2004-6-7
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 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 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. 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. 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.