Micropropagation Techniques Research Articles

Seed potato (Solanum tuberosum) production systems in India: A chronological outlook

Seed is a major and important input in potato (Solanum tuberosum L.) cultivation. On account of vegetative propagation, the requirement of seed potatoes (tubers) is voluminous and accounts for 40–50% to the total cost of production. Potato productivity in India is low in comparison to developed countries due to the non-availability of quality seed in required amounts. Seed potato production through micro-propagation (tissue culture) techniques can overcome the problems associated with the conventional multiplication system. The everlasting shortage of seed potatoes in most of the potato growing countries can be solved through hi-tech seed production system including micro-propagation and aeroponic techniques. Besides, rapid multiplication, production of disease-free mother stocks under controlled conditions followed by reduced number of field exposures as compared to conventional multiplication system, is an added advantage of seed potato production in these techniques. For expanding quality seeds, the entire seed production systems framework needs to be reviewed. The present review will be an endeavour to outline the historical background of seed potato production, issues and challenges, supply frameworks and policy implications in India.

Influence of Selected Antibiotics on the Tomato Regeneration in In Vitro Cultures

Generally, antimicrobial agents are frequently used in micropropagation techniques to obtain free elite clones or after genetic transformation to select putative transformants. Their successful application minimizes bacterial contamination however; they may be phytotoxic and may diversely affect the regeneration ability in plant tissue cultures. The objective of the current study was to estimate the effects of four antibiotics i.e. ampicillin, carbenicillin, cefotaxime and kanamycin on morphogenesis of three Polish tomato cultivars, cultured on MS medium with phytohormones. In this experiment the ability of tomato cotyledon explants to regenerate entire plants via indirect organogenesis was tested. Among four antibiotics tested, kanamycin was most harmful for the explants. This antibiotic, even at low doses (10-20 mg/L), inhibited tomato morphogenesis. On the other hand, the current study revealed significant influence of different concentrations of ampicillin, carbenicillin, cefotaxime on the frequency of bud formation. While the addition of cefotaxime at low concentration (100-200 mg/L) stimulated the bud formation, its increasing concentration adversely affected the organogenesis of tomato. The results clearly pointed out that carbenicillin and ampicillin at low concentrations (100-400 mg/L) were not only non-toxic, but they promoted bud regeneration. The obtained results show the crucial role not only of use of efficient antibiotics, but also of their proper doses in obtaining successful transformation and regeneration of tomato.
 
 *********
 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
 *********

Alpha monofluoro substitution at C5 in homotyphasterol enhances shoot production and multiplication rate of in vitro-grown marubakaido apple rootstock shoots

KEY MESSAGE: 5 fluoro-typhasterol is more effective than the most potent natural brassinosteroid, brassinolide, towards stimulation of shoot production in the marubakaido apple rootstock. Brassinosteroids (BRs) comprise a class of low-abundance plant steroids required for normal plant growth. Here we demonstrate that treatment of in vitro-grown shoots of the marubakaido apple rootstock with 2.5 µg per shoot of 5α-monofluoro homotyphasterol (5F-HTY), a synthetic derivative of the natural BR homotyphasterol (HTY), resulted in significant enhancement in the formation of primary lateral shoots. This treatment also resulted in increased length of primary lateral shoots and main shoots. This growth-stimulatory effect led to a significant increase in the multiplication rate for the rootstock. In contrast to what was found for 5F-HTY, neither HTY nor the synthetic derivative 3α-monofluoro homotyphasterol (3F-HTY) were able to significantly stimulate shoot formation. HTY and 3F-HTY were not able to stimulate primary lateral shoot elongation as well. However, both HTY and 3F-HTY were able to significantly stimulate main shoot elongation. The 5F-HTY-driven enhancement of the multiplication rate described here demonstrates the potential of this compound to improve micropropagation techniques, not only for the marubakaido apple rootstock.

