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The biosynthetic pathway of the most common cannabinoids in Cannabis plants. For each step, the relative enzyme has been indicated (if known), and the state of the alleles at the B locus is proposed, accounting for the chemical phenotype. The inset shows the B190 / B200 markers, obtained amplifying Cannabis DNA with the RAPD-deriving SCAR primers. Note the codominancy of this marker.
Source publication
The development and applications of molecular markers to hemp breeding are recent, dating back only to the mid-1990s. The main achievements in this field are reviewed. The analysis of Cannabis germplasm by RAPD, AFLP and microsatellites is discussed, with its consequence for the still debated species concept in Cannabis. DNA-based markers have also...
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... presently at GW Pharmaceuticals (UK). Different segregating F2s were obtained from initial crosses between inbred lines with contrasting chemotypes (I and III, i.e. almost pure THC and almost pure CBD); the genetic analysis of the gas-chromatographic data demonstrated that the F1 offspring was completely hybrid (chemotype II), while all three chemotypes were again present in the F2 generations, in a 1:2:1 proportion (pure THC:mixed THC + CBD:pure CBD) within each progeny; this finding was in agreement with the hypothesis of one gene and two codominant alleles ( B D and B T ) for chemotype determination. This hypothesis is not the only possible, but it is the simplest explaining of the presently available data. The F2 segregating groups were screened by RAPD markers using the bulk segregant approach, and several CBD- or THC-associated markers were identified. All these markers behaved as dominant, except one (named B190/B200 ; Figure 4 in- sert), deriving from a CBD-associated RAPD fragment, that once transformed into a SCAR marker, turned out to be codominant, and therefore able to genotype completely at the B locus the plants. The efficiency of correct identification of the chemotypes was 88% for pure THC plants, 95% for mixed chemotype plants, and 98% for pure CBD plants (de Meijer et al., 2003). However, these markers, very useful within the pedigrees created from the starting inbred lines, were not equally effective in unrelated materials, like the dioecious fiber varieties Carmagnola, Fibranova or Eletta Campana. Besides, despite the very good degree of association with the chemotype shown by marker B190/B200 , it cannot be taken into consideration for the marker-assisted identification of illicit crops and for legal purposes (P. Cantin, personal communication). In this case, in fact, a marker must be 100% linked to the chemotype, for its exploita- tion as an effective and reliable drug repression tool. The only marker with these characteristics is of course the gene itself. In the NCBI database, there are the sequences corresponding to the genes for the THC- and CBD-synthases (entry numbers AB057805, E55107, E55108, E55090 and E55091); these sequences have been patented by a research group of the Taisho Pharmaceuticals Company, Japan. The sequences of the genes coding for THC- and CBD-synthase show very high similarities; the identity along the 1635 bp coding sequence is 89.3%. The major difference is apparently a missing nucleotide triplet in the positions 757–759 of the THC-synthase sequence. The translated protein sequence is 545 and 544 aminoacids, for CBD- and THC-synthase, respectively. The THC-synthase has a missing aminoacid (SER) in position 253 of the sequence. Out of the 545 aminoacids stretch, only 87 (16%) are different between the two enzymes (including the missing one); about half of these variations, however, are between aminoacids of the same type. The aminoacid changes are quite evenly distributed throughout the sequence, the longest variant stretch consisting of six aminoacids in positions 491– 496. These differences are large enough to allow the construction of specific primers, able to identify in the different chemotypes the allelic complement of each plant. In our laboratory, we devised a three-primers system able to amplify, in a single PCR reaction of leaf tissue fragments, the DNA sequences identifying the allelic status at the B locus (A. Carboni, unpublished). Genetic analysis of heterozygous ( B D B T ) plants from different crosses, revealed that the THC:CBD ratio may vary slightly but consistently and heritably around the value of 1 (de Meijer et al., 2003). This sug- gests the possibility that several isoenzymatic forms of THC- and CBD-synthases exist in different germplasm. Confirmation of this