Towards a healthy banana TC industry

Thomas Dubois, t.dubois@cgiar.org

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.

test-tubes-to-farms

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
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.

Sustainable production and distribution of clean banana

Bi Irie Vroh, b.vroh@cgiar.org

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.

Growing banana from “seeds”

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 “selected” against seeded bananas and it is difficult or impossible to pollinate many banana varieties and successfully produce seeds.

Finding seeds in breeding plots in Namulonge, Uganda. Photo by IITA

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 don’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 “seed potatoes,” small potato tubers that are planted to produce a potato crop. Bananas do not form tubers; new plants derive from “suckers” 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 farmer’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 “seed system” designed to minimize the risks of spreading pathogens and pests.

Banana bicycle transport, Burundi
Banana bicycle transport, Burundi. Photo by IITA

The traditional means of obtaining banana planting material (“seed”) is to acquire suckers from one’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 “sick” 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 “sick” plants or positive selection for “healthy” 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 “clean” 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 “seed potatoes” 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 “seed” 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 isn’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).

Macropropagated banana plant in chamber. Photo by IITA

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.

Banana roadside market in rural southwest Uganda. Photo by IITA
Banana roadside market in rural southwest Uganda. Photo by IITA

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 “mother gardens” 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 “healthy seed”.

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.

Science meets industry

In Uganda, the local word for food is matooke, which is what the Ugandans call the green banana, their staple food. Nowhere is banana eaten in such a scale as in this East African nation of 31 million.

Ugandans reportedly eat, on average, more than a quarter of a kilogram of banana in a day, or in some areas, 450 kilograms per year! That’s a lot of bananas.

Bananas are as important to the Great Lakes region as rice is to East or Southeast Asia. They are a valuable source of vitamins, minerals, and carbohydrates or calories; they are the primary source of income for 16 million smallholder farmers in Uganda; and they play a central role in the sociocultural fabric of the country.

About one-third of the total global banana production comes from sub-Saharan Africa where millions of subsistence farmers and consumers depend on the crop as a staple food. Bananas are easy to grow especially in the Great Lakes region where growing conditions for the crop are ideal.

Enhancing small tissue culture plants with endophytes. Photo by IITA

But banana production in the region is being threatened by a complex of pest and disease problems, including Fusarium wilt (Fusarium oxysporum f.sp cubense), black leaf streak or sigatoka (Mycosphaerella fijiensis), viruses, banana weevils (Cosmopolites sordidus), and nematodes (e.g., Radopholus similis). The most serious threat at the moment is banana Xanthomonas wilt (BXW, Xanthomonas vasicola pv. musacearum), which could devastate the banana industry in East Africa. These pests and diseases damage the banana plants, cause yield loss, and eventually food insecurity and loss of livelihoods.

With the food security and livelihood of millions of farmers at stake, science and industry meet to save the crop and develop technologies to make production more sustainable. One technology involves the rapid, mass propagation of more robust bananas using endophyte-enhanced tissue culture,” said Thomas Dubois, biocontrol specialist and nematologist based in Uganda, who leads the team of IITA scientists that helped develop the technology.

“Old” technology
Tissue culture is not a new technology. Tissue-cultured banana is the norm in the rest of the world. Commercial tissue culture laboratories are beginning to emerge across East Africa to satisfy the rapidly rising demand for healthy planting material.

Tissue culture banana plants made in specialized private-sector laboratories are healthy and can grow faster than traditional plants. They are also ideal for establishing large plantations, which are then uniform, enabling better planning for harvests and marketing.

Tissue culture banana plantlets. Photo by IITA

Tissue culture produces clean plantlets without disease but also without a natural defense system. They are quite sensitive to the relatively harsh conditions in the East African fields, including attack by pests and diseases, and low soil fertility. The smallholder fields are burdened with biotic pest pressures and abiotic constraints, and the small-scale farmers do not practice essential high-input field maintenance. Thus, tissue culture adoption in Africa faces a “barrier”.

This is where IITA came to the rescue. “Endophytes” is a general term for naturally occurring microorganisms inside the plant that protect it from pests and diseases, and that enhance plant growth. Every single individual plant species, including banana, contains endophytes. They can be used as a natural form of control. Introducing endophytes in plants during propagation is like immunizing them. Plants inoculated or “vaccinated” with endophytes become resistant to pests or diseases.

Army against pests and diseases
The endophytes become part of the planting material before the young tissue culture plants are sold to farmers. Once inside, the endophytes go to work, boosting the plant’s immune system—so long as they get there first, before the pathogen.

Thus, farmers are provided with a weapon to fight the banana weevils and nematodes, which abound in the soil and which are transferred by farmer-to-farmer contact through exchange of infected planting material.

IITA, through its station in Kampala, Uganda, developed the endophyte technology to produce robust pest- and disease-free banana planting material, in collaboration with various national and international partners. Research on this technology started in 1997 with funding from the German Federal Ministry for Economic Cooperation and Development (BMZ).

