Hemp Varieties Research Articles

PSIV-5 High Desert Hemp Varieties Under Varied Nitrogen Fermentation Techniques Effects on Its Utilization as Livestock Feed Through in Vitro Fermentation

Abstract Nitrogen fertilizing of hemp varietals in high the high desert may assist in ensuring that production levels match the demand for growing hemp varietals. However, altering fertilizer levels may differently affect plant biomass and cannabinoid concentrations of plant tissues which changes the potential by-product utilizable for livestock feed. This study aimed to determine the influence of hemp fractions [flower (FL) vs stem and leaves (SL)] under three nitrogen fertilization regimens (0, 100, and 200 kg· ha-1) on in vitro rumen fermentation. Incubations runs consisted of triplicates of 500-mL bottles containing approximately 0.5 g of either ground SL or FL of hemp at the three nitrogen fertilization regimens. Rumen fluid was collected from two ruminally cannulated Angus steers, filtered through four layers of cheesecloth, and diluted to 4:1 with a standard buffer solution. A total incubation volume of 75 mL of the buffer: rumen fluid mix was added to each flask. Flasks were then placed in a rotating incubator (55 rpm) at 39°C, connected to an Ankom RF gas production system (Ankom Technology, Macedon, NY), and removed after 24, 48, and 96h. Total gas production (TGP), metabolizable energy (ME), ammonia nitrogen concentration (N-NH3), and total volatile fatty acids (VFA) were determined. Data were analyzed as a completely randomized design using lmer function in lme4 package in R with treatment and time as a fixed effect and replicates as a random effect. Statistical significance was established at P < 0.05 (Table 1). No differences were observed for N-NH3 (P > 0.05). Overall, SL samples had greater total VFA than FL, with T0SL having the greatest concentration among all treatments (P < 0.01). In congruence, acetate, isobutyrate, isovalerate, and the ratio between acetate and propionate concentrations were also greater for T0SL (P < 0.01). Concentrations of butyrate were greater for T200SL (P < 0.01), while T100SL had the greatest concentration of butyrate among all the treatments (P < 0.01). Overall, SL fractions of hemp seem to be more suitable as a ruminant feed source. The greater fat content of the FL compared with SL may detrimentally affect microbial populations and should further be explored. From our results, N supplementation significantly alters fermentation patterns during in vitro, which further warrants the evaluation of these feeds on in vivo experiments.

Industrial hemp (Cannabis sativa L.)—a valuable alternative crop for growing in agricultural soils contaminated with heavy metals

Hemp (Cannabis sativa L.) is a multiuse plant, which has been abundantly studied for phytoremediation purposes in recent years. The majority of experiments were performed in greenhouses with potted plants where hemp showed promising results. Only few studies tested hemp on site in heavy metal–polluted agricultural soil in real environmental conditions and practical assessments of hemp phytoremediation feasibility are lacking. We conducted a comprehensive study using 2 legal industrial hemp varieties (Futura 75 and Tisza) at three differently polluted locations (heavily polluted location, HP; moderately polluted location, MP; and slightly polluted location, SP) in the heavy metal contaminated Celje valley in Slovenia and determined the content of Pb, Zn, and Cd in 5 plant organs/tissues. The yield of each organ/tissue was determined as well to enable us to calculate the phytoremediation potential (PP). On average, plants grown in the HP location accumulated the highest values of all examined elements, followed by plants from the MP location and plants from the SP location, showing that the content of heavy metals in soil influences the accumulation in plants. Accumulation of Pb/Zn/Cd by plant organs/tissues was distributed in the following order: inflorescences (Pb-4.10/Zn-92.8/Cd-0.50 mg/kg) > seeds (Pb-1.79/Zn-92.6/Cd-0.27 mg/kg) > roots (Pb-1.15/Zn-15.0/Cd-0.44 mg/kg) > stem bark (Pb-0.42/Zn-12.4/Cd-0.23 mg/kg) > stem woody core (Pb-0.34/Zn-4.6/Cd-0.15 mg/kg). The only exception was for Cd, where roots accumulated a higher value than seed, yet lower than inflorescences. PP was calculated by multiplying hemp tissue/organ yield by the relative concentrations of heavy metal. The highest PP for Pb and Cd were achieved at the HP location (3.80 and 0.23 g/ha/vegetation period). On the other hand, tissue/organ yield was more important for high PP of Zn, where the SP location reached the highest PP for Zn (148.5 g/ha/vegetation period) due to the highest yields. Only seeds from HP and MP locations accumulated a too high content of Pb; otherwise, all other fibers and seeds can be safely used in the textile and food industry. Results of this study showed that hemp cannot be considered an efficient plant for the phytomanagement of contaminated areas. Nevertheless, hemp cultivation in heavy metal–polluted agricultural soils seems feasible since the majority of tissues/organs were not contaminated and different products can be obtained from various parts of the hemp plant.

