With Apples, All Roads Lead to Central Asia

Ever heard the saying, "The apple doesn't fall far from the tree"?

Well, the truth is that most apples that we love to eat do fall far—as in "the-other-side-of-the-world far”—from their original home!

Phil Forsline, a horticulturist with the Agricultural Research Service (ARS) Plant Genetic Resources Unit in Geneva, New York, says that the family history of the apples that are enjoyed everywhere today can be traced back to trees that grew thousands of years ago deep in the middle of the continent of Asia. Yes, even the yummy types that we love, like Red Delicious, Golden Delicious, and McIntosh began there!

Central Asia—especially the rugged, mountain-filled countries known today as Kazakhstan and Kyrgyzstan—is where traders and explorers discovered apples centuries ago.

Early traders and explorers took those apples along with them, and wound up spreading the apple seeds all over the world. On this continent, the process was helped along by a man named John Chapman. You may know him by his nickname: “Johnny Appleseed.” He planted apple trees throughout the wilderness that today is the location of Pennsylvania, Ohio, Indiana, and Illinois.

Naturally, the apples that were spread around the globe were the best-tasting and best-looking ones that Central Asia had to offer. That was great for people who ate the apples.  But it was bad for those who grew them.

Why? It all comes down to genes. Genes are sort of like instruction manuals located inside the cells of living things. Genes are passed down from parents to offspring and control how living things look and behave.

Those fine-looking, good-tasting apples didn't have all the genes in them that they needed to fend off attacks by plant diseases and fungi that were present at the new locations. Many of the most protective genes were in smaller, less tasty apples overlooked by the ancient traders. So U.S. apple growers have had to worry a lot about bad diseases like apple scab and fire blight that could ruin their crops.

Help Is on the Way

Now, ARS scientists in Geneva are working to use seeds, roots, and other parts from apple trees in Central Asia to make U.S. apples stand up better to those diseases. During the 1990s, the U.S. Department of Agriculture sent scientists to Asia and Europe to collect seeds, rootstocks, germplasm, and other material from trees that can link U.S. apple trees to their Asian ancestors. 

Rootstocks are the underground part of plants to which different tops can be attached, or grafted, to create a stronger or better new plant. Germplasm is material—like seeds in plants—that contains the features of a plant or animal. When genes from two “parent” plants or animals are combined through crossbreeding, for example, their features are carried to the next generation.

In all, the scientists collected 130,000 seeds from 949 apple trees in the wilds of Central Asia alone! In addition, they collected cuttings of the most interesting 50 trees that they observed. These were grafted, and now Forsline and his fellow researchers have exact replicas of those 50 trees growing at the ARS Plant Genetic Resources Unit in Geneva.

Forsline and plant geneticist Gennaro Fazio are finding that some of that plant material from Asia can indeed help make our apple trees stand up better to diseases. In groves and greenhouses outside of Geneva, they’ve planted seeds and trees from Kazakhstan and then tested them against diseases. They've also mixed the germplasm of those trees with that of U.S. trees, and have grafted U.S. trees to Asian rootstocks.

Forsline says the Kazak trees showed excellent resistance to apple scab, and they did fairly well against fire blight. Fazio found that the Kazak rootstocks could fend off microbes in the soil that cause diseases such as collar rot.

So, who knows? By the time everything’s said and done, distant Asian relatives of today’s apple trees may one day lead to better apples than the world has ever known and even change the entire apple industry.

By Luis Pons, formerly Agricultural Research Service, Information Staff.

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