Pineapple cultivation under agro-ecological management with biotechnology approaches

Intensive systems of production have been developed for pineapple, mostly based on systematic applications of pesticides to prevent any buildup of pathogen populations. A schedule of applications established from parasite monitoring results in a more reasonable use of pesticides. Intensive monocultural systems have lost ecosystemic services as regulatory functions provided by ecological agrosystems which allow natural balance between beneficial and pathogenic organisms. A strong societal demand to reduce environmental pollution and health risks has limited the availability of pesticides inputs. The challenge for the pineapple industries is to design new cropping systems respectful of the agroecology concept, which promotes an agriculture that protects man in a preserved environment. The most recent biotechnologies may help agronomists in elaborating new environmentally friendly practices, particularly for production of disease-free planting material and pest management. Production of disease-free material through micro-propagation techniques can be used to obtain pineapple vitroplants free of such viruses as the PMWaVs (Wilt) and then to mass produce planting material of selected cultivars. Using vitroplants in traditional field nurseries reduces the cost of the mass production of clean planting material. Weeds may be efficiently controlled by competition or allelopathic effects. Parasite and stress management can be accomplished using cover crops that are non-hosts for nematodes or symphylids or produce biopesticides that reduce inoculum levels. Non-specific systemic resistances induced in pineapple by endophytic bacteria or mycorrhizal fungi is a promising additional tool to control nematodes. Several biopesticides and biocontrol techniques (bacteria, fungi, essential oils) tested on pineapple may contribute to pest management. Nutrition management options include bacteria that may reduce the use of chemical fertilizers, fix nitrogen and solubilize potash and phosphorus. Some are also potential plant growth promoting organisms. Conclusion: biotechnology approaches ( cover crops, biopesticides, micro-organisms for biocontrol) will help to establish more environmentally friendly agrosystems for pineapple.

Bromatological characterization of fruits of ‘MD-2’ pineapple plants produced by micropropagation

Fruits of pineapple (Ananas comosus var. comosus) are in great commercial demand and among the most promising cultivars is 'MD-2', which has attracted consumers in recent years. As new cultivars become available, micropropagation techniques can speed the production of high quality plants (vitroplants) of selections with better agronomic characteristics. In Cuba, although some attempts have been made to introduce vitroplants under the production conditions used by State Entities and Agricultural Companies, this objective has not been satisfactorily achieved for various reasons. The present work was to determine the bromatological indicators of the fruits of 'MD-2' pineapple plants coming from micropropagation. These indicators were physical and chemical according to the 1982 Cuban Standards (total soluble solids (°Brix), titratable total acidity (%), ascorbic acid (mg 100 g(‑1) juice) and fruit pH). Bromatological analyses carried out on the fruits showed that they complied with the characteristics of 'MD-2' pineapple, even though the agrotechnics used were different from what is traditionally used for the 'MD-2' crop, the results obtained did not show differences in total soluble solids (12.8 to13.2 °Brix), titratable acidity (0.7 to 0.8%) or citric acid.

MICROPROPAGATION OF CHICKPEA FROM SHOOT TIP AND NODE SEGMENT

Present investigation was undertaken to standardize technique for in vitro micro-propagation of chickpea( Cicer arietinum ) cultivar Vishwas (Phule G 12). Micropropagation method for chickpea was established and this method enabled much more efficient propagation of plants. The present work was aimed at evolving a protocol for rapid multiplication of chickpea using micropropagation technique. Explants from shoot tip and node segment were cultured on MS medium supplemented with different concentrations of BAP and Kinetin (1.0 to 2.5 mg/l) and their growth responses like shooting were elucidated. The maximum multiple response was observed with 2 mg/l concentration of BAP from both types of explant. The highest number of shoots (12.5 ± 0.3) was achieved on MS medium with 2 mg/l BAP using node segments. The medium supplemented with 2 mg/l of BAP was found better than all other concentrations. Individual shoots were transferred to IBA and IAA (1.0-1.5 mg/l) for root induction. MS medium supplemented with 2 mg/l of IBA proved better for rooting. Rooted plantlets were successfully hardened in greenhouse and established in the pot.

