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Invitro tissue culture establishment is the most important phase in rice (Oryza sativa L.) genetic improvement studies. But, invitro tissue growth demands a sterile condition conducive for unhampered nutrient supply to the explant which otherwise face competition from unwanted microbial contamination of explant origin. To eliminate such contaminants, there are several surface sterilisation techniques available for Invitro culture establishment of mature rice seed explants, which include the application of either mercuric chloride or sodium hypochlorite as sterilizing agents. Therefore, a comparative study was conducted to determine the effect of these sterilization techniques on decontaminating the rice seed explants without affecting their invitro germination potential. The most effective sterilisation was obtained with 0.2% mercuric chloride treatment for 8 minutes, which produced 93.62± 0.191% of contamination free seeds. But, the highest germination (94.53± 0.210%) was obtained with 4% of NaOCl treatment for 10 minutes. The results demonstrated that the level of contamination decreases with increasing concentration of sterilising agents and the duration of the treatment. The germination percentage decreased with increasing concentration of mercuric chloride. Sodium hypochlorite enhanced germination until a concentration increase of 4% and then the germination percentage decreased with increasing concentration and treatment duration. These findings may help in determination of most appropriate surface sterilisation technique in rice for in vitro culture.

Dormancy in rice serves as a mechanism of survival by protecting the seed from germinating in the mother plants; however, it becomes a problem in germination during sowing in soil or under in vitro conditions. This study was conducted to determine the effect of heat treatment and sodium hypochlorite (NaOCl) treatment of seeds on dormancy alleviation. The seeds included both freshly harvested seeds and one-year-old stored seeds, which were tested for germination after different types of seed treatments. Both the treatments increased the germination percentage in seeds, however, it was lesser in the case of old seeds. The best results were obtained from 2% NaOCl treatment for 24 hrs in new seeds, i.e. 92.84±0.103 % germination percentage (GP). However, the higher GP in old seeds were obtained from 48 hrs of heat-treated seeds i.e. 82.9±0.509 % GP. The results of the experiment revealed that rice seeds start to lose viability within a year due to seed dormancy, but this can be reversed with proper measures. These methods of breaking seed dormancy can be considered effective to break seed dormancy and improve seed germination in rice.

A survey was conducted in King chilli growing areas of four Northeast states of India namely, Assam, Nagaland, Manipur and Meghalaya for virus disease incidence particularly Cucumber mosaic virus (CMV), Chilli veinal mottle virus (ChiVMV) and Chilli leaf curl virus (ChiLCV). The virus disease incidence based on symptomatology ranged from 15 to 65% with highest incidence recorded in Golaghat district of Assam and lowest in the Ukhrul district of Manipur. The polymerase chain reaction based detection using coat protein gene specific primers for the three viruses revealed the presence of CMV and ChiVMV in all the four states whereas ChiLCV was recorded only in one location from Assam. In two of the samples collected for CMV and ChiVMV, mixed infection of the two viruses was confirmed. Based on molecular method based detection, the incidence of CMV infection in King chilli among all the samples tested for the virus was 32.5% whereas it was 25.97% for ChiVMV.

The present work reports the prospective applicability of three indigenous rootstocks belonging to different species viz. Nemutenga, Tayum and Tasi cultivars of north eastern Himalayan region for producing Citrus tristeza virus (CTV; a viral species of the Closterovirus genus) free quality planting materials of Khasi mandarin (Citrus reticulata Blanco) through micrografting or shoot-tip grafting (STG). The development of disease-free plants through STG is essential as CTV is in vivo transmissible through infected bud sticks. The technique of STG along with the diverse culture parameters like effect of sucrose, plant growth regulators, pre-treatment of scion and stock, effect of scion size after thermotherapy and grafting method was analysed. Among the three indigenous tested rootstocks, Nemutenga was found superior showing maximum STG success of 58.5%. STGs using scion size ranging from 0.3 to 0.5 mm, survival was up to 42.0% and completely virus-free. Pre-treatment of scion and stock with kinetin (1.0 mg L−1) was found more suitable than N6-benzylaminopurine (BAP) and further increased the rate of micrografts. For further growth of micrografts, Murashige and Skoog medium fortified with 0.5 mg L−1 BAP and 0.1 mg L−1 indole-3-acetic acid (IAA) along with 5% sucrose resulted in maximum (56.8%) response. Considering the two techniques applied for STG, cleft grafting was found more suitable than inverted T grafting. Viral assessment with enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) revealed negative results for all plants from 0.3 to 0.5 mm scion while 0.7-mm scion-raised micrografts showed 60% negative with RT-PCR for CTV.

