晨读英语美文60篇六级58（在线收听）

[00:00.00]Genetically Modified Foods—Feed the World?

[00:03.67]If you want to spark a heated debate at a dinner party,

[00:08.68]bring up the topic of genetically modified foods.

[00:11.75]For many people, the concept of genetically altered,

[00:15.46]high-tech crop production raises all kinds of environmental,

[00:19.73]health, safety and ethical questions.

[00:22.70]Particularly in countries with long agrarian traditions—

[00:26.62]and vocal green lobbies—

[00:28.71]the idea seems against nature.

[00:30.77]In fact, genetically modified foods are already very much a part of our lives.

[00:36.46]A third of the corn and more than half the soybeans

[00:40.18]and cotton grown in the US last year were the product of biotechnology,

[00:44.99]according to the Department of Agriculture.

[00:47.63]More than 65 million acres of genetically modified crops

[00:52.32]will be planted in the US this year.

[00:54.53]The genetic is out of the bottle.

[00:57.03]The issue is simple and urgent:

[00:59.54]Do the benefits of biotech outweigh the risks?

[01:02.72]The statistics on population growth and hunger are disturbing.

[01:07.09]Last year the world’s population reached 6 billion.

[01:10.58]And by 2050, the UN estimates,

[01:13.77]it will probably near 9 billion.

[01:16.30]almost all that growth occer in developing countries.

[01:20.00]At the same time,

[01:20.82]the world’s available cultivable land per person is declining.

[01:25.40]The UN estimates that nearly 800 million people

[01:29.45]around the world are undernourished.

[01:31.53]The effects are devastating.

[01:33.40]How can biotech help?

[01:35.57]Biotechnologists have developed genetically modified rice

[01:39.73]that is fortified with beta-carotene --

[01:42.04]which the body converts into vitamin A—

[01:44.54]and additional iron,

[01:46.30]and they are working on other kinds of nutritionally improved crops.

[01:50.78]Biotech can also improve farming productivity in places

[01:54.71]where food shortages are caused by crop damage attribution to pests,

[01:59.65]drought, poor soil and crop viruses, bacteria or fungi.

[02:04.47]Damage caused by pests is incredible.

[02:07.19]The European corn borer, for example,

[02:09.71]destroys 40 million tons of the world’s corn crop annually,

[02:14.20]about 7% of the total.

[02:16.37]Incorporating pest-resistant genes into seeds can help restore the balance.

[02:21.51]In trials of pest-resistant cotton in Africa,

[02:24.59]yields have increased significantly.

[02:27.20]So far, fears that genetically modified,

[02:30.50]pest-resistant crops might kill good insects as well as bad appear unfounded.

[02:36.50]Viruses often cause massive failure in staple crops in developing countries.

[02:41.97]Two years ago, Africa lost more than half its cassava crop—

[02:46.01]a key source of calories—

[02:47.88]to the mosaic virus.

[02:49.52]Genetically modified,

[02:51.06]virus-resistant crops can reduce that damage,

[02:53.78]as can drought-tolerant seeds in regions

[02:57.17]where water shortages limit the amount of land under cultivation.

[03:00.69]Biotech can also help solve the problem of soil that contains excess aluminum,

[03:06.24]which can damage roots and cause many staple-crop failures.

[03:10.09]A gene that helps neutralize aluminum toxicity in rice has been identified.

[03:16.00]Many scientists believe biotech could raise overall crop productivity in developing countries

[03:22.10]as much as 25% and help prevent the loss of those crops after they are harvested.