A forensic application of genetic markers for distinction between drug-type and fiber-type Cannabis sativa L.

Genetic markers can represent a valuable tool for forensic purposes in discriminating between fiber-type and drug-type cannabis. The aim of this research was to evaluate developed genetic markers for tetrahydrocannabinolic acid synthase (THCAS) when applied on certified hemp (14 varieties) and forensic casework samples of four chemotypes (40 seizures). Chemotype-associated PCR-based markers did not enable reliable selective amplification despite the difference in cannabinoid composition. In order to characterize forensic samples of unknown origin, THCAS sequencing was performed. The comparison of THCAS sequences, including additional accessions, indicated high genetic similarity of hemp varieties. Confiscated samples of intermediate, THC, CBD and CBG type were clearly separated from fiber-type accessions and assigned to drug-type cluster. Despite the unknown origin, their position on the tree support the notion that they are more related to drug-type accessions than to the fiber-type. However, no clear distinction between chemotypes was found. Furthermore, 26 amino acid substitutions were revealed in THCAS that clearly separate hemp varieties and neither of them cluster with any other tested sample.

The Antioxidant and Neuroprotective Potential of Leaves and Inflorescences Extracts of Selected Hemp Varieties Obtained with scCO2.

Cannabis sativa, a versatile plant with numerous varieties, holds promising potential for a wide range of biological activity. As raw materials for research, we chose leaves and inflorescences of hemp varieties such as Białobrzeskie, Henola, and Tygra, which are cultivated mainly for their fibers or seeds. The choice of extraction is a key step in obtaining the selected compositions of active compounds from plant material. Bearing in mind the lipophilic nature of cannabinoids, we performed supercritical carbon dioxide (scCO2) extraction at 50 °C under 2000 (a) and 6000 PSI (b). The cannabinoid contents were determined with the use of the HPLC-DAD method. The antioxidant capabilities were assessed through a series of procedures, including the DPPH, ABTS, CUPRAC, and FRAP methods. The capacity to inhibit enzymes that play a role in the progression of neurodegenerative diseases, such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase was also studied. The dominant cannabinoids in the extracts were cannabidiol (CBD) and cannabidiolic acid (CBDA). The highest concentration of eight cannabinoids was detected in the Tygra inflorescences extract (b). The most notable antioxidant properties were provided by the Tygra inflorescences extract (b). Nonetheless, it was the Henola inflorescences extract (b) that demonstrated the most efficient inhibition of AChE and BChE, and tyrosinase was inhibited the most significantly by the Białobrzeskie inflorescences extract (b). Multidimensional comparative analysis enrolled all assays and revealed that the Henola inflorescences extract (b) showed the most substantial neuroprotective potential.

Using Detached Industrial Hemp Leaf Inoculation Assays to Screen for Varietal Susceptibility and Product Efficacy on Botrytis cinerea.