Sphagneticola calendulacea (L.) Pruski [synonym Wedelia chinensis (Osbeck) Merrill] is an important medicinal plant that possesses a variety of bioactive secondary metabolites. A stable transgenic hairy root culture has been developed using engineered Agrobacterium rhizogenes strain LBA1334 harboring pCAM:2 × 35S:gusA binary vector, to achieve high yield of secondary metabolites. Putative transgenic hairy roots appeared with highest transformation frequency (66.67%) when leaf explants were immersed in A. rhizogenes suspension for 10 min and co-cultivated for three days. Incorporation of foreign genes was confirmed by initial GUS staining assay followed by polymerase chain reaction analysis of rolA, rolB, rolC and gusA genes. Time course study revealed that the transgenic hairy roots grew rapidly in ½ Murashige and Skoog liquid medium with highest biomass production of 0.61 g per 50 ml dry weight after 28 days of culture. In the precursor feeding experiment, the biomass of hairy roots was further increased to 0.698 g per 50 ml dry weight when 0.5 mM phenylalanine was added to the 10 days old growing culture. High Performance Thin Layer Chromatography showed that the transgenic hairy roots accumulated enhanced level of wedelolactone (422.01 μg g−1 dry weight), which was 1.43 and 1.37 times higher than those of in vivo (294.44 μg g−1 dry weight) and in vitro-grown (308.28 μg g−1 dry weight) plantlets, respectively. Precursor feeding with phenylalanine further augmented the accumulation of wedelolactone to 440.33 μg g−1 dry weight in the transgenic hairy roots. In addition, the content of several important phenolic and flavonoid compounds were increased in the transgenic hairy roots as analyzed by High Performance Liquid Chromatography. The protocol offers a scope to introduce foreign genes and further regulate the production of secondary metabolites.

Citrus tristeza virus (CTV) infected plant samples from the North Eastern states of India namely Arunachal Pradesh (AR1), Assam (AS1), Nagaland (NL1), Meghalaya (M1), Sikkim (SK1) and Tripura (TR1) were examined through double antibody sandwich enzyme linked immunosorbent assay and reverse transcriptase polymerase chain reaction using coat protein (CP) gene specific primers, yielding amplicon of 672 base pair for all the isolates. The sequence analysis revealed nucleotide (nt) and amino acid (aa) sequence similarity with other exotic CTV isolates. AR1 and AS1 shared similarity with T3 isolate (Florida) at 98–99% and 95–99% for nt-aa respectively, whereas, M1 showed 99% similarity with stem pitting isolate B165 (Bangalore). SK1 and NL1 were 95–97% and 97–99% similar with Hawaiian isolate HA at nt-aa level. TR1 showed 97% homology with seedling yellowing Israeli isolate VT. The CP gene sequence based phylogenetic analysis grouped present isolates into four clades with reference severe isolates (i.e. VT, B165, HA and T3), indicating their probable evolution. TR1 and NL1 are the putative recombinant isolates and ASI and SK1 were the major and minor parents respectively. This might be due to the conserved nature of CP gene. Moreover, the CP gene sequences of present isolates showing nucleotide identity to the VT, T3 and B165 isolates also suggest the prevalence of severe CTV isolates in Khasi mandarin growing areas comes under North East (NE) region of India.

Coleus forskohlii syn. Plectranthus barbatus is a popular medicinal plant belonging to the family Lamiaceae and order Lamiales. The leaf and root extracts can be utilized for the treatment of various ailments like bronchitis, asthma, hay fever, angina and abdominal disorders. The major metabolite that is found exclusively in the cork cells of the root in C. forskohlii is forskolin, which is used commercially for the treatment of glaucoma, asthma and several heart ailments. The essential oil extracted from the tubers of the plant also exhibits anti-microbial properties. The present review recounts the existing reports on biotechnological approaches like direct, indirect organogenesis and somatic embryogenesis for mass propagation of plantlets; the amelioration of forskolin production through cell suspension and genetic transformation as well as slow growth storage for germplasm conservation. Additionally, the unexplored arenas and the prospective novel approaches are also addressed in this review that can be utilized in designing new experiments in near future on this plant.

The present research focused on enhancing the production of wedelolactone through cell suspension culture (CSC) in Eclipta alba (L.) Hassk. With an aim of attaining a sustainable CSC, various plant growth regulators, elicitors and agitation speed were examined. Nodal segments of in vitro propagated plantlets induced the maximum percentage (93.47 ± 0.61%) of callus inoculated on Murashige and Skoog (MS) medium fortified with picloram (2 mg L−1). The growth kinetics of CSC exhibited a sigmoid pattern with a lag phase (0–6 days), a log phase (6–18 days), a stationary phase (18–24 days) and then death phase thereafter. The highest biomass accumulation in CSC with 7.09 ± 0.06 g 50 mL−1 fresh weight, 1.52 ± 0.02 g 50 mL−1 dry cell weight, 1.34 ± 0.01 × 106 cell mL−1 total cell count and 57.00 ± 0.58% packed cell volume was obtained in the liquid MS medium supplemented with 1.5 mg L−1 picloram plus 0.5 mg L−1 kinetin at 120 rpm. High performance thin layer chromatography confirmed that yeast extract (biotic elicitor) at 150 mg L−1 accumulated more CSC biomass with 1.22-fold increase in wedelolactone (288.97 ± 1.94 µg g−1 dry weight) content in comparison to the non-elicited CSC (237.78 ± 0.04 µg g−1 dry weight) after 120 h of incubation. Contrastingly, methyl jasmonate (abiotic elicitor) did not alter the biomass but increased the wedelolactone content (259.32 ± 1.06 µg g−1 dry weight) to an extent of 1.09-fold at 100 µM. Complete plantlet regeneration from CSC was possible on MS medium containing N6-benzyladenine (0.75 mg L−1) and abscisic acid (0.5 mg L−1). Thus, the establishment of protocol for CSC constitutes the bases for future biotechnological improvement studies in this crop.