Exposure to Magnetic Fields Reveals a Positive Effect on In Vitro Propagation of Stevia rebaudiana (Bertoni)

Magnetopriming in seeds is an established phenomenon and has been successfully carried out in several crops. However, the effect of magnetic fields on in vitro responses has not been studied enough. We studied the effect of exposure to magnetic fields on in vitro nodal explants of a medicinal plant, Stevia rebaudiana, for its propagation through tissue culture. Nodal explants after surface sterilization (ranging in size from 0.5 to 1.5 cm long) were inoculated into test tubes of size 150 × 25 mm with 10 ml of Murashige and Skoog (MS) media supplemented with 0.5 mg/l of 6-benzylaminopurine (BAP). The cultures were exposed to two different magnetic fields of 50 and 100 milli Tesla (mT) for different durations such as 15, 20 and 30 min along with a control in an electromagnetic generator. Further culturing of these explants on to the same media facilitated the growth of the in vitro shoots. Observations on different parameters such as the number of shoots, shoot length and leaves were taken after 40 days of culture. It was found that the cultures exposed to 100 mT for 30 min produced significantly more number of shoots, leaves and the shoot length than the control. The in vitro raised plantlets were successfully hardened. The results of this study indicated that magnetic fields had a positive effect in increasing the efficiency of clonal propagation which is limited by conventional micropropagation techniques. Hence, this novel technology can augment the production of clones of Stevia rebaudiana which can be utilized for commercial extraction of steviosides.

A biolistic-based genetic transformation system applicable to a broad-range of sugarcane and energycane varieties

ABSTRACTSugarcane and energycane (Saccharum spp. hybrids) are prominent sources of sugar, ethanol, as well as high-value bioproducts globally. Genetic analysis for trait improvement of sugarcane is greatly hindered by its complex genome, limited germplasm resources, long breeding cycle, as well as recalcitrance to genetic transformation. Here, we present a biolistic-based transformation and bioreactor-based micro-propagation system that has been utilized successfully to transform twelve elite cane genotypes, yielding transformation efficiencies of up to 39%. The system relies on the generation of embryogenic callus from sugarcane and energycane apical shoot tissue, followed by DNA bombardment of embryogenic leaf roll discs (approximately one week) or calli (approximately 4 weeks). We present optimal criteria and practices for selection and regeneration of independent transgenic lines, molecular characterization, as well as a bioreactor-based micro-propagation technique, which can aid in rapid multiplication and analysis of transgenic lines. The cane transformation and micro-propagation system described here, although built on our previous protocols, has significantly accelerated the process of producing and multiplying transgenic material, and it is applicable to other varieties. The system is highly reproducible and has been successfully used to engineer multiple commercial sugarcane and energycane varieties. It will benefit worldwide researchers interested in genomics and genetics of sugarcane photosynthesis, cell wall, and bioenergy related traits.

Easy and efficient chemical sterilization of the culture medium for in vitro growth of gerbera using chlorine dioxide (ClO2)

Micropropagation techniques changed the production of clonal plantlets in the world. However, the high costs of micropropagated plantlets continue as the main constraint for the expansion of the technique. This paper aimed to test the use of the chemical sterilization of culture medium using chlorine dioxide (ClO2) for in vitro cultivation of gerbera. There was used gerbera in vitro shoots in the stage of rooting for these experiments, using 0.0035%, 0.0070% and 0.0105% of chlorine dioxide in the culture medium. Also, peracetic acid was tested previously for sterilization, but resulted in microbial contamination. Chemical sterilization of the culture medium was successfully using ClO2 at 0.0035% to 0.0105% (100% decontamination) at rooting and elongation stage of gerbera with production of plantlets with similar (number of leaves, total and root fresh weight) or higher quality (mainly aerial part) at rooting/elongation stage, compared with autoclaved culture medium. The increase of concentration of ClO2 also resulted in increasing of height and fresh weight of aerial part of gerberas. The ClO2 could replace the autoclaving with production of sterilized culture medium without phytotoxic problems to gerbera in vitro cultivation.

