Highest Multiplication Rate Research Articles

In vitro multiplication of Mentha piperita L. and comparative evaluation of some biochemical compounds in plants regenerated by micropropagation and conventional method

The aim of this study was to elaborate an efficient in vitro multiplication protocol for Mentha piperita L. (peppermint) and to perform a comparative evaluation of some biochemical compounds in plants regenerated by micropropagation and conventional method. The use of a plain Murashige and Skoog (MS) basal medium favored the induction of regenerative processes, the percentage of explants that started to grow four weeks after inoculation being 92%. The highest multiplication rate (7.12 shoots/explant) and the highest average shoot length (8.11 cm) were obtained on the MS medium supplemented with 1 mg/L benzylaminopurine, when nodal fragments were used as explants. The rooting phase was not necessary, the shoots developing roots on the multiplication medium. The acclimatization rate of in vitro regenerated plants to ex vitro conditions was 96%. Although biochemical investigations revealed some differences between in vitro regenerated plants and those obtained by conventional methods, the results obtained show that micropropagation can be used successfully to obtain high-quality peppermint biological material, a potential source of bioactive compounds with therapeutic effect.

Effect of Different Cytokinins on Shoot Outgrowth and Bioactive Compounds Profile of Lemograss Essential Oil

Lemongrass (Cymbopogon citratus) essential oil (EO) is a major source of bioactive compounds (BC) with anticancer activity such as α-citral, limonene, geraniol, geranyl acetate, and β-caryophyllene. Comparative studies about cytokinin effects on BC profiles in lemongrass are missing. Here, we evaluated four cytokinins (2iP, tZ, BAP, and KIN) in two different osmotic media, MS-N (3% sucrose, 3 g L−1 Gelrite™) and MS-S (5% sucrose, 5 g L−1 Gelrite™). It results in a higher multiplication rate in BAP containing medium compared to tZ, KIN, and 2iP (p ≤ 0.05). While shoots grown on MS-N/BAP, tZ, and KIN exhibited a highly branching morphology, MS-N/2iP produced a less branching architecture. BC profile analysis of established plants in pots revealed that their maxima production depends on the in vitro shoot growth conditions: i.e., highest content (80%) of α-citral in plants that were cultured in MS-S/BAP (p ≤ 0.05), limonene (41%) in MS-N/2iP, or geranyl acetate (25.79%) in MS-S/2iP. These results indicate that it is possible to increase or address the production of BC in lemongrass by manipulating the cytokinin type and osmotic pressure in culture media. The culture protocol described here is currently successfully applied for somatic embryogenesis induction and genetic transformation in lemongrass.

Effects of culture methods and plant growth regulators on in vitro propagation of Brassavola nodosa (L.) Lindl. hybrid

Brassavola nodosa (L.) Lindl. is an epiphytic orchid with great potential for the ornamental plant industry. The lack of information on propagation and production techniques limits the development of large-scale commercial production. Furthermore, this species is experiencing a reduction in population due to habitat destruction, the impact of climate change, and over-collection from native habitats. This study aimed at developing an efficient protocol for micropropagation of B. nodosa, which could be valuable towards the large-scale commercial production as well as for conservation of this species. Six different concentrations of plant growth regulators (BA or IBA, with or without adenine sulfate) were evaluated in modified Murashige and Skoog (MS) medium for shoot multiplication. In addition, two concentrations of either NAA or IBA were evaluated for rooting. Explants were cultured under three different culture media conditions: semi-solid medium, liquid medium (partial immersion), and liquid medium (complete immersion). Results indicate that B. nodosa could be successfully micropropagated in liquid culture with partial immersion. The modified MS medium supplemented with 2.0 mg L−1 BA and 30.0 mg L−1 adenine sulfate resulted in higher multiplication rates. Rooting was obtained using either 0.5 mg L−1 NAA or 1.0 mg L−1 IBA with no significant differences between both rooting treatments. Plantlets achieved 100% ex vitro survival after 30-d acclimatization.