A complete protocol for the in vitro induction of Eclipta alba tetraploids has been optimized to enhance the wedelolactone content, an anti-cancerous compound. The effects of different concentrations of colchicine (0, 0.01, 0.05, 0.1, 0.2 and 0.3%; w/v) along with treatment durations (12, 24, 36 and 48 h) were investigated on shoot tip (ST) and nodal segment (NS). The treated explants were then incubated on Murashige and Skoog (MS) medium having 1.5 mg L−1 N6-benzylaminopurine and 0.5 mg L−1 α-napthalene acetic acid for shoot regeneration and afterward root was induced on 1.0 mg L−1 indole-3-acetic acid enriched ½MS medium. The tetraploids of E. alba were proficiently induced by the treatment of 0.1% colchicine for 24 h. The highest tetraploid induction efficiency was obtained from ST (30.56%) in comparison to the NS (22.22%). Analysis by spectrophotometry and flow cytometry showed that colchicine treated plants contained higher quantity of DNA than diploid plants. Cytological studies demonstrated doubled the chromosome number in tetraploids (2n = 4x = 44) than diploids (2n = 2x = 22). The ploidy level enhancement lead to alteration of other traits, like increased plant height, stem diameter, leaf size, stomatal size and chlorophyll content. As determined through high performance thin-layer chromatography, the ultimate achievement of this technique is the higher accumulation of wedelolactone in tetraploid plants (300.32 µg g−1 dry weight) in evaluation to in vitro diploid (131.31 µg g−1 dry weight) and in vivo diploid mother plants (93.26 µg g−1 dry weight), thus improving the pharmaceutical value of E. alba.

Khasi mandarin is one of the most remunerative crop in North Eastern Hills region of India playing a very critical role in the socio-economic upliftment of the people. The orchards of this region were found to express the typical symptoms of citrus tristeza virus (CTV). An extensive survey of the Khasi mandarin orchard for six North Eastern states of India namely Arunachal Pradesh, Meghalaya, Assam, Nagaland, Sikkim and Tripura, was carried out to establish the identity of these viruses using ELISA and PCR/RT-PCR techniques. Out of 300 Khasi mandarin tree samples collected from the six states, 172 were found to be positive for CTV infection by DAS-ELISA indicating 57.33% overall CTV disease incidence. Results revealed presence of CTV in all the surveyed states showing a maximum incidence of 66.00% in Arunachal Pradesh followed by 62.00% in Assam, 60.00% in Meghalaya and Nagaland, 54.00% in Sikkim and 42.33% in Tripura. Higher CTV concentration was recorded in the age group > 15 years (69.09%) followed by 10–15 (57%) and 5–10 years (43.33%). However, this study, to the best of our knowledge, is the first report for the detection of CTV in Khasi mandarin from Arunachal Pradesh, Nagaland and Tripura and also the first authentic survey of overall disease incidence of CTV Khasi mandarins from the six major mandarin growing North Eastern states of India.

Sphagneticola calendulacea (L.) Pruski (synonym Wedelia chinensis (Osbeck) Merrill) has great significance in traditional systems of medicine and is popularly known for its hepatoprotective properties. A comprehensive micropropagation technique for its conservation and season-independent, large-scale production was established. Initial culture was established in different basal media [Murashige and Skoog (MS), Schenk and Hildebrandt (SH), Gamborg’s (B5), and Woody Plant medium (WPM)] following a non-toxic, simple, and effective sterilization of ex vitro shoot tip (ST) and nodal segment (NS) explants. MS medium favored the highest rate (∼87.27%) of multiple (∼2.03) shoot bud initiation from NS explants that was further multiplied with supplementation of thidiazuron (TDZ), kinetin, N6-(Δ2-isopentenyl) adenine, or zeatin in combination with indole-3-acetic acid (IAA) or α-naphthaleneacetic acid (NAA). MS medium containing TDZ (0.2 mg L−1) and NAA (0.05 mg L−1) resulted in the maximum (∼98.82%) response with the highest number (∼33.12) and length (∼6.04 cm) of multiple shoots. The maximum number (∼12.18) and length (∼6.24 cm) of healthy roots per plant was achieved on ½ MS medium plus 1 mg L−1 IAA. In a simple acclimatization process of 6 wk, the survival rate of plantlets cultured in a combination of soil, sand, and vermicompost (1:1:1; v/v/v) was 82.00%. DNA fingerprinting of the in vitro-regenerated plantlets via analysis of random amplification of polymorphic DNA and intersimple sequence repeat markers showed clonal fidelity of the plantlets with the mother plant.

Medicinal plants are in huge demand since the consumption is widespread and ever-increasing globally. The conventional breeding programs are generally environmental dependent; prone to different biotic and abiotic stresses as well as the secondary metabolite content is too low to harvest. In this context, developing polyploid individuals artificially would be a remarkable approach to increase vigor and attain this objective. Polyploids often exhibit some morphological features that are different or greater in forms than their diploid progenies. Polyploidization can be induced by quite a few antimitotic agents. The most frequently used antimitotic chemicals are colchicine, trifluralin, and oryzalin. The whole method of induced chromosome doubling consists of a series of steps, including an induction phase, regrowth phase, and a confirmation technique to evaluate the rate of achievement. The induction phase depends on different factors, such as explant types, antimitotic agents, its different concentrations, and exposure durations. To evaluate the accomplishment of polyploidization, morphological or anatomical observations are recorded as a rapid method. However, chromosome count and flow cytometry are the most eminent method for absolute confirmation. Despite significant prospects of polyploidization, there has been very little research on medicinal plants. The current review gives an overview of the different parameters of in vitro chromosome doubling, the history of the technique, and progress made over the last two decades.