In greenhouse production, grey mould caused by Botrytis cinerea Pers. is one of the most widespread and damaging diseases affecting medicinal cannabis (MC). Fungicide options to control this disease are extremely limited due to the regulations surrounding fungicides and chemical residues as the product end users are medical patients, often with compromised immune systems. Screening for alternative disease control options, such as biological and organic products, can be time-consuming and costly. Here, we optimise and validate a detached leaf assay as a quick and non-destructive method to evaluate interactions between plants and pathogens, allowing the assessment of potential pathogens' infectivity and product efficacy. We tested eight industrial hemp varieties for susceptibility to B. cinerea infection. Using detached leaves from a susceptible variety, we screened a variety of chemical or organic products for efficacy in controlling the lesion development caused by B. cinerea. A consistent reduction in lesion growth was observed using treatments containing Tau-fluvalinate and Myclobutanil, as well as the softer chemical alternatives containing potassium salts. The performance of treatments was pH-dependent, emphasizing the importance of applying them at optimal pH levels to maximise their effectiveness. The detached leaf assay differentiated varietal susceptibility and was an effective method for screening treatment options for diseases caused by Botrytis. The results from the detached leaf assays gave comparable results to responses tested on whole plants.

Features of populations of hemp varieties with different composition of cannabinoid compounds

Aim. To study the biological features of populations of hemp varieties with the absence of narcotic activity – tetrahydrocannabinol (THC) not higher than 0.08 %, but with the presence of non-psychoactive components of cannabinoids: cannabidiol (CBD) and cannabichromene (CBC); cannabigerol (CBG); CBG and CBD. To identify breeding prospects for increasing the content of cannabinoids that have therapeutic properties. Methods. Samples of elite plants were analyzed for cannabinoid content by gas-liquid chromatography (GC Agilent Technologies HP 6890, Series Hewlett Packard). Results. The limits of variation of the population variability of the sign of CBD content of the Medana variety are from 0.0253 to 3.3469 %, 75 % of the plants of which contain CBD in the range of 1.0-2.2 %. Studies of the Vik 2020 hybrid population confirmed a high correlation between CBD and THC and the absence of a relationship between CBD and CBG, THC and CBG. More than 11 % of plants in the population contain CBG from 3.5849 to 4.6207 %. There are no correlations between CBD and CBG, CBD and THC in these plants. The presence of such plants indicates the possibility of further increasing the content of СBG to 8 % and above, without exceeding the THC limit in our country (0.08 %). Conclusions. Conducted research has proven that with the current permissible level of THC, the content of CBD can be increased only to 2.5-3.0 % (Medana variety) through purposeful selection. The hybrid Vik 2020 is especially valuable, because in its population unique plants with the presence of several cannabinoid compounds with a THC content of no more than 0.08 % were found. The obtained valuable breeding material of the Medana variety and the Vik 2020 hybrid is a donor for its inclusion in hybridization and further multi-vector selection in the direction of increasing of the content of CBD, CBC and CBG with the absence of THC.

Sequential extraction approach for sustainable recovery of various hemp (Cannabis sativa L.) bioactive compounds

Cannabis sativa L. known as industrial hemp manifests high capability in the manufacturing of valuable nutraceuticals with health benefits. This study was focused on investigation of chemical profile and bioactive potential of extracts isolated from three hemp varieties (Helena, Marina and Fedora 17). In addition, great attention was directed towards the use of green extraction techniques and maximum utilization of raw material. In that regard conventional (hydrodistillation – HD) and novel extraction techniques (microwave-assisted hydrodistillation – MWHD, supercritical fluid extraction – SFE and microwave-assisted extraction – MAE) were applied for isolating various fractions (essential oil, lipid extracts and liquid extract) with promising bioactive potential. Essential oils and lipid extracts were characterized regarding yield, terpenoid profile determined by GC-MS and in vitro antioxidant activity towards DPPH and ABTS + radicals. Furthermore, the content of two major cannabinoids was determined in plant material and in extract obtained by SFE. Sequential SFE technique allows obtaining lipid extracts in the first step of process as well as raffinates after SFE in the second step. MAE was applied for isolation of polyphenolic fraction from raw materials and SFE raffinates. Polyphenolic content was determined by spectrophotometric assays and UHPLC-Triple-quadrupole-MS. The results suggested that hemp is an excellent source of valuable terpenoid, cannabinoid and polyphenolic antioxidant agents, and further research should be focused on their utilization in dietary supplements and functional foods.