hypothesis, presently in progress through the sequencing in our laboratory of these possible variants, could lead to the identification of further alleles of potential interest at the B locus. Besides, the identification, either by progeny analysis or by direct sequencing, of the alleles responsible for the synthesis of the several cannabinoids described in C. sativa , would open the possibility of assisted selection in Cannabis, bred not only as a fiber crop, but also for its pharmaceutical applications (see G. Guy and R. Pertwee contributions in this special issue). Chemotype IV and V, having CBG or no cannabinoids, are of remarkable interest for both fiber and pharmaceutical purposes; the identification of the alleles at the B locus responsible for the accumulation of CBG or for the absence of cannabinoids (Figure 4), would open the way to the development of molecular markers for these chemotypes. The knowledge of the genes and alleles responsible for the different chemotypes could also lead to the manipulation of the pathway in both plants and cell cultures; the availability of chemotype-specific cell cultures in which the cannabinoid biosynthesis is made active by manipulations of the key enzymes of their pathway, could lead to the development of bioreactors useful for the in vitro large-scale production of specific cannabinoids for the pharmaceutical industry. However, C. sativa remains primarily a fiber crop, and a great deal of work is being done for ...
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... presently at GW Pharmaceuticals (UK). Different segregating F2s were obtained from initial crosses between inbred lines with contrasting chemotypes (I and III, i.e. almost pure THC and almost pure CBD); the genetic analysis of the gas-chromatographic data demonstrated that the F1 offspring was completely hybrid (chemotype II), while all three chemotypes were again present in the F2 generations, in a 1:2:1 proportion (pure THC:mixed THC + CBD:pure CBD) within each progeny; this finding was in agreement with the hypothesis of one gene and two codominant alleles ( B D and B T ) for chemotype determination. This hypothesis is not the only possible, but it is the simplest explaining of the presently available data. The F2 segregating groups were screened by RAPD markers using the bulk segregant approach, and several CBD- or THC-associated markers were identified. All these markers behaved as dominant, except one (named B190/B200 ; Figure 4 in- sert), deriving from a CBD-associated RAPD fragment, that once transformed into a SCAR marker, turned out to be codominant, and therefore able to genotype completely at the B locus the plants. The efficiency of correct identification of the chemotypes was 88% for pure THC plants, 95% for mixed chemotype plants, and 98% for pure CBD plants (de Meijer et al., 2003). However, these markers, very useful within the pedigrees created from the starting inbred lines, were not equally effective in unrelated materials, like the dioecious fiber varieties Carmagnola, Fibranova or Eletta Campana. Besides, despite the very good degree of association with the chemotype shown by marker B190/B200 , it cannot be taken into consideration for the marker-assisted identification of illicit crops and for legal purposes (P. Cantin, personal communication). In this case, in fact, a marker must be 100% linked to the chemotype, for its exploita- tion as an effective and reliable drug repression tool. The only marker with these characteristics is of course the gene itself. In the NCBI database, there are the sequences corresponding to the genes for the THC- and CBD-synthases (entry numbers AB057805, E55107, E55108, E55090 and E55091); these sequences have been patented by a research group of the Taisho Pharmaceuticals Company, Japan. The sequences of the genes coding for THC- and CBD-synthase show very high similarities; the identity along the 1635 bp coding sequence is 89.3%. The major difference is apparently a missing nucleotide triplet in the positions 757–759 of the THC-synthase sequence. The translated protein sequence is 545 and 544 aminoacids, for CBD- and THC-synthase, respectively. The THC-synthase has a missing aminoacid (SER) in position 253 of the sequence. Out of the 545 aminoacids stretch, only 87 (16%) are different between the two enzymes (including the missing one); about half of these variations, however, are between aminoacids of the same type. The aminoacid changes are quite evenly distributed throughout the sequence, the longest variant stretch consisting of six aminoacids in positions 491– 496. These differences are large enough to allow the construction of