1,720,957 research outputs found
Editorial: Advances in breeding for wheat disease resistance
Full text linkWheat is the most widely planted crop on the planet and contributes up to 20% of total calorie intake for humankind. Maintaining wheat yields is crucial to feeding the world’s people, especially as climate models suggest that rising global temperatures will negatively affect wheat production (Asseng et al., 2015). Diseases of wheat take an important toll, annually robbing humanity of 20% or more of the crop on a global basis (Savary et al., 2019; Savary and Willocquet, 2021). Changes in weather patterns may accelerate pathogen life cycles and escalate shifts in pathogen populations and virulence, posing significant challenges to disease resistance breeding. As well, global trade may increase the chances for a pathogen to spread rapidly and adapt to novel environments and even hosts, leading to emerging diseases.
The release and use of wheat cultivars with effective and durable disease resistance is more important now than ever. This is so for multiple reasons. First, disease resistance stabilizes yields and reduces economic losses, saving money for producers who are already facing major challenges due to rising temperatures, more frequent and unpredictable natural disasters, and high and rising costs of inputs such as pesticides (FAO, 2021; Lüttringhaus et al., 2021; Miedaner and Juroszek, 2021). Second, greater reliance on disease resistance can slow pathogen spread and multiplication, prolonging the useful life of available pesticide chemistries so they will be effective when needed to manage severe epidemics (Brent et al., 2007). Third, the growing use of conservation tillage, which is vital for soil health and stabilization, has elevated the importance of diseases such as Fusarium head blight that cannot be completely managed with fungicides (Aboukhaddour et al., 2020).
Breeding for disease resistance in wheat has made major technological advances, but still faces important challenges. Prominent among those challenges is the need to develop cultivars for a tremendous diversity of agro-ecological environments, production practices, and discrete market classes (Cowger, 2021). Another challenge is that major genes such as those traditionally deployed to manage wheat rust diseases are often rapidly overcome. This requires a focus on quantitative and race non-specific resistance that may be harder to introgress, select for, and retain in a multi-trait context (Cowger and Brown, 2019; van Esse et al., 2020). The more genes are identified and their mechanisms of action elucidated, the more tools will be available to researchers and breeders to assemble genetically novel germplasm with improved and more durable resistance.
The authors who have contributed to this Research Topic tackle those challenges by providing new resources and tools to aid wheat breeders across the globe. The 18 original articles cover a good sample of the world’s most important wheat diseases and the state-of-the-art techniques applied by researchers to identify and evaluate the relevant disease resistance traits. For example, wheat blast is an emergent and damaging disease that has jumped continents from Latin America to Asia, as explained in a comprehensive review by Singh et al., 2021. A team of blast researchers has compared marker-assisted and genomic selection using precision phenotyping of blast resistance conferred by the 2NS translocation (Juliana et al., 2022), which is partial and sometimes background-dependent.
Another major threat to global wheat production is Fusarium head blight. Three articles in this Research Topic offer important new resources for breeding cultivars with effective FHB resistance. The Brazilian spring cultivar Surpresa provides a new source of resistance not currently used (Poudel et al. 2022). Three resistance loci (Fhb1, Fhb4, and Fhb5) were introgressed as a pyramid into desirable Chinese white and red semi-winter wheat lines (Zhang et al., 2021). And a novel technique could speed up the development of FHB-resistant winter wheat germplasm, increasing breeding generations from two to three per year (Zakieh et al. 2021).
Researchers used various approaches to identify new sources of resistance to the three wheat rusts (stem, stripe, and leaf). A new stem rust resistance gene was mapped in the durum wheat variety Kronos and introgressed into common wheat using co-segregating DNA markers (Li et al., 2021). The effects of combinations of leaf rust resistance genes were investigated in a Canadian wheat double-haploid population (McCallum and Hiebert, 2022) and in a durably resistant Canadian wheat cultivar (Bokore et al., 2022). A multi-parent advanced generation intercross (MAGIC) wheat population was used to map adult-plant and seedling resistance to stripe rust in Germany (Rollar et al., 2021). A genome-wide association study was used to identify stripe rust resistance loci in a panel of Chinese wheat landraces (Yao et al., 2021). And QTL mapping led to identification of stripe and leaf rust loci in an Afghan landrace (Zhang et al., 2022), a Chinese landrace (Wang et al., 2022), and the CIMMYT wheat line “Mucuy” (Lan et al., 2022; so far this is an abstract, need the URL to the full article when it’s available).
Breeding wheat cultivars with resistance to powdery mildew requires a constant stream of new resistance sources, thanks to the pathogen’s ability to rapidly overcome host resistance through adaptation. The efficacy of a set of new resistance genes introgressed from Middle Eastern wild wheat relatives was measured using powdery mildew populations from various wheat growing regions affected by the disease (Kloppe et al., 2022). A more unusual wild relative of wheat, Psathyrostachys huashanica, which is found only in the Huashan Mountains of China, also furnished novel resistance to wheat powdery mildew (Liu et al., 2021).
A previously unidentified source of resistance to Hessian fly was identified in spring wheat cultivars of the U.S. Pacific Northwest (Prather et al., 2022). And in a twist, a locus conferring not resistance but susceptibility, in this case to tan spot, was identified in U.S. bi-parental spring wheat mapping populations and narrowed to a region encompassing seven candidate genes (Running et al., 2022). Last but not least, an interesting look under the ground revealed that rhizosphere microbiomes differed among wheat genotypes and had an impact on pathogenicity of Rhizoctonia solani, suggesting the potential to manage Rhizoctonia root rot with wheat genotypes that recruit microbiomes associated with improved plant fitness and suppression of the fungal pathogen (Dilla-Ermita et al., 2021).
For this Research Topic, we have collected articles that demonstrate how cutting-edge approaches to breeding are being brought to bear on some of the chief diseases threatening the world’s wheat production systems. The authors’ contributions are of the highest quality, and illustrate the strong international interest in this topic. These reports help breeders everywhere assess and employ novel and potentially durable resistance to wheat diseases. They will make a practical difference in helping safeguard global wheat yields in the challenging years to come
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
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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