"A strain of Cannabis, almost solely of the Indica variety. The name "Kush" originates from the Hindu-Kush mountains where it was cultivated for thousands of years. This sweet smelling plant is part of the Cannabis Indica family, which leads the plant to be short and squat in appearance. Some forms of Kush, however, are in fact a hybrid between Cannabis Indica and Cannabis Sativa...which leads to greater harvests. Varieties of the Kush plant include,(But are not limited to), Hindu Kush, OG Kush, Purple Kush, Master Kush. Many crossbreeds exist as well."

google that shit. You get the same answer on multiple sources. And in my opinion cali is all hype. I have been to Venice Beach, many many times smoked the grand daddy, shishkaberry, green crack, blah blah blah, good stuff and all. But probably was bred somewhere else not to mention it doesn't come close to master kush, black jack, chocolope, c99 the list goes on dude. Now I am not bagging on cali, I do admit some dank shit comes out of cali, but to say its the best is arrogant. Its like comparing the wisdom between a child and a great grandfather. Sorry cali try's to hold it down MAD PROPS for getting the cog moving I hold no ill feelings towards their bud its dank. They just don't run the bud show.