Tea Research Association

Jorhāt, India

Tea Research Association

Jorhāt, India
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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.

Singh A.,Indian Institute of Remote Sensing | Dutta R.,University of Twente | Stein A.,University of Twente | Bhagat R.M.,Tea Research Association
International Journal of Remote Sensing | Year: 2012

This study analysed the monitoring of tea replantation using Linear Imaging Self-Scanning Sensor (LISS-III) and Cartosat-1 images and identified patterns based on wavelet approaches. Monitoring identifies four phases of replantation and rejuvenation, starting at the time of uprooting and finishing when new plants are planted. The study was conducted within the Dooars region of North East India. The perpendicular vegetation index and perpendicular soil index were derived to measure changes from bare soil reflectances caused by vegetation, whereas the soil index was designed to enhance brightness. Being a multi-resolution study, wavelets such as Haar, Daubechies and Symlet were compared at different levels of decomposition, and information was extracted at different scales. Using topographic and hydrological parameters, informative patterns for each stage of replantation were selected at individual sections within the estate on the basis of spatial correlation. The study showed that levels 3 and 4 gave superior information compared with the other levels. Anisotropic autocorrelation gave constant spatial variation at different scales and in different directions. The selected patterns were weakly correlated with slope, flow accumulation and the compound topographic index, whereas management activities and a small variation in elevation proved less efficient in explaining the extracted patterns. It also showed that hydrological processes could be evaluated using cross-correlations. From the study, it was observed that the asymmetric Daubechies-4 wavelet gave the best results for extraction of fine features, whereas the symmetric Symlet-8 wavelet best represented the extraction of smooth features. Although a strong quantitative linear relationship between the extracted patterns and topographic parameters could not be established, we conclude that wavelets are useful to extract patterns and interpret spatial variations observed at different phases of tea replantation. © 2012 Copyright Taylor and Francis Group, LLC.

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.

Vasanthakumar D.,Tea Research Institute | Babu A.,Tea Research Association
Experimental and Applied Acarology | Year: 2013

Green lacewing, Mallada desjardinsi Navas, is an important predator of red spider mite, Oligonychus coffeae infesting tea. Life history, life table and efficacy of M. desjardinsi were determined using red spider mite as prey under laboratory conditions. Duration of development of M. desjardinsi recorded was 5.1, 13.8 and 13 days for eggs, larvae and pupae respectively, with an average of 31.9 days from egg to adult emergence. After a mean pre oviposition period of 7.1 days, a single female laid an average of 252.6 eggs in its life time. Adult longevity of the male was recorded as 39.6 days while the females lived longer (58.2 days). The life table of M. desjardinsi was characterized by an intrinsic rate of increase (r) of 0.096 day, net reproductive rate (R 0) of 153.19 eggs/female, gross reproduction rate (∑mx) of 167.28 eggs/female, generation time (T) of 52.47 days, doubling time of 7.22 days and finite rate of increase(λ) of 1.1 day. The optimum predator-prey ratios were 1:50 and 1:33 under laboratory conditions however, 1:33 and 1:25 ratios were effective in green house conditions. The results of the study can be considered as a first step towards the utilization of this predator in an IPM program for the management of red spider mite infesting tea. © 2013 Springer Science+Business Media Dordrecht.

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 | 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.

Antony B.,Tea Research Association | Sinu P.A.,North Bengal Regional R and nter | Das S.,Tea Research Association
Journal of Invertebrate Pathology | Year: 2011

Tea production in North-East India hit a record loss due to the widespread severe outbreak of a mixed brood of three species of looper caterpillar pests of geometrid moths (Lepidoptera) in 2008-2010. In addition to Buzura suppressaria, two newly recorded geometrids, viz., Hyposidra infixaria and Hyposidra talaca have caused widespread severe damage in recent years. In the present study we report the nucleopolyhedroviruses (NPV) isolated from the tea looper caterpillar from North-East India. We identified and characterized the NPV by cloning and sequencing a partial segment of polyhedrin gene of virus infected larvae of B. suppressaria, H. talaca and H. infixaria. A comparison of deduced amino acids of polyhedrin gene among H. talaca, H. infixaria and B. suppressaria showed that same strain was found to infect all the three looper. s in India, which show high sequence identity with B. suppressaria Chinese isolates. Based on the polyhedrin sequence homology, it is predicted that a variant of B. suppressaria Chinese isolate of NPV found to infect H. talaca, H. infixaria and B. suppressaria in India. © 2011 Elsevier Inc.

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.,Tea Research Association | Bhagat R.M.,Tea Research Association
Food Research International | Year: 2010

Tea (Camellia sinensis L) is one of the most widely popular nonalcoholic beverage, consumed by over two-thirds of the world's population due to its medicinal, refreshing and mild stimulant effects. Mainly four types of made tea viz., black or red, oolong, green and white are used for tea infusion (water extract from fermented tea leaf) worldwide. Tea plays a major role in terms of the intake of a number of nutritional trace elements in humans. Besides essential macro- and microelements, experimental studies have demonstrated that the accumulation of significant amount of excess nonessential trace elements in tea leaves may eventually increase the metal body burden in humans. Different literatures have indicated that among different trace elements, levels of aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), fluoride (F) manganese (Mn), and nickel (Ni) in different tea infusions were 0.06-16.82mgL-1, trace-1.53μgL-1, trace-0.79μgL-1, below detectable limit-43.2μgL-1, 0.02-40.0mg L-1, 0.2-4.54mgL-1, 0.1-250mgL-1 and BDL-0.16mgL-1, respectively. It has also been reported that in some of the tea infusions, toxic metals exceed the maximum permissible limits stipulated for different countries. In the present review, an attempt has been made to update and evaluate the knowledge of the presence of some selected trace elements in tea leaves, made tea and tea infusion, based on the available literature. Existing reports suggested that the presence of trace elements in green tea is lower than the black tea in most cases. However, the available literatures still appear to have some limits and may need more detailed investigations before reaching the conclusions. © 2010 Elsevier Ltd.

Karak T.,Tea Research Association | Bhagat R.M.,Tea Research Association | Bhattacharyya P.,University of Wyoming
Critical Reviews in Environmental Science and Technology | Year: 2012

Municipal solid waste (MSW) is the abridgment of the waste generated from domestic, commercial, and construction activities by natural persons that is collected and treated by municipalities. Exponential growth of population and urbanization, and the development of social economy, coupled with the improvement of living standard, have resulted in an increase in the amount of MSW generation throughout the world. On average the developed countries typically generate 521.95-759.2 kg per person per year (kpc) and 109.5-525.6 kpc typically by developing countries. Recent estimates suggest that the MSW generation globally exceeds 2 billion tons per year, which is a potential threat to environmental dilapidation. Therefore, MSW management (MSWM) seems to be one of the key topics for environmental protection in present days and also in the future. The authors have illustrated MSW generation and composition analysis and have provided a comprehensive review of MSWM in different countries throughout the world based on the available literatures. Some of the important aspects of waste management, such as composting, landfilling, and incineration, are illustrated. Copyright © Taylor & Francis Group, LLC.

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