AGRICULTURE REPORT - Hybrids
AGRICULTURE REPORT - Hybrids 2
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Broadcast: Tuesday, June 08, 2004
This is Steve Ember with the VOA Special English Agriculture Report.
Since ancient times, farmers have chosen the seeds for the coming year from the biggest and best plants in their crop. The hope is that these seeds will have the same good qualities as their parent plants. This method is called inbreeding. But experts say it is not the best way to develop seed with strong, healthy qualities over time.
In nineteen-oh-six, the genetic 3 researcher G.H. Shull started work on breeding corn in New York State. He found that if he mated two inbred groups of corn plants, he could create a stronger new line of corn. This process is called crossbreeding. It produces hybrids from putting together different kinds of related plants.
Researchers soon recognized that they could crossbreed four inbred lines of corn. The result is stronger than corn crossbred only once. Hybrid 1 corn first appeared in nineteen-twenty-one. Today, almost all corn planted in the United States is hybrid. And farmers harvest about seven times more corn from each hectare than they did seventy years ago.
Corn is not the only hybrid crop. Yuan Longping is called the Father of Hybrid Rice. He and other Chinese scientists worked on this idea in the nineteen-sixties and seventies. The first hybrid rice appeared in nineteen-seventy-four. Mister Yuan used three lines of parent seed that produced fifteen to twenty percent more grain. By nineteen-ninety-five, half of all the rice grown in China was hybrid.
There are also hybrid animals. Long ago, farmers discovered that a female horse mated with a male donkey produces a mule 4. This animal is strong and good for work, although it cannot reproduce.
In the early nineteen-eighties, American fish farmers wanted to raise striped bass 5. This fish had almost disappeared from the wild. So researchers created a fast-growing hybrid bass. By two-thousand, fish farmers harvested almost seven-million kilograms of the new sunshine bass.
Hybrids are not the answer to every problem in agriculture. New hybrid seeds must be bought each year. They also cost more than other seed. Hybrids can take many years to develop. And not all crops can be crossbred successfully. But hybrids have been an important development for productivity.
This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.
- That is a hybrid perpetual rose.那是一株杂交的四季开花的蔷薇。
- The hybrid was tall,handsome,and intelligent.那混血儿高大、英俊、又聪明。
- All these brightly coloured hybrids are so lovely in the garden. 花园里所有这些色彩鲜艳的杂交花真美丽。 来自辞典例句
- The notion that interspecific hybrids are rare is ill-founded. 有一种看法认为种间杂种是罕见的，这种看法是无根据的。 来自辞典例句
- 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。
- A mule is a cross between a mare and a donkey.骡子是母马和公驴的杂交后代。
- He is an old mule.他是个老顽固。