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Making the Most of
Musa
As consumers throughout the world face higher food
prices, CGIAR scientists and their partners are moving on many
fronts to strengthen food security, including unprecedented efforts
to enhance the production and marketing of banana and plantain
(Musa spp.) in sub-Saharan Africa.
One country in the region that has experienced considerably less
food price inflation than others is Uganda. A chief reason is the
country's self-sufficiency in the production of banana, which
is much more important in local diets than internationally traded
grains. In fact, banana is so important in Uganda that the same
word - matooke - is used both for "banana" and
"food."
 A bunch of problems
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Sub-Saharan Africa produces about 30 million tons of banana and
plantain per year, providing food for about 100 million people. The
crops are especially important as staples and cash earners in
Eastern Africa's Great Lakes Zone and in the humid lowlands of
West Africa. During recent decades, however, yields in sub-Saharan
Africa have declined drastically, posing a serious threat to
regional food security. Harvests are failing because of a
combination of problems, which interact with one another to
compound losses.
One of the worst threats is a fungal disease called black
Sigatoka or black leaf streak disease. Originating in the Pacific,
it first appeared in West Africa during the 1980s, where it has
caused yield losses of 30 to 50 percent.
Another more recent disease problem in Africa is banana
Xanthomonas wilt (BXW), caused by a bacterium previously restricted
to Ethiopia. Reported in Uganda and the Democratic Republic of
Congo in 2001 and then in Rwanda in 2002, it emerged as a serious
threat to the region's food security. A survey in 2004 revealed
that fully one third of the banana plants were infected with BXW.
Yields dropped 30 to 50 percent on average and by up to 80 percent
in heavily infected areas.
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BXW
infected plant with sick bunch. photo: IITA.
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Further obstacles to progress in Africa's banana and
plantain production include major pests, particularly banana weevil
and parasitic nematodes, and the more general limitations of
declining soil fertility, inadequate crop management and weak
market links.
Research focus
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A few years ago, scientists feared that, in the absence of
adequate control measures, black Sigatoka and BXW could devastate
banana production in sub-Saharan Africa. In Uganda alone, it was
expected that about US$4 billion in income could be lost just to
BXW by 2010.
Fortunately, such dire consequences have been averted through
research and extension efforts, centering on practical, effective
and environmentally sound approaches to disease management. Helping
find such approaches is a central focus of banana and plantain
research at the International Institute of Tropical Agriculture
(IITA) and Bioversity International.
To curb the black Sigatoka threat, scientists at IITA developed
high-yielding, disease-resistant hybrids, an achievement that
earned them the CGIAR's 1994 King Baudouin Award. National
research partners are evaluating some of the resistant hybrids and
releasing them to farmers, with especially good adoption rates
reported in Cameroon, Ghana and Nigeria. Apart from the
hybrids' high yields and disease resistance, farmers appreciate
their capacity for rapid multiplication (a result of excellent
proliferation of the rhizomes, or "suckers," used for
propagation), their good taste and cooking qualities and their
resistance to other diseases and pests. Some farmers who have
adopted the hybrids are generating significant income from the sale
of suckers, in addition to boosting returns from the sale of
fruit.
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IITA Lead Scientist and
biotechnologist Leena Tripathi, discussing transgenic plants in the
containment facility with Gilbert Gumisiriza, Research
Technician.
Photo: IITA.
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The resistant hybrids are not suitable for the East African
highlands, though, where farmers prefer different qualities in
their bananas. Ugandan scientists are instead using genetic
modification to put black sigatoka resistance into the region's
most favored varieties. Field trials recently began at a secure
site in Kampala, Uganda, and preliminary results are
encouraging.
Banana researchers seeking genetic solutions to BXW, in
contrast, have yet to identify resistant varieties. Breeding for
resistance will require years of dedicated work because of the high
levels of sterility in most domesticated bananas.
Genetic engineering offers a possible solution, and
biotechnology specialists at IITA, working in partnership with
Uganda's National Agricultural Research Organization (NARO),
are exploring its potential. They have developed h undreds of
transgenic lines of banana, using genes from sweet pepper that
confer resistance against BXW. Screening of the lines for
resistance under lab conditions has given promising preliminary
results.