Potential of auxinary production bacterium in promoting the growth of micropropagate banana plant

The use of techniques of micropropagation have been used in order to improve the production of better-quality seedlings, which enables production of a larger number of plants in a short period of time, in addition to preventing the spread of plant disease. The objective of this study was to evaluated the effectiveness of phytohormones production by bacteria in promoting plant growth promotion in micropropagated banana seedlings. The may was conducted in wing seedlings for 60 days after the lab transfer to the greenhouse, in the controlled growing conditions, watering them daily. The experimental design was completely randomized, consisting of 26 treatments (25 strains and witness). After 60 days the seedlings were cut separating the shoot and root accommodated in paper bags for further evaluation. We evaluated the shoot height (PA Height), root length (length R), fresh weight of shoots (PA Fresh Weight), fresh root weight (weight fresh R), dry weight of shoots (Weight fresh PA) and dry root weight (Dry Weight R). The plant growth promotion micropropagated banana plantlets using bacterial promoters phytohormones showed significant differences in fresh weight and dry weight of roots of seedlings, conferred by S12 strain.

Field performance of micropropagated and mycorrhizal early globe artichoke plants

Abstract Early traditional varieties of globe artichoke are a profitable crop in southern Mediterranean regions. One of the main issues is the availability of propagative plant material that can ensure homogeneous and early production. This paper evaluates the micropropagation technique in association with mycorrhizal inoculation in terms of obtaining high-quality propagative material for Cynara cardunculus L. var. scolymus Fiori cultivar “Violet de Provence”. To confirm the morphological and productive performance of these plants, their agronomical assessment was studied under field conditions. In addition, the effects of mycorrhizal symbiosis were examined on the nutritional quality of artichoke heads. The results showed that micropropagated plantlets were healthy and homogeneous. The inoculation with Septoglomus viscosum improved the growth and development of the plantlets, alleviating the stress of post-transplanting. In the field, the micropropagated and mycorrhizal plants and the heads exhibited the standard morphological characteristics of the cultivar “Violet de Provence”. The productivity performance of the heads highlighted the positive effects of mycorrhizal symbiosis on the weight, earliness and total yield. Finally, arbuscular mycorrhizal (AM) fungus also had a very positive influence on the nutritional quality of the heads, in terms of essential macro-mineral, total phenolic and inulin content. Micropropagation and mycorrhizal techniques appeared to be an efficient and sustainable strategy for improving the yield and nutritional quality of globe artichoke heads under field conditions.

CALLUS INDUCTION OF CACAO CLONE SULAWESI 1 ON VARIOUS CONCENTRATIONS OF 2,4 -D AND COCONUT WATER VIA IN VITRO CULTURE

Cacao is one of important plantation crops grouped in the Sterculiaceae family. Sulawesi is the main area of cacao production and has a number of superior clones, such as Sulawesi 1 and Sulawesi 2. Based on data in 2012/2014 cacao production to consumption reached 174,000 tons, while in 2013/2014 was projected a deficit of 115,000 tonnes. Nonetheless, cacao agribusiness in Indonesia is still facing complex problems, among others gardener productivity is still low due to borer attacks cacao, the quality of products and the number is still low and still not optimal development of cacao products and providing superior amount of cacao seedlings. The primary problem of cacao production recently is low productivity. The main cause of low cacao productivity in Central Sulawesi is the use of inferior clones. To enhance cacao productivity, it is crucial to use cacao clones having high genetic potential via tissue culture or micropropagation techniques. The aim of this experiment was to assess the effect of different concentrations of 2,4-D and coconut water on the growth of cacao callus via in vitro culture. This experiment used Completely Randomozed Block Design in factorial patteren with treatments tested namely 2,4-D and coconut water concentrations. The concentrations of 2,4-D tested including 1 ppm, 2 ppm and 3 ppm, whilst coconut water concentrations tested consisting of 10%, 15% and 20%, and therefore there were 3 x 3 = 9 treatment combinations. Each treatment utilized 4 replications; and each unit combination used 5 explants (staminodia). Results of this experiment indicated that the addition of 3 ppm 2,4-D and 10% coconut water had a highly significant effect on the callus color 4 weeks after culture. The addition of 3 ppm 2,4-D in culture media showed a significant effect on callus color 4 weeks after culture, but had an insignificant effect on the callus formation, callus color 8 weeks after culture an callus texture. Supplementation of 20% coconut water had a significant effect on callus texture 8 weeks after culture, whilst the addition of 10% coconut water showed a significant effect on callus color 4 weeks after culture.

