I thought I'd start a thread about the scientific progress in cannabis taxonomy and it's possible implications on medical cannabis breeding and research I have never really been sure as to the speciation of cannabis and to this day despite reading dozens of papers on the subject I am still unclear as to the answer(s).
Please use this thread to post links to articles and discussions about cannabis taxonomy. I'll update with references as soon as I get a minute.
The speciation of cannabis is still disputed by various researchers as it has been for nearly 200 years.
The classic taxonomists were generally divided into three groups supporting the existence of either 1,2 or 3 species of cannabis.
The first group included Linnaeus and argued that the cannabis genus was monotypic and composed of of one highly variable species C. sativa based on the lack of breeding barriers between the putative species. Others using various arguments classified cannabis as polytypic consisting of C. sativa and C. indica some based their arguments on crude chemotaxonomic data; sativa called fiber hemp and indica called drug hemp.
Others argued for the existence of these two species as well as classifying the wild russian and central asian populations as C. ruderalis.
The advent of the polymerase chain reaction( PCR) and the resultant developments of Amplified fragment length polymorphism (AFLP) and Random fragment length polymorphism (RFLP) analysis added fuel to the debate but not much clarification.
More recently further advances in genetic research have again fanned the flames of the cannabis taxonomy debate. In 2005 Karl Hillig at IU published a paper entitled "Genetic evidence for Speciation in Cannabis (Cannabaceae)" This is the citation: Genetic Resources and Crop Evolution, Volume 52, Number 2, March 2005 , pp. 161-180(20)
and the abstract:
"Sample populations of 157 Cannabis accessions of diverse geographic origin were surveyed for allozyme variation at 17 gene loci. The frequencies of 52 alleles were subjected to principal components analysis. A scatter plot revealed two major groups of accessions. The sativa gene pool includes fiber/seed landraces from Europe, Asia Minor, and Central Asia, and ruderal populations from Eastern Europe. The indica gene pool includes fiber/seed landraces from eastern Asia, narrow-leafleted drug strains from southern Asia, Africa, and Latin America, wide-leafleted drug strains from Afghanistan and Pakistan, and feral populations from India and Nepal. A third putative gene pool includes ruderal populations from Central Asia. None of the previous taxonomic concepts that were tested adequately circumscribe the sativa and indica gene pools. A polytypic concept of Cannabis is proposed, which recognizes three species, C. sativa, C. indica and C. ruderalis, and seven putative taxa."
If Hillig turns out to be correct this would mean all those much sought after narrow leaved tropical sativas are actually indica strains regardless of photo period. All the 25% 50% etc sativa mixes we constantly see advertised would now be pure indica strains. Ruderalis crosses based on central asian stock would be the indica/sativa crosses, and so on ...Fun eh... If anyone has links to more scientific papers and discussions on Cannabis Taxonomy please post em.
HM
Please use this thread to post links to articles and discussions about cannabis taxonomy. I'll update with references as soon as I get a minute.
The speciation of cannabis is still disputed by various researchers as it has been for nearly 200 years.
The classic taxonomists were generally divided into three groups supporting the existence of either 1,2 or 3 species of cannabis.
The first group included Linnaeus and argued that the cannabis genus was monotypic and composed of of one highly variable species C. sativa based on the lack of breeding barriers between the putative species. Others using various arguments classified cannabis as polytypic consisting of C. sativa and C. indica some based their arguments on crude chemotaxonomic data; sativa called fiber hemp and indica called drug hemp.
Others argued for the existence of these two species as well as classifying the wild russian and central asian populations as C. ruderalis.
The advent of the polymerase chain reaction( PCR) and the resultant developments of Amplified fragment length polymorphism (AFLP) and Random fragment length polymorphism (RFLP) analysis added fuel to the debate but not much clarification.
More recently further advances in genetic research have again fanned the flames of the cannabis taxonomy debate. In 2005 Karl Hillig at IU published a paper entitled "Genetic evidence for Speciation in Cannabis (Cannabaceae)" This is the citation: Genetic Resources and Crop Evolution, Volume 52, Number 2, March 2005 , pp. 161-180(20)
and the abstract:
"Sample populations of 157 Cannabis accessions of diverse geographic origin were surveyed for allozyme variation at 17 gene loci. The frequencies of 52 alleles were subjected to principal components analysis. A scatter plot revealed two major groups of accessions. The sativa gene pool includes fiber/seed landraces from Europe, Asia Minor, and Central Asia, and ruderal populations from Eastern Europe. The indica gene pool includes fiber/seed landraces from eastern Asia, narrow-leafleted drug strains from southern Asia, Africa, and Latin America, wide-leafleted drug strains from Afghanistan and Pakistan, and feral populations from India and Nepal. A third putative gene pool includes ruderal populations from Central Asia. None of the previous taxonomic concepts that were tested adequately circumscribe the sativa and indica gene pools. A polytypic concept of Cannabis is proposed, which recognizes three species, C. sativa, C. indica and C. ruderalis, and seven putative taxa."
If Hillig turns out to be correct this would mean all those much sought after narrow leaved tropical sativas are actually indica strains regardless of photo period. All the 25% 50% etc sativa mixes we constantly see advertised would now be pure indica strains. Ruderalis crosses based on central asian stock would be the indica/sativa crosses, and so on ...Fun eh... If anyone has links to more scientific papers and discussions on Cannabis Taxonomy please post em.
HM