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A Preliminary Study of Pollen Dispersal in Cannabis sativa in Relation to Wind Direction
Abstract
Pollen of Cannabis sativa is disseminated by wind in large amounts and for long distances, and regulations concerning the production of pedigreed seed of industrial hemp, therefore, often call for extremely large isolation distances to prevent unwanted pollination. In Europe and Canada, a standard distance of 5 km is required for the highest classes of hemp seed. This study examines the relative distribution of pollen from an isolated field over the 3-week maximum flowering period, with particular reference to wind direction. The amount of pollen distributed downwind was about six times the amount distributed upwind. In effect, this means that an isolation distance of 5 km on the downwind side is about equivalent to an isolation distance of 0.9 km on the upwind side. In theory, at the experimental site examined, the required isolation area could be reduced by about 58% while still achieving the equivalent of 5 km isolation in all directions. Given that weedy and illegally cultivated plants are widespread, making it difficult to ensure their absence over a distance of 5 km, it seems advisable, when possible, to take advantage of the considerably reduced isolation distance that is necessary on the upwind side. Pollen distribution appeared to follow the expected leptokurtic curve, reducing rapidly with initial distance from the source, but much more slowly with increasing distance. This makes it impossible to guarantee complete absence of potentially contaminating pollen in the field and, for practical purposes, a very low amount of undesired gene flow needs to be tolerated.
... As such, the risk of pollination is significant and several studies have sought to establish "safe" buffer zones between hemp crops. Small and Antle (2003) studying a small plot, 0.4 ha, found that by 100 m pollen density had fallen to less than 1% of that found within the field (Small and Antle, 2003). They also established that the downwind dispersion was much greater than the upwind vector, thereby showing that an understanding of the wind dynamics is necessary for establishing buffer zones. ...
... As such, the risk of pollination is significant and several studies have sought to establish "safe" buffer zones between hemp crops. Small and Antle (2003) studying a small plot, 0.4 ha, found that by 100 m pollen density had fallen to less than 1% of that found within the field (Small and Antle, 2003). They also established that the downwind dispersion was much greater than the upwind vector, thereby showing that an understanding of the wind dynamics is necessary for establishing buffer zones. ...
... Holding to the notion of one pollen grain being needed to fertilize a flower, the buffer zone would preclude more than a few cultivations globally to prevent crosspollination. However, in an attempt to be reasonable, many governments have adopted a 5 km buffer zone between hemp and marijuana cultivations (Small and Antle, 2003). ...
Cross-pollination of commercial crops has been an ongoing issue in many species. Cannabis spp. encompasses the classifications of marijuana [high in Δ9-tetrahydrocannabinol (THC)] and hemp (below 0.3% THC). As such, cannabis is the most recent crop facing the dilemma of cross-pollination and is leading to litigation. These litigations are driven by the large misunderstanding of the impacts of cross-pollination within the cannabis industry. The misconception is that if hemp is cross-pollinated by high THC cannabis, the hemp will become “hot” (high in THC) thereby rendering the crop illegal under the 2018 Farm Bill. However, there are many factors that contribute to the amount of THC a plant may produce. This article examines and refutes the misconception of cross-pollination increasing THC levels by highlighting several methods of how THC may become high in a given hemp crop.
... In addition to the risk of losing crops for THC exceedance, farmers considering producing floral hemp also face the risk of contamination from nearby hemp fields. Field plot research suggests that hemp grown specifically for floral production should be isolated from hemp grown for other products to avoid cross-pollination (Small & Antle, 2003). Planting floral hemp near hemp for fiber or grain may dilute CBD titers and reduce the value of floral hemp (McCarty & Young, 2021). ...
... As with the introduction of other novel crops, producers considering including hemp in their operation must balance the opportunity costs of adopting hemp with limited information about net returns, market prices, and yield. The uncertainty and risk of hemp yields is driven by low germination rates, misidentification of plant sex (females are preferred), contamination due to cross-pollination among different hemp varieties, exceedance of permissible delta-9 tetrahydrocannabinol (THC) content, and low CBD titration in final products (McCarty & Young, 2021;Mark et al., 2020;Small & Antle, 2003). Market prices for hemp are another source of risk. ...
... Reproduction occurs through wind-dispersed pollen liberated from the flowers of staminate (i.e. male) plants (Chandra et al., 2017;Small and Antle, 2003). Chopra and Chopra (1957) described the parts of C. sativa used for the production of drugs as 'flowers, leaves (and the resinous matter derived therefrom), fruit, young twigs, and bark of the stem'. ...
... Kimura and Okamoto (1970) go in the same direction: although they do not refer to the word fruit, they distinguish 'bractlet' from 'flowers', the former appearing chronologically after the latter. They explain that bractlets bear a higher concentration of cannabinoids two months after analysing the staminate flowers, which are known to appear slightly before pistillate flowers and to have a maximum life duration of three weeks (Small and Antle, 2003). These observations could mean that pistillate flowers would survive five weeks or more after their staminate counterparts have lost the ability to pollinate them. ...
Objective: Identify a coherent nomenclature of products containing cannabinoids (whether derived from Cannabis sativa L. or not).
Design: Research undertaken in parallel to the three-year assessment of Cannabis derivatives by the World Health Organisation. The scope is limited to Cannabis products intended for human incorporation (internal and topical con- sumption). Primarily embedded in pharmacognosy, the study incorporates a wide range of scholarly and grey literature, folk knowledge, archives, pharmacopœias, international law, field pharmacy, clinical and herbal medicine data, under a philosophical scrutiny. Generic and Cannabis-specific nomenclatural frames are compared to determine the extent to which they coincide or conflict.
Results: All lexica reviewed use weak, ambiguous, or inconsistent terms. There is insufficient scientific basis for terms and concepts related to Cannabis at all levels. No sound classification exists: current models conflict by adopting idiosyncratic, partial, outdated, or utilitarian schemes to arrange the extraordinarily numerous and diverse derivatives of the C. sativa plant. In law and policy, no clear or unequivocal boundary between herbal and non-herbal drugs, nor natural and synthetic cannabinoids was found; current nomenclatures used need updates. In science, the botanical Cannabis lexicon overlooks parthenocarpy, and wide disagreement remains as to the taxonomy and systematics of the plant; chemical research should address differences in kinds between synthetic cannabinoids; pharmacopœias include little information related to Cannabis, and disagree on broader classes of herbal medicines, virtually failing to embrace many known Cannabis medicines. Since existing products and compounds fail to be categorised in an evidence-based manner, confusions will likely increase as novel cannabinoid compounds, genetic and biotechnological modifications surge.
Conclusions: The lack of clarity is comprehensive: for patients, physicians, and regulators. The study proposes an update of terms at several levels. It points at gaps in morphological descriptions in botany and pharmacognosy and a need for a metaphysical address of cannabinoids. Methods of obtention are identified as a common criterion to distinguish products; the way forward suggests a mutually exclusive nomenclatural pattern based on the smallest common denominator of obtention methods. In the context of a swelling number of Cannabis products being consumed (be it via medical prescription, adult-use, ‘hemp’ foodstuff and cosmetics, or other purposes), this study can assist research, contribute to transparent labelling of products, consumer safety and awareness, pharmacovigilance, medical standards of care, and an update of prevention and harm reduction approaches. It can also better inform regulatory policies surrounding C. sativa, its derivatives, and other cannabinoid-containing products.
Original article available at: https://journals.sagepub.com/doi/full/10.1177/2050324520945797
... All biotypes of C. sativa appear to be completely interfertile and there are no genetic barriers to interbreeding (Small 1972). Prodigious quantities of pollen are produced and distributed by wind over considerable distances (Small and Antle 2003), so spontaneous matings among populations have doubtless homogenized the gene pool of C. sativa (Gilmore et al. 2003;Dufresnes et al. 2017). Moreover, humans have very extensively deliberately cross-pollinated traditional land races and recent selections. ...
... The thickness of the hull was measured, post-fracturing, using an electronic caliper (accurate to 0.01 mm). In C. sativa, the hull is made up of the seed coat and the pericarp, and as the seed coat is very thin, the hull thickness is virtually the same as the pericarp thickness (Small and Antle 2003). ...
Cannabis sativa has been domesticated for stem fibre and oilseed (the two classes are both low in the euphoric cannabinoid THC and called “hemp”), and marijuana (high in THC), and also occurs as weedy, ruderal plants. Achenes (“seeds”) from herbarium collections representative of these classes were assessed for morphological characters and pericarp resistance to fracture. In contrast to ruderal plants, domesticated plants (both hemp and marijuana) possessed achenes that were significantly longer, heavier, covered with a less adherent perianth, and lacking a pronounced basal attenuation. All of these characteristics reflect traits that are advantageous in domesticated plants and are consistent with the “domestication syndrome” found in propagules of other crops. Marijuana achenes, in comparison with hemp achenes, tended to be about 26% shorter and about 32 shades darker (on a 256-bit grayscale). Achenes of fibre cultivars proved to be about 19% longer than the achenes of oilseed cultivars. Achenes of dioecious oilseed cultivars proved to be about 6% longer than the achenes of monoecious oilseed cultivars. The pericarps of hemp seeds were about 26% and about 15% more resistant to fracture than those of ruderal and marijuana plants, respectively.