Plant regeneration by means of somatic embryogenesis has been standardized for the first time in Eclipta alba (L.) Hassk. Explants like nodal segment, shoot tip, and leaf were tested on Murashige and Skoog medium supplemented with picloram, 2,4-dichlorophenoxyacetic acid, or α-naphthalene acetic acid for callus induction. Nodal segment exhibited the maximum response (92.80%) to callus induction on culture medium-containing 2.0 mg l−1 picloram. Furthermore, highest rate (88.40%) and number (34.83) of somatic embryo induction were found on medium fortified with 2.0 mg l−1 picloram, 0.5 mg l−1 thidiazuron, and 0.25 mg l−1 abscisic acid. Influence of abscisic acid on the somatic embryo regeneration was also tested with the highest frequency (95.50%) attained on medium-containing 0.75 mg l−1 N6-benzyladenine and 0.5 mg l−1 abscisic acid. Somatic embryo of torpedo stage was efficiently encapsulated with 2.5% sodium alginate and 75 mM calcium chloride, and exhibited 93.33% germination rate. The study revealed that storage at low temperature (8 °C) gave superior results where 86.67% of the synthetic seeds sprouted even after 60 days with a decline to 46.67% in 90 days post-storage. The rate of germination at 25 °C had been constantly low and failed to sprout after 75 days. The acclimatization of the regenerated plantlets was successfully taken place in garden soil, sand, and vermicompost in the ratio of 1:1:1 with 95% survival rate.

A practical and reliable method for in vitro tetraploidization of Sphagneticola calendulacea (L.) Pruski [synonym Wedelia chinensis (Osbeck) Merrill] has been established to enhance the production of wedelolactone. Shoot tip and nodal explants from in vitro-grown culture (2n = 50) were exposed to the antimitotic chemical, i.e., colchicine, at various concentrations (0, 0.025, 0.05, 0.1, 0.3, and 0.5%; w/v) for 12, 24, 36, 48, and 60 h. The treated explants were then incubated and proliferated on Murashige and Skoog (MS) medium fortified with 0.2 mg l−1 thidiazuron and 0.05 mg l−1 naphthalene acetic acid, followed by root induction in 1.0 mg l−1 indole-3 acetic acid enriched ½MS medium. Treatment of shoot tips with 0.05% colchicine for 24 h supported the maximum rate of survival (63.33%) of explants as well as tetraploid induction (42.93%). Morphological, stomatal, and cytological characteristics along with the secondary metabolite content of the in vitro tetraploids were compared to that of diploids. The recovered tetraploid plants possessed superior plant height, stem diameter, leaf size, root number, and increased length and width of stomata but decreased stomatal frequency. The tetraploid plants demonstrated twice the chromosome number (2n = 4x = 100) than the diploids as confirmed through cytology, spectrophotometry and flow cytometry. High-performance thin-layer chromatography showed a significant enhancement in the wedelolactone content of tetraploid plants (541.48 µg g−1 of dried sample) in comparison to diploid plants (325.43 µg g−1 of dried sample), signifying the prospective of this technique for the trade value improvement.

Background: Vitiligo is an acquired, idiopathic, and common depigmentation disorder. The values of various epidemiologic parameters are often doubtful due to the methodological weaknesses of the studies. Aims: To elicit the magnitude of various epidemiological parameters and important correlates of vitiligo. Materials and Methods: Every vitiligo patient attending the outpatient department of medical colleges spread over most of the Indian states were examined over a period of 1 year. Various epidemiological and clinical variables were examined and compared with age and sex-matched controls (registered in the Clinical Trial Registry of India CTRI/2017/06/008854). Results: A total of 4,43,275 patients were assessed in 30 medical colleges from 21 Indian states. Institutional prevalence of vitiligo was 0.89% (0.86% in males and 0.93% in females, P < 0.001). The mean age at presentation and mean age at onset were 30.12 ± 17.97 years and 25.14 ± 7.48 years, respectively. Head–neck was the most common primary site (n = 1648, 41.6%) and most commonly affected site (n = 2186, 55.17%). Most cases had nonsegmental vitiligo (n = 2690, 67.89%). The disease started before 20 years of age in more than 46% of cases. About 77% of all cases had signs of instability during the last 1 year. The family history, consanguinity, hypothyroid disorders, and depressed mood were significantly (P < 0.001) higher among the cases. First, second, and third-degree family members were affected in 269 (60.04%), 111 (24.78%), and 68 (15.18%) cases, respectively. Work-related exposure to chemicals was significantly higher among cases (P < 0.008). Obesity was less common among vitiligo cases [P < 0.001, odds ratio (OR) 0.78, 95% confidence interval (CI): 0.71–0.86]. Conclusion: This is one of the largest studies done on vitiligo in India. The prevalence of vitiligo was found to be 0.89% among hospital attendees. Prevalence of vitiligo was higher among females than in males and prevalence of family history, consanguinity, hypothyroid disorders were higher in vitiligo than among controls.

