What drove the development of major business centers in the south after the civil war?

Mostly the fact that the carpetbaggers, or Yankees seeking to make a fortune in the war torn south. Entrepreneurship began afterward, as well as the Reconstruction era, but most major centers didn't come about until the 1870's because the Reconstruction era was such a flop. Major Business centers were created mostly at the center of agricultural areas and in ports. 

Farm land would be my guess