Chemical Composition of Four Industrial Hemp (Cannabis sativa L.) Pollen and Bee Preference.

Apart from its economic value, industrial hemp (Cannabis sativa L.) is a prolific pollen producer, serving as a food source for bees. However, little is known regarding the extent to which varietal differences in hemp pollen chemistry influences bee preference. Here, we report the chemical profile of pollen from four hemp varieties (Canda, CFX-2, Henola, and Joey) and bee abundance and diversity, using direct visual counts and pan traps. The number and type of bees on each variety was recorded and the chemical composition (proximate analysis and mineral, amino, and fatty acid profiles) of pollen from each hemp variety was determined. During the entire sampling period, three bee types (bumble bees, honey bees, and sweat bees) were recorded, with a combined total of 1826. Among these, sweat bees and bumble bees were the most prevalent and were highest on the Joey variety. The four varieties expressed protein content ranging from 6.05% to 6.89% and the highest in Henola. Seventeen amino acids were expressed in all varieties, with leucine recording the highest content ranging from 4.00 mg/g in Canda to 4.54 mg/g in Henola. In general, Henola expressed high protein, amino acid, and saturated and monosaturated fatty acid contents and recorded significantly fewer bees compared with Joey, which had a low content of these components and a high content of polyunsaturated fatty acids. Our findings suggest that, while industrial hemp offers abundant and accessible pollen that would promote bee health and sustainability of their ecosystem services, the nutritional quality may not be adequate for bee growth and development as an exclusive pollen source.

Features of forming the productivity of modern hemp varieties using organic cultivation technology

Seed hemp can be used to produce products and restore soil fertility. The adaptive potential of cannabis varieties can be implemented by optimising their cultivation technologies. The purpose of this study was to substantiate the features of forming the productivity of cannabis varieties adapted to organic cultivation technologies. Field studies were conducted during 2019-2021 on leached chernozems. Research methods: field, laboratory, statistical and comparative calculation. The regularities of yield formation of hemp straws, fibre, and seeds depending on the genetic potential of varieties and cultivation technology were investigated. The suitability of five hemp varieties for organic cultivation was evaluated. It was established that the introduction of organic cultivation technology has a positive effect on crop productivity. With organic cultivation of Hliana and Hloba varieties, the increase in the yield of straw (0.07-0.11 t/ha) was statistically insignificant compared to inorganic technology. Cultivation of Zolotoniski 15 and Sula varieties using organic technologies increased the yield of hemp straw by 0.14 t/ha. The Lara variety showed an insignificant decrease in the straw yield. This confirmed the theory that the introduction of organic cultivation of hemp will not lead to a decrease in yields. Organic technologies for growing hemp contributed to an increase in their yield compared to the traditional one, provided that varieties were selected correctly. The best suitability for organic cultivation in terms of fibre yield was recorded in the Lara variety. The obtained results will be used to improve and introduce organic technologies for growing adapted hemp varieties, depending on the purpose of fibre or seeds

INDUSTRIAL HEMP VARIETIES PRODUCTIVITY POTENTIAL IN THE LATVIAN CLIMATIC CONDITIONS

Varieties grown for fibre-only will be established, managed and harvested differently than varieties grown for seeds or dual-purpose. The aim was analysed yield productivity and length of vegetation period dependency of the two types of hemp variety and identified perspective hemp variety for highest yield under different meteorological conditions in Latvia. Varieties/line from diverse European and Latvian origin (seed hemp varieties/ line 'Adzelvieši', 'Pūriņi', KA-2-2011, 'Finola', 'Henola' and fibre hemp varieties 'USO 31', 'Futura 75', 'Austa') were sown in randomized field experiments in Latvia. Biomass, stem, seed yield, fibre contents and vegetation period length were assessed across tree growing seasons from 2020 to 2022. Results show that hemp, seeds and fibre varieties/line, performed well giving high yield productivity between variety. Agrometeorological conditions for hemp growth and yield were favourable in 2022. In Latvian local climatic conditions, the seed hemp line KA-2-2011 and fibre hemp variety ‘Futura 75’ identified significant higher of biomass and stem yield as well as the seed hemp variety ‘Henola’ and fibre hemp variety ‘Austa’ significant higher of seed yield and fibre contents. The yield potential dependent from length of vegetation period length. The trial analyses identified positive and significant correlations between length of vegetation period and biomass (r = 0.97), stem yield (r = 0.98), and negative between length of vegetation period and seed yield (r = -0.89).

