Big Bertha is a hybrid cross of a pure Burmese strain and a North Indian Indica.  It is the largest yielding strain held in the Reeferman strainbase, producing huge yields of marijuana with a very strong acidic smell.  The buds have an indica structure and taste of old school skunk.  Reeferman once got 3.5lbs of dried marijuana of one plant produced from a random Big Bertha Seedling!