SARS-CoV-2 and Therapeutic Approaches

In 2019, the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) was first reported in Wuhan, China, affecting the population all over the globe. This ongoing pandemic is creating major havoc and has already taken the lives of many people. It has become really difficult to control the spread of the virus because of its high rate of multiplication in the host and transmission. The virus spreads by the means of droplets or direct contact with the infected person, causing pneumonia-like symptoms, such as fever, dry cough, throat pain, and breathlessness. This review presents the indications, mechanism of action, administration, and adverse effects of some antiviral, antibiotic, and immunomodulatory drugs, that are currently employed in the treatment of SARS-CoV-2. It also presents the effects and benefits of drugs on an infected person, when co-administered together.

Indirect Somatic Embryogenesis: An Efficient and Genetically Reliable Clonal Propagation System for Ananas comosus L. Merr. Hybrid “MD2”

The objective of this study was to establish an efficient—direct or indirect—regeneration system for pineapple (Ananas comosus L.) plants, with a high rate of multiplication and that would preserve the genetic identity of the donor genotype (Hybrid ‘MD2’) in the regenerated plants. Ten treatments, with different concentrations of 2,4-Dichlorophenoxyacetic (2,4-D) and Picloram (P), in the absence or presence of 6-Benzylaminopurine (BAP), were used for in vitro morphogenesis induction, as well as histological and molecular techniques, in order to characterize the morphogenic responses induced. Significant differences between treatments tested, to induce callus and buds, were assessed by the Kruskal Wallis method and the Mann–Whitney U-tests. Different pineapple regeneration routes were identified, showing the high regeneration potential of this species. The medium containing 2 mg L−1 2,4-D and 2 mg L−1 BAP, where indirect somatic embryogenesis occurred, was selected as the most efficient treatment, with an average of 120 somatic embryos per explant, differing significantly from the rest of the treatments. It was also demonstrated that the pineapple plants regenerated in vitro preserved the genetic identity of the donor genotype, which represents a high degree of confidence for the application of indirect somatic embryogenesis for A. comusus clonal propagation.

In Vitro Germination and Propagation of Dyckia brevifolia, An Ornamental and Endangered Bromeliad

Dyckia brevifolia is an endangered plant used for ornamental purposes. As no references to the in vitro propagation of the species exist, the present study aims at investigating the possibility of an efficient micropropagation protocol. Seeds collected from mother plants were germinated at high percentages (84–86%) at a range of 15–25 °C, without any pre-treatment, and demonstrated their highest germination speed index (191.51) at 25 °C. In vitro-grown seedlings were used as the starting material for micropropagation on solid, or liquid, MS medium, supplemented with a variety of concentrations of cytokinins (BA, KIN or 2IP). Shoots and leaves were used as starting explants. Liquid media supplemented with BA or 2IP at 1.0 mg L−1 led to high multiplication rate and 2.7, or 2.3, lateral shoots were regenerated while on 2IP a high percentage (77.5%) of rooting occurred at the same time. Rooted microshoots were acclimatised ex vitro at 100% and acclimatised plants were transplanted in pots where they grew with a survival rate of 100% after two months. The in vitro propagation protocol presented in this study could enhance the large-scale propagation use of D. brevifolia as an ornamental plant and, simultaneously, contribute to the ex-situ conservation of the species.

Effect of activated charcoal and ascorbic acid on in vitro morphogenesis and o-dihydroxyphenols content in Paphiopedilum insigne

Phenolic compounds limit micropropagation of many orchids in vitro. The aim of the study was to estimate the effect of activated charcoal (AC);1, 2 or 4 g/L) or ascorbic acid (AA; 10, 20 or 30 mg/L) added to the half strength MS medium on the growth and o-dihydroxyphenols content in Paphiopedilum insigne in vitro. A positive effect of AC on the shoot and root formation has been found. The highest multiplication rate (5.6 shoots/explant) and rooting frequency were obtained on medium containing 2 g/L of AC. However, AC reduced the leaf number as compared to the control. The lowest content of o-dihydroxyphenols was marked in Paphiopedilum insigne leaves when the shoots were grown on medium with 10 mg/L AA, followed by AC at 1 or 2 g/L.

