1,721,902 research outputs found
Genomics-Assisted Crop Improvement: an overview
No full textIn recent years, a truly impressive number of advances in genetics and genomics have greatly enhanced our understanding of structural and functional aspects of plant genomes but at the same time have challenged us with many compelling avenues of investigation. The complete genome sequences of Arabidopsis, rice, sorghum and poplar as well as an enormous number of plant expressed sequence tags (ESTs) have become available. In the next few years, the entire genomes or at least gene space will likely be sequenced for most major crops. However, improved varieties, not sequences per se, contribute to improved economic return to the farmer. Functional genomics and systems biology research are facilitating the identification of gene networks that are involved in controlling genetic variation for agronomically valuable traits in elite breeding populations. Furthermore, combining the new knowledge from genomic research with conventional breeding methods is essential for enhancing response to selection, hence crop improvement. Superior varieties can result from the discovery of novel genetic variation, improved selection techniques, and/or the identification of genotypes with improved attributes due to superior combinations of alleles at multiple loci assembled through marker-assisted selection. Although it is clear that genomics research has great potential to revolutionize the discipline of plant breeding, high costs invested in/associated with genomics research currently limit the implementation of genomics-assisted crop improvement, especially for inbreeding and/or minor crops. A critical assessment of the status and availability of genomic resources and genomics research in model and crop plants, and devising the strategies and approaches for effectively exploiting genomics research for crop improvement have been presented in two volumes of the book. While Volume 1, entitled “Genomics approaches and platforms”, compiles chapters providing readers with an overview of the available genomics tools, approaches and platforms, Volume 2, entitled “Genomics applications in crop improvement”, presents a timely and critical overview on applications of genomics in crop improvement. An overview on the highlights of the chapters of these two volumes has been presented in the present introductory chapter
Progress in understanding drought tolerance: From alleles to cropping systems
Full text linkImproving crop yields under rainfed environments is key to meeting the food security demands of an everincreasing population, but climate change-associated expansion of drought-affected arable land means that resilient crops and agronomic practices are critical. High-throughput plant phenomics and modern genetic approaches must be directed towards precise understanding of factors controlling crop yield. This special issue covers root dynamics, turgor management under desiccation, molecular responses to dehydration, impact of drought on plant development and seed abortion, and adjustment of traits to the most frequent patterns of drought. It also addresses interdisciplinary views for enhancing genetic gains and achieving a more sustainable climate-resilient agronomy
Improving crop performance under drought - cross-fertilization of disciplines
Full text linkBetter crop performance in dry environments is imperative for food security in the face of climate change. This has never been as true as in 2017, but the concern has existed for decades. The four InterDrought conferences held since 1995 have addressed issues associated with crop performance under drought with a clear multi-disciplinary approach. During this time Journal of Experimental Botany has been at the forefront in publishing the underlying experimental science encompassing the disciplines and scales of organization required in drought research. We hope that the papers highlighted here will be useful to, and instrumental for, broadening interdisciplinary understanding of drought tolerance
Loss and dispersion tailoring in 1D photonics band gap Bragg reflection waveguides: finite chirped claddings as a design tool
No full textWe exploit a simple and accurate matrix method to analyze the effects of introducing a linear chirp either in thickness or in refractive index of the cladding layers on the propagation characteristics (loss and dispersion) of 1D photonic band gap planar Bragg reflection waveguides (BRWs). We show that an appropriate chirp in the otherwise periodic claddings of finite extent BRWs could be gainfully exploited to tailor its leakage loss and waveguide dispersion features. In particular, we theoretically demonstrate that for some reported sample BRWs, leakage loss and waveguide dispersion could be significantly reduced by a factor of 30-50 and by about two orders of magnitude, respectively as compared to un-chirped BRWs. Furthermore, we also show that in contrast to un-chirped BRWs, how chirped BRWs could be designed with attractive feature like much less number of cladding layers and nearly wavelength independent losses. Our analysis and proposal should serve as a useful design tool to tailor the propagation characteristics of BRWs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Organization of retrotransposons and microsatellites in cereal genomes
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Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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