VOA慢速英语2010年-Development Report - Growing Crops Wit（在线收听）

This is the VOA Special English Development Report.

Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world's freshwater withdrawals from rivers, lakes and other water resources go toward irrigating fields.

Scientists are using biotechnology as well as traditional breeding methods to develop water-saving crops to feed a growing world.
　
Thomas Carter

Thomas "Tommy" Carter is a plant scientist in North Carolina. He works for the Agricultural Research Service in the United States Department of Agriculture. He leads Team Drought, a group of researchers at five universities. They have been using conventional breeding methods to develop and test soybeans that can grow well under dry conditions.

Tommy Carter started working on drought-resistant soybeans in nineteen eighty-one. His research has taken him as far as China, where soybeans have been grown for thousands of years.

Farmers in the United States, however, have grown soybeans for only about a century. Tommy Carter says the soybeans they grow are for the most part genetically similar. More differences, or diversification, could better protect crops against climate changes that can reduce production. Those changes include water shortages which could increase from global warming.

The Agriculture Department has a soybean germplasm collection, a collection of genetic material passed from one generation to the next. Members of Team Drought studied more than two thousand five hundred examples from the collection.

They looked at ones from the ancestral home of soybeans, Asia. They searched for germplasms that could keep plants from weakening and wilting during hot, dry summers in the United States.

Tommy Carter says they found only five. But these slow-wilting lines, he says, produce four to eight bushels more than normal soybeans under drought conditions. The yield depends on location and environment.

Scientists are also working on other plants that either use less water or use it better, or both. For example, companies like Monsanto, DuPont and Syngenta have been developing corn with reduced water needs. Monsanto expects to be ready in a few years to market its first corn seeds genetically engineered to resist drought.

And that's the VOA Special English Development Report, written by Jerilyn Watson. You can find transcripts, MP3s and podcasts of our reports -- and write comments -- at voaspecialenglish.com. I'm Steve Ember.