Posted 12-1-03

Hello! My first grade class asked the question: " What makes an apple an apple?" We decided one of the ways [to find out] was to ask a scientist. Could you e-mail us back with your scientific answer? We are anxious to hear from you! Thank you!

The reply to this teacher's question is based on a Sci4Kids phone interview between Jan Suszkiw and Phil Forsline, a horticulturist at the USDA-ARS Plant Genetic Resources Research Unit in Geneva, New York.

Apple A, B, Cs...

For starters, says Dr. Forsline of the apple, "It happens to be a fruit that grows in trees and has its origins in Kazakhstan (to learn more about this country check out the CIA's World Factbook, located on the Web at http://www.cia.gov/cia/publications/factbook/geos/kz.html.

Dr. Forsline, a horticulturist with ARS, notes the apple "Is called a pome (SAY "pom") and that the only other fruit in that same category is a pear. Pomes are fruits with five petals and five carpels, or compartments that contain seeds." The petals make up a flowering apple tree's blossoms.

The carpels, Dr. Forsline says, are arranged in a star-shaped fashion that you can see by cutting the apple in half horizontally. A little-known fact about apples is that they're related to roses because of the five-petal pattern their flowers both share. So, these features are what make an apple an apple.

From Kazakhstan to the United States...

Humankind's love affair with the pome fruit can be traced back several thousand years to the Central Asian country of Kazakhstan and the beginnings of trade along routes connecting the East (think China, for example) and the West (Europe). "As the dawn of agriculture started around 8,000 to 10,000 years ago," says Dr. Forsline, "trade routes opened up from the East to the West, and traders most likely found these beautiful apples growing in the forests." Finding the apples tasty and satisfying, these traders kept some of the fruit as specimens, eventually planting them in new areas.

Not surprisingly, hungry bears like the fruit too. In fact, Dr. Forsline credits bears and other animals with helping make sure the tastiest breeds of apple got spread around the most. "The apple very well may have been selected by animals such as bears," he says. "Bears have been selecting the fruit based on their eating quality."

It might've began when hungry bears scavenging for food in Kazakhstan's mountainous regions came across a tree or trees with especially tasty fruit. Chances are these apple-loving bears kept returning to their favorite trees, each time pooping the seed somewhere else so that it had a chance to sprout, grow and bear fruit in new areas. Who knows, maybe some of these trees happened to be near a trade route traveled by apple-loving humans, who collected specimens and carried them far and wide.

I've probably crunched history's time clock quite a bit, but eventually, such apples found their way to Europe and later--starting in the 1600s--aboard the ships of European settlers sailing to the "New World": America. That's where things really kicked in, first with the establishment of seedling orchards--thanks to the efforts of enthusiasts like Johnny Appleseed (John Chapman)--and more recently, with the use of tree-grafting techniques.

Dr. Forsline credits these early seedling orchards with fueling a kind of explosion of genetic diversity that has given rise to the apple varieties we eat today, including Red Delicious and Macintosh. In fact, there was a kind of rebound effect, whereby tasty, new apple breeds that got their start in America wound up finding favor among consumers in Europe and other parts of the world. "That's what makes the apple very American," Dr. Forsline says. In a sense, apples from America's early orchards "are the forebearers of today's varieties, globally," he adds.

Diving into the Gene Pool...

But Dr. Forsline and other apple researchers aren't content to rest on past successes. New apple diseases, pests and changing consumer trends have scientists on the constant look-out for new sources of apple genes that can pass along traits for resistance to those diseases or insects like the codling moth. New genes may even hold the key to unlocking exciting new flavors within the fruit that apple lovers have never even tasted before.

For these and other reasons, Dr. Forsline and fellow scientists often travel to Kazakhstan and other apple birthplaces so that they can collect specimens of locally grown apples or their wild relatives. The name for these specimens is "germplasm." Such germplasm often includes seed that, with luck, is packed with useful new genes.

By tapping into this collection, or "gene pool," today's apple breeders can create a new generation of varieties to meet the challenges of tomorrow.

"Perhaps 50 years from now we'll be talking about apples with new flavor components or disease resistance resulting from the Kazakhstan gene pool," says Dr. Forsline.

-- By Jan Suszkiw, ARS Sci4Kids, and Phil Forsline, ARS Plant Genetic Resources Research Unit, Geneva, New York.

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