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Search Results: 1 - 10 of 224202 matches for " R. Varma Penmetsa "
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Genetic Patterns of Domestication in Pigeonpea (Cajanus cajan (L.) Millsp.) and Wild Cajanus Relatives
Mulualem T. Kassa, R. Varma Penmetsa, Noelia Carrasquilla-Garcia, Birinchi K. Sarma, Subhojit Datta, Hari D. Upadhyaya, Rajeev K. Varshney, Eric J. B. von Wettberg, Douglas R. Cook
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039563
Abstract: Pigeonpea (Cajanus cajan) is an annual or short-lived perennial food legume of acute regional importance, providing significant protein to the human diet in less developed regions of Asia and Africa. Due to its narrow genetic base, pigeonpea improvement is increasingly reliant on introgression of valuable traits from wild forms, a practice that would benefit from knowledge of its domestication history and relationships to wild species. Here we use 752 single nucleotide polymorphisms (SNPs) derived from 670 low copy orthologous genes to clarify the evolutionary history of pigeonpea (79 accessions) and its wild relatives (31 accessions). We identified three well-supported lineages that are geographically clustered and congruent with previous nuclear and plastid sequence-based phylogenies. Among all species analyzed Cajanus cajanifolius is the most probable progenitor of cultivated pigeonpea. Multiple lines of evidence suggest recent gene flow between cultivated and non-cultivated forms, as well as historical gene flow between diverged but sympatric species. Evidence supports that primary domestication occurred in India, with a second and more recent nested population bottleneck focused in tropical regions that is the likely consequence of pigeonpea breeding. We find abundant allelic variation and genetic diversity among the wild relatives, with the exception of wild species from Australia for which we report a third bottleneck unrelated to domestication within India. Domesticated C. cajan possess 75% less allelic diversity than the progenitor clade of wild Indian species, indicating a severe “domestication bottleneck” during pigeonpea domestication.
Development and characterization of BAC-end sequence derived SSRs, and their incorporation into a new higher density genetic map for cultivated peanut (Arachis hypogaea L.)
Hui Wang, R Varma Penmetsa, Mei Yuan, Limin Gong, Yongli Zhao, Baozhu Guo, Andrew D Farmer, Benjamin D Rosen, Jinliang Gao, Sachiko Isobe, David J Bertioli, Rajeev K Varshney, Douglas R Cook, Guohao He
BMC Plant Biology , 2012, DOI: 10.1186/1471-2229-12-10
Abstract: Here, we report a large set of BAC-end sequences (BES), use them for developing SSR (BES-SSR) markers, and apply them in genetic linkage mapping. The majority of BESs had no detectable homology to known genes (49.5%) followed by sequences with similarity to known genes (44.3%), and miscellaneous sequences (6.2%) such as transposable element, retroelement, and organelle sequences. A total of 1,424 SSRs were identified from 36,435 BESs. Among these identified SSRs, dinucleotide (47.4%) and trinucleotide (37.1%) SSRs were predominant. The new set of 1,152 SSRs as well as about 4,000 published or unpublished SSRs were screened against two parents of a mapping population, generating 385 polymorphic loci. A genetic linkage map was constructed, consisting of 318 loci onto 21 linkage groups and covering a total of 1,674.4 cM, with an average distance of 5.3 cM between adjacent loci. Two markers related to resistance gene homologs (RGH) were mapped to two different groups, thus anchoring 1 RGH-BAC contig and 1 singleton.The SSRs mined from BESs will be of use in further molecular analysis of the peanut genome, providing a novel set of markers, genetically anchoring BAC clones, and incorporating gene sequences into a linkage map. This will aid in the identification of markers linked to genes of interest and map-based cloning.Cultivated peanut (Arachis hypogaea L.) originated in South America, and is grown in tropical and sub-tropical regions across 100 countries on six continents between 40°N and 40°S [1]. Seed dry matter is an important source of digestible protein (25 to 34%), cooking oil (44 to 56%) and vitamins such as thiamine, riboflavin, and niacin, which are particularly important for human nutrition in many developing countries [2]. As a legume, peanuts improve soil fertility by fixing nitrogen, providing up to 60 kg/ha nitrogen to the soil, thus benefiting crops subsequently planted in the same field [3].Cultivated peanut is a tetraploid (2n = 4 × = 40), self-pollin
Novel SSR Markers from BAC-End Sequences, DArT Arrays and a Comprehensive Genetic Map with 1,291 Marker Loci for Chickpea (Cicer arietinum L.)