... Pollination is anemophilous and xenogamous, i.e., pollination is by wind and occurs between two distinct individuals (Heslop-Harrison & Heslop-Harrison, 1969;Cruden, 1977;Small and Antle, 2003;Rana and Choudary, 2010). Flowers are typically imperfect, either staminate or pistillate, and incomplete. ...
Cannabis sativa L. (hemp) develops plants with either male or female flowers, and growers of hemp greatly prefer female flowers which bear the glandular trichomes that contain cannabinoids. Feminized (all female) seeds are highly desired, which are produced by crossing a female plant with a masculinized female plant. Masculinization is achieved through the inhibition of ethylene and/or addition of gibberellins before flower initiation in female plants. The hemp industry uses silver thiosulfate (STS) to masculinize hemp, but spraying silver poses environmental concerns. This study compared STS to three other ethylene-inhibiting agents: aminoethoxyvinylglycine (AVG), cobalt nitrate (CBN), and 1-methylcyclopropene (1-MCP). Treatments of STS and CBN also included gibberellic acid as a synergist. Plants treated with STS exhibited superior masculinization and pollen dispersal compared to plants treated with AVG, CBN or 1-MCP. Only plants treated with STS or AVG produced pollen in sufficient quantities for collection. This pollen was assayed for germination potential initially and after storage for up to five weeks at 22.2, 7.2, or 1.1°C. Pollen from plants treated with AVG remained viable for four weeks at 1.1°C, whereas STS-treated plants produced pollen that was viable for three weeks at 1.1°C. Due to phytotoxicity problems with AVG, STS remains the best treatment to masculinize female hemp plants when breeding for feminized seeds. In a separate study, flower tissues of hemp had considerably higher total cannabinoid concentrations compared to leaf tissues but significantly lower ratios of cannabidivarin (CBDV) to cannabidiol (CBD). To reduce variability, at least 1 g samples of fresh leaf or flower tissue should be extracted with 10 mL of methanol. Rapid throughput testing of cannabinoids as part of a breeding program should use flower tissue, preferably at the time typical of harvest.
... Hemp is an anemophilous pollinated plant; so when the male flowers reach maturity they produce pollen which is transported to the female flowers by the air, even across long distances (Small & Antle, 2003). At this point, the pool of secondary metabolites is altered in female flowers, reducing the production of cannabinoids, flavonoids and terpenoids (Pijlman, Rigter, Hoek, Goldschmidt, & Niesink, 2005;Wizenberg, Weis, & Campbell, 2020). ...
Cannabis sativa L. belongs to the Cannabaceae family and includes annual, robust, fast-growing and generally dioecious plants. Industrial hemp, and particularly the inflorescences, has been recently recognized as important source of bioactive extracts with antioxidant and antimicrobial effects. The goal of the present study was to explore botanical, phytochemical, and biological properties of water and hydroalcoholic hemp pollen extracts from male inflorescences. The extracts from hemp pollen were found rich in phenolic compounds, such as hydroxytyrosol, coumaric acid, and hesperitin. The phenolic profile was also consistent with the observed scavenging/reducing, enzyme inhibitory, and antimicrobial properties of the extracts. Regarding the antimicrobial effects, Escherichia coli, Trycophyton rubrum, and T. tonsurans were the most sensitive to growth inhibitory effects (MIC values: 9.92-79.37 µg/mL) of the extracts. Whereas, null effects on prostate PC3 and myocyte C2C12 cell viability, in the range 1-1000 µg/mL, are consistent with MIC values and suggest extracts’ biocompatibility. The experimental data obtained, which are not reflected in the literature as the topic of hemp pollen is almost completely unexplored, confirm the innovativeness of a product obtained directly from bees, which in the face of greater variability and complexity can reserve promising applications in food, pharmaceutical and cosmetic sectors.
... Cannabis sativa L. is a dioecious crop frequently cultivated for its cannabinoids, fibre and seeds [44][45][46][47][48][49][50]. This species is anemophilous, and its exine morphology reflects this dispersal strategy, meaning its pollen grains are not ornamented and thus well suited to rapid movement coinciding with any changes in air flow [51,52]. Industrial facilities that produce high cannabinoid yielding plants often produce sinsemilla, unpollinated floral biomass, because growing female plants in strict isolation of pollen is required to prevent a reduction in cannabinoid content and the length of trichome dense stigmas [53,54]. ...
Pollen grains are male gametophytes, an ephemeral haploid generation of plants, that commonly engage in competition for a limited supply of ovules. Since variation in reproductive capabilities among male gametophytes may influence the direction and pace of evolution in populations, we must be able to quantify the relative fitness of gametophytes from different sires. To explore this, we estimated the relative fitness of groups of male gametophytes in a dioecious, wind-pollinated model system, Cannabis sativa , by characterizing the non-abortion rate (measured via chemical staining) and viability (measured via in vitro germination) of pollen from multiple sires. Pollen viability quickly declined within two weeks of anther dehiscence, and pollen stored under freezer conditions did not germinate regardless of storage time. In contrast, pollen non-abortion rates declined slowly and persisted longer than the lifetime of a sporophyte plant under both room temperature and freezer conditions. Pollen samples that underwent both viability and non-abortion rate analysis displayed no significant correlation, implying that researchers cannot predict pollen viability from non-abortion rates, nor infer male gametophytic fitness from a single measure. Our work demonstrates two independent, differential approaches to measure proxies of male fitness in C . sativa .
... Hemp is an open-pollinated plant and, therefore, also more prone to nonuniformity. Pollen can disperse a few kilometers in relation to the wind direction [22], which could be one of the reasons for higher heterogeneity in Cannabis varieties. Additionally, newly bred populations and marijuana populations are more uniform and can be easily grouped by their desirable traits, such as high THC/CBD level, high limonene, or other terpenoid levels [15]. ...
Hemp (Cannabis sativa L.) cannabinoids and terpenoids have therapeutic effects on human and animal health. Cannabis plants can often have a relatively high heterogeneity, which leads to different phenotypes that have different chemical profiles despite being from the same variety. Little information exists about cannabinoid and terpenoid profiles in different hemp phenotypes within the same variety. For this study, 11 phenotypes from three different varieties (“Carmagnola” selected (CS), “Tiborszallasi” (TS), and “Finola” selection (FS)) were analyzed. The components of essential oil (29) were analyzed using gas chromatography with flame ionization detection (GC/FID), and 10 different cannabinoids of each phenotype were determined using high-performance liquid chromatography (HPLC). Principal component analysis (PCA) and analysis of variance (ANOVA) showed that according to the components of essential oil, FS and TS plants were more uniform than CS plants, where there were great differences between CI and CII phenotypes. The content of cannabinoid CBD-A was the highest in all four FS phenotypes. By comparing cannabinoid profiles, FS was clearly separated from TS and CS, while these two varieties were not clearly distinguishable. Phenotypes TV and CI had the highest total content of Δ-9-THC, while all phenotypes of FS had the highest total content of CBD. The highest total content of CBG was determined in phenotype CI. Obtained results are useful for the development of new supplementary ingredients, for different pharmacy treatments, and for further breeding purposes.
... With widespread habitat destruction and fragmentation, isolated forest fragments will depend on long-distance wind dispersal and pollination for maintaining genetic diversity and reducing inbreeding depression (42,43). And with increasing concern about engineered genes leaking from commercial forestry plantations into wild tree populations, wind strength and direction are likely to shape rates of genetic contamination (44,45). To help managers assess and mitigate these risks, future studies will need to further develop our understanding of how wind geography shapes gene flow at different timescales. ...
Significance
It is unknown whether wind currents shape large-scale gene flow in terrestrial organisms such as plants, though analogous river and ocean currents are known to strongly influence genetic patterns in aquatic organisms. We use newly developed “windscape” connectivity models in combination with a global multispecies forest genetics data set to demonstrate that wind shapes several distinct large-scale genetic patterns in many tree species, including population differentiation, migration direction, and genetic diversity. These findings advance our understanding of the spatial ecology and evolution of wind-dispersed and wind-pollinated plants. They also suggest that the geography of wind strength and direction could potentially influence patterns of forest vulnerability to human pressures like habitat fragmentation and climate change.
... One reason for C. dactylon abundance is could be the long-distance dispersal of its pollen by the wind in large amount [23]. Besides, this species also has unique morphology because it only requires 13 h to grow at 6.3-6.8 optimum pH of soil. ...
The role of vegetation is very important in ecosystem conservation. The present study was conducted to classify the existing ground flora in Tharparker, Pakistan. The distribution pattern of vegetation and species association was grouped into different communities by using ordination techniques. Both direct and indirect ordination methods were applied to classify the species into groups and communities, and also quantify the relationship of species with varied soil parameters (pH, EC, moisture, OM, K, P, Fe⁺³, Zn⁺², Mn⁺², Cu⁺²). Plant and soil samples were randomly collected using quadrat of 1 * 1 m². Two main groups and four communities were formed by species derived from fifty quadrat. Cynodon dactylon and Desmostachya bipinnata showed higher abundance over the broad range of all edaphic factor’s concentration. This study provided the significant results of least abundant and most abundant herbaceous species in the region of Tharparker, which will be helpful for land managing and planning.
