VOA标准英语2010年-Plant Scientists Fight Hunger Through

The United Nations is observing World Food Day (Saturday, Oct. 16). Food prices have been climbing in recent months because of bad weather in several major agricultural regions. Experts predict there will be more extreme weather as climate changes, jeopardizing¹ food supplies around the world. And that's in addition to the constant threats of pests, weeds, and disease. But scientists think they have a way to feed the ever growing human population.

In a greenhouse here at the University of Maryland, researchers are growing the next generation of wheat. Their goal is to help Maryland farmers deal with a disease that claimed half their wheat crop last year. Researcher Jose Costa leads the effort. "We're looking here at healthy seed, and then scabby seed," he said.

Wheat scab is a fungus² that turns the grains white...and poisonous.

"It causes vomiting³ in humans. So, we don't really want that in our bread or cookies," said Costa.

Scab is just one disease that infects wheat worldwide.

But just like some people don't get as sick as others, Costa says some wheat varieties are less likely to get scab. "One of them is from China. Ning 7840 that has scab resistance," he said.

The challenge, Costa says, is to mate a local wheat variety that produces a lot of grain with the Chinese variety that's resistant⁴ to scab - but doesn't produce as much. "One or two plants in a thousand [will] carry the right combination of genes⁵," he said.

Recent advances in genetics make the job easier.

Scientists are mapping the entire genetic⁶ code of wheat. They've already figured out the location of some of the key genes, including those for scab resistance and productivity. And to locate them quickly, they've found small stretches of DNA⁷ called markers, says graduate student Lydia Cardwell.

"Just like in real life you would use a landmark⁸ when you give directions, we use markers," she said.

Scientists mate the wheat plant from Maryland with the one from China by cross pollinating them.

Until recently, they relied on big test fields like this one to find that one-in-a-thousand plant that was both resistant and productive.

Now, they grow the plants in a room-sized incubator.

They extract the genetic material from a small piece of each offspring and look for the markers. That way they can identify the offspring they're looking for.

Costa says out in the field, some plants just get lucky and escape infection. "With markers, now we can tell if they do have the genes or not," he said.

Costa says with the challenges facing farmers - climate change, population growth, and the never-ending battle with pests and disease - he'll need all the help he can get. "It's the best we can do at this time. But it gives us a lot more weapons than what we had before," he said.

Costa hopes those same weapons will allow researchers around the world to ward⁹ off the looming¹⁰ threat of hunger.
 

1 jeopardizing   

危及，损害( jeopardize的现在分词 )

参考例句：

• Plans may also become inefficient in the attainment of objectives by jeopardizing group satisfactions. 用危及群体利益方法去达到目标的计划，也是无效率的。
• That boosted government revenues in the short term, but is now jeopardizing them. Morales将天然气工业，电信业和部分采矿业收归国有的举措吓跑了投资者们。

2 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

3 vomiting   

吐

参考例句：

• Symptoms include diarrhoea and vomiting. 症状有腹泻和呕吐。
• Especially when I feel seasick, I can't stand watching someone else vomiting." 尤其晕船的时候，看不得人家呕。”

4 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

5 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

6 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

7 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

8 landmark   

n.陆标，划时代的事，地界标

参考例句：

• The Russian Revolution represents a landmark in world history.俄国革命是世界历史上的一个里程碑。
• The tower was once a landmark for ships.这座塔曾是船只的陆标。

9 ward   

n.守卫，监护，病房，行政区，由监护人或法院保护的人（尤指儿童）；vt.守护，躲开

参考例句：

• The hospital has a medical ward and a surgical ward.这家医院有内科病房和外科病房。
• During the evening picnic,I'll carry a torch to ward off the bugs.傍晚野餐时，我要点根火把，抵挡蚊虫。

10 looming   

n.上现蜃景（光通过低层大气发生异常折射形成的一种海市蜃楼）v.隐约出现，阴森地逼近( loom的现在分词 )；隐约出现，阴森地逼近

参考例句：

• The foothills were looming ahead through the haze. 丘陵地带透过薄雾朦胧地出现在眼前。 来自《简明英汉词典》
• Then they looked up. Looming above them was Mount Proteome. 接着他们往上看，在其上隐约看到的是蛋白质组山。 来自英汉非文学 - 生命科学 - 回顾与展望