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July 12, 2007
by Zablon Odhiambo,
SciDev.Net
Crop scientists in South Africa have developed a maize variety
that is resistant to maize streak virus, a move they hope will
help alleviate food scarcity and promote the reputation of
genetically modified (GM) foods in Africa.
The scientists — from the
University of Cape Town
and the seed company
PANNAR Pty Ltd — claim the
new variety shows resistance to the virus in successive plant
generations and in crosses with other varieties.
The all African team hopes the technology will help to address
other viral diseases affecting African food crops such as the
wheat dwarf virus, sugarcane streak virus and other viruses that
affect barley, oats and millet.
They reported their findings this week (8 July) at the annual
meeting of the American Society of Plant Biologists in Chicago,
United States.
Maize streak virus (MSV), endemic to sub-Saharan Africa and the
Indian Ocean Islands, retards the growth of infected plants and
causes them to grow deformed cobs, decreasing the amount of
grain that can be harvested.
Instead of crossing varieties with different degrees of
resistance to MSV, the scientists mutated a viral gene that
encodes a protein the virus needs to replicate itself and
inserted it into maize plants.
When the virus infects the GM maize, the presence of the mutated
protein prevents the virus from replicating and killing the
plant. Field trials of the crop are scheduled to begin soon.
Simon Gichuki, director of the biotechnology department at the
Kenya Agricultural Research
Institute (KARI) said the new variety will have to be taken
through field trials before its resistance is fully proven.
He says KARI has used the approach to develop varieties of crops
such as pawpaw and sweet potato but some field trials were
unsuccessful. "The environment in the green house is different
from out there in the farms," Gichuki told SciDev.Net. Field
trials will also assess the new crops' impact on the
environment, he added.
Gichuki added that getting new plants to farmers takes time, as
any new resistant crop has to pass regulations and national
trials to determine their distinctiveness, uniformity and
stability.
The researchers also looked at 389 Ugandan MSV samples to assess
the diversity and genetic characteristics of the virus.
They found that most prevalent strains of MSV are a product of
recombination of different viral genotypes, a process that
helped highlight how the virus has evolved to cause disease in
crops.
Related SciDev.Net articles:
GM maize 'could help fight against iron-deficiency'
Wheat, maize and food security
Related links:
Kenya Agricultural Research
Institute
RELATED RELEASE:
First all-African produced
genetically engineered maize is resistant to maize streak virus
Other news
from Pannar |
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