... While the proportion of hermaphrodites in populations of marijuana is unknown, the frequency of seed formation within the hermaphroditic flower during indoor production is likely greater, despite the lower amounts of pollen produced, compared to a female flower dependent on wind-dispersed pollen from a male plant (indoors or outdoors). The distance over which pollen is dispersed from individual anthers in hermaphroditic flowers is probably limited to a few meters in indoor or outdoor growing facilities, compared to up to 3-5 km from male plants grown under outdoor field conditions, depending on wind speed and direction (Small and Antle, 2003). Male plants grow faster and are taller than female plants grown over the same time period, ensuring more rapid development of flowers and pollen dehiscence (Figure 7). ...
Cannabis sativa L. (hemp, marijuana) produces male and female inflorescences on different plants (dioecious) and therefore the plants are obligatory out-crossers. In commercial production, marijuana plants are all genetically female; male plants are destroyed as seed formation reduces flower quality. Spontaneously occurring hermaphroditic inflorescences, in which pistillate flowers are accompanied by formation of anthers, leads to undesired seed formation; the mechanism for this is poorly understood. We studied hermaphroditism in several marijuana strains with three objectives: (i) to compare the morphological features of this unique phenotype with normal male flowers; (ii) to assess pollen and seed viability from hermaphroditic flowers; and (iii) to assess the effect of hermaphroditism on progeny male:female (sex) ratios and on genetic variation using molecular methods. The morphological features of anthers, pollen production and germination in hermaphroditic flowers and in staminate inflorescences on male plants were compared using light and scanning electron microscopy. Seeds produced on hermaphroditic plants and seeds derived from cross-fertilization were germinated and seedlings were compared for gender ratios using a PCR-based assay as well as for the extent of genetic variation using six ISSR primers. Nei’s index of gene diversity and Shannon’s Information index were compared for these two populations. The morphology of anthers and pollen formation in hermaphroditic inflorescences was similar to that in staminate flowers. Seedlings from hermaphroditic seeds, and anther tissues, showed a female genetic composition while seedlings derived from cross-fertilized seeds showed a 1:1 male:female sex expression ratio. Uniquely, hermaphroditic inflorescences produced seeds which gave rise only to genetically female plants. In PCR assays, a 540 bp size fragment was present in male and female plants, while a 390 bp band was uniquely associated with male plants. Sequence analysis of these fragments revealed the presence of Copia-like retrotransposons within the C. sativa genome which may be associated with the expression of male or female phenotype. In ISSR analysis, the percentage of polymorphic loci ranged from 44 to 72% in hermaphroditic and cross-fertilized populations. Nei’s index of gene diversity and Shannon’s Information index were not statistically different for both populations. The extent of genetic variation after one generation of selfing in the progeny from hermaphroditic seed is similar to that in progeny from cross-fertilized seeds.
... Pollination occurs via wind, and to promote cross-pollination staminate flowers open and release their pollen approximately half an hour prior to the pistilate flowers, when they then become receptive to pollination (Rana and Chaoudhary, 2010). Downwind, pollen grains can be successfully carried up to 5km away from the parent plant (Doorenbos et al., 1971;Small and Antle, 2003;. This wind-assisting pollination is critical, because while insects have been observed to visit males, they do not visit females, therefore making exogenous intervention an ineffective pollination method (Doorenbos et al., 1971;Rana and Chaoudhary, 2010). ...
Late 2017, the ban on the cultivation and consumption of low tetrahydrocannabinol (THC) Cannabis sativa L. in Victoria, was lifted by the Federal Government of Australia. Its legalization presents the opportunity for Victoria to become a leading producer and distributer of these economically valuable hemp products. However, as a novel crop to Victoria, there is little information available for obtaining economically viable yields. Therefore, the objectives of this review were to firstly, develop an understanding of the environmental requirements shared by C. sativa cultivars, and what conditions promote fibre and grain yields. Secondly, it seeks to identify what farming practices have been conducted throughout Europe, Canada and China, and to explore whether these practices could be adapted to Victoria. Thirdly, the review will assist in making recommendations regarding which cultivars would be 'potential' candidates for commencing trials under Victorian climates so to find out the varieties that can provide high yields for fibre, grain and dual-purpose production. This review notes that Victoria shares a similar climate to central Europe, and has an ideal climate for the development of a successful hemp industry, as it has suitable lengths of daylight throughout spring and summer months and meets the precipitation requirements. This review has thus strongly suggested that the properties and attributes o f European varieties of C. sativa should be further researched for site-specific cultivation in Victoria for fibre, grain and dual-purpose production in order to maximise harvest yields.
... One of the properties of C. sativa was that its pollens were dispersed by wind in large amount to long distances. The distribution of pollen downwind was 6 times more than it was disseminated upwind (Small & Antle, 2003). One identified species in present study was C. sativa which is environmentally friendly species and also use as low cost feedstock. ...
Vegetation plays an important role in ecosystem maintenance. But the construction of dams transform the riparian vegetation into impoundment region. The present study was conducted to identify and quantify herbaceous flora around the vicinity of Mangla dam. Study area was divided into two zones on the basis of distance from the dam boundary. Pattern of vegetation distribution and their association in area was grouped in to different communities by using ordination techniques. Two ordination techniques TWINSPAN and DECORANA were used. A total of 37 species belonging to 17 families were identified from fifty quadrats. Random sampling was done by using 1 ×1 m sized quadrat. Percentage of vegetation was assessed by using Domin cover scale. TWINSPAN classified two groups and four communities in Zone-I, while in Zone-II two groups and six communities were formed. Dominance curve showed that Cynodon dactylon, Desmostachya bipinnata and Rhynchosia minima were dominant species in Zone-I and Croton bonplandianus, C. dactylon, D. bipinnata and Brachiaria decumbens were frequent species in Zone-II. DCA as indirect multivariate technique based on reciprocal averaging determined the environmental gradients that affect the species richness and also verified the groups of species and indicated four communities in both Zones. Monte Carlo test of significance was used to analyze stress in relation to number of axis/dimensionality under Non-metric Multidimensional Scaling (NMS) through p-value. This study provided the significant results of least abundant and most abundant herbaceous species around the dam which will be helpful for biodiversity conservation and in decision making for further land planning.
... Stokes et al. (2000) recorded that in August in the Midwestern United States (where cultivation of hemp is not permitted, but weedy hemp is common) hemp pollen represented up to 36 % of total airborne pollen counts! Because the pollen of Cannabis spreads remarkably, an isolation distance of about 5 km is usually recommended for generating pure-bred seed, exceeding the distance for virtually every other crop (Small and Antle 2003). Because of widespread clandestine cultivation, the pollen can be found, at least in small concentrations, over most of the planet. ...
Female flowers of Cannabis sativa in wild-growing populations and in hemp plantations are almost always well supplied with pollen. The style-stigma portion of the pistils of such plants was found to average only about 3 mm in length and to invariably be two-branched. By contrast, “buds” (congested female inflorescences), the standard form of marijuana now produced in the illicit and medicinal marijuana sectors, are protected against pollen. This report documents that in the absence of pollen, the style-stigma parts of virgin pistils expand notably, average over 8 mm in length, and tend to develop more than two branches and to increase in girth. From an evolutionary viewpoint, this expansion of pollen-receptive tissue is an apparent adaptation for increasing the probability of fertilizing the females when males are extremely scarce. From a practical viewpoint, the expanded presence of stigma tissues may be both advantageous and disadvantageous. The high-THC secretory gland heads of Cannabis tend to fall away from marijuana buds, significantly decreasing pharmacological potency, but many gland heads become stuck to the receptive papillae of the stigmas, reducing the loss. Although stigmas constitute a small proportion of marijuana, their distinctive chemistry could have health effects.
... A.D. 1260 could be explained by limited cultivation (as suggested by the low pollen frequencies) and retting, leading to CBN concentrations that are too low to be detected in the older samples, this hypothesis cannot explain the signifi cant differences observed between pollen and molecular signals for later periods (A.D. 1445-1490 and 1570-1720). Even though hemp pollen, which is disseminated by wind (e.g., Small and Antle, 2003), could come, in part, from outside the catchment (contrary to CBN, which is necessarily autochthonous), the high frequencies observed during this period leave no doubt concerning the reality of retting near Lake Aydat. No relationship between these discrepancy phases and the different sedimentological parameters expanded by Lavrieux et al. (2013) could be highlighted, underlining that the molecular signal is not determined by the sedimentation rate and/or the dilution in the mineral phase of the sediment. ...
Hemp (Cannabis sp.) has been a fundamental plant for the development of human societies. Its fibers have long been used for textiles and rope making, which requires prior stem retting. This process is essential for extracting fibers from the stem of the plant, but can adversely affect the quality of surface waters. The history of human activities related to hemp (its domestication, spread, and processing) is frequently reconstructed from seeds and pollen detected in archaeological sites or in sedimentary archives, but this method does not always make it possible to ascertain whether retting took place. Hemp is also known to contain phytocannabinoids, a type of chemicals that is specific to the plant. Here we report on the detection of one of these chemicals, cannabinol (CBN), preserved in a sediment record from a lake in the French Massif Central covering the past 1800 yr. The presence of this molecule in the sedimentary record is related to retting. Analysis of the evolution of CBN concentrations shows t
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.
After decades of prohibition of the cultivation and breeding of hemp ( Cannabis sativa < 0.3% ∆9‐tetrahydrocannabinol [THC]), there is untapped potential for genetic improvement of this crop to provide food, feed, fiber, and medicinal compounds. Successful breeding efforts will require the development and characterization of germplasm resources, optimization of crossing methods, better understanding of sex determination, high‐throughput phenotyping platforms, and deployment of genomic tools for rapid selection. This review provides a brief overview of these topics and some key opportunities for genetic improvement of hemp to support an emerging industry utilizing this newly legalized crop.