specific primers, able to identify in the different chemotypes the allelic complement of each plant. In our laboratory, we devised a three-primers system able to amplify, in a single PCR reaction of leaf tissue fragments, the DNA sequences identifying the allelic status at the B locus (A. Carboni, unpublished). Genetic analysis of heterozygous ( B D B T ) plants from different crosses, revealed that the THC:CBD ratio may vary slightly but consistently and heritably around the value of 1 (de Meijer et al., 2003). This sug- gests the possibility that several isoenzymatic forms of THC- and CBD-synthases exist in different germplasm. Confirmation of this hypothesis, presently in progress through the sequencing in our laboratory of these possible variants, could lead to the identification of further alleles of potential interest at the B locus. Besides, the identification, either by progeny analysis or by direct sequencing, of the alleles responsible for the synthesis of the several cannabinoids described in C. sativa , would open the possibility of assisted selection in Cannabis, bred not only as a fiber crop, but also for its pharmaceutical applications (see G. Guy and R. Pertwee contributions in this special issue). Chemotype IV and V, having CBG or no cannabinoids, are of remarkable interest for both fiber and pharmaceutical purposes; the identification of the alleles at the B locus responsible for the accumulation of CBG or for the absence of cannabinoids (Figure 4), would open the way to the development of molecular markers for these chemotypes. The knowledge of the genes and alleles responsible for the different chemotypes could also lead to the manipulation of the pathway in both plants and cell cultures; the availability of chemotype-specific cell cultures in which the cannabinoid biosynthesis is made active by manipulations of the key enzymes of their pathway, could lead to the development of bioreactors useful for the in vitro large-scale production of specific cannabinoids for the pharmaceutical industry. However, C. sativa remains primarily a fiber crop, and a great deal of work is being done for ...
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... model illustrating the enzymes involved and the alleles reputed responsible for the different steps of cannabinoid biosynthesis, is shown in Figure 4. The condensation of geranygeraniol diphos- phate with olivetolic acid (catalyzed by geranylgeran- iol:olivetolate transferase, GOT; Fellermeier and Zenk, 1998) is the step leading to the first Cannabis’ exclu- sive product, cannabigerol (CBG); this particular com- pound was also described as the prevalent cannabinoid in some plants (Fournier et al., 1987). These “mutants” could not therefore be considered belonging to any of the three formerly known chemotypes, and were assigned to a new chemotype (prevalent CBG, or chemotype IV; Figure 5). CBG is today widely accepted as the common precursor for the synthesis of both THC and CBD (Fellermeier et al., 2001). A further chemotype was found, with an undetectable amount of cannabinoids. This “zero cannabinoid” type, (we propose for it the creation of a chemotype V; see Figure 5 for its gas-chromatogram) has been described by some authors in different germplasm (G. Grassi and I. Virovets, personal communication), though it is not yet clear whether this absence was due to a metabolic block at the level of GOT, or rather to a very limited for- mation of glandular trichomes, the site of synthesis and accumulation of cannabinoids (Kim and Mahlberg, 2003). Usually, CBG is detected in very small amounts in Cannabis’ extracts, probably because it is almost completely utilized as substrate by the downstream synthases (THC- and CBD-synthases), transforming it into THC, CBD or other less common end products (such as cannabichromene, CBC; Figure 4). The two synthases are respectively coded by B D and B T , the two alleles at the B locus, and have very similar K m and V max (Taura et al., 1995, 1996). This peculiarity explains the fact that, when both enzymes are present (i.e. when the genotype at the B locus is B D B T ), the almost equal efficiency of oxidocycliza- tion of CBG into the respective end products, leads to a ratio close to the unity in the THC:CBD ratio. This produces the distribution along the median line of the THC vs. CDB scatter plots observed for chemotype II plants, and for all the F1 progenies of pure chemotype parentals. One of the main targets for fiber hemp has been for a long time the eradication of hemp plants bearing the B T allele, and consequently synthesizing more or less “illegal” amounts of THC. There have been, in ...
