What is the fastest growing fruit tree?
Tomatoe. Yes there are tomatoe "trees'. For what you really want my guess would be fig.
Red delicious is considered to be the fastest growing fruit tree. Other trees include yellow delicious and early harvest apple, which can also produce a significant crop. Visit http://www.ehow.com/facts_4912189_what-fastest-growing-fruit-tree.html for more details.
Well, from experience, blueberry trees!