In the late 60's and early 70's, there was a small group of guys in california and Arizona bringing in mountains of mexican and south american weed. I used to drive to Arizona twice a month and pick up 200 lbs wrapped in mexican newspaper. There were some bikers in the bunch that hired a couple of horticulturist from Berkley to cross the short flowering plants from pakistan and afghanistan with usual mexican to increase the yeild and speed up the flowering time of the mexican. It seems like those first hybrids started showing up around 74
Hybrid cannabis as we know it was invented on a dirt farm in mexico at the direction of smugglers and bikers. These roughnecks on both sides of the border gave us the first hybrids and layed the groundwork for the others that we know today to begin serious breeding work.
They were the most important breeders.