Able to quickly decimate wheat crops and send the world’s poor spiraling into famine, Ug99 is a major threat. A virulent strain of stem rust first discovered in Uganda in 1998, Ug99 has been in researchers’ crosshairs for a decade.
For more, see Ug99.
During the week on June 13, wheat disease researchers from around the world have attended the annual meeting of the Borlaug Global Rust Initiative, held in Minnesota. On Wednesday morning during a break from the proceedings, Ronald Coffman, director of Cornell University's Durable Rust Resistance in Wheat project, spoke with Delta Farm Press about Ug99’s progression, expectations for research, and the need for agricultural research funding. Among his comments:
On the conference highlights…
The initiative “focuses on three broad areas: surveillance, plant breeding and developing improved varieties resistant to Ug99, and ‘pre-breeding’ or the identification of new sources of resistance to this race of stem rust.
“As far as surveillance, we’ve learned that this disease is now widely distributed. It originated in Uganda (and was identified in 1988) and was named in 1999. It has been moving through Africa since. It’s now distributed down the entire east coast of the continent from (the southern portion of the Arabian peninsula in) Yemen all the way down to South Africa.”
On Ug99 in the Southern Hemisphere…
Ug99’s movement south through Africa “is noteworthy because it’s now in South Africa and is poised to move into the southern cone of South America and/or Australia.”
Presentations at the conference have shown “disquieting slides on how wind currents move things out of South Africa.”
This was illustrated “through the recent volcano eruption in South America. The winds have already carried that ash as far as Australia. We know those winds are operating in the southern hemisphere and could move the rust spores.
“The viability of those spores at high altitudes is something open to question. But the possibility of movement is certainly there.”
Ug99 in the Northern Hemisphere…
“In Yemen, there are currently all sorts of social and political problems. We can’t get in to learn very much about what’s going on – but we know the disease is there.
“We don’t think it’s epidemic. However, if it goes epidemic we won’t be able to do much about suppressing the spore load. There will be a lot of inoculum produced and winds out of Yemen can blow the spores in most any direction – especially into south Asia where you have the largest vulnerable population in India and Pakistan.
“We were talking last night about this and believe India, Pakistan and surrounding countries probably have single largest concentration of wheat in the world, even larger than China. And certainly the number of people dependent on wheat there is enormous. That area worries us very much.”
What about Iran? There were earlier reports that it had moved there. And there were worries Ug99 was poised to move into Syria. Has it moved farther north?
“It had been reported in Iran. However, the Iranians moved quickly to get out resistant material and the following year it wasn’t detected. The following year, it was detected again but there is no significant population.
“Indeed, it has been recorded in Iran but there is no indication it is developing there. The Iranians are on top of it.
“We’re more worried about it blowing into south Asia from Yemen.
“It hasn’t moved into any of the other Middle Eastern countries yet. Of course, it is quite inevitable that it will.”
Research
On ‘pre-breeding’…
“With pre-breeding we’re trying to identify new sources of resistance. The long-term goal is to use molecular techniques -- not transgenic, but using conventional breeding to incorporate genes – to determine which genes are present.
“In the past, using conventional breeding methods, you might incorporate one major gene for resistance. Then, when you try to incorporate another you can’t tell whether you have (the gene), or not. That’s because the first gene is causing resistance. So, it’s hard to screen.
“However, now we have molecular techniques that tell us of the presence or absence of a gene.
“So, our long-term strategy is to stack those genes up. Theory tells us if we have several genes deployed together, the fungus won’t be able to overcome them. That will provide durable resistance.