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A chemotaxonomic analysis of cannabinoid variation in Cannabis (Cannabaceae)
Author(s) -
Hillig Karl W.,
Mahlberg Paul G.
Publication year - 2004
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.91.6.966
Subject(s) - biology , cannabidiol , germplasm , chemotype , cannabinoid , botany , chemotaxonomy , cannabis , genetic variation , genetics , gene , taxonomy (biology) , psychology , receptor , psychiatry , essential oil
Cannabinoids are important chemotaxonomic markers unique to Cannabis . Previous studies show that a plant's dry‐weight ratio of Δ 9 ‐tetrahydrocannabinol (THC) to cannabidiol (CBD) can be assigned to one of three chemotypes and that alleles B D and B T encode alloenzymes that catalyze the conversion of cannabigerol to CBD and THC, respectively. In the present study, the frequencies of B D and B T in sample populations of 157 Cannabis accessions were determined from CBD and THC banding patterns, visualized by starch gel electrophoresis. Gas chromatography was used to quantify cannabinoid levels in 96 of the same accessions. The data were interpreted with respect to previous analyses of genetic and morphological variation in the same germplasm collection. Two biotypes (infraspecific taxa of unassigned rank) of C. sativa and four biotypes of C. indica were recognized. Mean THC levels and the frequency of B T were significantly higher in C. indica than C. sativa . The proportion of high THC/CBD chemotype plants in most accessions assigned to C. sativa was <25% and in most accessions assigned to C. indica was >25%. Plants with relatively high levels of tetrahydrocannabivarin (THCV) and/or cannabidivarin (CBDV) were common only in C. indica . This study supports a two‐species concept of Cannabis .