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... model illustrating the enzymes involved and the alleles reputed responsible for the different steps of cannabinoid biosynthesis, is shown in Figure 4. The condensation of geranygeraniol diphos- phate with olivetolic acid (catalyzed by geranylgeran- iol:olivetolate transferase, GOT; Fellermeier and Zenk, 1998) is the step leading to the first Cannabis’ exclu- sive product, cannabigerol (CBG); this particular com- pound was also described as the prevalent cannabinoid in some plants (Fournier et al., 1987). These “mutants” could not therefore be considered belonging to any of the three formerly known chemotypes, and were assigned to a new chemotype (prevalent CBG, or chemotype IV; Figure 5). CBG is today widely accepted as the common precursor for the synthesis of both THC and CBD (Fellermeier et al., 2001). A further chemotype was found, with an undetectable amount of cannabinoids. This “zero cannabinoid” type, (we propose for it the creation of a chemotype V; see Figure 5 for its gas-chromatogram) has been described by some authors in different germplasm (G. Grassi and I. Virovets, personal communication), though it is not yet clear whether this absence was due to a metabolic block at the level of GOT, or rather to a very limited for- mation of glandular trichomes, the site of synthesis and accumulation of cannabinoids (Kim and Mahlberg, 2003). Usually, CBG is detected in very small amounts in Cannabis’ extracts, probably because it is almost completely utilized as substrate by the downstream synthases (THC- and CBD-synthases), transforming it into THC, CBD or other less common end products (such as cannabichromene, CBC; Figure 4). The two synthases are respectively coded by B D and B T , the two alleles at the B locus, and have very similar K m and V max (Taura et al., 1995, 1996). This peculiarity explains the fact that, when both enzymes are present (i.e. when the genotype at the B locus is B D B T ), the almost equal efficiency of oxidocycliza- tion of CBG into the respective end products, leads to a ratio close to the unity in the THC:CBD ratio. This produces the distribution along the median line of the THC vs. CDB scatter plots observed for chemotype II plants, and for all the F1 progenies of pure chemotype parentals. One of the main targets for fiber hemp has been for a long time the eradication of hemp plants bearing the B T allele, and consequently synthesizing more or less “illegal” amounts of THC. There have been, in ...
Citations
... Historically, C. sativa plants have been classified into three chemotypes (sometimes also referred to as chemovars) based on the relative amounts of Δ 9 -THC and CBD: chemotype I (Δ 9 -THC > CBD), chemotype II (Δ 9 -THC and CBD at similar concentrations, Δ 9 -THC >0.3%), also indicated with the vernacular name "drug-type", and chemotype III (Δ 9 -THC < CBD, Δ 9 -THC <0.3%), also called "fiber-type" based on their main utilization [9]. Later, other chemotypes have been described, including a cannabigerol (CBG) predominant one (chemotype IV) [10] and chemotype V with no cannabinoids [11]. ...
... Based on both CBDA/THCA ratio and amount of the main cannabinoids, C. sativa plants can be classified in five chemical phenotypes (chemotypes): THCA is prevalent in chemotype I, chemotype II has both CBDA and THCA at similar concentrations, III is CBDA-dominant, IV is CBGA-dominant and V has only traces of cannabinoids (Mandolino and Carboni 2004). Chemotype I, II and III can be easily and rapidly distinguished by using molecular markers soon after seed germination. ...