Effect of Nutrients on Diatom Growth: A Review

Diatoms are one of the unicellular algae with a rare presence of unaltered, durable, transparent and species-specific silica frustules that persist even after cell death in the deposits of water bodies. Diatom has high capacity for absorption of metals for maintaining the water quality and high rate of multiplication. These characters promoted the use of this microbial biomass for effluent detoxification. These diatoms can also solve metal toxicity problems in aquatic ecosystems in the water polluted environment. In the present review, the focus is on several nutrients (nitrogen, phosphorus, iron and silica) that are essential for the growth of diatoms at very low concentrations, but most of them are toxic at high concentrations. It also shows the relationship between heavy metal stress and lipid body induction which may be a valuable indicator for the evaluation of heavy metal contamination of fluvial ecosystems.
 HIGHLIGHTS
 
 Diatoms are eukaryotic, unicellular, photosynthetic, silica-containing microscopic algae with distinct geometric forms
 Diatoms are used for biomonitoring purposes for taxonomic and morphological properties of ecosystems, community and human disturbances
 Diatoms are also the primary producer of oil in the world responsible for fixing 25 % of CO2 and 30 % of crude oil diatoms
 Many diatoms are appropriate for lipid development up to 70 % of their body volume and are investigated for biofuel as a hotspot
 
 GRAPHICAL ABSTRACT

Management of Biopesticides to Control Infestation of Insect Stored Grain Pest Triboloium castaneum (Herbst) (Coleoptera: Tenebrioide): A Review

Pulses and Cereals have great nutritional value in the daily human diet. Infestation of Stored grain is a serious issue since different life stages of several types of insects can cause it. Insect degrade the quality of stored grains and product, resulting in economic losses. The storage of grains has been linked to a high number of insect infestations. Almost all stored grain insect pests have remarkably high multiplication rates and may destroy 10-15 % of grains. The major pest of stored grains includes Weevil (Sitophilus oryzae, Sitophilus zeamais, Sitophilus granaries), Tribolium species (Tribolium castaneum and Tribolium confusum), Khapra beetles (Trogoderma granarium), lesser grain borer (Rhyzopertha dominica), Pulse beetles (Callosobruchus maculatus), Rice moth (Corcyra cephalonica), etc. Continuous and indiscriminate over use of insecticides are responsible for the development of resistance against these insect pesticides. Accumulation of synthetic chemical pesticide residues on pulses and cereals are unfortunately consumed by human. Recently, in agricultural practices in different areas of the world, attention has been given towards the exploitation of plant biochemical as a new approach in stored grain protection. Various scientific literature already documented the efficacy of plant derivatives against storage grain pests. Biopesticides kill and repel the insect pests, affect insect growth, development and metamorphosis. Farmers have used higher plants, medicinal plants, various herbs and traditional spices for stored grain insect pest management, but majority of farmer use chemical insecticide to increase productivity but it causes adverse effect on environment and non-target animal including human also, so there is more need for scientific research regarding the plant Biopesticides efficacy against stored grain pests.

Asynchrony of Apical Polarization, Luminogenesis, and Functional Differentiation in the Developing Thyroid Gland.

Follicular thyroid tissue originates from progenitors derived from a midline endodermal primordium. Current understanding infers that folliculogenesis in the embryonic thyroid designates the latest morphogenetic event taking place after the final anatomical shape and position of the gland is established. However, this concept does not consider the fact that the thyroid isthmus develops chronologically before the lobes and also contains all progenitors required for lobulation. To elucidate whether cells committed to a thyroid fate might be triggered to differentiate asynchronously related to maturation and developmental stage, mouse embryonic thyroid tissues from E12.5-17.5 were subjected to immunofluorescent labeling of biomarkers (progenitors: NKX2-1; differentiation: thyroglobulin/TG); folliculogenesis: E-cadherin/CDH1; luminogenesis: mucin 1/MUC1; apical polarity: pericentrin/PCNT; basement membrane: laminin; growth: Ki67), quantitative RT-PCR analysis (Nkx2.1, Tg, Muc1) and transmission electron microscopy. Tg expression was detectable as early as E12.5 and gradually increased >1000-fold until E17.5. Muc1 and Nkx2.1 transcript levels increased in the same time interval. Prior to lobulation (E12.5-13.5), MUC1 and TG distinguished pre-follicular from progenitor cells in the developing isthmus characterized by intense cell proliferation. Luminogenesis comprised redistribution of MUC1+ vesicles or vacuoles, transiently associated with PCNT, to the apical cytoplasm and the subsequent formation of MUC1+ nascent lumens. Apical polarization of pre-follicular cells and lumen initiation involved submembraneous vesicular traffic, reorganization of adherens junctions and ciliogenesis. MUC1 did not co-localize with TG until a lumen with a MUC1+ apical membrane was established. MUC1 delineated the lumen of all newly formed follicles encountered in the developing lobes at E15.5-17.5. Folliculogenesis started before establishment of a complete follicular basal lamina. These observations indicate that embryonic thyroid differentiation is an asynchronous process consistent with the idea that progenitors attaining a stationary position in the connecting isthmus portion undergo apical polarization and generate follicles already at a primordial stage of thyroid development, i.e. foregoing growth of the lobes. Although the thyroid isthmus eventually comprises minute amounts of the total thyroid volume and contributes little to the overall hormone production, it is of principal interest that local cues related to the residence status of cells – independently of a prevailing high multiplication rate – govern the thyroid differentiation program.

