VOA慢速英语2009年-Agriculture Report - Learning the Secrets

This is the VOA Special English Agriculture Report.

Scientists now have a genetic 1 map of the potato. The project is the work of a team from fourteen countries, the Potato Genome Sequencing Consortium.

Potatoes are one of the world's leading food crops. But potato breeders currently spend ten to twelve years developing new kinds. Now they will be able to locate genes 2 for any desired trait, improving quality, nutritional 3 value and disease resistance.
　
A farmer in northern Germany plants a genetically 4 engineered kind of potato in a test field

A genome contains information about every position along chromosomes 5, the structures that hold genes. Genes direct the making of proteins which do much of the work in building an organism, whether a person or a potato. A potato has twelve chromosomes and about eight hundred forty million base pairs. This is about one-fourth the size of the human genome.

The potato genome is not yet final but it shows the order of ninety-five percent of the genes. Most potato varieties carry four separate copies of their genes. But the researchers did much of their work with a phureja, a kind of a potato that has only one copy. Richard Veilleux, a professor at Virginia Tech, provided that variety of potato.

Plant biologist Robin 6 Buell at Michigan State University also worked on the genome. She says it will improve understanding of other crops because potatoes are related to tomatoes, peppers and eggplants.

In a separate development, another team reported completing a genome of the organism responsible for late blight 7. That disease can infect potatoes, tomatoes and some other plants. It causes several billion dollars a year in agricultural losses around the world.

But late blight was also the cause of the potato famine in Ireland in the middle of the eighteen hundreds. Potato shortages caused at least one million deaths and a wave of Irish immigration to America.

The scientists say that in the short term, studies based on the new genome may help explain why the pathogen has been so aggressive. And in the long term, they say, knowing where different genetic traits may be found on the map could lead to better plants. It could also reduce the need for chemicals.

Completion of the project was announced in the journal Nature. Researchers at Harvard University and the Massachusetts Institute of Technology led the work.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. You can find all of our reports, with transcripts 8 and MP3s, at voaspecialenglish.com. I'm Bob Doughty 9.