In the south cane and corn syrup and molasses were common....and less expensive than refined sugars. The original recipes for pecan pie probably used them for that reason.

Personally I like the flavors that they bring, but I'm sure you could use just sugar if you wanted.

Here's my recipe, after many pecan pies, this is the one I came up with that I like the best.

http://www.hizzoners.com/recipes/coo...outh-pecan-pie