Motanache

http://en.wikipedia.org/wiki/Grafting#Scientific_uses I saw a few trees grafted. Instead of making very small fruit, began to make large fruit. Whole different in shape, color. Instead of wild apples. They began producing big apples. I expect the fruit to be done after the tree genetic pattern. However, there are some living cells and theirs multiplying, is coordinated only by genetic information inside them. How could a small piece of another tree even change the color of the fruit?