market in Ikire, Nigeria. Photo by O. Adebayo, IITA.
Banana market in Ikire, Nigeria. Photo by O. Adebayo, IITA.

The University of Göttingen, in collaboration with IITA, is currently answering the following main research questions: (1) What are the determinants of TC banana adoption among farmers? (2) What are the impacts of this technology on on-farm productivity, household income and income distribution, and poverty and food security? (3) How do institutional factors in technology delivery and product marketing influence adoption and impact?

Some of these research questions have been answered. In Kenya, a substantial share of the population has heard about TC banana and is, therefore, generally aware of the technology’s existence, although only a few have had a chance to fully understand its performance and requirements. This study finds that farmers’ education, access to agricultural information, knowledge of the location of a TC nursery within a reasonable distance, and affiliation to social groups significantly increase the likelihood of the TC technology being adopted.

This study also highlights the positive role of access to credit and of gender in the adoption of TC material. Farmers with access to credit and female-headed households are more likely to adopt TC plants. The latter finding is particularly interesting from a policy perspective, because it shows that, when there is an equal chance for both men and women to acquire sufficient knowledge about an innovation, women are more likely to adopt it.

Transgenic banana for Africa

Leena Tripathi,

Banana (Musa spp.) are one of the most important food crops after maize, rice, wheat, and cassava. Annual production in the world is estimated at 130 million t, nearly one-third of it grown in sub-Saharan Africa, where the crop provides more than 25% of the food energy requirements for over 100 million people. East Africa is the region that produces and consumes the most banana in Africa. Uganda is the world’s second largest producer after India, with a total of about 10 million t.

Banana plantation damaged by Xanthomonas wilt. Photo by IITA.
Banana plantation damaged by Xanthomonas wilt. Photo by IITA.

The banana Xanthomonas wilt (BXW) disease caused by the bacterium Xanthomonas campestris pv. musacearum (Xcm) was first reported about 40 years ago in Ethiopia on Ensete spp., a close relative of banana. Outside Ethiopia, BXW was first identified in Uganda in 2001, subsequently in the DR Congo, Rwanda, Kenya, Tanzania, and Burundi. The disease is highly contagious and is spread plant-to-plant through the use of contaminated agricultural implements. It is also carried by insects that feed on male buds, and is present on plant material, including infected debris. The rapid spread of the disease has endangered the livelihoods of millions of farmers who rely on banana for staple food and cash.

Infection by Xcm results in the yellowing and wilting of leaves, uneven and premature ripening of fruits, and yellowish and dark brown scars in the pulp. Infected plants eventually wither and die. The pathogen infects all varieties, including East African Highland Banana (EAHB) and exotic types, resulting in annual losses of over US$500 million across East and Central Africa.

Options for BXW control using chemicals, biocontrol agents, or resistant cultivars are not available. Although BXW can be managed by following phytosaniary practices, including cutting and burying infected plants, restricting the movement of banana materials from BXW-affected areas, decapitating male buds, and using “clean” tools, the adoption of such practices has been inconsistent. They are labor-intensive and farmers believe that debudding affects the fruit quality.

The use of disease-resistant cultivars has been an effective and economically viable strategy for managing plant diseases. However, resistance to BXW has not been found in any banana cultivar. Even if resistant germplasm is identified, conventional banana breeding to transfer resistance to farmer-preferred cultivars is a difficult and lengthy process because of the sterility of most cultivars and also the long generation times.

Transgenic technologies that facilitate the transfer of useful genes across species have been shown to offer numerous advantages to avoid the natural delays and problems in breeding banana. They provide a cost-effective method to develop varieties resistant to BXW. Transgenic plants expressing the Hypersensitive Response Assisting Protein (Hrap) or Plant Ferredoxin Like Protein (Pflp) gene originating from sweet pepper (Capsicum annuum) has been shown to offer effective resistance to related Xanthomonas strains.

Plants established in confined field trial 5 months after planting. Source: L. Tripathi, IITA.
Plants established in confined field trial 5 months after planting. Source: L. Tripathi, IITA.