IITA isolated nonpathogenic strains of endophytes belonging to the Fusarium family from healthy plants growing under high levels of pest and disease pressure. Institute scientists developed a rapid, easy, and low-cost laboratory screening protocol for testing the numerous endophyte strains obtained against the banana weevil and the burrowing nematode. They also devised a more efficient technique to mass produce the best strains, and introduce them into the tissue-cultured plantlets. The endophyte-enhanced plants are then grown in screenhouses and in farmers’ fields to assess their performance against target pests.

Genetically modified endophyte strains with genes for fluorescent colors. Photos by IITA
Genetically modified endophyte strains with genes for fluorescent colors. Photos by IITA

Using endophytes as biological control agents offers several advantages. When endophytes enter the plants first, they get a head start over the other microorganisms, and once they are established, other microorganisms would offer less competition. Because the endophytes are already in the plantlets when they are transplanted, control can be targeted using low levels or doses, and performance is consistent. Using endophytes also makes it easier to control cryptic pests such as the banana weevil and the burrowing nematode, which are embedded within plant tissues.

As an off-shoot of work on endophytes, IITA-Uganda scientists realized that endophytes circumvent many of the barriers associated with conventional biopesticides. This has spurred novel research in using conventional biopesticides, such as Beauveria bassiana, as artifical endophytes in seed systems. B. bassiana worldwide is the most researched and commercialized fungal biopesticide against a variety of insect pests.

Laboratory and screenhouse studies have revealed the great potential of this entomopathogenic fungus for use against the banana weevil. However, impractical field delivery methods and high costs associated with its application prevent its use and commercialization in banana fields.

IITA’s research also showed that B. bassiana can “colonize” the internal banana tissues for at least four months and that B. bassiana-enhanced plants reduced larval damage by more than 50%. It kills the damaging insect stages inside the plant; it is protected from adverse biotic and abiotic factors; little inoculum is required, greatly reducing cost. Farmers do not need to apply the biological control organism themselves, as the technology is easily transferable to a commercial tissue culture producer.

But IITA’s research-for-development work does not end there. How does IITA make endophyte-treated plantlets available to farmers, the ultimate users of the technology, as a ready-to-plant product at low cost?

Confluence of science and industry
The Institute has established strategic alliances with several private and public sector entities to develop international public goods. It leads the research effort on endophyte-enhanced tissue culture technology, and a commercial tissue culture entity and a private biocontrol company handle the formulation, distribution, application, and storage of the plantlets. In the process, IITA and its partners are helping commercialize the banana industry in East Africa.

Endophyte-enhanced banana tissue culture research is undertaken with research partners that include the University of Bonn, Germany; the National Agricultural Research Organization (NARO), Uganda; the University of Pretoria, South Africa; Makerere University, Uganda; Wageningen University, the Netherlands; the Catholic University of Leuven, Belgium; and the Biologische Bundesanstalt fur Land-und Forstwirtschaft, Germany.
The work though is not confined to banana production in Africa. Bioversity International, in collaboration with IITA’s German partners, is testing endophyte-enhanced tissue culture with large-scale banana producers in Costa Rica, using Latin American endophyte strains.

Since IITA does not have the in-house capability to undertake large-scale endophyte-based research in its facilities, the Institute partnered with several private and public organizations involved in tissue culture: Agro-Genetic Technologies (AGT), a commercial tissue culture laboratory in Uganda; Jomo Kenyatta University of Agriculture and Technology (JKUAT) and RealIPM, a biopesticide company in Kenya.

An exploratory and collaborative effort to produce more robust tissue culture plantlets as research material has developed into a synergistic partnership that bridged upstream research and downstream application. On the other hand, linking up with large-scale tissue culture producers in Uganda and Kenya have helped refine and move the technology from the lab to the farmers themselves.

Researcher inspecting banana plantlets in greenhouse, DRC. Photo by IITA
Researcher inspecting banana plantlets in greenhouse, DRC. Photo by IITA

Through collaboration, endophyte-enhanced technology is now being tested in farmers’ fields in East and Central Africa. The technology enables the farmers to switch from subsistence to income generation, and more importantly to reach and create markets.

Following the research-for-development model, IITA and its partners realized that engaging and mobilizing the community of farmers is essential for the technology to succeed and gain wider adoption.

IITA saw the value of harmonizing public-private sector collaboration at the early stages of the project. It has adopted this approach in its R4D work in Africa, and is promoting its application in technology transfer work in other areas of research, mandate crops, and commodities.