Cadmium Bioconcentration and Translocation Potential in Day Neutral and Photoperiod Sensitive Hemp Grown Hydroponically for the Medicinal Market

Heavy metal contamination of agricultural soils is potentially concerning when growing crops for human consumption. Industrial hemp (Cannabis sativa L.) has been reported to tolerate the presence of heavy metals such as cadmium (Cd) in the soil. Therefore, the objectives of this study were to evaluate Cd uptake and translocation in two day-length sensitive (DLS) and two day-neutral (DN) hemp varieties grown for the medicinal market and to determine the impact of Cd exposure on cannabinoid concentrations in flowers. A hydroponic experiment was conducted by exposing plants to 0 mg·L−1 Cd and 2.5 mg·L−1 Cd in the nutrient solution. Cadmium concentrations ranged from 16.1 to 2274.2 mg·kg−1 in roots, though all four varieties accumulated significant concentrations of Cd in aboveground tissues, with translocation factors ranging from 6.5 to 193. Whole-plant bioconcentration factors ranged from 20 to 1051 mg·kg−1. Cannabinoid concentrations were negatively impacted by Cd exposure in DN varieties but were unaffected in DLS varieties. Biomass was reduced by Cd exposure demonstrating that these varieties might not be suitable for growth on contaminated soil or for phytoremediation. There is potential for Cd accumulation in flowers, showing the need for heavy metal testing of C. sativa consumer products.

The Desert Whale: the boom and bust of hemp in Arizona

BackgroundThis paper examines the factors that led to the collapse of hemp grown for cannabidiol (CBD) in Arizona, the United States of America (USA), and particularly in Yuma County, which is a well-established agricultural area in the state.MethodsThis research uses a combination of mapping analysis along with a survey of hemp farmers to assess the reasons why the hemp industry collapsed as well as to foster solutions to these problems.ResultsIn 2019, 5430 acres were sown with hemp seed in Arizona with 3890 acres inspected by the state to determine if they could be harvested. By 2021, there were only 156 acres planted, and only 128 of those acres were inspected by the state for compliance. (Crop mortality accounts for the difference between acres sown and acres inspected.)ConclusionsA lack of knowledge about the hemp life cycle greatly contributed to the failure of high CBD hemp crops in Arizona. Other problems included noncompliance with tetrahydrocannabinol limits, poor sources for seeds and inconsistent genetics of the hemp varieties sold to farmers, and diseases that hemp plants were susceptible to such as Pythium crown and root rot and beet curly top virus. Addressing these factors will go far in making hemp a profitable and widespread crop in Arizona. Additionally, hemp grown for other traditional uses (e.g., fiber or seed oil) as well as new applications (e.g., microgreens, hempcrete, and phytoremediation) offers other pathways for successful hemp agriculture in this state.

Evaluation of different hemp (Cannabis sativa L.) progenies resulting from crosses with focus on oil content and seed yield

One of the main breeding objectives for hemp (Cannabis sativa L.) cultivation is higher seed yield important also for the oil yields. However, there has been limited research on hemp breeding that focuses on these topical features. In this study, 17 crosses were created using 12 different hemp varieties. For each variety, five female inflorescences were selected for targeted crossing and one for self-pollination. Seeds from the crosses were sown in separate plots with a seeding density of 30 kg/ha. The number of male and female plants, plant height, internode length, steam thickness, inflorescence length, number of inflorescences per plant, and plant number per plot were measured in crossbred family plants. The absolute weight of seeds per plot, the degree of marbling and oil content were determined. The progeny of the cross between Helena and Tiborszallasi were found to have the highest 100 seed mass (1.546 g, upper half). The offspring of self-pollinated varieties Finola, Tiborszallasi, Fedora 17 and the cross between Helena and Tiborszallasi produced the highest oil content. The progeny of the cross between Futura 75 and KC Dora showed the most promising results in terms of high yield production. This study provided the first important data pertaining to hemp breeding with the goal of increasing oil content and seed yield.