A well-organized procedure was established for the conservation and distribution of Sphagneticola calendulacea (L.) Pruski [synonym Wedelia chinensis (Osbeck) Merrill] for the first time, using alginate-encapsulated nodal segments (NSs) as synthetic seeds. The ideal beads were obtained through a combination of 2.5% sodium alginate and 75 mM calcium chloride with 84.40 ± 2.20% rate of shoot emergence. The maximum regeneration (88.84 ± 2.24%) from synthetic seeds was achieved on liquid 1/2Murashige and Skoog (MS) medium in comparison to its other formulations. Furthermore, superior frequency (91.09 ± 2.24%) of complete plantlet (having both shoots and roots) formation was achieved when synthetic seeds were cultured on liquid 1/2MS (1.5% sucrose) fortified with 1.0 mg L−1 N6-benzyladenine plus 0.25 mg L−1 α-naphthalene acetic acid. Synthetic seeds could be effectively stored at low temperature (8 °C) up to 90 days with a survival rate of 52.38 ± 3.06%, whereas higher temperature (25 °C) did not support regeneration after 75 days of storage. The plantlets were successfully acclimatized to natural conditions with ~ 89% survival frequency. To by-pass the time-consuming in vitro culture step after encapsulation, synthetic seeds were directly regrown into complete plantlets ex vitro on sand, soil, and vermicompost (1:1:1; w/w). Regeneration rate of 42.22 ± 2.22% was attained when NSs were pretreated on 1/2MS medium containing 4.0 mg L−1 indole-3-acetic acid for 24 h in dark, prior to encapsulation. The random amplified polymorphic DNA and intersimple sequence repeat fingerprinting profiles demonstrated genetic uniformity amongst the regenerated plantlets, in vitro mother plant, as well as in vivo wild plant.

Khasi mandarin is one of the most remunerative crop in North Eastern Hills region of India playing a very critical role in the socio-economic upliftment of the people. The orchards of this region were found to express the typical symptoms of citrus tristeza virus (CTV). An extensive survey of the Khasi mandarin orchard for six North Eastern states of India namely Arunachal Pradesh, Meghalaya, Assam, Nagaland, Sikkim and Tripura, was carried out to establish the identity of these viruses using ELISA and PCR/RT-PCR techniques. Out of 300 Khasi mandarin tree samples collected from the six states, 172 were found to be positive for CTV infection by DAS-ELISA indicating 57.33% overall CTV disease incidence. Results revealed presence of CTV in all the surveyed states showing a maximum incidence of 66.00% in Arunachal Pradesh followed by 62.00% in Assam, 60.00% in Meghalaya and Nagaland, 54.00% in Sikkim and 42.33% in Tripura. Higher CTV concentration was recorded in the age group > 15 years (69.09%) followed by 10–15 (57%) and 5–10 years (43.33%). However, this study, to the best of our knowledge, is the first report for the detection of CTV in Khasi mandarin from Arunachal Pradesh, Nagaland and Tripura and also the first authentic survey of overall disease incidence of CTV Khasi mandarins from the six major mandarin growing North Eastern states of India.

The present review illustrates the pharmacological properties and production of planting materials through in vitro organogenesis of Stevia rebaudiana (Bertoni). The plant is native to Paraguay; however, the main producers of stevia are Japan, China, Taiwan, Thailand, Korea, Brazil, Malaysia and India. This plant is recorded as having a non-caloric natural sugar, alternative to artificially produced sugar substitutes and hence traditionally has been used to sweeten beverages. This article enumerates an overview on pharmacological and micropropagation aspects which are of use to researchers for further exploration for the indispensable improvement of this potential herb with medicinal importance.

Taro is an important tropical tuber crop, used as a staple food or subsistence food by millions of people in the developing countries. A program was done to analyze and identify the same promising 20 selected local and Indian accessions taro, aiming at the characterization of the extent and distribution of genetic diversity using morphological marker with the define objectives ‘to find genetic variability amongst the 20 taro genotypes collected from different agro-climatic zones in India, in respect of plant physical (like length of main sucker, no of petioles, length of leaf lamina, wt. of side tuber, number of side tuber, estimated Corm yield, breadth of leaf lamina)’. The present study revealed that the genetic diversity recorded through physical parameters corresponded with the genetic diversity revealed through molecular data analysis. On the basis of D2 statistics the 20 genotypes were grouped into six different clusters (I-VI). Most of the local taro genotypes collected from different locations (BCC-1, BCC-2, BCC10, BCC15, BCC18, BCC-21, BCC24 and BCC-25) were placed in Cluster II with moderate intra cluster distance indicating their closeness, and showed similar phenotypic characters. The genotypes viz. FC-4, FC-11 and PKS-1 were found to distantly relate to other genotypes and were grouped into Cluster III.

