1,721,003 research outputs found
The MAGIC maize: a multiparental population for high-power and high-definition QTL mapping in Zea mays.
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Atmospheric drivers affect crop yields in Mozambique
Full text linkClimate change has been inducing variations in the statistics of both the large-scale weather patterns and the local weather in many regions of the world, and these variations have been affecting several human activities, including agriculture. In this study, we look at the links between large-scale weather patterns and local weather as well as agriculture, with a specific regional focus on Mozambique between 1981 and 2019. First, we investigated linear trends and links between large-scale weather patterns and local weather in the region using the ERA5 dataset. We used the same data to investigate how climate change has been affecting the statistics of large-scale weather patterns. Then, we derived Mozambique country-level cereal yield data from FAO and linked it up with climate and weather data to assess what is the relationship between large-scale patterns and local agronomic outputs using a multiple linear regression (MLR) model with crop yield as the response variable and climate drivers as predictors. The results indicate that in Mozambique, the crop season warmed substantially and consistently with climate change-induced global warming, and the rainy season had become drier and shorter, with precipitation concentrated in fewer, more intense events. These changes in the local weather have been linked to variations in the statistics of large-scale weather patterns that characterize the (large-scale) atmospheric flow over the region. Our results indicate a negative impact on yield associated with climate change, with average yield losses of 20% for rice and 8% for maize over the analyzed period (1981–2019). This negative impact suggests that, at the country scale, further future warming during the growing season may offset some of the cereal yield gains from technological advances
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
A tropical grass resource for pasture improvement and landscape management: Themeda triandra Forssk
No full textThemeda triandra Forssk. is one of the most widespread grasses in the dry to mesic prairie ecosystems of Africa, Asia and Australia. It is of particular interest due to its high value as a forage species for wildlife and livestock, and its potential use in landscaping practices. In this review we have collated information from the many studies that have been devoted to this species since the 1960s to provide information about the species' distribution, taxonomy, morphology, ploidy and reproduction, and to describe its vegetation and germination and their relationship with the most important ecological aspects of its preferred habitats. Agronomic aspects are considered in detail, with particular focus on the role of T. triandra as a forage species and the relative importance of grazing, fire and rainfall regimes for its management. We also explore how this species can help with the rehabilitation of degraded areas, soil and water conservation, countering exotic species invasion and landscaping in general. We conclude with a brief discussion of the as yet unresolved taxonomic relationship between the African species T. triandra and the Australian species Themeda australis
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
Different genomic regions define florets number and spike- related traits in T durum ssp.
Full text linkWheat grain yield is a complex trait that can be further dissected in different components such as the number of grains per spike, the gr size/weight and the number of spike per plant, and each of these factors is in turn composed by several sub-components. These traits have subjected to strong selection during the domestication history of Triticeae and are still the main target of modern breeding.
In this study we focused on yield in terms of grains per spike, considering the number of fertile spikelets per spike and fertile florets per spikelet as main traits.
With the aim of identifying genetic components of these traits, we deployed a segregant population, resulting from the cross of a durum wheat cultivar (Latino) and a cultivated emmer accession (MG5323) that show a variability in the number of grain per spike.
Before performing a classic QTL mapping approach, we dissected at stereomicroscope the developing spikes of the parental lines to determine the morphological traits responsible for a different number of grains per spike. The analysis revealed that a different number of floret meristem set during spike development, and a different developmental timing, is at the basis of the observed differences.
For the QTL mapping analysis, the RIL population was phenotyped for spike morphology and florets-related traits in four environments. A total of 94 QTLs were detected along all chromosomes, grouped in 17 regions, based on their physical position. Five QTL groups were identified for floret number and eight for spikelet number/spike morphology. The QTL regions identified for spikelet and floret number are distinct and non-overlapping suggesting that these traits are under different genetic control. Finally, physical interval of our QTL was defined, and candidate genes proposed. Known genes involved in inflorescence meristem development an spike morphology, such as FUL2, FUL3, PPD -1, VRN-A1, and Q-5A, colocalized in our QTL regions and were investigated by qRT-PCR in parental lines of the segregant population
Environmental genome-wide association studies across precipitation regimes reveal that the E3 ubiquitin ligase MBR1 regulates plant adaptation to rainy environments
No full text: In an era characterized by rapidly changing and less-predictable weather conditions fueled by the climate crisis, understanding the mechanisms underlying local adaptation in plants is of paramount importance for the conservation of species. As the frequency and intensity of extreme precipitation events increase, so are the flooding events resulting from soil water saturation. The subsequent onset of hypoxic stress is one of the leading causes of crop damage and yield loss. By combining genomics and remote sensing data, it is now possible to probe natural plant populations that have evolved in different rainfall regimes and look for molecular adaptation to hypoxia. Here, using an environmental genome-wide association study (eGWAS) of 934 non-redundant georeferenced Arabidopsis ecotypes, we have identified functional variants of the gene MED25 BINDING RING-H2 PROTEIN 1 (MBR1). This gene encodes a ubiquitin-protein ligase that regulates MEDIATOR25 (MED25), part of a multiprotein complex that interacts with transcription factors that act as key drivers of the hypoxic response in Arabidopsis, namely the RELATED TO AP2 proteins RAP2.2 and RAP2.12. Through experimental validation, we show that natural variants of MBR1 have different effects on the stability of MED25 and, in turn, on hypoxia tolerance. This study also highlights the pivotal role of the MBR1/MED25 module in establishing a comprehensive hypoxic response. Our findings show that molecular candidates for plant environmental adaptation can be effectively mined from large datasets. This thus supports the need for integration of forward and reverse genetics with robust molecular physiology validation of outcomes
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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