IITA, in partnership with the National Agricultural Research Organization (NARO)-Uganda and the African Agriculture Technology Foundation (AATF), has developed transgenic banana expressing the Hrap or Pflp gene using embryogenic cell suspensions or meristematic tissues of four banana cultivars, Sukali Ndiizi, Mpologoma, Nakinyika, and Pisang Awak. More than 300 putatively transformed plants were regenerated and validated via PCR assay and Southern blot. Of these, 65 transgenic plants have exhibited strong resistance to BXW in the laboratory and screenhouse tests. The plants did not exhibit any differences from their nontransformed controls, suggesting that the constitutive expression of these genes has no effect on plant physiology or other agronomic traits.

The 65 resistant lines were planted in a confined field trial in October 2010 at the National Agriculture Research Laboratories (NARL), Kawanda, Uganda, after approval was obtained from the National Biosafety Committee. These transgenic lines are under evaluation for disease resistance and agronomic performance in field conditions. The transgenic lines are slated for environmental and food safety assessment in compliance with Uganda’s biosafety regulations, and procedures for risk assessment and management, and seed registration and release. After completing the necessary biosafety validation and receiving approval from the Biosafety Committee, the Xcm-resistant cultivars are expected to be deregulated for cultivation in farmers’ fields in Uganda.

We plan to stack the Pflp and Hrap genes in the same cultivars to enhance the durability of resistance against Xcm. We have developed more than 500 transgenic lines with the double genes construct (pBI-HRAP-PFLP) which are being evaluated for disease resistance under contained screenhouse conditions.

This technology may also provide effective control of other bacterial diseases such as moko or blood disease, of banana occurring in other parts of the world. The elicitor-induced resistance could be a very useful strategy for developing broad-spectrum resistance. The elicitor is a protein secreted by pathogens that induce resistance. The transgenic banana carrying these genes may also display resistance to fungal diseases such as black sigatoka and Fusarium wilt. Experiments on this are being conducted in our lab in Uganda.

Confined field trial of banana plants. Source: L. Tripathi, IITA.
Confined field trial of banana plants. Source: L. Tripathi, IITA.

We are also planning to stack genes for resistance to Xcm and nematodes into one line to produce cultivars with dual resistance that would tackle two of the most important production constraints in Eastern Africa.

The development of Xcm-resistant banana using the transgenic approach is a significant technological advance that will increase the available arsenal of weapons to fight the BXW epidemic and save livelihoods in Africa. It can become a high-value product for farmers.

This research is supported by the Gatsby Charitable Foundation, AATF, and USAID.

Note: The Pflp and Hrap genes are owned by Taiwan’s Academia Sinica, the patent holder. IITA has negotiated a royalty-free license through the AATF for access to these genes for use in the commercial production of BXW-resistant banana varieties in sub-Saharan Africa.

A hot bath for the suckers!

An effective treatment against nematode and weevil pests of banana and plantain

Plantain plant with three sword suckers, field trial on IITA campus, Ibadan, Nigeria. Photo by A. zumFelde, IITA.
Plantain plant with three sword suckers, field trial on IITA campus, Ibadan, Nigeria. Photo by A. zumFelde, IITA.

Banana and plantain (Musa spp.) are important food crops for millions of people all over the world. The banana is the most popular fruit in the world and number one in international trade. The FAO estimates that over 100 million t of banana and plantain were produced worldwide in 2007. In sub-Saharan Africa (SSA), over 70 million smallholder farmers depend on the two crops for their food and income.

Banana and plantain production is greatly constrained by pests and diseases that lead to annual losses of millions of US dollars. The most important pests are nematodes (several species) and weevils (Cosmopolites sordidus) that are found in the soil and roots.

Nematodes attack the roots, hampering the uptake of nutrients from the soil and drastically reducing yield. In severe cases, they topple the whole plant. Weevils, on the other hand, attack the plant’s underground corm, weakening the plant and causing stem breakage. Average production losses from nematodes are estimated at 30% of the harvests of highland banana in East Africa and can exceed 60% for plantain in West Africa.

These two pests are spread from one farm to another through the planting of infested suckers. Farmers can avoid infesting their farms by ensuring that they plant disease- and pest-free suckers, such as those derived from tissue culture. These are, however, out of reach for the millions of small-scale farmers in sub-Saharan Africa.

Farmers dipping peeled suckers in boiling water. Source: D. Coyne, IITA.
Farmers dipping peeled suckers in boiling water. Source: D. Coyne, IITA.