Erostus Njuki Nsubuga: Lessons on partnership

AGT CEO and Managing Director Erostus Nsubuga
AGT CEO and Managing Director Erostus Nsubuga

R4D Review interviewed Erostus Njuki Nsubuga, the chief executive officer and managing director of Agro-Genetic Technologies Ltd (AGT), to get his insights on the IITA-AGT partnership. AGT is the first and only private commercial tissue culture (TC) laboratory in Uganda and so far the biggest single supplier of banana TC planting material in East and Central Africa. It produces up to 8 million tissue culture plantlets per year, of which 1 million are banana plants.

Nsubuga wants to see AGT become well established and profitable by increasing its capacity to provide the region with quality TC planting material at affordable prices and introducing other services such as plant and soil analysis, and produce organic fertilizers. His dream is for AGT to become a one- stop shop that provides total solutions to farmers.

Nsubuga was born in Uganda and spent his early years there. Because of the war, he and his family had to move to other countries in Africa and Europe. He started living on his own at 16, studying in Europe and USA for 24 years to obtain an MSc (Agriculture) and MBA (International Marketing). He worked in international companies and managerial positions for over 20 years but his dream was always to come back, to help his mother who had survived all the wars, to sustain himself and his family, and to contribute to the development of his people and country.

What made you establish AGT?
I had completed one contract and was about to start a new job when I decided to start a TC laboratory at my house. I employed and trained two people to produce TC plants out of my kitchen while I was traveling. At that time (2001–02) banana and coffee wilt diseases were spreading like wildfire in Uganda. It was easy to start with these two crops as there was great demand for disease-free planting material to reduce the spread of diseases and restore healthy plantations. Over time, using my own finances, AGT built a state-of-the-art TC facility and we grew significantly. Our technical team now includes five university graduates and a retired professor. Degree students from Makerere University have been doing their internships at AGT’s laboratory with their programs embedded in our production line.

How did the AGT and IITA partnership come about?
It started when Dr. Thomas Dubois called me out of the blue. IITA was looking for a commercial enterprise to start testing and producing its endophyte-enhanced plants. Under a mutual agreement, AGT and IITA have worked on fine-tuning the enhancement of TC plants with endophytes. We identified and established on-farm trials together, using the same farmers. In the short run, IITA assisted us with laboratory chemicals and AGT also benefited from publicity. In the longer run, production of endophyte-enhanced TC material would be greatly beneficial to AGT and other commercial producers in the region. Now that the original project has expired, we are trying to get this unique product commercialized to supply farmers facing high pest and disease pressure.

Please give some insights on public-private collaboration.
Collaboration can be very important in developing and disseminating research products. For IITA, it has forced them to think commercially from the onset. A good example has been the experimental protocol for endophyte inoculation. After piloting it in my lab, IITA quickly abandoned the use of a nutrient solution in favor of fertilizer-amended soil along the lines of the system used in commercial nurseries. Such partnerships should be developed as early as possible, especially for a technology such as this. This would help AGT to build up its technical, human, and financial capacity to take on the research products once they reach commercialization. Also a very clear agreement has to be drafted and this is sometimes a balancing act.

How could IITA improve its relationship with the private sector?
AGT indicated to IITA that it was open to other research products but wanted to be involved at an early stage. This is what we call a demand-driven research agenda where the consumer is sure of getting research products through private sector involvement. We are now backstopping a socioeconomic study looking at full commercialization of our nurseries in Uganda and Rwanda. At present AGT sells mainly through NGOs and institutions. Direct marketing to farmers would be better.

What lessons have you learned from the partnership with IITA and others?
It is great that research organizations such as IITA have realized the role of private sector involvement in agricultural research and in the product value chain. Such partnerships are relatively new and we still have much to accomplish. Personally, I feel many governments and international research institutions, even IITA, are working too much for the donors, not the farmers. We should tell the donors what needs to be funded. More impact assessment is needed on some research products.

Any suggestions for future collaboration or collaborators?
I hope IITA can do more demand-driven research by including the private sector in the development of research products as early as possible with specific roles for each partner clearly defined.

What do you think makes AGT successful?
I have a professional approach and commitment, with many years of experience in agriculture and entrepreneurship and good relationships, local and international. AGT started when diseases such as banana bacterial wilt and coffee were at their peak, so I was in the right place at the right time.

How else could development organizations and private entities such as AGT help farmers and consumers?
AGT is getting farmers involved in production, distribution, and training by establishing banana nurseries and demonstration gardens owned by local farmers. The farmer then becomes the AGT distributor for that community and the nursery the focal point for training others in modern agricultural practices.

What is your dream for Uganda?
Uganda is the second largest producer but seventy-fifth in banana exports. The Government and all development partners should industrialize this crop and thus lift many out of poverty.

Any thoughts about the world food crisis, food security, GMOs, or development in general?
African countries are the poorest in the world today with many problems. We urgently need biotechnology tools, including GMOs, to address problems. We should not waste time blaming others for creating poverty and hunger but make efforts ourselves to get out of the rut. I still have far to go but I am contributing to the well being of farmers in Uganda and the whole region.