BACKGROUND: When we buy apples at the store, they don't come from seeds, but a 2,000-year-old technique. This involves grafting the shoots and branches of an existing apple tree, called a scion, onto a new trunk and root system -- called a rootstock -- and planting the hybrid in the ground. Scientists are now trying to determine the links between specific genes and the most desirable apple traits, especially disease resistance.
WHY WE NEED CLONES: If you plant a Golden Delicious apple seed, you won't get a tree that produces Golden Delicious apples. Each seed has too much genetic variability. Usually this produces a crab apple, the "mutt" of the apple world. Apple breeders must make clones of Gala or Macintosh or other specific varieties, every generation. It has less to do with genetics and more to do with influence. Rootstocks seem to switch on dormant genes already present in the scion.
FUN APPLE FACTS:
- The science of growing apples is called pomology
- The Greeks, Etruscans, and Romans all practiced grafting their favorite apple varieties to other apple rootstocks
- 7,500 varieties of apples are grown throughout the world
- In 2001, Americans ate an average of 45.2 pounds of fresh apples and processed apple products
- The pilgrims planted the first U.S. apple trees in the Massachusetts Bay Colony
- The largest apple ever picked weighed three pounds
- Actress Gwyneth Paltrow named her baby daughter Apple