Growers have increasingly expressed frustration over the negative externalities created by their neighbor's production practices. These spatial agricultural network problems include issues such as cross‐pollination and herbicide drift. We develop novel methods for estimating parameters that allow us to adapt and apply general network diffusion models to these spatial agricultural network problems. Doing so allows us to calculate externality damage within a region and calculate cost‐effective policies for alleviating that externality. We empirically illustrate, motivate, and test this approach by applying it to hemp. We find that network structure is an important factor in externality size and cost‐effective policy response for spatial agricultural network problems. We also find that policies that are implemented early and proactively are more likely to be successful and cost effective than policies implemented retroactively. Finally, we find that in our application of limiting the cross‐pollination damage experienced by growers of feminized hemp from non‐feminized hemp growers, the most cost‐effective policy is to establish a regional quota on non‐feminized production combined with intertemporal cultivar spacing. This policy response will likely change across time and region as economic and network variables evolve.
Cannabis (Cannabis sativa L.) is a dioecious plant that produces both male and female inflorescences. In nature, male and female plants can be found with nearly equal frequency, which determines species out-crossing. In cannabis farming, only female plants are preferred due to their high yield of cannabinoids. In addition to unfavorable male plants, commercial production of cannabis faces the appearance of hermaphroditic inflorescences, species displaying both pistillate flowers and anthers. Such plants can out-cross female plants, simultaneously producing undesired seeds. The problem of hermaphroditic cannabis triggered a search for analytical tools that can be used for their rapid detection and identification. In this study, we investigate the potential of Raman spectroscopy (RS), an emerging sensing technique that can be used to probe plant biochemistry. Our results show that the biochemistry of male, female and hermaphroditic cannabis plants is drastically different which allows for their confirmatory identification using a hand-held Raman spectrometer. Furthermore, the coupling of machine learning approaches enables the identification of hermaphrodites with 98.7% accuracy, whereas both male and female plants can be identified with 100% accuracy. Considering the label-free, non-invasive and non-destructive nature of RS, the developed optical sensing approach can transform cannabis farming in the U.S. and overseas.
Marijuana (Cannabis) belongs to family Cannabaceae. This plant is a great natural source of cannabinoids, which have several medical applications such as it is used for the treatment of anxiety and psychosis, disorders of motility and epilepsy. However, this plant is also notorious for its pollen allergic reactions. Mainly two species, that is, C. sativa L. and C.indica Lam. are involved in allergic reactions. In this study, morpho‐palynological studies of both the species were conducted. A number of morphological differences were observed in the both species. C. sativa is tall with narrowed leaves and fibrous stalk plant while C. indica is short, bushier, broad leaves, and having woody stalk plant. Both the species are varied in their pollen characteristics. The polar diameter of C. sativa observed was 7.5 μm and equatorial diameter was 8 μm, and its shape was oblate‐spheroidal. C. indica had 7 μm polar diameter, 7.5 μm equatorial diameter but its shape was similar to C. sativa, that is, oblate‐spheroidal. About 40%‑50% people were affected with both these marijuana species and had symptoms of allergies like dry cough, congestion, itchy eyes, sore throat, nausea, a runny nose, watery eyes, and sneezing. It was concluded that both species' pollen are allergy causing and pollen of both species are different with variations in morphological and allergic symptoms. Marijuana has great therapeutic importance but it is also notorious for its pollen allergic reactions. Two species of Marijuana, that is, Cannabis sativa L. and Cannabis indica Lam mainly responsible for these pollen allergies. The present research work focused the morpho palynological analysis of these two Marijuana species through light and scanning electron microscopy. Palynological analysis of Marijuana species causing allergies.
This study was undertaken to compare cannabinoid levels and yields in floral extracts from unpollinated and artificially pollinated industrial hemp (Cannabis sativa L. cv. Finola) flowers grown under identical growth chamber conditions. Of the 16 cannabinoids analyzed using high performance liquid chromatography (HPLC), the levels of 10, cannabichromene (CBC), cannabichromenic acid (CBCA), cannabidivarin (CBDV), cannabigerol (CBG), cannabicyclol (CBL), cannabinol (CBN) cannabinolic acid (CBNA), ∆⁸-tetrahydrocannabinol (∆⁸⁻THC), tetrahydrocannabivarin (THCV) and tetrahydrocannabivarinic acid (THCVA) were near or below the limit of quantification. Total ∆⁹-tetrahydrocannabinol (THC), was present at concentrations below the legal limit of 0.3% (w/w). The level of cannabidiol (CBD) in extracts from pollinated flowers was the same as that from unpollinated flowers, but cannabidiolic acid (CBDA) and cannabidivarinic acid (CBDVA) levels were not. This suggested that, although pollination changes the pool sizes of the precursors in the metabolic pathway leading to CBD production, cannabinoid levels in floral extracts from the Finola cultivar, were reduced but not eliminated, by pollination of hemp flowers compared with levels in floral extracts from unpollinated flowers.
Cannabis sativa is a versatile crop that can be cultivated for fiber, seed, or phytochemicals. To take advantage of this versatility and the potential of Cannabis as a feedstock for the bioeconomy, genomics-enabled breeding programs must be strengthened and expanded. This work contributes to the foundation for such by investigating the phytochemistry and genomics of feral Cannabis populations collected from seventeen counties across the climate gradient of Nebraska. Flower tissue from male and female plants (28 total) was studied using (i) gas chromatography-mass spectrometry to assess cannabinoid profiles and (ii) RNA sequencing to determine transcript abundances. Both male and female flower tissues produced cannabinoids, and, though the compounds were more abundant in female flower tissue, the primary cannabinoid in both was usually cannabidiol. The expression of genes that mediate early steps on the cannabinoid biosynthetic pathway were upregulated in female relative to male flowers, suggesting that female versus male flower tissue cannabinoid abundance may be controlled at least in part at the transcriptional level. DNA sequencing was used to place feral Cannabis plants from Nebraska into a previously described genomic context, revealing that all the plants studied here are much more similar to previously characterized hemp-type Cannabis plants than to drug-type Cannabis plants, at least at the genetic level. This work provides foundational phytochemical knowledge and a large set of high-quality single nucleotide polymorphism markers for future studies of feral Nebraska Cannabis.
The evolution of the behaviour of the Cannabis taxon in the Region of Murcia, Spain, has been analysed (in the cities of Cartagena, 1993–2020; Murcia, 2010–2020; and Lorca, 2010–2020). An attempt has been made to establish the origin of Cannabis pollen in this region to determine whether it is transported locally or from long distances based on air mass origins. Cannabis is an herbaceous, normally dioecious and anemophilous plant, which produces large quantities of pollen grains. It has been widely used for fibre (hemp), bird food (hempseed), essential oils and narcotics. The origin of Cannabis pollen grains has been established by calculating back trajectories at the altitudes of: 750, 1500 and 2500 m above mean sea level (m amsl); 350, 500 and 650 m amsl; and 10, 100 and 250 m amsl, using the HYSPLIT model. Considering this data, 29 days of Cannabis pollen potentially originating in Africa were identified in Cartagena, 19 days in Murcia and 15 days in Lorca. Of the remaining days, the air mass back trajectories showed local or regional pollen origins. These were 83 days in Cartagena, 61 days in Murcia and 56 days in Lorca. The presence of Cannabis in the bioaerosol of the Region of Murcia is irregular, and it is considered a minority pollen type. However, from 2017 to 2020, concentrations increased, with a positive and significant trend of 90% in the Annual Pollen Integral. The pollen season can be defined between June and August. This increase in the concentration of Cannabis pollen grains during this period coincides with an increase in local transport, suggesting the possibility of increased Cannabis cultivation in the study area.
Premise:
Precise pollen collection methods are necessary for crop breeding, but anemophilous pollen is notoriously difficult to capture and control. Here we compared a variety of methods for the controlled capture of cannabis pollen, intended to ease the process of cross-fertilization for breeding this wind-pollinated plant, and measured the utility of light spectroscopy for quantifying relative pollen yield.
Methods and results:
In two independent trials, we compared a control method of pollen collection (hand collection) to either vacuum-, water-, or bag-collection methods. We used visible light spectroscopy to quantify relative pollen yield, and validated this approach using microscopic pollen counts. We determined that pollen yield was highest when using hand collection or vacuum collection, but efficiency did not differ significantly among methods.
Conclusions:
To maximize yield, pollen should be collected by hand or vacuum, but all collection methods were equally efficient in a relative sense because yield increased with collection time. We also found that light spectroscopy is an accurate and rapid method of quantifying pollen abundance (R2 = 0.86) in a liquid suspension.
PREMISE: How genetic variation within a species affects phytochemical composition is a fundamental question in botany. The ratio of two specialized metabolites in Cannabis sativa, tetrahydrocannabinol (THC) and cannabidiol (CBD), can be grouped into
three main classes (THC-type, CBD-type, and intermediate type). We tested a genetic model associating these three groups with functional and nonfunctional alleles of the cannabidiolic acid synthase gene (CBDAS).
