Although most translations of Genesis only refer to a “fruit,” generally people envision the downfall of humanity to be an apple (thanks a lot, Adam and Eve).  This association likely comes from a Latin play on words.  In Latin, malum is the word of “apple” and “evil.”  One source notes that the fruit probably wasn’t an apple because it is too hot in the Middle East (thus, the Garden of Eden) for apples to thrive. 

This source is probably looking too far into things…   Eve was just created from a rib.  A snake just talked.  I don’t think an apple growing in an atypical climate should really be that shocking.