Identification of Characteristic Parameters in Seed Yielding of Selected Varieties of Industrial Hemp (Cannabis sativa L.) Using Artificial Intelligence Methods

Currently, there is a significant increase in interest in hemp cultivation and hemp products around the world. The hemp industry is a strongly developing branch of the economies of many countries. Short-term forecasting of the hemp seed and grain yield will provide growers and processors with information useful to plan the demand for employees, technical facilities (including appropriately sized drying houses and crop cleaning lines) and means of transport. This will help to optimize inputs and, as a result, increase the income from cultivation. One of the methods of yield prediction is the use of artificial intelligence (AI) methods. Neural modeling proved to be useful in predicting the yield of many plants, which is why work was undertaken to use it also to predict hemp yield. The research was carried out on selected, popular hemp varieties—Białobrzeskie and Henola. Their aim was to identify characteristic factors: climatic, cultivation and agrotechnical, affecting the size and quality of the yield. The collected data allowed the generation of Artificial Neural Network (ANN) models. It has been shown that based on a set of characteristics obtained during the cultivation process, it is possible to create a predictive neural model. Modeling using one output variable, which is seed yield, can be used in short-time prediction of industrial crops, which are gaining more and more importance.

First Report of Seedling Damping-Off of industrial Hemp (Cannabis sativa L.) caused by seed-transmitted Alternaria rosae in Italy.

In the years 2020-2021 as part of the activity of the Campania region hemp fiber project, variety comparison trials were carried out on 7 hemp varieties among those relevant for bast fiber production. During the trials, in particular on the cv. Fibrante, a consistent problem was noted: a noticeable germination failure (80-90%) occurred during the emergence of seedlings. Therefore, experiments were conducted to ascertain the possible presence of seed-borne pathogens. Tests were carried out on 100 seeds that were surface disinfected with 2% sodium hypochlorite solution for 3 min, rinsed in sterile distilled water three times and dried on sterile filter paper. The seeds were plated on potato dextrose agar (PDA Oxoid™) amended with 100 mg L-1 of streptomycin sulphate, kept at 24°C in the dark and observed daily. Growing colonies were subcultured on PDA for 10 days and, subsequently, twenty purified fungal isolates were obtained by single spore isolation. Colonies of these isolates on PDA were initially grayish-white and then turned dark olive green with abundant cotton-like aerial hyphae. On potato carrot agar (PCA) medium, these isolates produced light brown and solitary conidiophore with septum. Conidia were obclavate or pyriform, brown, with 1-3 transverse septa and 0-3 longitudinal septa, and measured 12.5 to 28.5 × 5 to 15 µm (n=50). The morphological characteristics observed under the light microscope were consistent with that of Alternaria spp. (Simmons 2007). In order to characterize the representative isolate, total DNA was extracted using the DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) and 3 genes were PCR-amplified: the ITS spacer using the primer pair ITS1-ITS4 (White et al., 1990), the transcription elongation factor 1- using the primer pair EF1-983F/ EF1-2218R (Rehner and Buckley., 2005) and the RNA polymerase II second largest subunit (RPB2) using the primer pair RPB2-5F2/fRPB2-7cR (Sung et al 2007; Liu et al 1999). The size-expected amplicons were purified and sequenced at the BMR Genomics (Padova, Italy) and the resulting sequences were deposited in GenBank under the accession numbers ON556507, ON601003, ON601004. BLAST-n analysis revealed 98 to 99% nucleotide identity with some representative isolates of Alternaria rosae E.G. Simmons & C.F. Hill (KU375630.1, XM_046169884.1, XM_046168987.1). To fulfill Koch's postulates, 100 hemp-certified seed were disinfected as mentioned above, left to germinate on the water-agar to discard potentially infected seeds and finally sowed in sterile peat-soil mix (1:1 v/v). The inoculum consisted of 10 mL of 105 conidial suspension obtained by the representative isolate (Ar_H1). Negative control seeds were inoculated with sterile water. After 5-7 days 100% of inoculated seedlings showed weak germinative vigor with yellowing of the epicotyls and dark areas on the root. The tissue narrowed and turned necrotic with abundant white mycelium covering the entire seedling. Small pieces of necrotic roots were plated on PDA and the same Alternaria-like colonies grew in 10 days. DNA sequencing confirmed the presence of A. rosae. Alternaria spp. are fungi that produce a wide range of toxic metabolites, harmful to food safety in the food uses of the seed. This finding further highlights that the quality of the hemp seed must be considered as a priority aspect in the entire hemp supply chain. To the best of our knowledge, this is the first report of A. rosae as seed-borne fungus on hemp.