Improving Macropropagation and Seed Germination Techniques for Conservation of Threatened Species

Populations of threatened plants are declining rapidly in natural habitats due to various anthropogenic activities. Reinforcement of the dwindling populations through reintroduction is a promising aspect for conservation of threatened plants. However, due to lack of standardized propagation methods of such plants, mass production of planting materials has become a challenge, thereby constraining the replenishment process. Identification of factors constraining the seed germination of threatened plants and addressing it effectively, are among the most cost-effective strategies for large-scale multiplication and subsequent conservation of the threatened species. Similarly, conventional low-cost vegetative propagation techniques such as grafting, air layering, and regenerating plantlets from root-suckers, apical meristems, and stem cuttings often prove more successful for multiplication than relatively costly micropropagation techniques. In this article, we present a few case studies on low-cost mass propagation techniques of threatened plant species of India through seed, stem/apical shoot cutting and airlayering, that helped in the restoration of the species.

Micropropagation’s Complete Protocol of Red Araçá (Psidium cattleianum, Myrtaceae) from Germinated Seeds in vitro

Red Araçá’s (Psidium cattleianum) micropropagation processes have shown enormous potential both in terms of research and as a sustainable native resource to be used in the areas of food production, ecology, and pharmacology. Currently, however, despite that potential, research efforts involving this myrtaceae, native to the Brazilian Atlantic Forest, have been scarce. With that in mind, this study set out to establish micropropagation techniques that would allow the development of a feasible protocol to be used with Red Araçá, achieving its mircropropagation from in vitro germinated seeds. Different types of explants were tested for in vitro establishment. For the multiplication of nodal segments, different concentrations of BAP and IAA combinations were tested in an MS medium. Using the same medium, different concentrations of ampicillin were applied in order to determine its influence on the decontamination of the apical segments. The BAP and IAA combinations were also used to test their effects on the in vitro explants’ development and rooting. During pre-acclimatization, survival of in vitro rooted plants was tested in a nebulizer chamber, using a commercial substrate and that same substrate mixed with washed sand (1:1). In essence, it was indeed possible to develop a complete protocol for the micropropagation of the Red Araçá from seedlings obtained by in vitro germination. The in vitro introduction of the Red Araçá was rather efficient, independently of the type of explants used. As the BAP and IAA concentrations increased, so did the in vitro seedlings’ development (7 leaves explant-1) and rooting (67%). Additionally, the in vitro rooted plants exhibited a high rate of survival (80%) in the pre-acclimatization phase, independently of the substrate used.

In Vitro Proliferation of Female Buds for Induction of Somatic Embryogenesis from False Horn Plantain (AAB, cv. Curraré).

Most cultivated bananas (Musa spp.) are polyploids, and their fruits are seedless and propagated exclusively vegetatively; however, they can also be cloned by micropropagation techniques, viz., direct organogenesis (DO) or somatic embryogenesis (SE). Banana indirect SE (ISE), with an embryogenic callus phase, is possible using young male or female flowers as direct explant depending on the genotype or shoot tips (scalps). For the False Horn Plantain, cv. Curraré (AAB, plantain subgroup), which has a degenerating male bud, female flowers are used to regenerate plants through ISE. Here, a protocol for increasing the number of initial explant material from a single mother plant and its embryogenic response is described. For those purposes, hands with young female buds are in vitro proliferated in the presence of 1 μM indole-3-acetic acid and 2.5 μM thidiazuron. Friable embryogenic cultures, here called ISE-2, obtained from the new proliferative secondary female bud clusters are initiated on medium containing auxins. Embryogenic suspensions are then established from the ISE-2 cultures. Regeneration of plants is achieved from embryogenic suspensions after plating on semisolid medium free of plant growth regulators; greenhouse acclimatized plantlets are ready for banana farming. This study demonstrates that proliferative female buds are a proper choice for ISE.