Conservación ex situ mediante el establecimiento de cultivo in vitro de semillas de Prosopis limensis “Huarango” de Ica, Perú

The “Huarango” Prosopis limensis is a woody species of the Fabaceae family that is in the dry forest of Ica, of key importance in this ecosystem and considered for different reasons in a state of danger. The in vitro cultivation of seeds of this species is presented as an adequate conservation strategy, due to high multiplication rates it promotes, the economy in time and production costs, and the future possibilities of improvement and reforestation. The objective of this study is the establishment of an effective methodology for the optimal germination of stored seeds of this species. The seeds were obtained from 4 representative experimental accessions from the department of Ica, which were subjected to a physical scarification treatment, immersing them in hot water (70 °C) and leaving it at rest until reaching a temperature of 37 °C. After conventional sterilization processes, seeds were sown in basic M&S medium with vitamins thiamine HCl (1,0 mg/l) and m-inositol (100 mg/l), sucrose 2% and agar 0,6%, and incubated at 23 °C +/- 2 h, for a photoperiod of 16 light hours. At 24 days the CPUC-117 accession the germination percentage was in the range of close to 95%. The results of this work constitute the necessary precedent to initiate larger-scale in vitro micropropagation trials of “Huarango” for conservation purposes.

An efficient micropropagation protocol for Ficus carica cv. Golden Orphan suitable for mass propagation

Fig ( Ficus carica L.) is from the Moraceae family and is rich in essential nutrients, natural fiber and vitamins. The Golden Orphan cultivar is a yellow fig that is sweet, firm and can thrive in tropical climates. Current conventional propagation methods for the multiplication of plant stocks were found to be less efficient in producing healthy plant stocks. Micropropagation offers an alternative in the production of plant stocks resembling the quality of mother plants. The current study aims to fine tune the micropropagation protocol of the Golden Orphan cultivar for efficient production of plant stocks. Sterile nodal bud explants were subjected to different media treatments, carbon source and combinations of auxin and cytokinin. Rooting of explants was induced in auxin and rooted explants were acclimatized in cocopeat. The optimal basal medium for shoot elongation was Murashige and Skoog (MS) Medium, whereas 20 g/L sucrose resulted in the highest shoot length (2.00 ± 0.22 cm) facilitating the production of nodal segments for subsequent multiplication. The highest shoot induction (4.15 ± 0.43 shoots/explant) was observed in the treatment of 0.8 mg/L 6-Benzylaminopurine (BAP), whereas the combination of 0.8 mg/L BAP and 0.5 mg/L indole-3-acetic acid (IAA) resulted in the highest shoot length (2.23 ± 0.09 cm). Treatment of 0.4 mg/L indole-3-butyric acid (IBA) produced the optimal percentage of rooting (83.33%) whereas acclimatization with cocopeat resulted in maximum survival rate. The present study has successfully optimised the crucial aspects of micropropagation for the Golden Orphan cultivar suitable for rapid plant stock production. • The establishment of micropropagation protocol for Ficus carica cv. Golden Orphan. • High multiplication rate in basal medium, minimal amount of sucrose and cytokinin. • Maximum acclimatization efficiency in cocopeat. • Acclimatized plants successfully produced fruits that resembles mother plants.

