1,720,964 research outputs found
Broccoli yield response to environmental factors in sustainable agriculture
No full textA reduced rank factorial regression was carried out to assess effects of environmental factors in sustainable agriculture on yield performances of homogeneous (one F1 hybrid) and heterogeneous (one landrace, LR, and two derived synthetics) broccoli varieties under Organic Agriculture (OA) and Low-Input (LI) management systems. The study was motivated by a general lack of data on environmental variables that affect broccoli yield. Agronomic trials were carried out for three years in three locations in Central Italy with different pedo-climatic conditions. Reduced rank factorial regression was efficient in summarising the effect of environmental variables on the pattern of Genotype (G). ×. Environment (E) interactions. Nitrogen content, together with rainfall, minimum temperature and clay content, were the most important environmental variables and explained 91% of the variability in the G. ×. E interaction matrix. A mild and nitrogen-rich environment allowed good performances to be achieved with all genotypes and maximised the F1 hybrid yield. The synthetic varieties and the LR tolerated a high clay content, even though broccoli crops prefer, in general, alluvial, deep and permeable soils without water stagnation. This suggests that the above mentioned varieties are the best materials for these yield-limiting environments, possibly because they were selected under those conditions. The results highlight the needs (i) to carry out further agronomy research aimed at identifying the most suitable areas and optimizing the control of environmental variables in OA and LI (in particular, type, quantity and time of application of N fertilization), (ii) to develop specific breeding programs for OA and LI and, while carrying them out, (iii) to evaluate the responses of the genotypes under selection to limiting environmental variables
Assessment of spatial–temporal variation in natural populations of Brassica incana in south Italy: implications for conservation
No full textBrassica incana is a secondary-gene pool wild relative of Brassica oleracea. Twenty-two B. incana populations are recorded in Italy, where the species has recently been pointed out as in priority need of conservation. While data on the spatial and temporal variation of B. incana Italian populations are completely lacking, this information is useful in conservation planning for this species. Three populations from the Sorrento peninsula and from the islands of Ischia and Capri, collected in 1984 and 2012, were characterised for 12 morpho-phenological and 21 genetic traits to assess their spatial–temporal variation. The populations were quite different for morpho-phenological and genetic traits. Spatial differentiation was high and easily explained by the isolation. Temporal differentiation between the Sorrento and Ischia populations was high and explained by a reduction in the population census across time, while it was not significant between the two Capri accessions as such pointing to a major effect of genetic drift. Numerical dimension is extremely relevant in evaluating conservation priorities since it has a major impact on population dynamics over time. The Sorrento and Ischia populations are under threat and urgently need conservation actions, suggesting an alarming scenario for the survival of other crop wild relative populations which are similar in census. Our data also show that, in an allogamous and self-incompatible species like B. incana, populations of 100–200 individuals maintain high allelic diversity. According to obtained results, natural populations of species with similar reproductive system and census can be considered at low risk of genetic erosion. © 2018, Springer-Verlag GmbH Austria, part of Springer Nature
Evolutionary breeding for sustainable agriculture: Selection and multi-environmental evaluation of barley populations and lines
No full textIn the manuscript we present the results of a 25 year evolutionary breeding program (EBP) carried out under low-input management condition. During the program, a Composite Cross Populations was developed and multiplied for several years allowing natural selection to occur. After this period, new populations and 13 best lines were selected. Yield performances and stability of selected materials were evaluated in multi-environmental trials for four years under organic and low-input conditions and in comparison with several controls. All the produced data were analysed by using modern and sophisticated statistical (including spatial, AMMI, and factorial regression) analyses.
According to our results, the heterogeneous populations and some of the derived lines showed the best combination of yield and yield stability in the tested Environments confirming the utility of EBP for the selection of varieties for sustainable agriculture
A new list and prioritization of wild plants of socioeconomic interest in Italy: toward a conservation strategy
Full text linkWild harvested plants (WHP) and crop wild relatives (CWR), part
of the segment of natural diversity that is collectively known as
‘Plant Genetic Resources’, have great socioeconomic importance
for humans because they are used either directly or in
crop breeding. In order to lay down a solid base for constructing
conservation strategies for Italy, an updated annotated list of
CWR and WHP was produced for the country including information
on known uses. Taxa included in the list were then prioritized
using a pragmatic approach based on their value, native
status, and need of protection or monitoring
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
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