Agricultural crop production has been seriously hampered by various detrimental environmental conditions all over the world. Such conditions modify the growth and development of plants and ultimately reduce the economic yield enormously. These detrimental effects can be overcome by developing better stress-tolerance plants utilizing different genetic techniques. Therefore, there is a need to develop a marker system for the identification of stress responsive genes in order to combat the losses. Single nucleotide polymorphisms (SNPs) have become a more preferable marker over microsatellites because of their frequent occurrence in the genome and low rate of mutations. The discovery of SNPs in many crop species facilitates the availability and identification of many genes or quantitative trait loci (QTLs) associated with traits related to abiotic stress. Hence, identification of SNP flanking the genomic regions containing QTLs for aspects of abiotic stress tolerance would strongly expedite the targeted integration of this trait into another susceptible germplasm. Such identification of SNPs will not only promote marker-assisted breeding for abiotic stress tolerance but also open a vista for cloning and evaluation of primary genetic factors suitable for engineering improved abiotic stress tolerant plants. This review presents the present status of SNP marker technologies for abiotic stress tolerance in crop plants.

Protocorm-like bodies (PLBs) were induced directly at high frequency from wounded surface of Anthuriumandreanum cv. CanCan shoot tip-ends, used as explants. In order to obtain PLB directly, the influence of different types and concentrations of cytokinins were evaluated. Amid the cytokinins, N6-(∆2-isopentenyl)-adenine (2-iP) at a concentration of 15 μM was most effective in inducing PLB whereby ~98 (97.8) % of explants induced PLB with an average of 120 PLBs per shoot tip within 50 days of culture. Stereomicroscopic observation meticulously revealed the sequential changes from initiation to maturation of PLB gradually forming shoot apical meristem, shoot primordia and leaf primordia. Mature PLBs showed significant shoot proliferation (98.4 %) in media containing 10 μM 6-furfurylaminopurine forming 17 shoots per PLB within 30 days. The inclusion of activated charcoal (AC) in media containing auxin had promotive effect on rooting whereby 5 μM indole-3-butyric acid plus 500 μM AC resulted in highest number and length of roots. Successfully acclimatized plants, subjected to random amplified polymorphic DNA assessment for genetic fidelity, did not show any variation. Thus, this complete study has successfully outlined a rapid, high frequency direct induction of PLB of Anthurium from shoot tips inclusive of shoot proliferation, rooting and acclimatization.

An innovative protocol on accelerated in vitro propagation and acclimatisation was developed in Aloe vera L. Culture was initiated with rhizomatous stem where Murashige and Skoog (MS) medium fortified with 0.5 mg L(-1) α-naphthalene acetic acid and 1.5 mg L(-1) N(6)-benzylaminopurine (BAP) promoted earliest shoot induction. Maximum shoot multiplication was achieved in MS medium supplemented with 2.5 mg L(-1)BAP. The best in vitro rooting was observed in the MS medium with 0.5 mg L(-1) indole-3-acetic acid plus 2 g L(-1) activated charcoal. The simple acclimatisation process, primarily with a combination of sand and soil (1 : 1 v/v) and finally with a blend of sand, soil and farm yard manure (2 : 1 : 1 v/v), ensured a 98% survival rate. Overall, 192 true-to-type plantlets were achieved from a single explant within 85 days. Morphologically, in vitro generated plants performed better than conventionally propagated plants; nevertheless the similarity in aloin content, gel content and superoxide dismutase activity was corroborated.

To induce variation through chromosome doubling in Gerbera jamesonii Bolus cv. Sciella, two-week-old in vitro grown shoots were treated with various concentrations of colchicine (0.01, 0.05, 0.10, 0.50 or 1% w/v) for 2, 4 or 8 h. Treated shoots were then cultured on Murashige and Skoog (MS) medium supplemented with 8.8 μM 6-benzyladenine (BA) and 155 μM adenine sulphate (ADS), and subsequently transferred to fresh MS medium containing 2.85 μM indole-3 acetic acid (IAA) for rooting. When shoots were treated with 0.1% colchicine for 8 h, 64% of recovered plantlets were tetraploid. Ploidy of plantlets was confirmed by flow cytometry, stomatal analysis, and morphological characters. Tetraploid plantlets displayed slower proliferation along with higher vigor and thickened broad leaves. Moreover, tetraploid plants developed larger flowers, longer stalks, and have improved vase-life, all contributing to higher ornamental value of gerbera.

A novel, efficient, and simple protocol was developed on in vitro mass propagation and acclimatization of Gerbera jamesonii Bolus cv. Sciella, an ornamental plant with attractive flowers. Shoot tip was used as the primary explant for in vitro establishment in which Murashige and Skoog (MS) medium supplemented with a low level of NAA (0.5 mg l−1) and BAP (1.5 mg l−1) promoted earliest axillary bud initiation within 5 d in 91.6% of the inoculants. Five axillary buds were initiated from a single explant within 13 d after inoculation. A very high rate of shoot multiplication (14 shoots per inoculated axillary bud) and proliferation was achieved when MS medium was fortified with a relatively higher level of BAP (2 mg l−1) and 60 mg l−1 ADS within 27 d of multiple shoot culture. A maximum number of well-developed roots per plant was observed in MS medium with 0.5 mg l−1 IAA in the next 26 d. In the easy low-cost acclimatization process of 20 d, a combination of sand, soil, cow urine, and tea leaves extract (1:1:1:1; v/v) ensured 95% survival rate. Sixty-one well-acclimatized plants were obtained from a single shoot tip within 86 d. The sustained multiple shoot culture for 15 mo paved the way toward the conservation of genetic resources as well as beneficial economics. The clonal fidelity study of micropropagated and sustained cultured clones using ISSR primers ensured the continuous supply of quality propagules retaining genetic uniformity. The in vitro-generated plants performed better over conventionally propagated plants in the field condition.

