NERICA: The new rice for Africa
The traditional African rice species
Rice has a long and varied history in Africa .
African farmers probably domesticated this grain at the same time as Asian
farmers – about 3,000 years ago. African farmers developed the species Oryza glaberrima, while Asian farmers
developed Oryza sativa.
African rice Oryza glaberrima has
been cultivated for 3,500 years and is well adapted to the African environment.
African rice has profuse vegetative growth, which serves to smother weeds; it
is also resistant to drought,
the insect pest African rice gall midge, rice yellow mottle virus and blast
disease. However, African rice has relatively low yields, because it lodges, or
falls over, when grain heads are full. Grains may also shatter, further
reducing yield.
Oryza sativa was introduced to Africa
about 500 years ago, however, and peasants there have adapted it to their rice
production systems, developing many local varieties of the Asian species and
turning Africa into an important secondary
source of diversity.
Cultivation of African rice has been abandoned for
the cultivation of high-yield Asian varieties of Oryza
sativa. Asian varieties are poorly adapted to African conditions as their
cultivation requires abundant water. Asian rice cannot compete with weeds due
to their semi-dwarf phenotypes and are susceptible to pests and diseases in
African conditions.
Most of the 20
million rice farmers in West Africa are bound
to an environmentally degrading slash-and-burn farming system. Asian rice
species which entered Africa 450 years ago
can't compete with the weeds, so after a crop or two it's time to clear more
land. Planting the traditional African rice species is not worthwhile for
farmers as it simply does not produce enough rice.
Although 240 million people in West Africa rely on rice as the primary source of food
energy and
protein in their diet, the majority of this rice is imported, at a cost of USD 1
billion. Self-sufficiency in rice production would improve food security and
aid economic development in West Africa .
Finding out the new rice varieties for Africa
In 1991, a
biotechnology-based programme was initiated to combine the best traits of the
Asian and African rices. Vital to the effort were gene banks that contain seeds
of 1500 African rices - which had faced extinction as farmers abandoned them
for higher yielding Asian varieties.
The rapid
advances in agricultural science enabled the development of NERICA. Scientists
at the West Africa Rice Development Association (WARDA) overcame a series of
disappointing failures when they succeeded in crossing two species using embryo
rescue techniques.
The first
Nerica variety was developed in 1994 by researchers at WARDA, using an Oryza sativa japonica variety (WAB
56-104) and an African Oryza glaberrima
variety (CG 14).
New Rice for Africa ("NERICA")
is an interspecific cultivar
of rice developed
by the Africa Rice
Center Guinea , Nigeria , Côte
d’Ivoire , and Uganda ,
according to the Africa
Rice Center
The new
varieties, named “New Rice for Africa ” (hence
NERICA), are a cross between O.
glaberrima and O.
sativa. They
combine the hardiness of the African species with the productivity of the Asian
species. Scientists at the West African Rice Development Association (WARDA)
succeeded in crossing the two species by employing embryo rescue techniques
that ensure the crosses are fertile and mature successfully due to high levels
of hybrid vigor .
In doing so, they used seeds of African rice
varieties that local farmers, many of them women from Guinea
The new rice
smothers grain-robbing weeds like it's African parents, resists droughts and
pests, and is able to thrive in poor soils. The trait of higher productivity
conferred by it's Asian parents is also present, meaning that with few
additional inputs the farmers using NERICA rice can double production and raise
incomes. It is helping to meet multiple needs - food, nutrition and income -
for millions of people in the humid tropics of West Africa .
The panicles
of this rice variety can hold 400 grains compared to the 75-100 grains of it's
African parents. Further improvements in the plants architecture such as longer
panicles with forked branches, strong stems and panicles that hold grain
tightly and prevent shattering- will allow the new varieties to out yield
others and produce bountiful harvests with modest fertilisation.
They mature
30-50 days earlier than traditional varieties allowing farmers to grow extra
crops of vegetables or legumes. They are taller thus making harvesting easier
and they grow better on the fertile, acid soils that comprise 70% of the upland
rice area in the region. In addition, there is 2% more body building protein in
these new varieties than either their African or Asian parents.
Key features of the new varieties
include:
-An increase in grain head size from
75-100 grains per head to 400 grains per head.
-An increase in yield from 1 tonne per
hectare to 2.5 tonnes per hectare, yield increases to 5 tonnes per hectare with
fertilizer use.
-Contains 2% more protein than their
African or Asian parents.
-They are taller than most rices,
which makes harvesting easier.
-They resist pests, and they tolerate drought and
infertile soils better than Asian varieties.
NERICA
varieties shade out weeds, are resistant to pests and droughts, grow in poor
soils, and mature 30–50 days earlier than traditional varieties. Moreover, they
produce 400 grains per plant (as opposed to 75–100 in the older varieties),
contain 2% more proteins and, as a bonus, are said to taste like African rice.
The high
productivity conferred on the NERICA strains by their Asian parents means that
yields can be increased from the previous 1 ton per hectare to 1.5 tons without
major inputs. With fertilizers and good care yields can double or even triple.
Thus, the new rice holds great promise for a region in desperate need of
decreasing hunger and increasing food security.
Some NERICA lines show high
growth with low uptake of water and seem to be appropriate for long periods of
cultivation in drought condition.
If 25% of rice farmers in Guinea , Côte
d'Ivoire and Sierra Leone Asia .
The enormous
scientific efforts that produced NERICA will result in a “Green Revolution” in
which nearly 1.7 million West African farmers will benefit from increased food
security. It will help their countries save millions of dollars in rice
imports. The basis for this success story is to be found in those West African
farmers who continued to grow the ancient O.
glaberrima varieties of rice despite the introduction of the
new Asian species. Their knowledge, expertise, and continued adherence to their
traditional rice provided the basis for experiments that resulted in the
creation of a promising new hybrid. Thus, both cultural and ecological
variables entered significantly into these developments.
Preferences:
1-"NERICA COMPENDIUM".
WARDA. 2006. Retrieved 2008.
4-GRAIN — Nerica: a 'wonder' rice? www.grain.org/article/entries/752-nerica-a-wonder-rice.
5-Farmers embrace African 'miracle' rice-www.un.org/en/africarenewal/vol17no4/174rice.htm.
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