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Rani P.,Indian Agricultural Research Institute | Pant R.P.,National Research Center for Orchids | Jain R.K.,Indian Agricultural Research Institute
Journal of Phytopathology

Cymbidium mosaic and Odontoglossum ringspot viruses infecting orchids were identified by coat protein (CP) properties. The Cymbidium mosaic virus (Cym-MV) CP gene is 672 nt long, potentially encoding 223 amino acids (aa). The Odontoglossum ringspot virus (ORSV) CP gene is 477 nt long, potentially encoding 158 aa. The CP gene of CymMV and ORSV isolates originating from different locations was highly conserved both at the nucleotide and amino acid levels (94-100%). Polyclonal antibodies against CymMV and ORSV were separately produced using bacterially expressed recombinant CP as immunogens. Antisera to CymMV (titre 1: 2000) and ORSV (titre 1: 250) detected the viruses by direct antigen-coated enzymelinked immunosorbent assay (DAC-ELISA) in orchid samples collected from Sikkim, India. Survey results indicated the prevalence of mixed infection of CymMV and ORSV in Cymbidium spp. The immunoreagents we developed will be useful for virus indexing in orchid certification programmes. © 2010 Blackwell Verlag GmbH. Source

Mohanty P.,National Research Center for Orchids | Das J.,Institute of Bioresources and Sustainable Development IBSD
Plant Growth Regulation

Artificial seeds were obtained through encapsulation of protocorm-like bodies (PLBs) of Dendrobium densiflorum in calcium alginate beads. This paper demonstrates the alginate-encapsulation and conversion (complete plantlet regeneration) from PLBs, the effect of storage conditions (at different temperature; 4, 8, 16 °C, RT and duration; 15, 30, 45, 60, 75, 90 days) on viability of encapsulated plant materials as well as the assessment of genetic fidelity of the regenerants. Individual PLBs were encapsulated in calcium alginate beads for mass propagation, short-term storage and germplasm sharing. The superior gel matrix for encapsulation was obtained using 3 % sodium alginate and 100 mM calcium chloride (CaCl2·2H2O). The highest percentage of conversion (100 %) of encapsulated PLBs (capsules) was obtained on MS2 medium (MS medium + 2 mg/l BAP). Capsules were successfully stored till 60 days at 8 °C with conversion frequency of 95.5 %. Plantlets regenerated from encapsulated beads were acclimatized successfully with 95 % survival rate. A total of 40 primers were screened, out of which 10 primers successfully generated 39 scorable bands, ranging from 0.2 to 1.3 kb amplicons. The uniform RAPD banding profile among the plantlets derived from encapsulated PLBs following 60 days of storage confirmed genetic fidelity. © 2013 Springer Science+Business Media Dordrecht. Source

Sailo N.,Indian Agricultural Research Institute | Sailo N.,National Research Center for Orchids | Verma R.,Indian Agricultural Research Institute | Pandey R.,Indian Agricultural Research Institute | Jain V.,Indian Agricultural Research Institute
Indian Journal of Plant Physiology

Two wheat genotypes differing in ploidy level viz. PBW 343 (hexaploid) and PDW 274 (tetraploid), and rye genotype WSP 540-2 (diploid) were grown under elevated CO2 (EC: 550 ± 50 ppm) and ambient CO2 (AC: 380 ppm) to study the changes in nitrogen assimilatory pathway enzymes. Elevated CO2 increased nitrate reductase (NR) activity in flag leaves of the three genotypes at milk stage, and activity was highest in rye (diploid). At dough stage, hexaploid and tetraploid genotypes showed higher NR activity in plants grown under EC. Elevated CO2 resulted in higher expression of NR gene (NIA1). Activity of glutamine synthetase (GS) in flag leaves was higher in all the three genotypes under EC at milk stage but the activity declined at dough stage. The expression of GS1 increased in flag leaves of plants grown under EC at both milk and dough stages, while the expression of GS2 declined during the reproductive stages, especially in ears of EC grown plants. Nitrate content decreased in leaf tissues of all the three genotypes by 90 DAS in EC grown plants. This indicated enhanced nitrate assimilation in leaves by NR under EC at reproductive stage. However, lower GS2 expression and lower GS activity during late reproductive phase (dough stage) indicated inhibition of consequent steps. © 2013 Indian Society for Plant Physiology. Source

Naik S.K.,National Research Center for Orchids
Communications in Soil Science and Plant Analysis

Field experiments were conducted on rice (cv 'IET 4094') in an Aeric endoaquept (pH 7.2) to evaluate the various zinc (Zn) extractants in lowland rice soil under the influence of Zn sulfate and chelated Zn. The diethylenetriaminepentaacetic acid (DTPA), 0.1 N hydrochloric acid (HCl), and 0.05 N HCl-extractable Zn concentrations in soil increased initially up to the Z29 stage of crop growth when Zn was applied as a single basal source, being greater with Zn ethylenediaminetetraacetic acid (Zn-EDTA) compared to zinc sulfate (ZnSO4) application. Among the various extractants, the performance of 0.1 N HCl in extracting Zn was better than the other two extractants and followed the trend 0.1 N HCl > 0.005 M DTPA > 0.05 N HCl. The greatest increase in grain and straw yield of rice was 37.8 and 20.4%, respectively, over the control in the treatment T7 (1 kg Zn ha-1 as Zn-EDTA at basal). © Taylor & Francis Group, LLC. Source

Meena N.K.,National Research Center for Orchids | Medhi R.P.,National Research Center for Orchids

Field experiments were conducted to test the efficacy of five insecticides and three botanical products against two spotted spider mite, Tetranychus urticae on Cymbidium 'HC Aurora' during 2008-09 and 2009-10. Study revealed that all the treatments were noticed significantly superior over control in reducing the mite population. The highest per cent mortality in mite population (98.67and 99.00%) was recorded in Bifenthrin (Talstar) 10 EC followed by Propargite 57 EC reduced 97.20 and 98.72 per cent mite population in 2008 and 2009, respectively at seven days after treatment. Dicofol 18.5 EC, Imidacloprid 17.8 SL and Ethion 50 EC were proved as moderately effective treatments, whereas, tobacco extract 5% was being least effective in curtailing mite population 79.10 and 79.82 per cent next to Achook 1500 ppm (84.33 and 86.23%) and Neem oil 0.03 EC (85.56 and 87.18%). Source

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