LIGHT QUALITY IN THE IN VITRO INTRODUCTION OF Corymbia HYBRID CLONES

ABSTRACT Micropropagation via axillary bud proliferation is recommended for rejuvenation or reinvigoration of selected clones, as well as for improving clonal seedlings rooting. The success of a micropropagation protocol depends on the in vitro introduction, since following phases, multiplication, elongation, and rooting can only take place once the aseptic crop with vegetative vigor has been established. This study aims to assess the effect of light on the in vitro introduction of hybrid clones of Corymbia torelliana x C. citriodora e Corymbia citriodora x C. torelliana by the micropropagation technique through proliferation by axillary buds. The mini-stumps, suppliers of explants for in vitro introduction, were conducted in semi-hydroclonal mini-clonal hedge. Nodal segments from three Corymbia torelliana x C. citriodora (TC01, TC02 e TC03) clones and one Corymbia citriodora x C. torelliana (CT01) clone were collected, disinfested and inoculated in JADS culture medium, in order to compare the effects of light quality from a dark/fluorescent lamp, a fluorescent lamp, and white and red/blue LEDs. At 30 days after inoculation, the following characteristics were evaluated: average contamination percentage, oxidation, non-reactive explants, shoot length and average number of shoots per explant greater than 0.5 cm. Gathered data showed that the use of red/blue LED light source obtained the best results in all assessed characteristics in the in vitro introduction.

Effects of indolebutyric acid, stem cutting positions and substrates on the vegetative propagation of <i>Stevia rebaudiana</i> Bertoni

Stevia rebaudiana Bertoni es una especie de alta importancia económica debido a la producción de edulcorantes naturales con bajo valor calórico. La producción de semillas de esta especie es irregular y las técnicas de micropropagación aumentan el costo de la producción de plántulas. Por lo tanto, este trabajo tuvo como objetivo optimizar la propagación vegetativa de un genotipo brasileño de esta especie a través de estacas de tallo. El material vegetal se recogió de plantas maduras con 1 año de edad. Se realizaron dos experimentos para determinar la mejor concentración de ácido indolbutírico (IBA) para mejorar el enraizamiento y evaluar la interacción entre la posición de corte del tallo (apical, mediana y basal) y sustratos (Tropstrato HT®, vermiculita y mezcla de vermiculita y Tropstrato HT®). Las estacas de tallos se vieron afectadas por las concentraciones de IBA. Se recomienda la aplicación de 710 mg L-1 de IBA para mayores porcentajes de enraizamiento. Las estacas de tallos de la región apical de las plantas mostraron mayor porcentaje de enraizamiento que las medianas y basales (medias de 70, 45,8 y 7,5%, respectivamente). Se observaron resultados similares para el número, longitud y masa de raíz fresca y seca. El sustrato Tropstrato HT® promovió mayores porcentajes de enraizamiento de las estacas de tallo y menor mortalidad en comparación con la vermiculita.

Micropropagation of Agave Species.

The genus Agave originates from the American continent and grows in arid and semiarid places, being México the center of origin. Many species of the genus are a source of diverse products for human needs, such as food, medicines, fibers, and beverages, and a good source of biomass for the production of biofuels, among many others. These plants are gaining importance as climate change becomes more evident as heat is reaching temperatures above 40 °C worldwide and rains are scarce. Many species of the genus grow in places where other plant species do not survive under severe field conditions, due to their CAM pathway for fixing CO2 where gas exchange occurs at night when stomata are open, allowing them to avoid excess loss of water. Most of the important species and varieties are usually propagated by offshoots that develop from rhizomes around the mother plant and by bulbils that develop up in the inflorescence, which are produced by the plant mostly when there is a failure in the production of seeds.Areas for commercial plantations are growing worldwide and therefore in the need of big amounts of healthy and good quality plantlets. Although many Agave species produce seeds, it takes longer for the plants to reach appropriate maturity and size for diverse purposes. Micropropagation techniques for the genus Agave offer the opportunity to produce relatively high amounts of plants year around in relatively small spaces in a laboratory. Here, a protocol for micropropagation that has proven good for several Agave species (including species from both subgenera) is presented in detail with two different kinds of explants to initiate the process: rescued zygotic embryos and small offshoots that grow around a mother plant.