Mahendar Thudi, Abhishek Bohra, Spurthi N. Nayak, Nicy Varghese, Trushar M. Shah, R. Varma Penmetsa, Nepolean Thirunavukkarasu, Srivani Gudipati, Pooran M. Gaur, Pawan L. Kulwal, Hari D. Upadhyaya, Polavarapu B. KaviKishor, Peter Winter, Günter Kahl, Christopher D. Town, Andrzej Kilian, Douglas R. Cook, Rajeev K. Varshney
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027275
Abstract: Chickpea (Cicer arietinum L.) is the third most important cool season food legume, cultivated in arid and semi-arid regions of the world. The goal of this study was to develop novel molecular markers such as microsatellite or simple sequence repeat (SSR) markers from bacterial artificial chromosome (BAC)-end sequences (BESs) and diversity arrays technology (DArT) markers, and to construct a high-density genetic map based on recombinant inbred line (RIL) population ICC 4958 (C. arietinum)×PI 489777 (C. reticulatum). A BAC-library comprising 55,680 clones was constructed and 46,270 BESs were generated. Mining of these BESs provided 6,845 SSRs, and primer pairs were designed for 1,344 SSRs. In parallel, DArT arrays with ca. 15,000 clones were developed, and 5,397 clones were found polymorphic among 94 genotypes tested. Screening of newly developed BES-SSR markers and DArT arrays on the parental genotypes of the RIL mapping population showed polymorphism with 253 BES-SSR markers and 675 DArT markers. Segregation data obtained for these polymorphic markers and 494 markers data compiled from published reports or collaborators were used for constructing the genetic map. As a result, a comprehensive genetic map comprising 1,291 markers on eight linkage groups (LGs) spanning a total of 845.56 cM distance was developed (http://cmap.icrisat.ac.in/cmap/sm/cp/thu?di/). The number of markers per linkage group ranged from 68 (LG 8) to 218 (LG 3) with an average inter-marker distance of 0.65 cM. While the developed resource of molecular markers will be useful for genetic diversity, genetic mapping and molecular breeding applications, the comprehensive genetic map with integrated BES-SSR markers will facilitate its anchoring to the physical map (under construction) to accelerate map-based cloning of genes in chickpea and comparative genome evolution studies in legumes.
Analysis of BAC-end sequences (BESs) and development of BES-SSR markers for genetic mapping and hybrid purity assessment in pigeonpea (Cajanus spp.)
Abhishek Bohra, Anuja Dubey, Rachit K Saxena, R Varma Penmetsa, KN Poornima, Naresh Kumar, Andrew D Farmer, Gudipati Srivani, Hari D Upadhyaya, Ragini Gothalwal, S Ramesh, Dhiraj Singh, Kulbhushan Saxena, PB Kavi Kishor, Nagendra K Singh, Christopher D Town, Gregory D May, Douglas R Cook, Rajeev K Varshney
BMC Plant Biology , 2011, DOI: 10.1186/1471-2229-11-56
Abstract: A set of 88,860 BAC (bacterial artificial chromosome)-end sequences (BESs) were generated after constructing two BAC libraries by using HindIII (34,560 clones) and BamHI (34,560 clones) restriction enzymes. Clustering based on sequence identity of BESs yielded a set of >52K non-redundant sequences, comprising 35 Mbp or >4% of the pigeonpea genome. These sequences were analyzed to develop annotation lists and subdivide the BESs into genome fractions (e.g., genes, retroelements, transpons and non-annotated sequences). Parallel analysis of BESs for microsatellites or simple sequence repeats (SSRs) identified 18,149 SSRs, from which a set of 6,212 SSRs were selected for further analysis. A total of 3,072 novel SSR primer pairs were synthesized and tested for length polymorphism on a set of 22 parental genotypes of 13 mapping populations segregating for traits of interest. In total, we identified 842 polymorphic SSR markers that will have utility in pigeonpea improvement. Based on these markers, the first SSR-based genetic map comprising of 239 loci was developed for this previously uncharacterized genome. Utility of developed SSR markers was also demonstrated by identifying a set of 42 markers each for two hybrids (ICPH 2671 and ICPH 2438) for genetic purity assessment in commercial hybrid breeding programme.In summary, while BAC libraries and BESs should be useful for genomics studies, BES-SSR markers, and the genetic map should be very useful for linking the genetic map with a future physical map as well as for molecular breeding in pigeonpea.Pigeonpea [Cajanus cajan (L.) Millsp.], also known as tuar or arhar, is an economically important legume crop with an annual production of 3.65 Mt. Cultivation of pigeonpea occurs on ~5 million hectares, primarily in Asia and countries of eastern and southern Africa, and to a lesser extent in countries of Latin America and the Caribbean. As a member of the sub tribe Cajaninae, pigeonpea is contained in an early diverging lineage
Ocular toxicity of Ethambutol (A clinical study)
Narang R,Varma BMD
Indian Journal of Ophthalmology , 1979,
Abstract:
Strongly Interacting W's and Z's and the Existence of a Heavy Fourth Generation of Fermions
Silas R. Beane,Samir Varma
Physics , 1993, DOI: 10.1016/0370-2693(93)91207-4
Abstract: By employing the dictum that axiomatic principles are devoid of predictive power, we find that the elastic unitarity constraint, applied to strong W$_L$W$_L$ scattering, does not alter the assumed spectrum of intermediate states. We consider intermediate states involving a heavy Higgs and heavy fermions of a hypothetical fourth generation doublet. In contrast to recent studies, we find no p-wave resonance, and therefore no violation of the S parameter upper bound. We conclude that the elastic unitarity constraint sheds no light on the existence of a heavy fourth generation.