Phytoremediation of Cadmium-, Lead-, and Nickel-Polluted Soils by Industrial Hemp

The restoration of polluted soils is crucial for ecosystem recovery services. Evidently, phytoremediation is a biological and sustainable technique that includes the use of plants to remediate heavy-metal-contaminated land; the plants should be tolerant to the contamination and capable of uptake or immobilization of the heavy metals in the soil. Moreover, defining an economically efficient approach to the remediation of a contaminated area, with the possibility of further utilization of phytoremediation biomass, renders energy crops a great option for this technique. Energy crops, in fact, are known for their ability to grow with low agricultural input, and later, the biomass product can be used to produce biofuels, bioenergy, and bioproducts in a sustainable and renewable way, creating economic potential, especially when these crops are cultivated in marginal lands. The aim of this work is to test two monoecious industrial hemp varieties in different levels of Cd, Pb, and Ni in soil. Both varieties were tolerant to levels of Cd and Pb contamination that were higher than the limit for commercial and industrial use, while Ni showed a significant effect at all the tested concentrations. The variety Futura 75 performed better than Kc Dora in terms of productivity and tolerance.

The phenological stage of hemp inflorescences affects essential oil yield and its chemical composition

The inflorescences of Cannabis sativa L. represent a high-value by-product of industrial hemp cultivation, and their volatile fraction has recently attracted attention due to the applications of hemp-derived Essential Oil (EO) in several fields. Following a previous evaluation of the EOs profile in diverse hemp genotypes, the current study investigated how the phenological stage of inflorescences affects the EO chemical composition and hydrodistillation yield. Two hemp varieties with different flower behaviour, Codimono (monoecious) and Fibrante (dioecious), were cultivated in open field, and the flowering tops were collected at five developmental stages. The air-dried samples were hydrodistilled with a Clevenger apparatus, and the obtained EOs were analysed by Gas Chromatography coupled with Mass Spectrometry (GC-MS). All the samples showed terpenes and phytocannabinoids as major chemical classes. Among the former class, sesquiterpene hydrocarbons were the most abundant components in the EOs at all phenological stages, ranging from 34.1% to 67.6% and 33.8–73.8% in Codimono and Fibrante, respectively, while oxygenated sesquiterpenes were highest at the final stage (27.7% in Codimono and 24.0% in Fibrante). Phytocannabinoids, instead, were the second major chemical class, accounting for 29.3% in Codimono and 30.5% Fibrante. The EO yield increased with phenological development, reaching the highest rate at seed harvest time in both genotypes (0.018–0.265% w/w in Codimono and 0.026–0.265% w/w in Fibrante).

Variation in Hydric Response of Two Industrial Hemp Varieties (Cannabis sativa) to Induced Water Stress

