GrowingHigher
Active member
Cannabigerol (CBG) dominant plants are becoming the rage for next season among smokeable/raw hemp flower growers (almost entirely due to the USDA interim rule making most CBD varieties susceptible to testing hot).
So I want to discuss and compile some information about breeding for CBG varieties that will pass for compliance.
Firstly some background:
Identification of a New Chemotype in Cannabis sativa : Cannabigerol - Dominant Plants, Biogenetic and Agronomic Prospects
-CBG dominant plant first ID'd by Fournier at al, 1987.
The draft genome and transcriptome of Cannabis sativa
Gene duplication and divergence affecting drug content in Cannabis sativa
-showed there were multiple THCAS/CBDAS sequence homologs in individual plants
Sequence heterogeneity of cannabidiolic- and tetrahydrocannabinolic acid-synthase in Cannabis sativa L. and its relationship with chemical phenotype.
-different synthases have different efficiencies (CBDAS is leaky towards THC production to various extents; null alleles are variable in their production of some THC/CBD)
-some synthase alleles result in the expression of multiple synthase enzyme variants.
-expression levels of synthases doesn't seem to determine cannabinoid levels
A physical and genetic map of Cannabis sativa identifies extensive rearrangements at the THC/CBD acid synthase loci.
This paper shows (at least for one variety of fiber hemp (Finola) and one marijauna (Purple Kush)) that the fiber-derived linked cannabinoid synthases (CBDAS, THCAS) are very different in their arrangement. This suggests:
- A lot of derivation once the two gene pools separated.
-The putative THCAS identified by Kojoma et al, 2006 in hemp are actually CBCAS. Both Purple Kush and Finola had CBCAS.
The Inheritance of Chemical Phenotype in Cannabis sativa L
This paper talks about chemotype inheritance and crosses a fiber-dervied CBG variety to a high THC drug variety. in the F2 the CBG segregates, and again produces no detectable THC:
The inheritance of chemical phenotype in Cannabis sativa L. (IV): cannabinoid-free plants.
This 2009 deMiejer Paper talks about the inheritance of cannabinoid free plants and an alternative CBG producing genotype derived from the USO-31 hemp variety. This variety apparently has two gene knockouts; one that prevents cannabinoid production when homozygous and severly suppresses it in heterozygotes, and another that blocks CBD production causing CBG to accumulate. The USO-31 derived region responsible for CBG accumulation produces extremely pure CBG (99.75% of cannabinoids) with residual CBD (0.25%).
DeMiejer also has a 2014 book chapter in the "Handbook of Cannabis" that discusses a similar cross using fiber-derived versus a marijuana-derived (high-THC variety that had a CBG variant) CBG gene region. The fiber-derived linked synthase region produce residual amounts of CBD and almost no THC. Whereas the marijuana derived CBD region variant produces residual THC.
Breeding forward:
Recently Oregon CBD made their CBG variety announcements on instagram. In their post, they explained how they crossed a marijuana derived CBG variety (that produces THC at about 1:100-200 ratio CBG:THC) with a (probably) hemp derived CBG variety that has a ratio of ~1:27. (you can see their tests here). EDIT: I had originally assumed the opposite where the fibre-derived region in The White was more efficient and less leaky.
By doing this they have rather cleverly prevented people from producing F2s that will all be compliant (though on a field level the average still would be). I suspect that, because one of their CBG variants is compliant 1:100-200 ratio plants will emerge easily among the F2 progeny, which would be truebreeding for CBG if these are inbred to F3+. Of course the MTA they have you sign means you aren't even permitted to save seed for on farm use, let alone breed with any of their germplasm, anyway.
Active THCAS and CBDAS are tightly linked, (with residual THC currently thought to result from CBDAS synthase leaking THC product (2022)).
Ultimately, I suspect for those looking to breed for CBG, if you use a Bx allele that results in high-ratio CBG:THC, you will be able to easily produce a true-breeding, CBG-dominant, THC-compliant hemp variety -with crosses mostly behaving as a simply inherited single locus with some residual THC from CBDAS.
It seems that both fiber-derived and marijuana-derived THCAS/CBDAS regions can result in CBG:THC ratios that range from~1:25 to 1:200, depending on the specific variant. It would be helpful to describe the differential efficiencies of the various Bo variants present in high-CBG varieties. If you start with a lower ratio null allele, you will be bound by the 0.3% limit to a lower total potency (~7.5% for the 1:25, to unachievable high for the very high ratio alleles).
CBG seed sources:
CanapaRoma- 8%CBG under 0.1%THC. No MTA. putatively truebreeding for complaint (at about a 1:65 THC:CBG ratio), fiber derived CBG variant.
Sovereign Fields-$2/seed, unknown specs. MTA required
HGH seed- 15+% CBG, Matterhorn CBG, $1+/seed. not sure about MTA
Oregon CBD- 15+% CBG, $1/seed, MTA required
Dutch Passion- CBG photo and auto
CannaBiogen- CBG auto?
European fiber varieties (I am not certain, but these are probably protected by plant variety protection (PVP), meaning you can save seed for on-farm use and breed with them):
Santhica-27: monecious 1-3% CBG, CBD residual
Carma - monecious ~3% CBG
USO-31- monecious. low cannabinoid, some cannabinoid free plants, some CBG dominant plants with very little residual CBD production.