Research has shown that peeling and treating the suckers in hot water, at 50 °C, can effectively remove both nematodes and weevils and their eggs. This method has worked successfully for commercial farms and organized cooperatives but not for small-scale farmers. This is because a thermometer must be used to ensure precision and the right temperature and this is not readily accessible to the farmers in SSA.

IITA’s scientists Danny Coyne and Stefan Hauser have developed an easier method that is just as effective by simply immersing the peeled or unpeeled suckers in boiling water for 20–30 seconds.

The counting
The duration of 20–30 seconds can be achieved by simply counting from 1 to 30. Farmers can also use small objects, such as pebbles, to mark the time: picking the pebbles one by one and placing them in a small container. The counting takes about 1 second/item but farmers can check the time for more accuracy.

This technique has proven to be friendly to small-scale farmers and is better than the hot water treatment at 50 °C as the time taken to treat a sucker is reduced and the measurement of the temperature and timing is simplified. It effectively disinfects suckers of various sizes without affecting their germination

Plantain field planted with suckers treated in boiling water. Photo by A. zumFelde, IITA.
Plantain field planted with suckers treated in boiling water. Photo by A. zumFelde, IITA.

The method is radical and requires skill and care when it is promoted to farmers who may be sceptical at first. The scientists recommend the use of a demonstration plot to introduce the technology and convince farmers to adopt it. They must keep within 30 seconds as otherwise they risk damaging the suckers, especially those that are small-sized.

Although the technology requires a fuel/energy source and the process has to be followed precisely, it is definitely a much easier method to use than the hot water treatment.

Using boiling water to treat the suckers has the potential to improve banana and plantain productivity by eliminating the two pests.

Sustainable production and distribution of clean banana

Bi Irie Vroh,

Banana (Musa spp.) including the plantain type are among Africa’s most important staple food and cash crops. Nearly 30 million t of banana are produced yearly in Africa, mostly by smallholders and consumed locally.

The major edible types are parthenocarpic (produces fruit without fertilization) and seedless. They are propagated traditionally by planting corms and suckers (daughter plants that grow from the rhizomes at the base of mother plants).

However, propagation material derived from the infected mother stocks results in perpetuation of diseases (e.g., viruses such as banana bunchy top, banana streak) and pests (e.g., nematodes and weevils) leading to low yields and poor quality fruits.
Due to the unavailability of disease- and pest-free or clean planting materials, farmers in sub-Saharan Africa traditionally plant suckers derived from their own plantations, most of which are affected with pests and diseases.

IITA has been using three approaches to generate clean planting material of farmer-favored banana cultivars:

Boiling water treatment of suckers: Suckers are submerged in boiling water for 30 seconds to kill nematodes and weevils. This method is efficient and easy for farmers, but it has low output and is laborious.

IITA’s Emmanuel Njukwe, Paula Bramel, and Bi Irie Vroh visit the Fritz Jakob Foundation. Source: B. Vroh, IITA.
IITA’s Emmanuel Njukwe, Paula Bramel, and Bi Irie Vroh visit the Fritz Jakob Foundation. Source: B. Vroh, IITA.

Macropropagation using the PIF technique: Through the technique known as PIF (plantes Issues de Fragments de tige) tens of good quality plantlets are produced within two months at relatively low costs. In this approach, the primary buds of entire suckers or fragments of corms are destroyed and axillary buds are exposed to high humidity to induce sprouts which are then harvested, hardened, and distributed.

This approach can be implemented in remote rural areas near farmers’ fields or by NGOs in direct contact with farmers for training and the distribution of good planting materials. This procedure is simple to replicate using locally made humidity chambers.

Micropropagation: Also known as in vitro production of tissue culture (TC) material this is the most efficient approach to the production of clean planting material in terms of throughput and germplasm exchanges across international borders. In vitro plantlets are micropropagated in the TC laboratory of IITA in Ibadan, Nigeria, and hardened first in the acclimatizing rooms, then in screenhouses before being distributed to farmers. Planting materials from preferred landraces and improved hybrids are propagated through TC, and hardened for use or maintained in a conservation cold room where each genotype is replicated several times from the initial meristem for future use.

IITA’s Delphine Amah holding racks of TC plants in a growth room. Source: B. Vroh, IITA.
IITA’s Delphine Amah holding racks of TC plants in a growth room. Source: B. Vroh, IITA.