Micropropagation of the Halophyte Sarcocornia fruticosa (L.) A. J. Scott

Details of investigation to evaluate the effects of the number of nodes (one, two or three) of Sarcocornia fruticosa explants on growth and multiplication rate of plantlets are presented in this paper. The responses of the 3-node explants to some supplementary sources of different aminoacids and growth regulators indol-3-acetic acid, 6-benzylaminopurine and gibberellins A3 were also analysed. Plantlets from 3-node explants showed a marked increase in growth and number of lateral shoots, indicating that Sarcocornia does not respond well when explants are very small. The addition of 100 mg l-1 casein hydrolysate plus 150 mg l-1 glutamine, and 100 mg l-1 casein hydrolysate plus vitamins showed to be good growth promoters in micropropagating Sarcocornia, giving longer plantlets and higher multiplication rates.

Development of direct regeneration protocol for mass multiplication of Musa spp. variety Udhayam (Pisang Awak, ABB) using different explants

Musa spp. variety Udhayam (Pisang Awak, ABB) is the first high yielding selection from ICAR-NRCB, Trichy released during 2005. The demand for quality planting material shows an increasing trend because of its higher yield (40%) than the local Karpuravalli. But this variety is highly recalcitrant for shoot tip culture owing to its high phenolic exudation, and very low shoot proliferation rate (<2.0). Therefore, in the present study, attempts were made to develop direct regeneration protocol for the aforementioned variety using various explants like cormlets and male floral hands other than shoot tips. Results revealed that the direct regeneration protocols using cormlets and male floral hands were totally free from latent contamination and recorded high rate of shoot multiplication as against shoot tip explants. Among the three explants used, immature male floral hands showed not only higher multiplication rate under in vitro conditions and also performed better under field conditions compared to shoot tip and cormlet derived plants. The plantlets derived from different explants were found to be true to type as confirmed using ISSR markers. Field performance of the plants derived from various explants indicated that though all are suitable for direct regeneration, male floral hands was superior followed by sucker, shoot tip and cormlets in terms of bunch yield and crop duration. Key message: Immature male flower buds are the best explants for mass multiplication through direct regeneration and commercial exploitation in banana variety Udhayam (Pisang Awak, ABB).

Biological activity of entomopathogenic nematodes on Anastrepha fraterculus (Diptera: Tephritidae)

Anastrepha fraterculus (Wiedemann) is one of the main pests of fruit farming, and entomopathogenic nematodes (EPNs) represent an important control tool of this species. Thus, the objective of this study was to evaluate the biological activity of different isolate against A. fraterculus larvae and adults. Bioassays were performed using a suspension of three isolates of Heterorhabditis amazonensis IBCB 24, Steinernema carpocapsae IBCB 02 and Steinernema feltiae IBCB 47 at six concentrations (control - without nematodes), 50, 150, 300, 500, 1000 and 1500 infective juveniles (IJs)/mL of water per 3º instar larvae. It was verified the susceptibility of larvae of A. fraterculus to isolates of EPNs and a significant increase of the pupal mortality in the function of the concentration of IJs inoculated by larva (above 75%). After the dissection of pupae and adults of A. fraterculus from infected larvae, the concentration of 1500 IJs/mL of EPNs provided the highest rate of multiplication of IJs by insect, equating to maximum concentration tested 1500 IJs/mL. Adults of A. fraterculus from larvae infected with EPNs longevity of five days, being less than adults from uninfected larvae by IJs (135 days). H. amazonensis IBCB 24, S. carpocapsae IBCB 02, and S. feltiae IBCB 47 proved to be promising as agents of biological control of A. fraterculus.

