Why Modern Medical Cannabis Strains have Minimal CBD
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Sam the Skunkman says that nearly all modern cannabis is pretty much CBD-free or the levels are so low as to be miniscule, landrace indicas are the way to go.
Right now there's simply no strains available where cbd will make up more than 2% of the overall cannabinoids (.5% of the flower weight) and no way of cultivating a noticeably higher cbd content. For the most part conversion of cbg into cbd is controlled by a single gene (Bd) which is codominant with the gene that converts cbg into thc.
For example a plant that inherits a Bd gene from one parent and a Bt gene from the other will have roughly equal content of Cbd and Thc. However, if the plant is homozygous for Bd it will have very little thc and if its homozygous for Bt it will have very little Cbd.
While it is true that afghani landraces can have a high cbd content. Since having a Bd gene will replace half of the thc content with cbd seed companies always remove the Bd allele from the gene pool in order to maximize thc potency and stay competitive. Right now Breeders choice is working on several indicas from afghanistan, pakistan, and north india as well as Sativas from Hokkaido and intending to produce versions both with the Bd gene for producing high cbd levels and without. All of the plants produce high cannabinoid levels. The six hokkaido strains we're working with are very hardy and fast flowering. They can be planted pretty much anywhere and left uncultivated/unfertilized and as long as they aren't eaten by wild animals harvested by mid august. They have a fairly low frequency of the Bd allele with most of the plants produce 5-10% thc but I believe the Bd allele does still occur in at least some of them. This makes a very good strain for medical users who require high cbd levels. Since depending on the plant high cbd strains don't produce as much of, if any high it is important for the plants to be effortlessly grown clandestinely and take very little effort and resource which can be taken away from primary thc producing plants. The Hokkaido strains which still possess the bd allele are perfect for this scenario. Since the nature of the genes which control cbd production only allow for plants to produce either veryl low levels cbd, rough 50/50 thc/cbd or very low levels of thc manufacture of hashish or honey oil allows for the med user to mix high cbd and high thc plants at a ratio which produces the desired medicinal effects.
Source: Zamolito