METHODS: We characterized cannabinoid content and assayed CBDAS genotypes of >300 feral C. sativa plants in Minnesota, United States. We performed a test cross to assess CBDAS inheritance. Twenty clinical cultivars obtained blindly from the National Institute on Drug Abuse and 12 Canadian-certified grain cultivars were also examined.
RESULTS: Frequencies of CBD-type, intermediate-type, and THC-type feral plants were 0.88, 0.11, and 0.01, respectively. Although total cannabinoid content varied substantially, the three groupings were perfectly correlated with CBDAS genotypes. Genotype frequencies observed in the test cross were consistent with codominant Mendelian inheritance of the THC:CBD ratio. Despite significant mean differences in total cannabinoid content, CBDAS genotypes blindly predicted the THC:CBD ratio among clinical cultivars, and the same was true for industrial grain cultivars when plants exhibited >0.5% total cannabinoid content.
CONCLUSIONS: Our results extend the generality of the inheritance model for THC:CBD to diverse C. sativa accessions and demonstrate that CBDAS genotyping can predict the ratio in a variety of practical applications. Cannabinoid profiles and associated CBDAS segregation patterns suggest that feral C. sativa populations are potentially valuable experimental systems and sources of germplasm.
Madagascar poses a significant challenge for understanding how people colonized islands. While its inhabitants also share an African ancestry, language, genetics, and culture all point to the arrival on the island of Austronesian-speaking settlers from the far side of the Indian Ocean. Recent decades have seen increasing acceptance of a late first-millennium BC date for Madagascar’s initial settlement, based principally on arguments relating to the purported antiquity and presence of cut-marked animal bones and the pollen of humanly introduced Cannabis plants. More recently, these claims have been pushed much further back in time by the discovery of stone tools at Lakaton’i Anja and cut-marked bones at Christmas River and Lamboharana. Such arguments must be based on firm foundations if they are to be accepted. This paper evaluates them against criteria developed for assessing the timing and credibility of claims of pre-Clovis settlement in the Americas and early Polynesian presence in Remote Oceania. It concludes that they do not meet them and that for now there is thus no convincing evidence that Madagascar was settled before the mid-first millennium AD. Colonization around that time fits much better with broader patterns of contact, trade, and settlement in the wider Indian Ocean world, including other islands off Africa’s eastern coast.
Addictive “social drugs” that are derived from plants range from reputable stimulants (e.g., coffee and tea) to stigmatized and dangerous preparations (e.g., ephedrine and cocaine). Both legal and illicit global trade has increased the geographic distribution of plants from which the principal social drugs are obtained. In turn, this range expansion increased opportunities to transfer genes controlling production of high levels of secondary chemicals because of increases in overlapping geographic distributions with sexually compatible domesticated, wild, and weedy relatives. We review the literature for evidence that the introduction of these chemicals into ecosystems could occur through gene flow in ten common, addictive, social drug crops: coca, coffee, cola, ephedra, khat, marijuana, opium poppy, tea, tobacco and yerbe maté. From the published literature of the potential evolutionary and environmental consequences of gene flow from popular social drug crops, we also analyse the subsequent unintended ecological or evolutionary consequences, such as increased weediness, loss of genetic diversity in sexually compatible wild relatives, or health and fitness consequences for herbivores of these crops. Given the rapid industrialization of many of these crops, we identify knowledge gaps and call for renewed attention to the study of their ecology and evolution.
Marijuana Community Impact Study
Executive Summary
In December of 2016, the Pueblo County Commissioners contracted with the newly-established Institute of Cannabis Research (ICR) at Colorado State University - Pueblo to study the impacts of legal cannabis on Pueblo County. In the years since 2012, the year that Colorado voters approved Amendment 64, Pueblo has opened the door wider to legal cannabis than many other Colorado counties. In addition to licensing medical and retail cannabis dispensaries, Pueblo County has also approved cannabis grows and cannabis product development companies. It is reasonable to assume that newly legalized cannabis dispensaries, grows, and product development companies will have a significant impact on Pueblo County. Rather than operating in the dark, the Pueblo County Commissioners requested an Impact Study from the Institute of Cannabis Research that focuses on the following subject areas:
Scope of Services and Impact Study Team Researchers
Demographics
Investigator: Timothy McGettigan, PhD
Poverty and Homelessness
Investigator: Timothy McGettigan, PhD
Education
Investigators: Tim Peters, PhD
Jobs
Investigators: Brad Gilbreath, PhD and Patrick Radigan, PhD
Crime and Prison Populations
Investigator: Jennifer Schlosser-Couch, PhD
Public Health & Health Care System
Investigators: Joe Franta, PhD, Leslie Murtagh, PhD, Jacinda Heintzelman, PhD, Lisa Persons, PhD
Community Attitudes
Investigators: Carol Langer, PhD, Fawn Amber-Montoya, PhD, Colleen Hackett, PhD
Impacts on Social Services
Investigator: Arlene Reilly-Sandoval, PhD
Impact Study Principal Investigators
Jane Fraser and Leonardo Bedoyavalencia - Energy & Water
Aun Hassan and Mike Wakefield - Economic Impacts
Brian Vandenheuvel - Hemp Buffer Zones
Joe Franta and Tim McGettigan - Social Impacts
Impact Study researchers began meeting on a weekly basis in January, 2017, and continued meeting throughout the balance of the Spring 2017 semester. Regular meetings helped Impact Study researchers maintain a shared vision while working on individual reports. Regular meetings also enabled Impact Study researchers to share insights about common problems and helped researchers remain in step with the agreed-upon timetable.
After Impact Study researchers submitted final drafts of their individual reports the ICR Steering Committee appointed an Impact Study Finalization Committee. The Finalization Committee coordinated the process of transforming individual reports from investigators from more than a dozen disciplines into a unified final report.
Summaries of Individual Reports
1 - Demographics, Timothy McGettigan, PhD
In his research on demographics, Timothy McGettigan, PhD notes that cannabis has not been legal long enough to have a major impact on Pueblo County’s demography. Puebloans have demonstrated a clear pattern of voter support for legal cannabis, which is consistent with nationwide trends. So far, the demographic impacts of legal cannabis on Pueblo have been modest. Since the passage of Amendment 20, Pueblo’s population has increased at much the same rate as prior to legalization. There is no evidence that legal cannabis has reduced Pueblo’s population.
There is evidence of increased migration to Pueblo since the passage of Amendment 64. Opinion is divided about whether migrants have had a positive or negative impact on Pueblo. Educational achievement in Pueblo still lags behind the rest of Colorado. To combat that deficit, Pueblo County has instituted the world’s first cannabis tax funded college scholarships.
Household income in Pueblo falls well below incomes in Colorado’s more affluent counties. Jobs created by the legal cannabis industry should help Puebloans narrow stark income gaps.
The National Survey on Drug Use and Health recently revealed that cannabis use has declined steeply among 12- to 17-year-olds. While adolescent use has been declining, cannabis use among elderly Americans has increased dramatically.
2 - Poverty and Homelessness, Timothy McGettigan, PhD
In his investigation of poverty and homelessness, Timothy McGettigan discovered that since the passage of Amendment 64, poverty has neither increased nor decreased in Pueblo. Poverty rates are persistently higher in Pueblo than in the rest of Colorado. Thus far, legal cannabis has neither reduced, nor increased poverty disparities between Pueblo and more affluent Colorado counties.
There is evidence that homelessness has increased in Pueblo in recent years. The 2017 Point in Time Study indicates that Pueblo has much higher rates of homelessness than other Colorado counties. Some have argued that legal cannabis is the cause of exploding rates of homelessness in Pueblo, but there is no scientific evidence to support that argument.
Counterintuitively, Colorado’s economic boom may itself be the cause of increases in homelessness. Front Range wages have not kept pace with the cost of living and hourly wage earners are having a difficult time affording shelter. Also, while homelessness among military veterans has been decreasing all across the US, it has been increasing in Colorado. This might be due to veterans who are migrating to Colorado to obtain legal cannabis as a PTSD medication.
Cannabis refugees have a real but unknown impact on homeless statistics in Pueblo. Cannabis refugees are people who cross state lines to acquire cannabis to treat their own or loved ones’ illnesses. The enduring federal prohibition on cannabis is the root cause of homeless cannabis refugees.
The most significant cause of homelessness in Pueblo is Black Hills Energy. In 2016 alone, Black Hills Energy disconnected utilities to more than 7,000 Pueblo homes. "It's the number one reason families are becoming homeless in our community," explained Posada director Anne Stattelman.
3 - Education, Tim Peters and Colleagues
The K12 Cannabis Study was initiated to find answers to questions related to K-12 education raised by the legalization of recreational cannabis in Colorado and in particular, Pueblo County and southern Colorado. Four areas of inquiry were studied. The first was a secondary data analysis of high school student use of, and perceptions towards, cannabis that compared changes in use and perceptions from 2013 to 2015 between communities in south central Colorado that permitted recreational cannabis sales and those communities that did not permit these sales. The second area is a descriptive study of regional administrators regarding marijuana prevention education efforts and policies within the school districts. The third is a pilot study to test a marijuana education curriculum, and the fourth, is planning and preparation activities to support restorative justice practices around marijuana offenses in Pueblo County Schools. The following report is organized into the four areas of inquiry and each will describe more fully the background, methods, results and conclusions of the individual efforts.