Information on industrial hemp (Cannabis sativa) water use and water stress is sparse. We studied water stress impact in two essential-oil hemp cultivars (‘Wife’ and ‘Cherry’) prompted by anecdotal differences in growth and water use. In a greenhouse setting, we measured water relations, water use, growth, and essential oil (CBD-cannabidiol and THC-delta-9 tetrahydrocannabinol) concentrations. Water stress did not significantly affect THC and CBD concentrations, but both cultivars responded to water stress by reducing transpiration through notably different mechanisms. ‘Cherry’ had more anisohydric behavior, maintaining high stomatal conductance (Gs) and more negative leaf water potential until root zone water depletion triggered partial afternoon stomatal closure to moderate stress, resulting in lower flower and CBD yield. By contrast, water-stressed ‘Wife’ rapidly defoliated half its leaf area in balance with less applied water and so maintained high Gs and flower yield on par with well-watered plants, suggesting potential for deficit irrigation to conserve water and reduce post-harvest vegetation management. Differences in water use translated to provisionally suggested crop coefficients of 1 for ‘Cherry’ and 1.3–1.5 for ‘Wife’, but further research is needed. Because hemp is genetically diverse, and cultivar naming conventions are currently lax, further germplasm screening and research are needed to determine the extent to which either conservative ‘Cherry’ or the water-stress defoliation response of ‘Wife’ is found in the larger population of hemp cultivars.

Microbial consortium inoculant and rock mineral fertiliser differentially improved yield and nutrient uptake of industrial hemp (Cannabis sativa L.) varieties

Industrial hemp (Cannabis sativa L.) production is attracting widespread attention in agriculture but is facing cultivation challenges in nutrient-poor sandy soils. The crop has a fibrous deep taproot system known to have a good association with the rhizosphere soil microbiome. However, there are few reports on incorporating microbial inoculants with or without rock mineral fertilisers to facilitate nutrient mineralisation and stimulate growth of industrial hemp. To test whether microbial consortium inoculant with or without fertiliser improves the growth and yield of industrial hemp by increasing root biomass and nutrient uptake, we assessed the impact of microbial inoculant and rock mineral fertiliser in two hemp varieties (Morpeth and Han FNQ). The experiment was conducted in a randomised complete block design with four treatments: control (CTRL), consortium microbial inoculum (MI), rock mineral fertiliser (MF) and combined microbial inoculum and mineral fertiliser (MI+MF). Plants were grown in compost in a controlled-environment phytotron and harvested 30 and 70 days after sowing (DAS). Han FNQ had higher root dry weight, shoot length, leaf chlorophyll, Mn and Zn uptake than Morpeth at 30 DAS, and Han FNQ in the MI+MF treatment also had greater root volume than Morpeth in all treatments at 30 DAS. At 70 DAS, Morpeth had a higher seed yield than Han FNQ and Morpeth in the MI treatment had greater shoot and root dry weight, leaf chlorophyll, root length and volume, and higher uptake of all macro- and micronutrients in shoots and seeds than Han FNQ in all treatments. These findings suggest that the resource stoichiometry and trade-balance model in plant-microbes symbiosis govern the effectiveness of MI on industrial hemp. The application of MF and the initial nutrients abundance in the compost might suppressed MI activity at 30 DAS whereas, the nutrient limiting condition at 70 DAS might triggered MI activity and symbiotic trade of nutrients between plant and microbes which facilitated root growth and nutrient uptake particularly, in the variety Morpeth.

Comprehensive Transcriptome and Metabolome Analysis of Hemp (Cannabis Sativa L.) in Soil Under NaCl Stress

ABSTRACT Planting economic crops in soil with salt imbalances can improve land use efficiency. Hemp, which can be planted in low-salinity soil, is a crop with a very high economic value. To reveal the salt tolerance mechanism of hemp, the leaves of Longma #3 and #9 were collected at 0, 2, 4, and 6 days after salt stress in this study, and transcriptome and metabolome joint analysis were performed. The concentration of glutamic acid, succinic acid and gamma-aminobutyric acid (GABA) was 12 times that of the control group. The large increase in succinic acid led to the maintenance of peroxidase and superoxide dismutase levels at normal values and a decrease in H2O2 and catalase. The enriched KEGG pathway citrate cycle (TCA cycle) contains the metabolic regulation of succinic acid. Succinic acid was positively correlated with the MAPK gene. The MAPK pathway is a key pathway of plant tolerance in a high-salt environment. This study provides a reference for research on NaCl tolerance in plants and can also provide an important reference for the cultivation of NaCl-tolerant hemp varieties.