"Granddaddy Purple is an indica marijuana strain that goes by many different names, including "Grand Daddy Purp," "Granddaddy Purps," "GDP," and "Grandaddy Purple Kush." Popularized in 2003 by Ken Estes, Granddaddy Purple (or GDP) is a famous indica cross of Mendo Purps, Skunk, and Afghanistan."

-Leafly