Search Challenge (Wed Aug 25, 2010): Where did seedless grapes come from?

As I was driving through California's central valley the other day, I went past mile after mile of grape vines, rolling off into the distance.  Some of these were industrial wine grapes... but the vast majority were (I knew from reading elsewhere) seedless grapes for eating (either fresh or as raisins).

And that made me wonder--what's the backstory on seedless grapes?  It can't be an evolutionary boon to be seedless after all, so it must have been some human intervention that made seedless grapes possible.

So for my own education I wanted to look up the story about how seedless grapes came to be.

If you were a reference librarian, you might think "uh oh, this is VERY ambiguous."  And you'd be right.  But this is my internal intent, my only slightly-processed question.  A big part of the sensemaking story (particularly wrt search) is how to transform your vaguely-described-task-intent into actions and search questions you can actually satisfy.

But for the purposes of this blog, let me dissect the question a bit more into a few parts:

1.  Where did the first seedless grape originate?  (Can I get a lat/long??) 
2.  What's the story behind its production?
3.  If it diverged from a previous kind of grape, what was that progenitor?  

Good luck!