Check out Epigenetics.
External environmental factors can turn on genes that have been inactive, and change the phenotypical expression. Sometimes it's inheritable and all future plants will have that gene switch turned on from seed. The cannabis we grow isn't very stable now because of all the crossing over the past century, so the various phenos are more easily triggered.
External environmental factors can turn on genes that have been inactive, and change the phenotypical expression. Sometimes it's inheritable and all future plants will have that gene switch turned on from seed. The cannabis we grow isn't very stable now because of all the crossing over the past century, so the various phenos are more easily triggered.