Susceptibility of the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae), to four species of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from Mizoram, North-Eastern India

BackgroundOutbreak of the fall armyworm Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) occurred in Mizoram, North-Eastern India. The infestation spread in the entire state covering a total area of around 2840 hectares of maize cultivated land. Entomopathogenic nematodes (EPNs) represent potential candidates for the biological control of S. frugiperda. In the study, the susceptibility of the pest against 4 locally isolated EPN species Heterorhabditis indica, H. baujardi, Steinernema sangi and S. surkhetense was evaluated.ResultsThe results indicated that all the isolated EPN species showed a high rate of larvicidal and pupicidal activities against the pest. Mortality between 43.75–100.00 and 25.00–100.00% of 3rd and 5th larval instars, respectively (at concentrations 10–800 IJs/larva), and 37.50–68.75% mortality of pupae (at concentrations 200–1600 IJs /pupa) were found after exposure to the EPN species. The mortality rate of the pest showed significant variations with life stages of the host insect, nematode concentrations and incubation time. Based on the median lethal concentration (LC50), H. indica was the most pathogenic species, followed by S. sangi, H. baujardi and S. surkhetense. The LC50 values of H. indica at 72 h post-incubation were 20.26 and 62.07 IJs/larva for the 3rd and 5th larval instars, respectively, and 913.34 IJs/pupa. The penetration assay showed that H. indica had the highest penetration rate into the hosts, 27.24, 21.30 and 20.00% in the 3rd, 5th larval instars and pupae, respectively. Furthermore, all the EPN isolates were capable of successful multiplication inside the cadaver of S. frugiperda that showed significant differences with the EPN isolates and life stages of the pest. Among the isolates, H. indica showed the highest multiplication rates, 17,692.25 ± 2103.59, 8345.63 ± 785.34 and 79,146.38 ± 5943.73 IJs per 3rd instar larva, 5th instar larva and pupa, respectively.ConclusionsThe study revealed that the 4 species of EPNs showed a high potency against S. frugiperda, thereby having the potential to be developed as a biological control agent against the pest. Moreover, the isolated EPN species could potentially serve as alternatives for chemical insecticides and could further be incorporated into the Integrated Pest Management (IPM).

P–354 Analysis of pregnancy and miscarriage rates in anti-centromere antibodies (ACA)-positive patients treated with ART

Abstract Study question Do ACA have an effect on pregnancy and miscarriage rates of human embryos? Summary answer The present results suggest that in ACA-positive cases, the pregnancy rate per transfer was significantly lower, although the miscarriage rate was not affected. What is known already We have previously shown that patients with high levels of anti-centromere antibody (ACA), (one of the anti-nuclear antibodies (ANA)), frequently have dispersal of the female chromosomes in the cytoplasm. Additionally, we reported that the clinical outcome was characterized by a low oocyte maturation rate following ovum pick up and high multiple pronuclear formation rate after fertilization. However, the post-implantation course of embryos with ACA-positive cases has not yet been reported. Therefore, in this study, we analyzed the pregnancy and miscarriage rates in ACA-positive patients treated with Assisted Reproductive Technologies (ART). Study design, size, duration 6581 patients who underwent embryo transfer after antinuclear antibody testing between January 2014 and February 2020 were included in the analysis. Participants/materials, setting, methods The subjects were classified into three groups: ANA-negative (without ACA or any other ANA), ACA-positive (with only ACA) and ANA-positive (with ANA but not ACA). The cycle in which the gestational sac was confirmed was considered a positive pregnancy. The pregnancy and miscarriage rates were compared among the groups using “Ryan Test” for statistical analysis. Main results and the role of chance Of the 6581 eligible cases, the incidence of antinuclear antibody were 71.3% (4695/6581; ANA-negative), 0.9% (61/6581; ACA-positive) and 27.7% (1825/6581; ANA-positive). The pregnancy rates based on the total number of embryo transfer cycles for each were ANA-negative: 31.5% (5283/16792), ACA-positive: 17.6% (41/233), and ANA-positive: 32.4% (1891/5833). The pregnancy rates were significantly lower in the ACA-positive group than in the other groups. The miscarriage rate was 29.4% (1553/5283) in ANA-negative, 31.7% (13/41) in ACA-positive, and 28.0% (529/1891) in ANA-positive, with no significant difference between the three groups. Limitations, reasons for caution Retrospective analysis Wider implications of the findings: ACA-positive patients may benefit from a treatment strategy to increase the absolute number of oocytes by obtained in order to increase the chances of normal fertilization and attainment of implantation. Trial registration number none