In Cannabis sativa L. the presence of delta 9-tetrahydrocannabinolic acid (THCA) above legal limit is a challenging issue that still restricts the industrial exploitation of this promising crop. In recent years, the interest of entrepreneurs and growers who see hemp as a dynamic and profitable crop was joined by the growing knowledge on C. sativa genetics and genomics, accelerated by the application of high throughput tools. Despite the renewed interest in the species, much remains to be clarified, especially about the long-standing problem of THCA in hemp inflorescences, which could even result in the seizure of the whole harvest. Although several hypotheses have been formulated on the accumulation of this metabolite in industrial varieties, none is conclusive yet. In this work, individuals of a population of the hemp cultivar 'FINOLA' obtained from commercial seeds were investigated for total THC level and examined at molecular level. A marker linked to THCA synthase was found at a high incidence in both male and female plants, suggesting a considerable genetic variability within the seed batch. Full-length sequences encoding for putatively functional THCA synthases were isolated for the first time from the genome of both female and male plants of an industrial hemp variety and, using transcriptional analysis, the THCA synthase expression was quantified in mature inflorescences of individuals identified by the marker. Biochemical analyses finally demonstrated for these plants a 100% association between the predicted and actual chemotype.
... Since then, large-scale cultivation as ∆ = 0.15 pg/2C [50]. Early sex determination is usually carried out using male-associated DNA markers [61][62][63][64][65][66][67], but the accuracy and reproducibility of some of them have been questioned [67,68]. Based on the above, there is no doubt that developing a method of sex detection through flow cytometry, as previously suggested [50], would be of great interest. ...
Cannabis sativa has been used for millennia in traditional medicine for ritual purposes and for the production of food and fibres, thus, providing important and versatile services to humans. The species, which currently has a worldwide distribution, strikes out for displaying a huge morphological and chemical diversity. Differences in Cannabis genome size have also been found, suggesting it could be a useful character to differentiate between accessions. We used flow cytometry to investigate the extent of genome size diversity across 483 individuals belonging to 84 accessions, with a wide range of wild/feral, landrace, and cultivated accessions. We also carried out sex determination using the MADC2 marker and investigated the potential of flow cytometry as a method for early sex determination. All individuals were diploid, with genome sizes ranging from 1.810 up to 2.152 pg/2C (1.189-fold variation), apart from a triploid, with 2.884 pg/2C. Our results suggest that the geographical expansion of Cannabis and its domestication had little impact on its overall genome size. We found significant differences between the genome size of male and female individuals. Unfortunately, differences were, however, too small to be discriminated using flow cytometry through the direct processing of combined male and female individuals.
... This barrier is difficult to overcome, and would require fundamental restructuring of regulations on both national and international levels [14]. Thanks to recent advances in molecular markers and genetic engineering methods (e.g., CRISPR), it is possible to detect and/or produce cannabis with very low levels of THC [43,44]. Though there could still be complications differentiating ornamental from medicinal varieties, cannabis cultivars that produce low cannabinoid levels might help the ornamental industry to overcome legal barriers and prevent unwanted diversion. ...
... Various molecular genetic markers have also been employed in the cannabis field to analyze genetic variations, sex determination, chemotype inheritance, and genetic mapping (reviewed by Hesami et al. [30]). For instance, Mandolino and Carboni [44] employed molecular markers to study chemotype inheritance in cannabis. They discovered a chemotype with an undetectable amount of phytocannabinoids (almost zero phytocannabinoids) and classified it as chemotype V [44]. ...
... For instance, Mandolino and Carboni [44] employed molecular markers to study chemotype inheritance in cannabis. They discovered a chemotype with an undetectable amount of phytocannabinoids (almost zero phytocannabinoids) and classified it as chemotype V [44]. Johnson and Wallace [64] employed genotyping by sequencing (GBS) to evaluate chemotype inheritance in cannabis. ...
The characteristic growth habit, abundant green foliage, and aromatic inflorescences of cannabis provide the plant with an ideal profile as an ornamental plant. However, due to legal barriers, the horticulture industry has yet to consider the ornamental relevance of cannabis. To evaluate its suitability for introduction as a new ornamental species, multifaceted commercial criteria were analyzed. Results indicate that ornamental cannabis would be of high value as a potted-plant or in landscaping. However, the readiness timescale for ornamental cannabis completely depends on its legal status. Then, the potential of cannabis chemotype Ⅴ, which is nearly devoid of phytocannabinoids and psychoactive properties, as the foundation for breeding ornamental traits through mutagenesis, somaclonal variation, and genome editing approaches has been highlighted. Ultimately, legalization and breeding for ornamental utility offers boundless opportunities related to economics and executive business branding.