Identification and successful deployment of efficient molecular markers can minimize ambiguity in varietal identification and registration in mung bean (Vigna radiata). Eighty accessions of mung bean having diverse origin and nature were classified based on agro-morphological traits. Using fifteen representative accessions, ten PCR-based efficient primers, were identified with higher polymorphic information content (PIC) values and higher Marker Indexes (MI). Even the combination of only two primers was found sufficient to differentiate all fifteen genotypes. In addition, it was observed that one resistance gene analogue (RGA) primer, designed from soybean, could able to amplify 445bp fragment only in MYMV tolerant lines of mung bean. One mung bean genotype (B1) was differentiated from wild and cultivated accessions belonging to twelve other indigenous Vigna species and subspecies by employing one each of microsatellite, ISSR and RAPD primers. One decamer (5′ GTC GCC GTC A 3′) could successfully identify an inter-sub-specific hybrid as well. The highly informative primers identified in this study, could be utilized in generating useful molecular descriptors for fingerprinting mung bean genotypes from Indian Subcontinent.

Phosphate availability is a major factor limiting tillering, grain filling vis-a-vis productivity of rice. Rice is often cultivated in soil like red and lateritic or acid, with low soluble phosphate content. To identify the best genotype suitable for these types of soils, P acquisition efficiency was estimated from 108 genotypes. Gobindabhog, Tulaipanji, Radhunipagal and Raghusail accumulated almost equal amounts of phosphate even when they were grown on P-sufficient soil. Here, we have reported the presence as well as the expression of a previously characterized rice gene, phosphate starvation tolerance locus (PSTOL1) in a set of selected genotypes. Two of four genotypes did not show any detectable expression but carried the gene. One mega cultivar, Swarna did not possess this gene but showed high P-deficiency tolerance ability. Increase of root biomass, not length, in P-limiting situations might be considered as one of the selecting criteria at the seedling stage. Neither the presence of PSTOL1 gene nor its closely-linked SSR RM1261, showed any association with P-deficiency tolerance among the 108 genotypes. Not only this, but the presence of PSTOL1 in recombinant inbred line (RIL) developed from a cross between Gobindabhog and Satabdi, also did not show any linkage with P-deficiency tolerance ability. Thus, before considering PSTOL1 gene in MAB, its expression and role in P-deficiency tolerance in the donor parent must be ascertained.

Pointed gourd is an important tropical high value vegetable crop, which is mainly affected by fruit and vine rot disease in field conditions. Causal organism of this devastating disease is Phytophthora melonis as revealed through morphological criteria as well as by molecular tools based on the restriction fragment length polymorphism (RFLP) of non-coding Internal Transcriber Spacer (ITS) region and ITS sequencing. Sequencing of ITS region of our Ph. melonis isolate has 100% similarity with the five isolates of GenBank including a Ph. sinensis. The pathogen, Ph. melonis, is a new report from India and as regards host ranges a possible new report globally.

Various factors, including increase in traffic volume and weight, structural aging, and environmental impact, cause damage in structural members. This raises the importance of the maintenance, rehabilitation, and strengthening of reinforced concrete members. External post-tensioning is one of the widely-used strengthening techniques in many countries due to its advantages over other strengthening methods. Although flexural strengthening of existing structural members is a well-established method, shear strengthening of structural members, especially with existing shear cracks, has attained very little attention from researchers. Similarly, external fiber-reinforced polymer (FRP) bonding for shear strengthening of structural members, especially with existing shear cracks, is a relatively new area of research. This paper presents the results of an experimental study on the shear strengthening of reinforced concrete (RC) beams with existing shear cracks by external post-tensioning and external FRP bonding. The test result showed that the combined strengthening technique of external post-tensioning and external FRP bonding can effectively increase the shear capacity of RC beams with existing shear cracks.

The present study employed recombinant inbred lines (RILs) derived from the cross between a susceptible cultivar Sonali and resistant wild relative of mungbean (Vigna radiata var. sublobota to map molecular markers linked with mungbean yellow mosaic Indian virus (MYMIV) resistance and yield attributing traits in mungbean. Resistance to the virus was evaluated in RIL population under field conditions during two consecutive years 2013 and 2014. A set of 224 molecular markers were employed for the identification of polymorphism between parents. Only 46 markers showed polymorphism between Sonali and V. radiata var. sublobota. Twenty two polymorphic markers were used to construct a linkage map comprising 11 linkage groups. QTL analysis identified molecular markers linked with MYMIV resistance and agronomic traits viz., no. of pods per plant, no. of seeds per pod and 100seed weight. Molecular markers identified to be linked with MYMIV were confirmed in 93 diverse mungbean accessions screened for yellow mosaic disease. The molecular markers linked to the MYMIV and yield attributing traits identified in this study will be useful in marker assisted breeding for development of high yielding mungbean varieties resistant to MYMIV.

