Characterisation of cannabinoid composition in a diverse Cannabis sativa L. germplasm collection

The ability to characterise cannabinoid chemical phenotype (chemotype) accurately is important for the development of Cannabis sativa L. cultivars specific for pharmacological, hemp fibre, or seed end use. Although a number of chemotyping and genotyping methods have previously been developed to predict and characterise cannabinoid composition, only a subset of the gene pool has been examined. A representative survey from a wide range of geographically and genetically diverse C. sativa accessions using liquid chromatography-mass spectrometry (LC-MS) cannabinoid profiling together with dominant and co-dominant DNA marker assays was performed. Overall variability of chemotype across the gene pool was found to be three-fold greater within heterozygote genotypes than previously reported. Interestingly, an individual plant of East Asian origin was found to exhibit a rare propyl alkyl cannabinoid homologue and a chemotype inconsistent with the predicted genotype. We propose that in order to carry out comprehensive screening of genetic resource collections and to identify chemotypic variants specific for end-use pharmacological applications, a strategy which adopts both cannabinoid profiling and the co-dominant DNA marker assay is required. Further research with consideration of propyl-alkyl-cannabinoid homologues should explore the relationship between chemotype and genotype in greater detail.