... According to scientific studies, there are three cannabis species with distinct phenotypic differences, namely C. sativa L., C. indica Lam (Lamarck), and C. ruderalis [7,8]. However, the majority of classifications performed to date evidence the existence of C. sativa Within a given cannabis species, cultivars are categorised into groups based on their chemotype, from I to V, according to the number and ratio of main cannabinoids [16]. These compound profiles can be employed both as quality markers and fingerprints for cannabis standardization. ...
Cannabis (Cannabis sativa L.), also known as hemp, is one of the oldest cultivated crops, grown for both its use in textile and cordage production, and its unique chemical properties. However, due to the legislation regulating cannabis cultivation, it is not a well characterized crop, especially regarding molecular and genetic pathways. Only recently have regulations begun to ease enough to allow more widespread cannabis research, which, coupled with the availability of cannabis genome sequences, is fuelling the interest of the scientific community. In this review, we provide a summary of cannabis molecular resources focusing on the most recent and relevant genomics, transcriptomics and metabolomics approaches and investigations. Multi-omics methods are discussed, with this combined approach being a powerful tool to identify correlations between biological processes and metabolic pathways across diverse omics layers, and to better elucidate the relationships between cannabis sub-species. The correlations between genotypes and phenotypes, as well as novel metabolites with therapeutic potential are also explored in the context of cannabis breeding programs. However, further studies are needed to fully elucidate the complex metabolomic matrix of this crop. For this reason, some key points for future research activities are discussed, relying on multi-omics approaches.
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Keywords: cannabis; genomics; metabolomics; multi-omics; transcriptomics
... Previously described microsatellites validated in (Köhnemann et al. 2012, Houston et al. 2015, Presinszka et al. 2015, Dufresnes et al. 2017, Mandolino and Carboni 2004 and sourced from (Alghanim and Almirall 2003, Gilmore and Peakall 2003, Gao et al. 2014 were chosen due to their repeatedly demonstrated ability to differentiate between Cannabis sativa L. subspecies. ...
... This study found the mean number of alleles per locus was 10.3. Across three microsatellite studies, the average number of alleles found was 9 (Mandolino and Carboni 2004). The alleles per locus are higher in this study's results; this could be due to the method of microsatellite allele quantification, the microsatellites used, or it could be due to sampling and replication 43 differences. ...
... In addition, there are differences among studies which may or may not play a role in the number of alleles found. Overall, Gilmore and Peakall found more alleles on average than Alghanim and Almirall's work, but more alleles were detected with greater sample size (Mandolino and Carboni 2004). ...
Cannabis sativa L. is a crop plant that is native to Asia. It is a primarily dioecious annual agriculturally used for its seed, fiber, and flowers. After recent legislative action legalized hemp nationally for research and cultivation in the US, distinct classifications had to be made. Cannabis sativa L. cultivars are presently separated into two major categories by the FDA: medical marihuana and hemp. Within the hemp classification, there is CBD-type hemp and industrial hemp. These classifications are based on Cannabis sativa L.’s chemical composition, which varies throughout the plant’s tissue. The desired cannabinoid chemicals for CBD-type hemp and medical Cannabis (high THC) are found in high concentrations in the female flowers. To differentiate CBD-type hemp from medical marihuana, the USDA’s current regulations limit tetrahydrocannabinol (THC) concentration to no more than 0.3% total. Genetic research on the plant has been, until recently, limited to legal applications of differentiating industrial hemp from medical marihuana. This study has been completed to ascertain Cannabis sativa L.’s current chemical composition and genetic diversity among Maryland growers. Hemp growers located across Maryland provided the field sites and samples. Chemical composition was determined from an analysis of flowers through a partnership with a Morgan State University chemistry lab. The determination of genetic diversity was completed on hemp leaves through the analysis of 12 standard and novel microsatellites. Cannabis sativa L. samples were taken from eight field sites across twenty eight distinct cultivars. Cultivars #5 and Cherry had the highest CBDA content among the strains studied. Microsatellite analysis determined that the most genetically variable cultivars were A-B1 and #5. With this research, CBDA type hemp growers in Maryland will be able to determine some strains which have high concentrations of their desired cannabinoids and which cultivars are more genetically variable.