Improvement of rice with respect to resistance to biotic and abiotic stresses through introgression of alien genetic variation is an important breeding objective of wide hybridization. Anther culture of an interspecific hybrid between Oryza sativa L. cv. pankaj x O. rufipogon Griff. (both of them having "AA" genome) was done to obtain submergence tolerant high yielding recombinant type. Inoculation of anthers in five basal media viz. N6, modified N6, R3, He2 and He5 each one supplemented sith NAA (2 mg l-1), kinetin (0.5 mg l-1) and sucrose (5%) showed that the rate of callusing was highest (8.3%) in He2 medium. Calluses initiated in all the above five media when transferred to regeneration medium [MS medium containing NAA (0.5 mg l-1), kinetin (2 mg l-1) and sucrose (3%)], percentage of green plant regeneration was also high (13%) in calluses initiated in He2 medium. Androgenic doubled haploid plants, showed 1:1 segregation of the traits for most of the morphological characters studied whereas, different segregating ratios were found in F2 population. Wider range of variation for different agronomic characters were noted in androgenic population as compared to F2>. Of the 533 field grown doubled haploid plants, five plants were O. sativa type parental forms with fine grains and submergence tolerant (tested at ten days old seedling stage). Further screening has helped to select only one awnless, fine grain, submergence tolerant line tested at seedling stage and six weeks old plant age.

The implication of molecular biology in crop improvement is now more than three decades old. Not surprisingly, technology has moved on, and there are a number of new techniques that may or may not come under the genetically modified (GM) banner and, therefore, GM regulations. In cisgenic technology, cisgenes from crossable plants are used and it is a single procedure of gene introduction whereby the problem of linkage drag of other genes is overcome. The gene used in cisgenic approach is similar compared with classical breeding and cisgenic plant should be treated equally as classically bred plant and differently from transgenic plants. Therefore, it offers a sturdy reference to treat cisgenic plants similarly as classically bred plants, by exemption of cisgenesis from the current GMO legislations. This review covers the implications of cisgenesis towards the sustainable development in the genetic improvement of crops and considers the prospects for the technology.

The Naga King Chilli (Capsicum chinense Jacq) is one of the hottest chillies in the world. This chilli is native to the north eastern region of India and subsequently the geographical indication (GI) of goods tag for this chilli has been obtained by the Nagaland State Government. The chilli was recorded to be the hottest chilli in the world in 2006 with a Scoville heat unit (SHU) rating of 1,001,304. Currently it occupies the fifth position among the hottest chillies in the world. Due to its high potential commercial value, many studies has been carried out in this crop including scientific cultivation, in vitro regeneration, diversity and evolution studies and its diseases and their management etc. This review is an attempt to bring into account the various research work carried out so far in the crop including the traditional and ethno-medicinal uses.

Different explants of local chrysanthemum cultivars available in West Bengal including leaf, shoot tip and ray floret were employed to compare their efficiency for direct in vitro regeneration system. The explants were inoculated in Murashige and Skoog (MS) media supplemented with varied combinations of indole acetic acid (IAA), benzylaminopurine (BAP). The auxins indole -3-butyric acid (IBA) was used to induce rooting. Maximum multiple shoots production occurred at 1.0 mg/L BAP and 0.1 mg/L NAA for leaf explants, 2.0 mg/L BAP and 0.2 mg/L NAA combination for shoot tip explants and BAP (4.0 mg/L) + NAA (0.1 mg/l) for ray floret explants. Among the treatments, IBA 1.0 mg/L for both leaf and shoot tip regenerated plants and 0.5 mg/L for ray floret regenerates proved to be the best for promoting root regeneration as compared to the other treatments tried. Among the various carrier substrates tested for acclimatization, soil + sand + FYM (1:2:1) fortified with ½ strength MS plant salt mixture proved to be ideal substrate as maximum plant survived and a maximum of 82.3% survivability was obtained from shoot tip derived plantlets. Therefore, shoot tip explants are the most suitable type of explants for plant regeneration of chrysanthemum through direct somatic embryogenesis. However, direct plant regeneration through ray floret explants will also be useful to recover the flower colour mutants.

The leaves, tubers and other morpho-culinary characters of nine taro [Colocasia esculenta var. antiquirom (L) Schott.] cultivars were considered for development of distinct, uniform and stable (DUS) standards using digital morphometrics and computational methods besides taking help from prototypes of hand-held digital field guides and various robotic systems to bring them under IPR-related regimes. Out of 48 morphoculinary characters studied maximum were polymorphic in nature. Some cultivars possessed unique stable characters helpful for their identification. The study revealed that DUS descriptors using digital morphometrics can be used effectively for identification and grouping of taro germplasm.

Lathyrus sativus L. (Grasspea) is a protein rich pulse crop. Enough information about genetic diversity of Lathyrus germplasm is needed to improve this crop. Molecular characterization is one of the tools to identify the hidden genetic diversity. The present study was undertaken to reveal the genetic diversity in a set of 20 grasspea genotypes using RAPD (Randomly Amplified Polymorphic DNA) marker system. For the 15 primers, various efficiency parameters that include Polymorphism Information Content (PIC), Marker Index (MI), Resolving Power (RP) and Diversity Index (DI) were studied. Finally Principal coordinate analysis (PCoA) and dendrogram was perfomed to find out the genetic diversity among the germplasm. The screened RAPD markers will facilitate further studies in population genetics and utilization of this crop.