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Characterization of autochtonous Walnut germplasm in Fiuli Venezia Giulia
No full textJuglans regia is mostly distributed in the temperate and subtropical regions of the Northern Hemisphere. During the last ice age, the species survived only in refugial areas. In Europe it survived in the Italian and Balkan peninsulas. Friuli Venezia Giulia is the natural corridor where the two populations met during the re-colonization after the glaciation. In the present study 220 autochtonous accessions were sampled and georeferenced and a genetic analysis with 20 microsatellite loci taken from the literature was carried out. The local population shows a moderate genetic diversity and can be classified in two clusters. The first one shows a great mixture between genotypes coming from different areas, even particularly far away from each other. To this first cluster belongs the vast majority of the samples. The second cluster consist of three genotypes originated from an import of Walnuts from Russia at the beginning of the XX century.
On the genotypes that during the investigation produced enough fruits carpometric analysis were performed. The best accessions were included in a ranking list compiled using a multivariate analysis considering all the traits valuable for breeding and selection, such as nut weight, kernel weight, shell thickness, kernel skin colour, ease of kernel extraction and fruit appearance. These best accessions will either be selected as they are for vegetative propagation or employed in breeding programs.
For every genotype that produced fruits the oil content and its acidic spectrum were determined. Both turned out not to be influenced by the year of sampling. The studied wild walnut trees shown a significant linear relationship and a positive relationship between the minimum daily temperature and the oleic acid content. Many of the accessions could be used in breeding programs for the selections of cultivars with high oil contents and with differentiated acidic spectra, depending on the purpose of the oil.
The last part of the investigation was about the diffusion in Friuli Venezia Giulia of two non-local walnut pests come from America, a leafminer belonging to the genus Coptodisca and the carpophagous Rhagoletis completa.
Coptodisca lucifluella has been found in 55 out of the 219 considered sites. This is the first report of the species for the region. The species has been identified not only by typical leaf symptoms but also by means of mitochondrial DNA barcode. The DNA sequences were submitted to Genebank. The level of pest infestation in Friuli Venezia Giulia resulted lower than in other Italian areas and its diffusion was negatively correlated with the altitude. The species was observed in sites above 600 m a.s.l. The low infestation observed could be associated with the activity of native natural enemies, as parasitoids of the genus Chrysocharis (Hymenoptera, Encyrtidae) that were observed into the mines. Rhagoletis completa was found in 89 out of the 185 walnut trees with fruits. In many sites, especially in lowland localities, the infestation level was very high, as to suggest treatments with insecticides. The level of infestation decreased with altitude: at sites above 700 m a.s.l. either there was no infestation or the infestation was very low. No correlation has been found between the average weight of the fruits and the level of infestation
Kernel oil content and oil composition in walnut (Juglans regia L.) accessions from north-eastern Italy
No full textBACKGROUND:Walnut oil use is currently limited by its poor oxidative stability due to the high percentage of polyunsaturated
fatty acids. Modifying the oil composition may be a goal in walnut breeding to increase interest in this crop. Exploring natural
variability and identifying the main environmental factors affecting oil quality are necessary in crop selection. Therefore 190
wild accessions were collected and evaluated during 2013 and 2014 for oil content and its fatty acid profile and compared with
five commercial cultivars as references.
RESULTS: High variation inkerneloil content andfatty acid compositionwas foundin thenativewalnut.Kerneloil content ranged
from 54.2 to 72.2% (w/w). The major fatty acids were linoleic (range 46.9–68.6%), oleic (10.0–25.1%), linolenic (6.9–17.6%),
palmitic (3.9–11.4%) and stearic (1.1–5.2%) acids. Some accessions had oil with a fatty acid ratio very different from the
reference commercial cultivars, especially the oleic acid/polyunsaturated fatty acid (PUFA) ratio. A significant linear relationship
and positive correlation between the daily minimum temperature and oleic acid content was observed in the wild walnuts.
CONCLUSION: The wide variation in fatty acid content and composition allows superior accessions to be selected for diffusion
among growers. A suitable strategy would be to make a selection against PUFA content rather than just for high oleic acid.
In addition, the selected high oleic accessions, before being utilized per se or as donor parents in breeding programs, have to
demonstrate they are not adversely affected by the environment
Morphological and carpological variability of walnut germplasm (Juglans regia L.) collected in North-eastern Italy and selection of superior genotypes
No full textNuts collected from wild accessions of Persian walnut (Juglans regia L.) in the Friuli Venezia Giulia region (North Eastern Italian Alps) were evaluated during 2013–2015. The analyses carried out were mainly on fruit traits, the only morphological traits that could be observed and statistically analysed, being less dependent on the area of sampling, considering geographic features such as altitude, slope, soil, and climate. Such fruit traits proved to be very variable. The nut weight ranged from 2.2 to 17.3 g, the shell thickness from 0.35 to 2.30 mm, the color of kernel skin from light to amber. The fruit nut appearance, evaluated by a panel of consumers, varied from 2.50 to 6.83 in a scale from 0 (very bad) to 10 (very attractive). A multivariate analysis carried out considering traits valuable for breeding and selection, such as nut weight, kernel weight: nut weight ratio, shell thickness, kernel color, and fruit appearance, produced a ranking list, that included, at best, accessions that could be either selected as such for vegetative propagation and distribution to growers or used in breeding programs. A disadvantage of these selections is their terminal bearing habit which is not appreciated by breeders, who prefer the most productive genotypes with lateral bearing habit
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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