Cannabinoid Composition of F1 Hybrids between "Drug" and "Non-drug" Strains of Cannabis
E. Small and H. D. Beckwith. 1979. In E. Small, The Species Problem in Cannabis. Corpus. Toronto. p 121-127
Abstract Twenty-five sets of F1 hybrids [an F1 hybrid means the plants grown from the seed of a cross pollination between types] , mainly between "drug strains" of Cannabis (those in which the resin is chiefly of tetrahydrocannabinol[THC]) and "non-drug strains" (those in which the resin is composed chiefly of cannabidiol [CBD]) were examined. The majority of these were chemically intermediate between their respective parents, showing no dominance toward either parent.
[So, in the plants grown from the resulting seed (the "F1" generation), THC went down with respect to the "marijuana" parent and up with respect to the "hemp" parent. The converse was true of CBD.]
Discussion:
...It appears that generally crosses between drug strains and non-drug strains produce plants of intermediate potency.
...[In studies of drug strains...] The importance of protecting the [genetic] stock against contamination from pollen by non-drug strains is stressed by the fact that the amount of THC may be halved in hybrid plants.
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What these authors don't go on to discuss is what would happen next, in practical terms.
We know, then, that the first generation has been degraded by half. If that "mixed-blood" seed is grown hidden again among hemp plants that will again provide the pollen, then the next generation will again lose by half, gradually by this means (it's called a "backcross" by plant breeders) converging toward the hemp type. But it is unlikely it would get that far as the material would be undesirable after the first contamination.
This is why marijuana growers want to stay away from hemp.
E. Small and H. D. Beckwith. 1979. In E. Small, The Species Problem in Cannabis. Corpus. Toronto. p 121-127
Abstract Twenty-five sets of F1 hybrids [an F1 hybrid means the plants grown from the seed of a cross pollination between types] , mainly between "drug strains" of Cannabis (those in which the resin is chiefly of tetrahydrocannabinol[THC]) and "non-drug strains" (those in which the resin is composed chiefly of cannabidiol [CBD]) were examined. The majority of these were chemically intermediate between their respective parents, showing no dominance toward either parent.
[So, in the plants grown from the resulting seed (the "F1" generation), THC went down with respect to the "marijuana" parent and up with respect to the "hemp" parent. The converse was true of CBD.]
Discussion:
...It appears that generally crosses between drug strains and non-drug strains produce plants of intermediate potency.
...[In studies of drug strains...] The importance of protecting the [genetic] stock against contamination from pollen by non-drug strains is stressed by the fact that the amount of THC may be halved in hybrid plants.
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What these authors don't go on to discuss is what would happen next, in practical terms.
We know, then, that the first generation has been degraded by half. If that "mixed-blood" seed is grown hidden again among hemp plants that will again provide the pollen, then the next generation will again lose by half, gradually by this means (it's called a "backcross" by plant breeders) converging toward the hemp type. But it is unlikely it would get that far as the material would be undesirable after the first contamination.
This is why marijuana growers want to stay away from hemp.