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Giáo dục Việt Nam

Monday, May 9, 2011

Scientists Develop Green Super Rice

Green Super Rice: Voanews had a focus on "Green Super Rice project". "Green" meaning enviromentally friendly because it will grow as much or more grain with fewer inputs; and "super" because it will be better able to tolerance drought, flooding, salty water, insect pests and more (IRRI).

Researchers are working to develop rice varieties which require much less water, fertilizer and pesticide than modern types of rice demand.

Rice feeds roughly three billion people in Asia alone, and is a staple food around the world. Modern rice plant varieties yield double or triple the amount of grain possible before the 1960s.

When the International Rice Research Institute (IRRI) first introduced these varieties, they were called "miracle rice" because they helped ward off famine is Asia. But they have some major shortcomings.

"When farmers don't have these fertilizers, they fail them miserably," says Jauhar Ali, an IRRI senior scientist.

Petrochemical-based fertilizers are costly and becoming more so. The same is true of the pesticides farmers use to control insects and weeds. Also, the pollution they cause is ruining aquatic ecosystems in many parts of the world.

In addition, they need to be irrigated. But experts say water supplies are increasingly challenged by urbanization and climate change.

Sustainability concerns growing

These were secondary concerns as famine loomed in the 1960s, according to Colorado State University rice researcher Jan Leach.

"[Back then, they said], 'OK, we just need more yield. We need to produce more rice,'" she says. "Now we can step back and say, 'OK, now we know how to get more rice. Now let's think about how to get more rice and be sustainable.'"

Today, IRRI is working on what it calls Green Super Rice - "green" meaning environmentally friendly - because it will grow as much or more grain with fewer inputs; and "super" because it will be better able to tolerate drought, flooding, salty water, insect pests and more.

"All this will be combined into one," Ali says, "Plus disease resistance also. And not only that. We will do it in what they like to eat."

Huge program

If it sounds like a big job, that's because it is. Each one of those traits can be controlled by multiple genes. Combining all the right genes into one plant - without using genetic engineering - takes a whole lot of plant breeding, says Anna McClung, head of a major U.S. government rice breeding center.

"The magnitude of what they're doing is really quite unique and tremendous," she says. "We're talking 10-fold more than a regular program would do. Maybe 100-fold more."

The project spans 16 countries. IRRI and the Chinese Academy of Agricultural Sciences have spent the last 12 years mating hundreds of different varieties from the world's largest rice collection.

Hidden diversity

Colorado State's Jan Leach says with that many varieties to choose from, researchers can find valuable traits hidden in the rice genome.

"Many of the traits are present, but they are not turned on until you get them into the right genetic background, or sometimes in the right environment," she says.

For example, some of the genes that help a new variety survive prolonged periods underwater came from a variety that would drown in those conditions. The genes were there, they were just switched off. Ironically, that plant is fairly good at surviving the opposite extreme: drought.

Several first-generation Green Super Rice varieties should be available to farmers in eight target countries in Asia and eight in Africa in about two years. Meanwhile, researchers continue stacking more traits into new varieties to help farmers produce more with less, in order to feed a growing world.

Steve Baragona | Washington, D.C.

Source: http://www.voanews.com/english/news/africa/Scientists-Develop-Green-Super-Rice-114938889.html

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