Please share any relevant information on CBG breeding and seed sources. Thanks!
So I want to discuss and compile some information about breeding for CBG varieties that will pass for compliance.
Firstly some background:
Identification of a New Chemotype in Cannabis sativa : Cannabigerol - Dominant Plants, Biogenetic and Agronomic Prospects
-CBG dominant plant first ID'd by Fournier at al, 1987.
The draft genome and transcriptome of Cannabis sativa
Gene duplication and divergence affecting drug content in Cannabis sativa
-showed there were multiple THCAS/CBDAS sequence homologs in individual plants
Sequence heterogeneity of cannabidiolic- and tetrahydrocannabinolic acid-synthase in Cannabis sativa L. and its relationship with chemical phenotype.
-different synthases have different efficiencies (CBDAS is leaky towards THC production to various extents; null alleles are variable in their production of some THC/CBD)
-some synthase alleles result in the expression of multiple synthase enzyme variants.
-expression levels of synthases doesn't seem to determine cannabinoid levels
A physical and genetic map of Cannabis sativa identifies extensive rearrangements at the THC/CBD acid synthase loci.
This paper shows (at least for one variety of fiber hemp (Finola) and one marijauna (Purple Kush)) that the fiber-derived linked cannabinoid synthases (CBDAS, THCAS) are very different in their arrangement. This suggests:
- A lot of derivation once the two gene pools separated.
-The putative THCAS identified by Kojoma et al, 2006 in hemp are actually CBCAS. Both Purple Kush and Finola had CBCAS.
The Inheritance of Chemical Phenotype in Cannabis sativa L
This paper talks about chemotype inheritance and crosses a fiber-dervied CBG variety to a high THC drug variety. in the F2 the CBG segregates, and again produces no detectable THC:
The inheritance of chemical phenotype in Cannabis sativa L. (IV): cannabinoid-free plants.
This 2009 deMiejer Paper talks about the inheritance of cannabinoid free plants and an alternative CBG producing genotype derived from the USO-31 hemp variety. This variety apparently has two gene knockouts; one that prevents cannabinoid production when homozygous and severly suppresses it in heterozygotes, and another that blocks CBD production causing CBG to accumulate. The USO-31 derived region responsible for CBG accumulation produces extremely pure CBG (99.75% of cannabinoids) with residual CBD (0.25%).
DeMiejer also has a 2014 book chapter in the "Handbook of Cannabis" that discusses a similar cross using fiber-derived versus a marijuana-derived (high-THC variety that had a CBG variant) CBG gene region. The fiber-derived linked synthase region produce residual amounts of CBD and almost no THC. Whereas the marijuana derived CBD region variant produces residual THC.
Breeding forward:
Recently Oregon CBD made their CBG variety announcements on instagram. In their post, they explained how they crossed a marijuana derived CBG variety (that produces THC at about 1:100-200 ratio CBG:THC) with a (probably) hemp derived CBG variety that has a ratio of ~1:27. (you can see their tests here). EDIT: I had originally assumed the opposite where the fibre-derived region in The White was more efficient and less leaky.
By doing this they have rather cleverly prevented people from producing F2s that will all be compliant (though on a field level the average still would be). I suspect that, because one of their CBG variants is compliant 1:100-200 ratio plants will emerge easily among the F2 progeny, which would be truebreeding for CBG if these are inbred to F3+. Of course the MTA they have you sign means you aren't even permitted to save seed for on farm use, let alone breed with any of their germplasm, anyway.
Active THCAS and CBDAS are tightly linked, (with residual THC currently thought to result from CBDAS synthase leaking THC product (2022)).
Ultimately, I suspect for those looking to breed for CBG, if you use a Bx allele that results in high-ratio CBG:THC, you will be able to easily produce a true-breeding, CBG-dominant, THC-compliant hemp variety -with crosses mostly behaving as a simply inherited single locus with some residual THC from CBDAS.
It seems that both fiber-derived and marijuana-derived THCAS/CBDAS regions can result in CBG:THC ratios that range from~1:25 to 1:200, depending on the specific variant. It would be helpful to describe the differential efficiencies of the various Bo variants present in high-CBG varieties. If you start with a lower ratio null allele, you will be bound by the 0.3% limit to a lower total potency (~7.5% for the 1:25, to unachievable high for the very high ratio alleles).
CBG seed sources:
CanapaRoma- 8%CBG under 0.1%THC. No MTA. putatively truebreeding for complaint (at about a 1:65 THC:CBG ratio), fiber derived CBG variant.
Sovereign Fields-$2/seed, unknown specs. MTA required
HGH seed- 15+% CBG, Matterhorn CBG, $1+/seed. not sure about MTA
Oregon CBD- 15+% CBG, $1/seed, MTA required
Dutch Passion- CBG photo and auto
CannaBiogen- CBG auto?
European fiber varieties (I am not certain, but these are probably protected by plant variety protection (PVP), meaning you can save seed for on-farm use and breed with them):
Santhica-27: monecious 1-3% CBG, CBD residual
Carma - monecious ~3% CBG
USO-31- monecious. low cannabinoid, some cannabinoid free plants, some CBG dominant plants with very little residual CBD production.
Please share any relevant information on CBG breeding and seed sources. Thanks!
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