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Jorhāt, India

The transovarial transmission of Hyposidra infixaria nucleopolyhedroviruses (HyinNPV) in the tea looper caterpillar H. infixaria was investigated. H. infixaria larvae reared from eggs (surface sterilised) collected from a tea garden showed typical signs of nucleopolyhedrosis virus infection. The polyhedrin gene amplified from larvae confirmed HyinNPV infection and provided clear evidence of vertical virus transmission from parent to offspring (transovarial transmission). This study reveals important aspects of HyinNPV that could be exploited in biological control programmes; HyinNPV can persist in larval populations and be passed on to the next generation, and thus it may be useful for the long-term control of H. infixaria. © 2013 Taylor & Francis.

Karak T.,Pollution Control Board | Karak T.,Tea Research Association | Bhattacharyya P.,University of Wyoming
Resources, Conservation and Recycling | Year: 2011

Organically agricultural products are gaining popularities through out the world as it gives the consumer satisfaction with a basket of safer and better trusted foods. It is also well established that intensive conventional agricultural practices can introduce contaminants into the food chain with adverse affect on environment. However, organic agricultural practices give an alternative environmental friendly sustainable agriculture among the farmers. Beside this fact, organic crops contain fewer nitrates, nitrites, pesticide residues and trace elements than conventional crops. Even though, in organic systems generally have 20% lower yields than conventionally produced crops. One of the major constrains of organic farming is decrease of raw organic matters to prepare compost. Therefore, scientists are looking forward for different organic sources which are plenty in nature and available at little-to-no cost. Human urine is one of them, and has been gaining popularities as a raw material for organic cultivation. However, several important merits and demerits of application of human urine are needed to be addressed in agriculture. © 2010 Elsevier B.V.

Das A.,North Bengal Agricultural University | Das A.,ICAR Research Complex for NEH Region | Das S.,Tea Research Association | Mondal T.K.,North Bengal Agricultural University | Mondal T.K.,National Research Center on Fingerprinting
Plant Molecular Biology Reporter | Year: 2012

Drought is an important abiotic stress that limits the production of tea in different regions of the world. Young roots of tea are responsible for nutrient and water uptake; hence, they are the first tissues to perceive drought stress. In this study, a forward suppression subtractive hybridization library was constructed from the tender roots of drought-tolerant tea (Camellia sinensis (L.) O. Kuntze) cultivar (TV-23) subjected to 21 days of drought stress. A total of 572 quality expressed sequence tags were generated by sequencing of 1,052 random clones which have resulted to 246 unigenes comprising 54 contigs and 192 singlets. The unigenes were assigned to various functional categories, i. e. cellular components, biological processes and molecular functions as defined for the Arabidopsis proteome. There were 13. 04% of differentially regulated genes that have been associated to various stresses. A total of 123 putative drought-responsive genes were identified which include candidate genes of ubiquitin-proteasome, glutathione metabolism and sugar metabolism pathways and several transcription factors. In order to determine the possible expression, 10 genes associated to drought-responsive pathways were further analysed by reverse transcription polymerase chain reaction. This study provides a basis for studying the drought tolerance mechanism of this important commercial crop which will also be a valuable resource for the functional genomics study of woody plants in future. © 2012 Springer-Verlag.

Dutta R.,University of Twente | Stein A.,University of Twente | Bhagat R.M.,Tea Research Association
Food Chemistry | Year: 2011

This study quantifies the effects of green leaf and black tea parameters that influence tea quality in Northeast India. It was motivated by a decline in tea quality that is of concern to tea growers. The rationale of the study is to identify the different parameters that have a significant influence on liquor brightness and other variables measuring tea quality. Here, we investigate several methods for estimating tea quality based on tea quality data, near infrared spectroscopy and remotely sensed data (NDVI). Attention focused on two high yielding clones (TV1 and S3A3). NDVI was obtained from ASTER images. Statistical analysis shows that liquor brightness is affected by the levels of caffeine content, theaflavins and catechins. Relationships exist between quality parameters and remote sensing in particular for the S3A3 clone. NDVI has a positive relation with caffeine, theogallin, EC, and ECG. NIR is negatively related to caffeine, theogallin, and catechins. We conclude that NDVI and Near Infrared (NIR) spectroscopy have a large potential to be used for monitoring tea quality in the future. © 2011 Elsevier Ltd. All rights reserved.

Karak T.,Pollution Control Board | Karak T.,Tea Research Association | Abollino O.,University of Turin | Bhattacharyya P.,University of California at Riverside | And 2 more authors.
Chemosphere | Year: 2011

The distribution pattern and fractionation of arsenic (As) in three soil profiles from tea (Camellia sinensis L.) gardens located in Karbi-Anglong (KA), Cachar (CA) and Karimganj (KG) districts in the state of Assam, India, were investigated depth-wise (0-10, 10-30, 30-60 and 60-100. cm). DTPA-extractable As was primarily restricted to surface horizons. Arsenic speciation study showed the presence of higher As(V) concentrations in the upper horizon and its gradual decrease with the increase in soil depths, following a decrease of Eh. As fractionation by sequential extraction in all the soil profiles showed that arsenic concentrations in the three most labile fractions (i.e., water-soluble, exchangeable and carbonate-bound fractions) were generally low. Most arsenic in soils was nominally associated with the organic and Fe-Mn oxide fractions, being extractable in oxidizing or reducing conditions. DTPA-extractable As (assumed to represent plant-available As) was found to be strongly correlated to the labile pool of As (i.e. the sum of the first three fractions). The statistical comparison of means (two-sample t-test) showed the presence of significant differences between the concentrations of As(III) and As(V) for different soil locations, depths and fractions. The risk assessment code (RAC) was found to be below the pollution level for all soils. The measurement of arsenic uptake by different parts of tea plants corroborated the hypothesis that roots act as a buffer and hold back contamination from the aerial parts. © 2011 Elsevier Ltd.

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