Hvede: Ny slem svampe-variant – denne gang i Sydafrika

JOHANNESBURG, 3 September 2012 (IRIN): As the world’s supply of staple grains (grundnæringsmidler såsom korn) grows tight, scientists are learning about the discovery in South Africa of yet another deadly variant of Ug99 stem rust (stængel-skimmel), a virulent fungal disease (ondartet svampesygdom) that can devastate wheat crops within weeks.

The world’s top wheat scientists are gathering in Beijing, China, for a global symposium on the rapidly mutating (gendanner sig ved foran-dring) disease, organized by the Borlaug Global Rust Initiative (BGRI).

The discovery of the new variant brings the total number of new forms of Ug99 in South Africa to four, scientists at the forum told IRIN.

“There are two possibilities for the surfacing of Ug99 variants in South Africa,” said Zacharias Pretorius, professor of plant pathology at the University of the Free State, in South Africa:

“Firstly, migration of the fungal spores (svampe-sporer) by wind movement from countries to the north of us, where we have detected similar races mutations. Secondly, I believe that at least one of the four variants developed locally through mutation.”

Fortunately, Pretorius said, the wheat race (sort) that seems particularly susceptible (modtagelig) to the new Ug99 variant is not very popular among consumers. Still, the emergence of this new rust variant is an indication of how virulent the fungus remains.

It also places the wheat fields in Australia, one of the world’s major producers, under threat.

Dave Hodson, a scientist with the Mexico-based International Maize and Wheat Improvement Centre (CIMMYT), points out that stem rust spores have travelled from South Africa to Australia three times before – the last time in 1973.

When spores of the fungus travelled from South Africa to Australia in 1969, it caused outbreaks that destroyed hundreds of thousands of dollars of wheat.

The polio of agriculture