Micropropagation of arrow cane, Gynerium sagittatum (Aubl.) P. Beauv. cv. Criolla, Criolla 1, and Martinera, in a double-phase medium

To evaluate the micropropagation response of arrow cane, Gynerium sagittatum (Aubl.), plants using a double-phase medium in the multiplication stage, explants consisting of stem sections with axillary meristems from cultivars Criolla, Criolla 1, and Martinera were established in vitro in a semisolid medium. Then, they were multiplied using a double-phase medium supplied at several Benzylaminopurine (BAP) concentrations (0.0, 0.5, 1.0, 1.5, and 2.0 mg/L), followed by rooting in a culture medium supplied at several Naphthaleneacetic acid (NAA) concentrations (0.0, 0.5, 1.0, 1.5, and 20 mg/L). Both multiplied unrooted and rooted microshoots were transferred ex vitro. Treatments were distributed with a completely randomized design; data were analyzed with an ANOVA and means separated with Tukey’s test. Explants from Criolla and Martinera cultured with 0.5 mg/L BAP resulted in higher multiplication rates. All microshoots transferred to the rooting medium rooted, although NAA significantly increased the number of roots and reduced root length. Plants from all three cultivars, in vitro rooted or unrooted transferred to ex vitro conditions, showed 100 % survival and adaptation. For Criolla and Martinera, 0.5 mg/L BAP statistically increased shoot multiplication rates and NAA increased adventitious root formation and reduced root length. Plants of all cultivars survived and adapted 100 % to ex vitro conditions.

Flower power: floral reversion as a viable alternative to nodal micropropagation in Cannabis sativa.

The legalization of recreational and medicinal Cannabis sativa L. has been gaining global momentum, therefore increasing interest in Cannabis micropropagation as growers look for large-scale solutions to germplasm storage and clean plant propagation. Mother plants used in commercial propagation are susceptible to pests and disease and require considerable space. While micropropagation can produce disease-free starting material in less space, current published in vitro methods are not robust and few report high multiplication rates. Furthermore, these micropropagation methods rely on photoperiod-sensitive plants maintained in a perpetual vegetative state. Current methods are not adaptable to long-term tissue culture of day-neutral cultivars, which cannot be maintained in perpetual vegetative growth. In this study, we developed a micropropagation system which uses Cannabis inflorescences as starting materials. This study used two Cannabis cultivars, two plant growth regulators (PGR; 6-benzylaminopurine and meta-topolin) at different concentrations, and two different numbers of florets. Here, we show that floral reversion occurs from meristematic tissue in C. sativa florets and that it can be used to enhance multiplication rates compared to existing in vitro methods. Floret number was shown to have a significant impact on percent reversion, with pairs of florets reverting more frequently and producing healthier explants than single florets, while cultivar and PGR had no significant effect on percent reversion. Compared with our previously published nodal methods, the current floral reversion method produced up to eight times more explants per subculture. Floral reversion provides a foundation for effective inflorescence-based micropropagation systems in Cannabis.

Seed Yam Production Using High-Quality Minitubers Derived from Plants Established with Vine Cuttings

Yam (Dioscorea spp.) is a valuable food security crop in West Africa, where 92% of the world production occurs. The availability of quality seed tubers for increased productivity is a major challenge. In this study, minitubers weighing 1, 3, and 5 g produced from virus-free single-node vine cuttings of two improved yam varieties (Asiedu and Kpamyo) growing in an aeroponics system were assessed for suitability in seed production at a population of 100,000 plants ha−1. A 3 × 2 factorial experiment with randomized complete block design and three replications was set up during the cropping seasons of 2017 to 2019 at the International Institute of Tropical Agriculture Research Station in Kubwa, Abuja, Nigeria. Results showed field establishments of 87%–97.8%. Yields differed with minituber size, variety, and cropping season; the highest was 31.2 t ha−1 in 2019 and the lowest, 10 t ha−1 in 2018 from 5 and 1 g Kpamyo minitubers, respectively. The estimated number of tubers produced per hectare by 1, 3, and 5 g minitubers was 101,296, 112,592, and 130,555, with mean weights per stand of 159.2, 187.3, and 249.4 g, respectively. We recommend using less than 6 g minitubers for seed yam production due to their high multiplication rates.