Big Data Usage Intention of Management Accountants: Blending the Utility Theory with the Theory of Planned Behavior in an Emerging Market Context  [PDF]
Ashish Varma
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.813176
Abstract: This work blends the utility theory with the theory of planned behavior to investigate the management accountant’s (MA) intention in using big data. The study was conducted in early 2017 using a partial least squares-structural equation modeling technique with a sample of 203 MAs in 11 Indian cities. The research identified attitude as the most significant antecedent of intent to use big data followed by the subjective norms. These findings have significant managerial relevance for the firms in sensitizing their accounting teams on the benefits of using big data to achieve more voluntary buy in from the MAs. The investigation also contributes to the methods by illustrating the application of two advanced techniques, multi group analysis (MGA) and importance-performance map analysis (IPMA) in validating the theory of planned behavior in an emerging market context.
Mobile Banking Choices of Entrepreneurs: A Unified Theory of Acceptance and Use of Technology (UTAUT) Perspective  [PDF]
Ashish Varma
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.814183
Abstract: This study applies the unified theory of acceptance and use of technology (UTAUT) to investigate the entrepreneurial usage of mobile banking services. The study was conducted during 2017-18 using a partial least squares-structural equation modeling technique. A sample of 206 entrepreneurs, from fourteen sub-urban towns in India, was studied. The study found that mobile banking intentions mediates the relationship between all three; effort expectancy and use behavior, performance expectancy and use behavior and social influence and use behavior. There was no gender-based difference between the banking behavior among the entrepreneurs. The study also validates the UTAUT theory in an emerging market context. These findings are significant as the entrepreneurial choices regarding mobile banking in emerging markets demands more research. Mobile phones have a deep penetration in the emerging markets and so its role in facilitating the banking needs of the entrepreneurs should be ascertained. The study also contributes to the methods by illustrating the use of importance performance map analysis (IPMA) in the UTAUT context.
Qualitative Evidence for a Behavioral Extension of the Expectancy Valence Theory: The Netflix-Twitter-Yakult Case  [PDF]
Ashish Varma
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.815212
Abstract: The Netflix movie “To all the boys I’ve loved before” released in the USA on 17th Aug 2018 was linked to a substantial increase in sales of the probiotic drink Yakult. This study probes the phenomenon with an analysis of tweets for the first three weeks after the release of the movie and also assesses reasons for the phenomenon with the theoretical underpinning of the Expectancy Valence (EV) theory. The first section of the study was conducted by undertaking a probe on 1922 tweets made during 17th Aug 2018 (the release date of the movie in the USA) till 6th September 2018. The second part of the study was conducted by taking intensive in-depth interviews of the target segment after 6th September 2018. The study highlights the growing significance of social media in shaping the sentiments by influencing perception and opinion (valence), which eventually influences the sales of products (expectation). The study found out that the sharp increase in sales was due to positive behavioral sentiment created by the social media.
Do Culturally Intelligent Management Accountants Share More Knowledge?—The Mediating Role of Coopetition as Evident from PLS SEM and fsQCA  [PDF]
Ashish Varma
Theoretical Economics Letters (TEL) , 2019, DOI: 10.4236/tel.2019.91009
Abstract:
This work investigates whether management accountants (MA) who have experience of working in multicultural environments are more open to share their knowledge, learning and insights with others or not. The study was conducted in early 2018 by using a Partial Least Squares-Structural Equation Modeling (PLS-SEM) technique with a sample of 107 MAs working in India in 7 different cities and in different multinational organizations. The research identified that coopetition mediated the relationship between cultural intelligence (CQ) and the intention to share knowledge (ISK) as evidenced by both PLS-SEM and fsQCA methods. This finding is significant for both theory and practice as coopetition involves both collaboration and completion amongst the MAs. The Multi Group Analysis (MGA) revealed no significant gender related differences amongst the practicing management accountants. The study also contributes to the methods by illustrating the modelling of the second order construct “cultural intelligence”, formatively. Thus, this study illustrates the use of second order reflective-formative constructs in management accounting literature, for exploring the theory. This architecture can be of significant use for future researchers.
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