Thinking inside the Box: Tissue Culture for Plant Propagation in a Key Ecological Species, <i>Andropogon gerardii</i>

Intraspecific diversity has widespread effects on ecological communities and ecosystems. To elucidate the mechanisms underlying these effects, manipulative studies require a rigorous and efficient empirical approach. Yet, replicating sufficient numbers of genetically identical individuals remains a challenge. As a result, we are limited in our understanding of the mechanisms underlying the ecological effects of intraspecific diversity. In contrast, large sample sizes are routinely produced in horticultural research using micropropagation, or tissue culture. In order to determine the potential usefulness of micropropagation technique for ecological studies, we investigated the efficiency and efficacy of micropropagation on the ecologically important non-model C4 grass species, Andropogon gerardii. Our preliminary results demonstrate that micropropagation is a rapid and effective technique for producing large numbers of genetically identical clones at up to 100 times the rate of traditional propagation. Key intraspecific differences among clones of A. gerardii were also retained through the micropropagation process. Given that traditional techniques used to test the effects of intraspecific diversity manipulations are time-limiting (greenhouse propagation) or can be biologically misrepresentative (seeds) for some species, we suggest that micropropagation might be a powerful tool for advancing ecological genetics studies in many plant systems.

Effect of phytohormones on rapid In vitro propagation of dendrobium thyrsiflorum Rchb.f.: An endangered medicinal orchid

Pharmacognosy Magazine,2018,14,58,495-500.DOI:10.4103/pm.pm_155_18Published:November 2018Type:Original ArticleAuthors:Leimapokpam Tikendra, Thoungamba Amom, and Potshangbam Nongdam Author(s) affiliations:Leimapokpam Tikendra, Thoungamba Amom, Potshangbam Nongdam Department of Biotechnology, Manipur University, Imphal, Manipur, India Abstract:Background: Dendrobium thyrsiflorum is highly vulnerable to extinction in its natural habitats due to overexploitation for the medicinal and horticultural purposes. The poor seed germination in a natural condition and slow plant production through vegetative approach make in vitro micropropagation techniques an ideal choice for effective plant propagation. There are very limited reports on the in vitro culture of this orchid. Objective: The objective of the study is to establish efficient in vitro regeneration protocols for rapid mass propagation of D. thyrsiflorum. Materials and Methods: Five-month-old undehisced capsule was surface sterilized with 0.4% mercuric chloride. To study the influence of growth regulators on in vitro development of shoots and roots, the seeds obtained from the capsule were inoculated on freshly prepared Mitra medium supplemented with different concentrations and combinations of 6-benzylaminopurine (BAP), kinetin (KN), indole -3-butyric acid (IBA), indole-3-acetic acid (IAA), and 1-naphthyl acetic acid (NAA). Results: The KN either singly or with IAA produced more effective shooting than BAP at similar concentration and combination. Maximum shoot production (3.83 ± 0.48) was achieved in medium fortified with 1.0 mg/L KN and 2.5 mg/L IAA. IAA was the most influential among auxins tested in promoting rooting and shooting. Prominent shoot development (3.04 ± 0.73) and maximum root formation (6.52 ± 0.37) were noticed in medium supplemented with 2.0 mg/L IAA. The regenerated plantlets were subsequently hardened with 91% survival rate in greenhouse and field condition. Conclusion: The present investigation revealed the possibility of developing effective and reproducible in vitro regeneration protocols for rapid propagation of D. thyrsiflorum. The established in vitro protocols can be employed for fast regeneration of the orchid for useful phytochemical extraction without depending on the already depleted natural population. Keywords:Auxin, Cytokinin, Dhanzyme gold, Propagation, ProtocormView:PDF (1.74 MB)