http://www.scidev.net/sub-saharan-africa/agriculture/news/new-strain-of-wheat-pathogen-in-ethiopia-causes-alarm.html
*New strain of wheat pathogen in Ethiopia causes alarm*
28/04/14
Maina Waruru
[NAIROBI] A strain of a fungus that causes wheat stem rust is devastating
the crop in southern Ethiopia and has the potential to spread to other
countries in East Africa and the Middle East.
Scientists are racing against time to tame its potentially harmful effects
on food security, according to a statement released by the International
Maize and Wheat Improvement Center (CIMMYT) last month (26 March).
Researchers at CIMMYT, the Ethiopian Institute of Agricultural Research,
the US Department for Agriculture's Cereals Disease Laboratory and the
Global Rust Reference Center in Denmark, say the strain is similar to the
one detected in Egypt, Germany and Turkey between 2007 and 2013, but where
no impact on production was noticed.
"From spore dispersal models run by [the UK-based] Cambridge University,
the most likely movements of spores out of Ethiopia are in a south-westerly
direction - towards Kenya, Rwanda Tanzania and Uganda," says David Hodson,
a senior scientist with CIMMYT's Global Rust Cereal Monitoring Programme in
Ethiopia.
Hodson adds: "There are concerns for Kenya since one popular variety is
believed to have the same resistance gene broken down in Ethiopia. This
situation is being monitored closely, but there are no confirmed reports of
the strain in Kenya yet".
According to CIMMYT, in Ethiopia, where some 10,000 hectares are infected,
the disease has attacked digalu, a popular local variety resistant to other
types of rust. Digalu, is used to make bread, the country's staple.
"Continuous cultivation of wheat in Ethiopia provides green tissue needed
for the pathogen to survive, while highland equatorial environments may
play a role in increasing mutation rates due to high UV radiation levels
conducive for rust," says Hodson.
The latest disease caused by a strain of the fungus Puccinia graminis
produces brick-red blisters on the plant, causing grains to shrivel on the
digalu wheat, a variety resistant to types and strains including stripe (or
yellow) rust. CIMMYT says Ethiopia is Africa's biggest wheat producer.
Scientists now believe that East African highlands are hotspots for the
strain that causes wheat stem rust, including the dreaded strain called
Ug99 first detected in Uganda in 1999, and are looking at contributing
factors.
Douglas Miano, head of plant pathology unit at the department of plant
science and crop protection at the University of Nairobi, Kenya, says
favourable climate could be a contributor, but researchers must keep
developing resistant varieties.
"The tropics are always a good environment for any organism, since the
climate is conducive throughout the year. We do not have winters to break
the cycles," Miano explains.
Miano says the fungus could be controlled by genetic engineering and
developing resistant varieties that reduce interaction between pathogen and
the host.
Hodson adds that other ways of solving the problem include; good
agricultural practices, farmer awareness, use of fungicides and continued
surveillance.
This article has been produced by SciDev.Net's Sub-Saharan Africa desk.
Received on Mon Apr 28 2014 - 09:59:10 EDT