"Developing resistant varieties is a sustainable solution
for controlling pests and diseases. Improving the plant's
defense mechanism against BXW through genetic engineering offers
many advantages," says IITA molecular biologist Leena
Tripathi.
Meanwhile the disease has been partially brought under control
through a combination of research on crop management and education
in improved practices. "We discovered what worked to control
the disease, and how to encourage farmers to manage their
plantations with this in mind," says Eldad Karamura, a
Bioversity scientist who has been instrumental in the campaign
against BXW.
The global network of banana researchers managed by Bioversity
was of great value in the campaign. "Our experience with
bugtok, a similar disease in Asia, gave us the approach we
needed to deal with BXW," says Emile Frison, director general
of Bioversity. That approach consists of a two-pronged strategy. A
management component helps farmers to sustain production in
affected areas and to slow or even halt the spread of the disease,
while a surveillance component ensures that new outbreaks are
spotted quickly and dealt with appropriately.
To ensure that the advice offered to farmers is sound, CGIAR
scientists collaborated with colleagues at NARO to test control
options. Working with Catholic Relief Services (CRS) and other
partners, researchers developed a comprehensive package of measures
that has been rolled out now to more than 31,000 farmers. Despite
glitches that inevitably arise when coping with a new disease, more
and more success stories show that the disease can be
contained.
Wider impact
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To widen the impact of achievements in Musa genetic
improvement and other research will require stronger support for
national and community-based efforts to make improved cultivars and
practices more readily available. That's why IITA and
Bioversity International included several of those technologies in
an inventory of "best bets" for boosting sub-Saharan
Africa's crop production, which was compiled recently by CGIAR
scientists in collaboration with the World Bank. Lucrative
small-scale enterprises are already emerging in parts of Africa,
which employ in vitro techniques to produce disease-free
banana and plantain plantlets for massive dissemination of improved
cultivars.
Meanwhile, banana breeders have expanded the scope of their work
to include other traits that are important for poor producers and
consumers, such as postharvest qualities and nutritional value.
Researchers are also engaged in major efforts to conserve and
better understand Musa diversity, which is critical for
continued crop improvement. They are working toward that end
through systematic assessment of cultivated and wild samples, for
example, and by further developing germplasm information
systems.
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Serving matooke in Uganda. Photo:
IITA.
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Best minds
For decades, banana and plantain research has centered mainly on
the development of technologies that can help boost and stabilize
production. As farmers gain better access to new germplasm and
knowledge generated by that research, they will be better able not
only to enhance crop productivity but to strengthen their ties with
markets for surplus production.
New opportunities to accomplish both ends are rapidly emerging.
For example, large international banana producers have recently
announced plans for strategic investment in commercial banana
production in sub-Saharan, with the aim of catering to lucrative
markets in the Middle East and Europe. Sub-Saharan Africa offers
other options as well for better marketing of banana and plantain
within the region. A major challenge is to find ways of ensuring
that small farmers are able to capture benefits from such
developments through stronger market links.
In an unprecedented attempt to confront that challenge, CGIAR
Centers, together with regional and national partners are
organizing the first-ever pan-African banana and plantain
conference designed to link research with marketing. Its
organization is being led by IITA, in partnership with Bioversity,
the Forum for Agricultural Research in Africa (FARA), International
Society of Horticultural Science (ISHS) and Kenya Agricultural
Research Institute (KARI). The event will bring together the best
minds from both the public and private sectors at Mombassa, Kenya,
in early October, with support from the Bill and Melinda Gates
Foundation, FARA, the Belgium Directorate General for Development
Cooperation (DGDC), and many others, who are recognized on the
event Web site at www.banana2008.com.
Participants will hammer out a 10-year strategy for radically
improving the way banana and plantain are produced and marketed in
Africa. New partnerships involving the public and private sectors
as well as civil society will figure importantly in this renewed
effort to realize the vast potential of Musa spp. for
strengthening food security and contributing to agricultural
growth.
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