Combining the TC pipeline with the macropropagation through PIF, IITA regularly distributes thousands of seedlings to NARS, NGOs, and farmers in West and Central Africa. Besides the preferred local varieties, the most distributed improved materials include the plantain hybrids PITA 14, PITA 21, and PITA 23 and the cooking banana hybrid BITA 3. These hybrids express a higher level of tolerance for black Sigatoka diseases compared with local varieties.

IITA trains farmers in applying boiling water treatment of suckers and macropropagation by PIF to produce clean planting material. However, IITA primarily uses micropropagation as the method of choice for conservation, propagation, and distribution of germplasm, and also to support its breeding programs. IITA also provides training programs on TC operations for NARS. For IITA’s projects in West Africa, clean planting materials are produced by TC or by PIF, hardened and raised in screenhouses, and then transferred to specific project sites.

Hardening of clean planting materials produced by TC and PIF methods. Source: B. Vroh, IITA.
Hardening of clean planting materials produced by TC and PIF methods. Source: B. Vroh, IITA.

In rural communities, IITA emphasizes training for farmers and rural entrepreneurs so they can produce clean planting materials in their own communities. These various efforts enhance the farmers’ access to clean planting materials and also encourage involvement of commercial operators in distribution of planting materials. The improvement of the capacity of NARS and the involvement of the private sector are needed to scale up the technologies for the sustainable production of clean planting materials of banana and plantain.

Bacterial wilt-resistant banana

Crop scientists have successfully transferred genes from green pepper to banana that enable the crop to resist the Banana Xanthomonas Wilt (BXW). BXW or bacterial wilt is one of the most devastating diseases of banana in the Great Lakes region of Africa. It causes about half a billion dollars worth of damage yearly.

The transformed banana, infused with plant ferredoxin-like amphipathic protein (Pflp) or hypersensitive response-assisting protein (Hrap) from green pepper, have exhibited strong resistance to BXW in the laboratory and screenhouses.

The Hrap and Pflp are novel plant proteins that give crops enhanced resistance against deadly pathogens. They work by rapidly killing the cells that come into contact with the disease-spreading bacteria, preventing them from spreading any further. They can also provide effective control against other BXW-like bacterial diseases in other parts of the world such as “Moko”, Blood, and “Bugtok”. The genes used in this research were acquired under an agreement from the Academia Sinica in Taiwan.

The mechanism is known as hypersensitivity response and activates the defense of surrounding and even distant uninfected banana plants leading to a systemic acquired resistance.

Scientists from IITA and the National Agricultural Research Organization of Uganda, in partnership with African Agricultural Technology Foundation, would soon be evaluating these promising resistant lines under confined field trials after the Ugandan National Biosafety Committee recently approved the conduct of the tests.

Presently, there are no commercial chemicals, biocontrol agents, or resistant varieties that could control the spread of BXW. Developing a truly resistant banana through conventional breeding would be extremely difficult and would take years, given the sterile nature and long gestation period of the crop.

Banana 2008 [update!]

Banana2008 logo

Representatives from the banana research and industry from all over Africa had an excellent meeting in Kenya in October 2008. The ambition to develop a 10-year strategic roadmap that would harmonize and guide efforts to promote the marketing and trade of the crop in the continent has been kick-started with contributions of key players in the banana world and critical reviewers. The prospects look promising and further details will be released post-conference.

The conference on “Banana and plantain in Africa: Harnessing international partnerships to increase research impact” took place at the Leisure Lodge Resort in Mombasa, Kenya on 5-9 October. This was the first Pan-African banana conference that links research to markets within the African context.

The event was organized and coordinated by IITA in cooperation with Bioversity International, Forum for Agricultural Research in Africa (FARA), Kenya Agricultural Research Institute (KARI), and the International Society for Horticultural Science (ISHS), and supported by the International Service for the Acquisition of Agri-Biotech Applications, the National Agricultural Research Organization of Uganda, Du Roi, and Bill and Melinda Gates Foundation.

The conference had three major themes: markets and trade, production, and innovation systems. The role of research and the importance of public-private sector partnerships were also highlighted.

The strategy document shapes and changes the way bananas are produced and marketed in Africa, linking state-of-the-art research to new markets and stimulating trade. In the long term, the impact will be to change commercial banana production from a donor aid-supported system to one which is sustained by an invigorated private sector that actively seeks technological interventions.