... Recent increase in the agricultural areas that are used for hemp production requires automated approaches that can be used for confirmatory differentiation between male and female plants prior to their flowering. PCR-based markers have been identified specific to male plants (Mandolino and Carboni 2004) and are routinely used by service laboratories; however, these tests are costly and time consuming. ...
Main conclusion
Hand-held Raman spectroscopy can be used for highly accurate differentiation between young male and female hemp plants. This differentiation is based on significantly different concentration of lutein in these plants.
Abstract
Last year, a global market of only industrial hemp attained the value of USD 4.7 billion. It is by far the fastest growing market with projected growth of 22.5% between 2021 and 2026. Hemp (Cannabissativa L.) is a dioecious species that has separate male and female plants. In hemp farming, female plants are strongly preferred because male plants do not produce sufficient amount of cannabinoids. Male plants are also eliminated to minimize a possibility of uncontrolled cross-fertilization of plants. Silver treatments can induce development of male flowers on genetically female plants in order to produce feminized seed. Resulting cannabinoid hemp production fields should contain 100% female plants. However, any unintended pollination from male plants can produce unwanted males in production fields. Therefore, there is a growing demand for a label-free, non-invasive, and confirmatory approach that can be used to differentiate between male and female plants before flowering. In this study, we examined the extent to which Raman spectroscopy, an emerging optical technique, can be used for the accurate differentiation between young male and female hemp plants. Our findings show that Raman spectroscopy enables differentiation between male and female plants with 90% and 94% accuracy on the level of young and mature plants, respectively. Such analysis is entirely non-invasive and non-destructive to plants and can be performed in seconds using a hand-held spectrometer. High-performance liquid chromatography (HPLC) analysis and collected Raman spectra demonstrate that this spectroscopic differentiation is based on significantly different concentrations of carotenoids in male vs female plants. These findings open up a new avenue for quality control of plants grown in both field and a greenhouse.
... Chemotype IV also has low THC contents but with the potent percentage of CBG. Furthermore, the chemotypes producing very little to almost zero cannabinoid compounds (neutral) are grouped as chemotype V -was first described by Mandolino et al. (Cascini et al., 2012;Hartsel et al., 2016;Mandolino and Carboni, 2004). Apart from cannabinoid (THC, CBD) content, drug and fiber-type plants have significant genetic variation. ...
Cannabis sativa L. has been one of the oldest medicinal plants cultivated since 10,000 years for several agricultural and industrial applications. However, the plant became controversial due to some psychoactive components that have adverse effects on human health. In this review, we analyzed the trends in cannabis research for the past two centuries. We discussed the historical transitions of cannabis from the category of an herbal medicine to an illicit drug and back to a medicinal product post-legalization. In addition, we address the new-age application of immuno-suppressive and anti-inflammatory extracts for the treatment of COVID-19 inflammation. We further address the influence of the legal aspects of cannabis cultivation for medicinal, pharmaceutical, and biotechnological research. We reviewed the up-to-date cannabis genomic resources and advanced technologies for their potential application in genomic-based cannabis improvement. Overall, this review discusses the diverse aspects of cannabis research developments ranging from traditional use as an herbal medicine to latest potential in COVID, legal practices with updated patent status, and current state of art genetic and genomic tools reshaping cannabis biotechnology in modern age agriculture and pharmaceutical industry.
