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New Rice
for Africa (NERICA)
Offers
Hope to Women Farmers
and Millions More
Bintu clears brush from new land, then
plants rice seeds of the Asian rice species that entered Africa about 450
years ago. But Asian rices—developed
for high-input irrigated farming—can’t compete with the weeds on
Bintu's rainfed farmland, which soon take over. So, after a crop or two,
Bintu must clear more land.
She would rather plant the traditional
African rice species that her ancestors grew. It has wide, droopy leaves
that smother weeds, and has thrived in harsh environments for 3500 years.
The African rice also resists drought, acid soils, and local pests that
plague the Asian rices.
Bintu also likes how the African rice
tastes. It’s served at weddings and festivals.
But Bintu can’t plant her traditional
African rice, because it doesn’t produce enough to feed her
family—much less enough to sell surplus grain.
For years, scientists have dreamed of
combining the ruggedness of the African species with the productivity of
the Asian species. But the two are so different, attempts to cross them
have failed. Until now.
Advances in agricultural research in
recent years have helped scientists cross the two species—a breakthrough
that is changing Bintu’s life. Using a technique called embryo-rescue,
scientists are able to assure that crosses between the two varieties
survive and grow to maturity. The new rice for Africa, like its
African parent, smothers grain-robbing weeds, and resists drought,
pests and problem soils. It also inherited higher productivity from the
Asian species, and can double production with just a few inputs.
Rice in West Africa
Nowhere is the struggle for food more
desperate than in West Africa—home to 240 million, one of every three
persons on the continent. More than half the population survives, somehow,
on less than one US dollar per day.
"Keep in mind that ‘food’ means
‘rice’ for many people in West Africa today," says Dr Kanayo F.
Nwanze, director general of the West Africa Rice Development Association (WARDA),
based in Côte d’Ivoire. It was WARDA that developed the rices, dubbed
NERICAs (NEw RIce for AfriCA).
"Ironically, rice was considered a
luxury food in West Africa only two decades ago," Nwanze adds.
"Today, it’s the staple." Rice now contributes more calories
and protein than any other cereal in humid West Africa, and about the same
as all roots and tubers combined. Demand for rice is growing faster here
than anywhere in the world.
In three decades, rice imports have
increased eight-fold, to over 3 million tonnes a year, at a cost of almost
US$ 1 billion.
About 40% of West Africa’s 4.1 million
hectares of rice is upland, or dryland, grown like wheat or maize.
Fertilizer and pesticide use is minimal, and yields are only about 1 tonne
per hectare.
Breeding strategy
"The African and Asian species
evolved separately over millennia," explains Dr Monty Jones, WARDA
rice breeder. The African species lodges, or falls over, when grain heads
fill. It also shatters easily, wasting more precious grain. The
higher-yielding Asian species has largely replaced its African cousin.
West African farmers in rainfed (dryland)
areas can’t grow the semidwarf rices that have revolutionized irrigated
production in Asia, because they don’t compete well with weeds, or
tolerate drought and local pests. And African farmers are too poor to
invest much in herbicides, other pesticides, or fertilizers.
In 1991, Monty Jones initiated a
biotechnology-based program to combine the best traits of the Asian and
African rices. Key to the effort were gene banks that hold seeds of 1500
African rices—which had faced extinction as farmers abandoned them for
higher-yielding Asian varieties.
Traits of the New
Rice for Africa
Scientists were testing the new rice
for Africa—progeny of African–Asian
crosses—in rainfed conditions by the mid-1990s.
"Genetic differences in the two
species made breeding difficult—but also gave the new rices high levels
of heterosis or hybrid vigor," Jones says. Heterosis is
the phenomenon in which the progeny of two genetically different parents
grow faster, yield more, or resist stresses better than either parent.
Weeding accounts for 30 to 40% of all
labor—mostly by women and children—invested in a West African rice
crop.
The NERICAs inherited wide, droopy leaves
from their African parent, which smother weeds in early growth. That
reduces labor, and allows farmers to work the same land longer, rather
than having constantly to clear new land.
The structure of the panicles, or grain
heads, has also been changed. Panicles of the African species produce only
75-100 grains. The new rices inherited, from their Asian parent, longer
panicles with ‘forked’ branches, and hold up to 400 grains.
Like their Asian parent, the new rices
hold grains tightly, not allowing them to shatter. They produce more
tillers than either parent, with strong stems to support the heavy grain
heads.
The new rices outyield others with no
inputs—but respond bountifully to even modest fertilization.
"In trials, we’re getting yields
as high as 2.5 tonnes per hectare at low inputs—and 5 tonnes or more
with just minimum increase in fertilizer use," Jones says.
"We’re talking about 25% to 250% production increases."
The new rices mature 30 to 50 days
earlier than current varieties, allowing farmers to grow extra crops of
vegetables or legumes. They’re taller than most rices, which makes
harvesting easier—especially for women with babies strapped to their
backs. They resist pests and tolerate drought better than the Asian rices—vitally
important for rainfed-rice farmers. The new rices grow better on
infertile, acid soils—which comprise 70% of West Africa’s upland rice
area.
They also have about 2% more
body-building protein than their African or Asian parents.
Dr Susan McCouch of Cornell University
and the Rockefeller Foundation Rice Biotechnology Program is helping
develop a molecular map of the new rices, plotting genes that control
traits like droopy leaves.
"Using biotechnology to exploit
genes from the African species could significantly increase global
biodiversity in rice," McCouch says.
Spread and hope for the future
More than 1300 farmers participated in a
1998 program to start the new rices in Guinea, followed by a 1999 national
seed increase and farmer awareness program. Average farm yields are rising
from about 1 tonne to more than 1.5 tonnes per hectare with low
inputs—and at least double that with good management and intermediate
inputs.
WARDA projects that farmers will grow the
new rices on almost 5000 hectares in Guinea in 2000, and 330,000 ha by
2002.
Several new NERICA rices, yielding at
least 25% more than conventional varieties, will be released in West
Africa in 2000. Research shows that 10% adoption in just three
countries—Guinea, Côte d’Ivoire and Sierra Leone—will return an
extra US$ 8 million to farmers per year. Adoption by 25% of farmers will
return $20 million.
The new rice for Africa may also help
farmers who grow upland rice on 17 million ha in Asia, and 4 million ha in
Latin America.
The following publications are available
on-line.
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