I'm Faith Lapidus with the VOA Special English Agriculture Report.

We often think of agriculture as planting seeds and harvesting crops. But many crops do not come from seeds. Many kinds of trees and plants are grown from pieces cut from existing trees and plants. This is called grafting.

Farmers cut branches or young growths, called buds, from one plant and place them on a related kind of plant. The branch or bud that is grafted is called a scion (pronounced SY-uhn). The plant that accepts the graft is called the root stock.

Over time, the parts from the two plants grow together. The grafted plant begins to produce the leaves and fruit of the scion, not the root stock.

A graft can be cut in several ways. A cleft graft, for example, requires a scion with several buds on it. The bottom of the scion is cut in the shape of the letter V. A place is cut in the root stock to accept the scion. The scion is then securely placed into the cut on the root stock. Material called a growth medium is put on the joint to keep it wet and help the growth.

Grafting can join scions with desirable qualities to root stock that is strong and resists disease and insects. Smaller trees can be grafted with older scions. The American Environmental Protection Agency says grafting can reduce the need to use pesticides on crops. The E.P.A. found that grafting stronger plants cost less than using chemicals. Also, poisons can be dangerous to people and the environment.

Agriculture could not exist as we know it without grafting. Many fruits and nuts have been improved through this method. Some common fruit trees such as sweet cherries and McIntosh apples have to be grafted.

Bing cherries, for example, are one of the most popular kinds of cherries. But a Bing cherry tree is not grown from seed. Branches that produce Bing cherries must be grafted onto root stock. All sweet cherries on the market are grown this way.

And then there are seedless fruits like navel oranges and seedless watermelons. Have you ever wondered how farmers grow them? The answer is: through grafting.

The grapefruit tree is another plant that depends on grafting to reproduce. Grapes, apples, pears and also flowers can be improved through grafting. In an age of high-technology agriculture, grafting is a low-technology method that remains extremely important.

This VOA Special English Agriculture Report was written by Mario Ritter. Our reports are on the Web at voaspecialenglish.com. I'm Faith Lapidus.