4 - Jobs, Brad Gilbreath, PhD and Patrick Radigan, PhD
This study focuses on the quality of jobs in Pueblo County’s hemp- and marijuana-related businesses. The study draws upon the work of job-quality researcher Arne Kalleberg to construct a thorough assessment of whether the legal cannabis industry is creating good jobs. Job quality will be assessed both objectively and from the perspective of those working in the industry. Our study is one of the first to explore the concept of job quality in the cannabis industry.
Other factors influencing job quality include hours of work, future prospects (promotion and job security), how hard or difficult the job is, job content (interest, prestige, independence), interpersonal relationships (Clark, 1998), and supervisor behavior and management practices (Seltzer & Numerof, 1988; Gilbreath & Benson, 2004). We plan to assess all of those factors in our study of job quality in the cannabis industry.
5 - Crime and Prison Populations, Jennifer Schlosser, PhD
Controversy continues to surround legalized cannabis in Colorado, and Pueblo County. The data presented here were gathered through a working relationship with the Pueblo County Sheriff’s Department and the City of Pueblo Police Department. The data include statistical information on various crimes conducted from 2010-2017 as well as the results of 20 individual interviews with city police officers.
In 2013, the Cole Memo stated that the Federal Government would not challenge Colorado’s ability to regulate the retail sale of marijuana under the condition that “state and local governments would implement strong, effective regulatory and enforcement systems to address public safety, public health, and other public interests” (Blake & Finlaw, 2014). In response, David Blake the Deputy Attorney General for Legal Policy and Government Affairs in Colorado and Jack Finlaw, the Chief Legal Counsel for Colorado Governor John Hickenlooper outlined in a report for the Harvard Law and Policy Review (2014) the issues that Colorado continues to face after legalization. Their report lists many questions, potential problems, and issues that states considering decriminalizing marijuana will face. As will be shown in this report, these agencies are expected to uphold both state and federal law in the maintenance of public safety, but are provided with little financial support and even less regulatory clarity.
6 - Public Health & Health Care System, Joe Franta, PhD, and Colleagues
(No report yet)
7 - Community Attitudes, Carol L. Langer, PhD, Fawn-Amber Montoya, PhD, and Maria A. Trujillo
Religion and Marijuana
Over the last few years, many states have changed their laws regarding the use of medicinal and recreational marijuana. These changes in legislation have increased the legal availability of marijuana. The purpose of this study is to examine whether or not a person’s religious beliefs and background have any correlation with their views on the use of medicinal and/or recreational marijuana.
Multiple studies have secured findings that support the notion that regular church attendance and a sense of security in religious beliefs were factors that contributed to whether or not an individual was likely to participate in the consumption of marijuana and other substances. The data in this study showed that 38% of church members reported trying marijuana, and 18% of church members reported using the substance more than six times in a month. In comparison, 47% of nonmembers reported trying marijuana at least once, while 25% reported using the substance more than six times in a month. This same study found that members of the Church of the Latter Day Saints had the lowest percentage of young members trying or being heavy users of all substances. Participants who were from the Episcopal and Presbyterian churches had the next lowest percentage of using marijuana heavily. The study showed that the fundamentalist religions and the most proscriptive of religions proved to be most effective in preventing the use of alcohol and substances, such as marijuana. The more liberal and prescriptive religions proved to be next most effective in preventing the use of marijuana.
8 - Community Attitudes, Colleen Hackett, PhD
Parenting Practices, Attitudes, and Marijuana Education
Abstinence-based approaches are the prevailing ideology behind many drug education programs and mainstream messaging about illicit substances. Given that more than half of high school students are likely to experiment with drugs of any type, abstinence-based educational approaches are clearly not working (MTF 2014). Though this report is not an endorsement of teenage cannabis use, it does borrow from the latest drug education literature that attempts to stray from scare tactics and zero-tolerance approaches and to adopt a “smart” framework instead.
The following study starts with the research question: How are parents in Pueblo County talking to their teenage children about marijuana in a state that has legalized marijuana? This research intends to explore what parents’ general views on marijuana and cannabis products are, while additionally documenting what – if anything – parents teach their teenage child or children about marijuana. The study explores whether parents are adhering to an abstinence-only model, or if they are choosing to stray from traditional educational tactics.
9 - Impacts on Social Services, Arlene Reilly-Sandoval, PhD
In the past five years, laws centered around the possession, sale, and transfer of medicinal and recreational cannabis have changed drastically. This social impact study looked at the effect of cannabis legalization within the CPS system in Pueblo County, Colorado. The subject of cannabis legalization and child welfare is multi-faceted, and further complicated by issues such as poverty, unemployment, homelessness, availability of safety net benefits, and mental health challenges that are experienced by families referred to Pueblo County DSS for services.
In November of 2012, Colorado voters passed Amendment 64, allowing the recreational use of cannabis, and the sale of recreational cannabis in Colorado began in January 2014. The impact of cannabis on children has been a matter of major concern in the discussion of legalization of medical and recreational cannabis. The Colorado Department of Public Safety (2016) found that the trend for students reporting first use of marijuana has gradually declined in the past two survey administrations by about 6 percentage points (CDPS, 2016). Pueblo County had the highest incident in Colorado of high school and middle school youth reporting using marijuana in the last 30 days, with 32.1% and 22.8% respectively (CDPS, 2016). While the Colorado Department of Human Services Trails data does not track specific drugs or alcohol issues experienced by families referred to the agency, the Child Health Survey found that “…of parents with children ages 1-14, 4% reported using marijuana in the past month, and 7% reported having marijuana in the household” (CDPS, 2016, p. 71).
Currently, there is a lack of research on the specific topic of the impact of legalizing cannabis has on children and families in the CW System, such as how referrals and investigations are affected, the availability of treatment options, the education and training of caseworkers handling cases involving legal cannabis, and how to manage CW cases when the primary caregiver is using legal cannabis. More research is needed on these important topics.
Additional Reports from Impact Study Principal Investigators
1 - Energy & Water, Jane Fraser, PhD, and Leonardo Bedoyavalencia, PhD
Practices and opinions vary about the growth of cannabis. The industry is far from having established best practices to minimize the use of inputs such as water and electricity. A preliminary finding, based on interviews with six people involved in cannabis production, is that cannabis can be grown indoors with ½ gallon per plant per day; outdoor grows use more water. Energy use varies widely and interviews are continuing to determine the range of practices and usage. A Systems Dynamics model with seven sectors (demographics, housing, attractiveness, land use, business attractiveness, energy, and water) has been developed to analyze the region's energy and water demand variation when a new supply chain system in introduced.
We report on preliminary findings of a study of the impact of the legalization of cannabis on water and energy use in Pueblo County. First, we studied how much energy and water are needed to grow cannabis. Second, we created a systems dynamics model to project the effects under different scenarios.
2 - Economic Impacts, Aun Hassan, PhD, and Mike Wakefield, PhD
No report yet.
3 - Hemp Buffer Zones, Brian Vandenheuvel, PhD
Hybridization of High THC Cannabis (Marijuana) with Low THC Cannabis (Hemp) can result in crop loss for both growing operations. If genes that promote high levels of tetrahydrocannabinol (THC) are transferred by pollen from High THC Cannabis to Low THC Cannabis, the resulting seed could result in subsequent generations of plants that test over the permitted THC limit, requiring the crop to be destroyed and result in large investment losses (Small and Antle 2003). This is probably a less frequent occurrence because High THC Cannabis growers and Low THC Cannabis growers who are producing crops for cannabidiol (CBD) production normally eliminate male plants, or grow female clones, and the extent to which pollen from High THC or High CBD Cannabis cultivation represents a large pollen source is unknown and probably minimal. On the other hand, pollen from Low THC Cannabis hybridizing with High THC or High CBD Cannabis cultivation who depend on unfertilized flowers for their product is a major concern, as fertilized flowers and seed production in the High THC or High CBD production fields will significantly reduce the value of the crop. Both Low THC Hemp growers (industrial hemp) and High THC or High CBD growers are faced with a perennial problem of ensuring that their plants are adequately protected from contaminating pollen.
Debates over Cannabis sativa L. and C. indica Lam. center on their taxonomic circumscription and rank. This perennial puzzle has been compounded by the viral spread of a vernacular nomenclature, “Sativa” and “Indica,” which does not correlate with C. sativa and C. indica. Ambiguities also envelop the epithets of wild-type Cannabis: the spontanea versus ruderalis debate (i.e., vernacular “Ruderalis”), as well as another pair of Cannabis epithets, afghanica and kafirstanica. To trace the rise of vernacular nomenclature, we begin with the protologues (original descriptions, synonymies, type specimens) of C. sativa and C. indica. Biogeographical evidence (obtained from the literature and herbarium specimens) suggests 18th–19th century botanists were biased in their assignment of these taxa to field specimens. This skewed the perception of Cannabis biodiversity and distribution. The development of vernacular “Sativa,” “Indica,” and “Ruderalis” was abetted by twentieth century botanists, who ignored original protologues and harbored their own cultural biases. Predominant taxonomic models by Vavilov, Small, Schultes, de Meijer, and Hillig are compared and critiqued. Small’s model adheres closest to protologue data (with C. indica treated as a subspecies). “Sativa” and “Indica” are subpopulations of C. sativa subsp. indica; “Ruderalis” represents a protean assortment of plants, including C. sativa subsp. sativa and recent hybrids.