... Chemical applications can be used to influence sex development of male flowers on female Cannabis plants [24], the resulting XX pollen can be used to pollinate female flower to produce "feminized seed" (i.e., all resulting seedlings will be XX female genotype) [6,25,26]. Unfortunately, propagation through "feminized seed" can demonstrate a high degree of variation with a cultivar [25,27] at early generation followed by extreme inbreeding after several generations of feminized seed production (i.e., self-pollination) [6]. Mendelian genetics demonstrates that feminized seed must be at the fifth generation of inbreeding (F 5 ) to contain <10% heterozygosity, which should be kept under consideration when looking for stable seed sources [28]. ...
To support the rapidly expanding industrial hemp industry, a commercial supply of high-quality starter plants with low genetic variability from nurseries will be key to consistent and efficient cultivation efforts. Rooting success was evaluated across four propagation medias, five rooting hormones, and eight commercially available high-cannabidiol (CBD) essential oil hemp cultivars. Cuttings were placed in a climate-controlled room and assessed for rooting success 12 days after cloning. Rooting success was determined by quantifying total root number, cumulative total root length, and total root mass. Propagation media had the greatest effect on rooting success (13-80%). Rockwool had the highest rooting success resulting in 10-fold increases in rooting traits over the next highest scoring medium (Berger BM6). Hormone applications significantly improved (15- to 18-fold) rooting success compared to no hormone application, while non-statistical differences were observed across auxin hormone concentrations and application methods. Genetic variation in rooting response was observed between cultivars with 'Cherry Wine' outperforming all other cultivars with an approximate 20% increase in rooting success over the next highest rooting cultivar, 'Wife'. Although the ideal combination was not specifically identified in this study, findings provide insight into how rooting hormone application and medium selection impact vegetative propagule rooting success of essential oil hemp.
... [19][20][21] Sexual dimorphism is a critical factor in Cannabis-based production systems and is essential for genetic improvement of germplasm. [22] For phytocannabinoid production, genetically female plants are grown in the absence of pollen. Male and hermaphroditic plants have less floral biomass, reduced phytocannabinoid yield, and also negatively impact female inflorescence quality via fertilisation and initiation of seed development. ...
Cannabis is a mostly dioecious multi-use flowering plant genus. Sexual dimorphism is an important characteristic in Cannabis-based commercial production systems, which has consequences for fibre, seed, and the yield of secondary metabolites, such as phytocannabinoid and terpenes for therapeutic uses. Beyond the obvious morphological differences between male and female plants, metabolic variation among dioecious flowers is largely undefined. Here, we report a pilot metabolomic study comparing staminate (male) and pistillate (female) unisexual flowers. Enrichment of the α-linolenic acid pathway and consensus evaluation of the jasmonic acid (JA) related compound 12-oxo-phytodienoicacid (OPDA) among differentially abundant metabolites suggests that oxylipin signalling is associated with secondary metabolism and sex expression in female flowers. Several putative phytocannabinoid-like compounds were observed to be upregulated in female flowers, but full identification was not possible due to the limitation of available databases. Targeted analysis of 14 phytocannabinoids using certified reference standards (cannabidiolic acid (CBDA), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid A (Δ9-THCAA), Δ9-tetrahydrocannabinol (Δ9-THC), cannabichromenic acid (CBCA), cannabichromene (CBC), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabinolic acid (CBNA), cannabinol (CBN), cannabidivarinic acid (CBDVA), cannabidivarin (CBDV), tetrahydrocannabivarinic acid (THCVA), and tetrahydrocannabivarin (THCV)) showed a higher total phytocannabinoid content in female flowers compared with the male flowers, as expected. In summary, the development of a phytocannabinoid-specific accurate-mass MSn fragmentation spectral library and gene pool representative metabolome has the potential to improve small molecule compound annotation and accelerate understanding of metabolic variation underlying phenotypic diversity in Cannabis.
