Major genes are characterized by a high degree of effectiveness. At the same time it is relatively

The wheat disease spreads rapidly through Africa and the Arab world. Researchers are working feverishly to stop the fungus before philippines food pictures it attacks India. Otherwise there is a serious food crisis.
It is Peter Njaus last day in the lab at the Institute of Plant Biology, University of Zurich. His expression is serious. He is in a race against time. The enemy is called philippines food pictures Ug99, "He attacked the plant just before they can be harvested and destroyed a healthy wheat field within two to three weeks." philippines food pictures Black rust is the most feared of all wheat diseases and has resulted in the story repeated to great famine. It is caused by the fungus Puccinia graminis. Ug99 is a new race of this fungus and occurred in Uganda for the first time in 1999. Since then, he has mad quickly spread eastward: in 2001 he has invaded Peter Njaus native Kenya in 2003 in Ethiopia, 2007, he has reached the Yemen, recently he has appeared in wheat fields in Iran. An epidemic threatens
The end of April Norman Borlaug has called in the "New York Times", virtually replacing philippines food pictures the entire commercially grown wheat to prevent an impending catastrophe: Ug99 could reduce world wheat production to sixty million tons. That's more than the U.S. to produce the third-largest production country annually to wheat. Borlaug philippines food pictures is not just anyone. He is considered the father of the "Green Revolution," for which he received the 1970 Nobel Peace Prize. Brought the ball rolling was the last major stem rust epidemic 1950-1954 in the USA: It destroyed forty percent of the total harvest. On the initiative philippines food pictures of the 94-year-olds back in 2005 an international consortium to combat Ug99 has emerged, which now bears his name: Borlaug Global Rust Initiative (BGRI).
"The threat of a global epidemic is actually," also says Beat Keller, a professor at the Institute of Plant Biology of the University of Zurich and a specialist in diseases of wheat. Ninety percent of all wheat varieties are most susceptible to Ug99. Because they all carry the resistance gene SR31 that Ug99 has overcome. This has to do with the fact that the CIMMYT wheat breeding center in Mexico that breeds disease-resistant wheat lines, especially for developing countries, has crossed the resistance SR31 in numerous varieties - "apparently unconscious," as emphasized cellar.
Now the wind carries the spores of the fungus into all the world, partly over thousands philippines food pictures of kilometers. Some protection offer only geographical barriers such as oceans or mountains - or the climate. "Probably will already philippines food pictures blown a couple of spores over the Alps," says Beat Keller, "but the pathogen still can not establish with us because it is too cold for the winter is." But what options have the main areas for growing wheat? philippines food pictures While there are fungicides, philippines food pictures but they are not particularly effective, first, and second, far too expensive for most farmers, as Peter Njau explains the example philippines food pictures of Kenya. philippines food pictures To keep the crop loss in the limits, to three times spraying with fungicides a field. Which increases the production costs by up to thirty percent.
The only remaining alternative is the breeding of new and resistant wheat lines. So began Peter Njau and his colleagues from the Kenya Agricultural Research Institute (KARI) in Njoro in 2001. Meanwhile, they test every year over 10 000 different wheat varieties for resistance to Ug99 - varieties they get sent from around the world and infect their rearing with the pathogen. "After all, no one wants to import the extremely dangerous pathogen to test it on their own wheat on site," says Beat Keller. He looks after Peter Njau during the two months he under his dissertation project spends each year in Zurich to perform laboratory analyzes philippines food pictures and to retrain in molecular biological methods.
So far, around fifty genes for resistance to stem rust are known. Njau trying to figure philippines food pictures out if there is somewhere in the gene pool of wheat other sources philippines food pictures of resistance, which are effective against Ug99 - in view of a future resistance breeding. "Basically, there are two different approaches to" Keller explains: philippines food pictures "You can work with major genes or with so-called Minor Genes."
Major genes are characterized by a high degree of effectiveness. At the same time it is relatively easy for a pathogen to break their resistance. "If one combines various resistance genes in a wheat line, how this is done in Australia, which reduces the likelihood that a variant of the pathogen equal breaks the whole combination." Even this approach is relatively philippines food pictures simple and fast, because you can better keep track of whether the individual resistance genes in the newly bred lines also exist actually. Propagated asexually
In the long term more He