Cannabis sativa has been utilized for millennia, primarily as a source of a stem fiber (both the plant and the fiber termed “hemp”) and a resinous intoxicant (the plant and its drug preparations commonly termed “marijuana”), and secondarily as a source of edible seeds. In domesticating the species for these divergent purposes, humans have altered the morphology, chemistry, distribution and ecology of cultivated forms by comparison with related wild plants. Wild-growing plants appear to be either escapes from domesticated forms or the results of thousands of years of widespread genetic exchange with domesticated plants, making it impossible to determine if unaltered primeval or ancestral populations still exist. There are conflicting botanical classifications of Cannabis, including splitting it into several alleged species. The different approaches to classifying and naming plants such as Cannabis, with interbreeding domesticated and wild forms, are examined. It is recommended that Cannabis sativa be recognized as a single species, within which there is a high-THC subspecies with both domesticated and ruderal varieties, and similarly a low-THC subspecies with both domesticated and ruderal varieties. Alternative approaches to the classification of Cannabis that do not utilize scientific nomenclature are noted.
Cannabis is a predominantly diecious phenotypically diverse domesticated genus with few if any extant natural populations. International narcotics conventions and associated legislation have constrained the establishment, characterization, and use of Cannabis genetic resource collections. This has resulted in the underutilization of genepool variability in cultivar development and has limited the inclusion of secondary genepools associated with genetic improvement strategies of the Green Revolution. The structured screening of ex situ germplasm and the exploitation of locally-adapted intraspecific traits is expected to facilitate the genetic improvement of Cannabis. However, limited attempts have been made to establish the full extent of genetic resources available for pre-breeding. We present a thorough critical review of Cannabis ex situ genetic resources, and discuss recommendations for conservation, pre-breeding characterization, and genetic analysis that will underpin future cultivar development. We consider East Asian germplasm to be a priority for conservation based on the prolonged historical cultivation of Cannabis in this region over a range of latitudes, along with the apparent high levels of genetic diversity and relatively low representation in published genetic resource collections. Seed cryopreservation could improve conservation by reducing hybridization and genetic drift that may occur during Cannabis germplasm regeneration. Given the unique legal status of Cannabis, we propose the establishment of a global virtual core collection based on the collation of consistent and comprehensive provenance meta-data and the adoption of high-throughput DNA sequencing technologies. This would enable representative core collections to be used for systematic phenotyping, and so underpin breeding strategies for the genetic improvement of Cannabis.
Few plant genera have received as much attention concerning their taxonomy and
domestication as Cannabis. “Solving the taxonomy puzzle” is important for botanical,
agricultural, legal, political and medical reasons (Lausen, 2015). However, for the authors
of this rebuttal, resolving the issue of one or more species is not as fascinating as
understanding the evolution of Cannabis. It is in this context that we offer our rebuttal.
In his comprehensive literature review Ernest Small covers diverse topics such as
hemp fibers and processing, hemp seed nutrition, cannabinoid biosynthesis,
cannabinoid-receptor interactions, medical uses and modes of action, among many
more. The author’s concise narrative style, and excellent illustrations (including naïve
art), add to the educational tone of this long contribution. However, the authors of this
rebuttal challenge Small’s use of outdated terminology, question his renaming of the
functional evolutionary and taxonomic groupings, support the use of cultivar names, are
confused by his conclusions concerning resin gland function, and wish to elaborate on
the particulars of drug Cannabis domestication.
Cannabis sativa has been employed for thousands of years, primarily as a source of a stem fiber (both the plant and the fiber termed “hemp”) and a resinous intoxicant (the plant and its drug preparations commonly termed “marijuana”). Studies of relationships among various groups of domesticated forms of the species and wild-growing plants have led to conflicting evolutionary interpretations and different classifications, including splitting C. sativa into several alleged species. This review examines the evolving ways Cannabis has been used from ancient times to the present, and how human selection has altered the morphology, chemistry, distribution and ecology of domesticated forms by comparison with related wild plants. Special attention is given to classification, since this has been extremely contentious, and is a key to understanding, exploiting and controlling the plant. Differences that have been used to recognize cultivated groups within Cannabis are the results of disruptive selection for characteristics selected by humans. Wild-growing plants, insofar as has been determined, are either escapes from domesticated forms or the results of thousands of years of widespread genetic exchange with domesticated plants, making it impossible to determine if unaltered primeval or ancestral populations still exist. The conflicting approaches to classifying and naming plants with such interacting domesticated and wild forms are examined. It is recommended that Cannabis sativa be recognized as a single species, within which there is a narcotic subspecies with both domesticated and ruderal varieties, and similarly a non-narcotic subspecies with both domesticated and ruderal varieties. An alternative approach consistent with the international code of nomenclature for cultivated plants is proposed, recognizing six groups: two composed of essentially non-narcotic fiber and oilseed cultivars as well as an additional group composed of their hybrids; and two composed of narcotic strains as well as an additional group composed of their hybrids.
The objective of this study was to determine the seed chemical composition of ten industrial hemp cultivars grown in Québec. The fatty acid and tocopherol composition, as well as the concentrations of crude protein, oil, ash, cellulose, hemicellulose and lignin were quantified. The seed oil concentration varied between 269 and 306 g/kg, while the crude protein concentration ranged between 238 and 280 g/kg. The hemp seed oil is mainly composed of unsaturated fatty acids, and the dominant fatty acids are linoleic acid (597 g/kg) and α-linolenic acid (170 g/kg). For all ten cultivars, γ-tocopherol was present at a much higher concentration than δ-tocopherol (2481 vs. 774 μg/g). Out of the ten cultivars analyzed, Anka was the richest in phenolics (5.16 g/100 g), whereas CRS-1 had the lowest phenolic content (1.37 g/100 g). Seed ash concentration ranged between 51 and 58 g/kg, while neutral detergent fibre and acid detergent fibre concentrations ranged between 327 and 388, and 259 and 298 g/kg, respectively. In conclusion, our results reveal noticeable differences among cultivars in terms of the essential fatty acid, oil, protein, and antioxidant content of industrial hemp seed. Collectively, this study suggests that the seed of Canada-grown hemp is a balanced health product.
Much has been written about the history of the medical uses of cannabis (1). In the past two centuries, there have been numerous references to the use of cannabis extracts for a wide range of disorders
(2). In the early part of the 20th century, a standardized cannabis elixir was marketed in the United States. Following the
introduction of synthetic drugs such as barbiturates and opioids into medicine, interest in cannabis elixir declined. The
discovery of the primary active constitutent in marijuana, Δ9-tetrahydrocannabinol (THC), in 1964 (3) rekindled interest in the area. However, the emphasis shifted to synthetic cannabinoids rather than the plant or plant extracts.
For example, in the 1970s, clinical studies were conducted in an effort to determine the efficacy of THC as an analgesic (4), antiemetic (5), antidepressant (6,7), appetite stimulant (7), and for treatment of glaucoma (8). These efforts resulted in the approval of THC (dronabinol, Marinol™) for treatment of chemotherapy-induced nausea and vomiting
in 1985 and for appetite stimulation in 1992.
This chapter describes the published mass spectrometric (MS) methods that have proven most effective for quantitative measurement
of Δ9-tetrahydrocannabinol (THC) and its major metabolites in physiological specimens. Because determination of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA) in urine continues to be the most frequently used indicator of marijuana use, the first portion
of the chapter will discuss methods for measurement of THCA in urine. However, the major portion of the chapter is devoted
to the most recent developments for measuring THC and its metabolites in other biological specimens including blood, plasma,
meconium, oral fluids, hair, and other tissues. Table 1–7 are designed to facilitate location of references describing analytical
methods involving key components for analysis of cannabinoids in various matrices.
Cannabis plants produce many compounds of possible medical importance. This chapter briefly explains the life cycle, origin, early
evolution, and domestication of Cannabis, plus provides a brief history of drug Cannabis breeding and looks into the future of Cannabis as a source of medicines. Cannabis is among the very oldest of economic plants providing humans with fiber for spinning, weaving cloth, and making paper; seed
for human foods and animal feeds; and aromatic resin containing compounds of recreational and medicinal value. Human selection
for varying uses and natural selection pressures imposed by diverse introduced climates have resulted in a wide variety of
growth forms and chemical compositions. Innovative classical breeding techniques have been used to improve recreational drug
forms of Cannabis, resulting in many cannabinoid-rich cultivars suitable for medical use. The biosynthesis of cannabinoid compounds is unique
to Cannabis, and cultivars with specific chemical profiles are being developed for diverse industrial and pharmaceutical uses.
The Cannabis plant and its products consist of an enormous variety of chemicals. Some of the 483 compounds identified are unique to Cannabis, for example, the more than 60 cannabinoids, whereas the terpenes, with about 140 members forming the most abundant class,
are widespread in the plant kingdom. The term “cannabinoids” [note: “ ” represents a group of C21 terpenophenolic compounds found until now uniquely in Cannabis sativa L. (1). As a consequence of the development of synthetic cannabinoids (e.g., nabilone [2], HU-211 [dexanabinol; ref. (3), or ajulemic acid [CT-3; ref. 4]) and the discovery of the chemically different endogenous cannabinoid receptor ligands (“endocannabinoids,” e.g., anandamide,
2-arachidonoylglycerol) (5,6), the term ’“phytocannabinoids’” was proposed for these particular Cannabis constituents (7).
