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Africa Rice Center
makes another breakthrough
 In
contrast to the NERICA, which was designed for the
upland (rainfed) rice ecology in sub-Saharan Africa (SSA),
the new rice has been developed for the African
lowlands, one of the most complex rice ecologies in the
world.
It was developed in close partnership with the national
programs in West Africa through the Réseau ouest et
centre africain du riz (ROCARIZ). Given the high
potential of the lowlands in Africa, the new rice is
expected to make an even bigger impact than the NERICA.
The lowlands—where rice is grown in bunded fields that
are flooded for at least part of the growing
season—offer great potential for the sustainable
intensification of rice in SSA. But the lowland ecology,
representing about 20–50 million hectares in West Africa
alone, poses a huge challenge for rice researchers
because of its heterogeneity and constraints, such as
the lack of water control, iron toxicity, weeds, rice
yellow mottle virus (RYMV), African rice gall midge (AfRGM),
stemborers and nematodes.
A team of researchers from WARDA and the national
programs—led by Dr Moussa Sie, Lowland Rice Breeder, and
Dr Kouamé Miézan, Irrigated Rice Breeder—has
successfully used the NERICA technology to tap into the
African rice species for traits of resistance to some of
these stresses in order to produce suitable plant types
for African lowlands.
NERICA—the technology versus NERICA—the product
NERICA is more than just a product. It is a
technological process, which has opened up a world of
opportunities for scientists to develop hundreds of rice
varieties suitable for various niche ecologies.
The NERICA technology refers to the successful crossing
by WARDA researchers of the two species of cultivated
rice—Oryza glaberrima (African rice) and Oryza sativa
(Asian rice)—to produce fertile plants that combine the
best traits of both parents: high yields from the Asian
parent and the ability to thrive in harsh environments
from the African parent. The NERICA name was trademarked
by WARDA in 2004.
Developing new rice varieties for African lowlands
At the Africa Rice Center, Dr Moussa Sié, and Dr Kouamé
Miézan, in close partnership with national programs of
West Africa, have used the NERICA technology to go
beyond the present NERICA product, which has been a
remarkable breakthrough for upland rice ecologies, but
has had little impact in the lowland and irrigated
ecologies.
For creating the new rice varieties for African
lowlands, the scientists focused on crossing specific
varieties of the African rice that were known for their
resistance to some of the major lowland stresses with
popular—but susceptible—Asian rice varieties.
The other difference was in the selection of the Asian
rice varieties. The Asian rice O. sativa has two main
strains, japonica (traditional rainfed or ‘upland’ rice
and indica (traditional irrigated or ‘lowland’ rice). In
the creation of NERICA, japonica varieties were used in
the crosses, while for developing the new lowland rice,
the indica varieties were used.
In the same way as for NERICA, developing the new rice
for African lowlands posed a formidable scientific
challenge because the two rice species have evolved
separately over millennia and often attempts to cross
them do not lead to reliable variety development. But
the researchers overcame the sterility blockage by
backcrossing (crossing the hybrid to O. sativa to
restore fertility).
A new plant type adapted to African lowlands, endowed
with good resistance to local stresses, yield potential
of 6-7 t per ha, growth duration of 120 days and
acceptable plant height, is now available for farmers.
It also responds well to nitrogen fertilizer
application.
 About
60 varieties of the new plant type have already been
selected by farmers through the participatory varietal
selection (PVS) process in several African countries—an
approach that was successfully used in accelerating the
dissemination of the upland NERICAs. In early 2005, four
varieties of the new rice for lowlands, now officially
known as the Lowland NERICAs, were released in Burkina
Faso and two in Mali.
“We are delighted that our prophetic vision is coming
true and another amazing breakthrough has been achieved,
thanks to the initiative taken by our scientists and the
valuable contribution of the national programs,”
Director General Dr Kanayo F. Nwanze commented. “The
lowlands are indeed the most promising environments for
rice expansion in Africa and the Lowland NERICAs, within
a sustainable and diversified land use systems approach,
has a high potential for transforming the prospects for
food security in the region.”
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