The power of molecular recognition and effective interaction of specific binding partners have been exploited to develop assay
technologies for diverse biochemical analysis. The unique features of immunoglobulins and technological advancement in antibody
engineering and manipulation have made antibodies the most versatile binding reagents for detecting analytes of interest in
a variety of matrices. The term immunoassay is customarily used to denote antibody-mediated analytical procedures; however, there are assortments of nomenclature for
various immunoassay techniques that usually are named after the reaction principle of the particular immunoassay format.
Marijuana is the most frequently used illegal drug in the world today. Some 146 million people, or 3.7% of the population
15–64 years of age, consumed Cannabis in 2001–2003 (1). In the United States, 95 million Americans over the age of 12 have tried marijuana at least once. In 2002, an estimated
15 million Americans had used the drug in the month before a survey (2), representing 6.2% of the population age 12 years and older. Marijuana was used either alone or in combination with other
drugs by 75% of the current illicit drug users. Approximately 2-3 million new users of marijuana are added each year, with
about 1.1% becoming clinically dependent on it (3). In the case of young people, according to a recent survey of high school students known as Monitoring the Future, supported
by the US National Institute on Drug Abuse (NIDA) and conducted yearly, at least 19% of 8th graders had tried marijuana at
least once and 18% of 10th graders were “current” drug users (i.e., had used the drug within the past month before the survey).
Among 12th graders, nearly 48% had tried marijuana at least once, and approx 21% were “current”marijuana users (4). Marijuana use by young people has increased or decreased at various times during the last decade, possibly as a result
of its potency, which has been on the rise, although nonsignificantly from a 3% concentration of Δ9-tetrahyrocannabinol (THC; marijuana’s active chemical constituent) in 1991 to 4.4% in 1997—possibly because of changes in
the perceptions of youths about marijuana’s dangers or other unknown factors. Research suggests that marijuana use usually
peaks in the late teens to early 20s, and then declines in later years (5).
After alcohol, marijuana is the most popular recreational drug in North America. Its effects are largely predictable in type,
but not in degree, although they do appear in a roughly dose-dependent manner. The effects discussed here make a very convincing
case for the potential for marijuana to impair driving, although as noted, the extent to which that potential is realized
in a given case will be related to many other factors.
In most of the western world where industrial hemp, Cannabis sativa, is licensed for cultivation, the plants must not exceed
a level of 0.3% tetrahydrocannabinol (THC), the principal intoxicating constituent of the species. Because there are no publicly
available germplasm hemp collections in North America and only a very few, recent North American cultivars have been bred,
the future breeding of cultivars suitable for North America is heavily dependent on European cultivars and European germplasm
collections. Based mostly on material from Europe, this study surveyed THC levels of 167 accessions grown in southern Ontario,
making this the largest survey to date of germplasm intended for breeding in North America. Forty-three percent of these had
THC levels ≥0.3% and, therefore, are unsuitable for hemp development in North America. Discrepancies were found between THC
levels reported for some germplasm holdings in Europe when they were grown in Canada and, accordingly, verification of THC
levels developed in North America is necessary.
As a result of aerobiological samples taken on the Costa del Sol (S. Spain), Cannabis sativa L.
(marihuana) pollen was detected from May to September 1991-1996, always sporadically and usually
during the afternoons. Sampling was by two volumetric spore traps set up in Malaga and Estepona, two
coastal towns approximately 90 km apart. A study of the days when this pollen was recorded points to the
movement of air masses from North Africa to southern Spain. Furthermore, the isentropic air trajectories
calculated for these days reinforce the possibility of the pollen originating in marihuana plantations in
northern Morocco (Rif). This study demonstrates the application of aerobiology to the control of the
source, quantity and phenology of the crop.
Pollen grains of 10 anemophilous and entomophilous species of angiosperms were kept at 4 relative humidities (RH) (15, 51, 79 and 98%) and their viability tested by fluorochromatic reaction after time lapses ranging from 6 to 144 h. Pollen viability in the anemophilous species decreased more rapidly than in the entomophilous ones with the exception of the dioecious palm Chamaerops humilis. The modes of anther and flower opening, times of anther exposure etc. were recorded; Cytological data are discussed and compared with these aspects of reproductive ecology.
One of the most discussed environmental effects associated with the use of transgenic plants is the flow of genes to plants in the environment. The flow of genes may occur through pollen since it is the reproductive system that is designed for gene movement. Pollen-mediated gene escape is hard to control in mating plants. Pollen from a wind pollinator can move over distances of more than 1000 m. To investigate the efficiency of transgenic pollen movement under realistic environmental conditions, the use of bait plants might be an effective tool. In this study, cytoplasmic male-sterile (CMS) sugar beets were tested with regard to their potential for monitoring transgene flow. As the pollen source, transgenic sugar beets were used that express recombinant DNA encoding viral (beet necrotic yellow vein virus) resistance, and antibiotic (kanamycin) and herbicide (glufosinate) tolerance genes. In a field trial, the effectiveness of a hemp (Cannabis sativa) stripe containment strategy was tested by measuring the frequency of pollinated CMS bait plants placed at different distances and directions from a transgenic pollen source. The results demonstrated the ineffectiveness of the containment strategy. Physiological and molecular tests confirmed the escape and production of transgenic offspring more than 200 m behind the hemp containment. Since absolute containment is unlikely to be effective, the CMS–bait plant detection system is a useful tool for other monitoring purposes.
A 26-year aged non-atopic criminological technician reacted to hemp (Cannabis sativa) and hashish with urticarial eruptions on hands and lower arms, rhinitis and conjunctivitis. Rubbing tests with pollenrich hashish were strongly positive. As hemp antigens were unavailable a hyposensitization therapy with hop (Humulus lupulus)--a plant belonging to the Cannabacea family--was begun.
We have noted several patients who had rhinitis and/or asthma symptoms when exposed to Cannabis plants in the summer months. Cannabis plants are common in the Midwest.
To examine whether Cannabis might be a clinically important allergen, we determined Cannabis pollination patterns in the Omaha area for 5 years, the prevalence of skin test positivity, and the association with respiratory symptoms.
Airborne Cannabis (and other weed) pollens were collected using a Rotorod air impactor, and pollen counts were done using a standardized protocol.
Measurable Cannabis pollen count was not recorded until the last 2 weeks of July. Peak pollination typically occurred during mid- to late-August, and comprised up to 36% of the total pollen counts. Cannabis pollen was not observed after mid-September. To determine the prevalence of skin test positivity, we added Cannabis to the multi-test routine skin test battery. Seventy-eight of 127 patients tested (61%) were skin test positive. Thirty of the 78 patients were randomly selected to determine if they had allergic rhinitis and/or asthma symptoms during the Cannabis pollination period. By history, 22 (73%) claimed respiratory symptoms in the July through September period. All 22 of these subjects were also skin test positive to weeds pollinating during the same period as Cannabis (ragweed, pigweed, cocklebur, Russian thistle, marsh elder, or kochia).
The strong association between skin test reactivity, respiratory symptoms, and pollination period suggests that Cannabis could be a clinically important aeroallergen for certain patients and should be further studied.
The wind-borne distance and viability of hemp pollen. Pages 77-85 in: Raboti po biologi, selekcii semenovodstva konopli
- A P Demkin
- A V Astachova
Demkin, A.P. and Astachova, A.V., 1952. The wind-borne distance and viability of hemp pollen. Pages 77-85 in: Raboti po biologi, selekcii semenovodstva konopli. Selhozgiz, Moskwa, U.S.S.R. (In Russian)
Variability of pollen grains of polyploid hemp
- A I Zhatov
Zhatov, A.I., 1983. Variability of pollen grains of polyploid hemp. Tsitologiya i Genetika 17: 47-51. (Allerton Press, Inc. translation) RECEIVED: 6 September 2002 ACCEPTED IN REVISED FORM: 17 December 2002
Morphology of hemp (Cannabis L.) pollen
- N D Migalj
Migalj, N.D., 1969. Morphology of hemp (Cannabis L.) pollen. Botanicheskiy Zhurnal 54: 274-276. (In Russian)
Textbook of pollen analysis Pollen dispersal and effect of pollen density on seed production in Larix leptolepis seed orchard
- K Faegri
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- K Krzywinski
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Faegri, K., Iverson, J., Kaland, P.E., and Krzywinski, K., 1989. Textbook of pollen analysis. 4th edition. John Wiley & Sons, New York, NY. Jo, D.K., Kwon, H.M., Choi, S.K., and Kim, J.H., 1984. Pollen dispersal and effect of pollen density on seed production in Larix leptolepis seed orchard. Research Report of the Institute of Forest Genetics 0(20): 58-64. (In Korean) Lemeshev, N.L., Rumyantseva, L., and Clarke, R.C., 1995. Report on the maintenance of hemp (Cannabis sativa L.) germplasm accessioned in the Vavilov Research In-stitute gene bank–1994.
History of botanical science Organic farming and gene transfer from genetically modified crops How far can wind-born pollen be disseminated?
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Morton, A.G., 1981. History of botanical science. Academic Press, London. Moyes, C.L. and Dale, P.J., 1999. Organic farming and gene transfer from genetically modified crops. John Innes Centre, Norwich, U.K. <http://www.gmissues.org/orgreport/ gmissues[1].htm>. Sack, S.S., 1949. How far can wind-born pollen be disseminated? J. Allergy 20: 453-460.