1,720,966 research outputs found
Genetic analysis using next-generation sequencing method to disclose genomic variants in grapevine cultivars
No full textThe grapevine (Vitis vinifera L.) is one of the most economically important crops globally, distinguished by its significant genetic diversity, which is reflected in a variety of cultivars with unique morphological, agronomic, and qualitative traits. Understanding the genetic basis of this variability is essential for effective grapevine management, the conservation of genetic resources, and the development of advanced breeding strategies. Recent advances in next-generation sequencing (NGS) technologies, such as genotyping-by-sequencing (GBS) and double-digest RAD sequencing (ddRADseq), have provided powerful tools for analyzing genetic variation, identifying functional genes, and characterizing loci associated with important agronomic traits.
This research aims to explore the population structure, genetic diversity, and key genetic loci in a collection of clones derived from Campanian and Apulian grapevine varieties, known for their desirable traits in viticulture and winemaking.
The first study analyzed a total of 138 clones from six autochthonous grapevine varieties from southern Italy, sampled in Campania and Apulia. These clones are traditionally cultivated in environments with different climatic conditions. The Campanian clones include two red-berried varieties, CAMAIOLA And AGLIANICO LASCO, and the white-berried GRECO B. The Apulian clones include two red-berried varieties, NERO DI TROIA and MALVASIA NERA DI BRINDISI, as well as the white-berried Minutolo b. Two reduced representation sequencing methods were used to extract single-nucleotide polymorphism (SNP) markers.
The study revealed high genetic diversity, particularly among clones within the same variety. Population structure analysis and fixation index (FST) calculations indicated significant genetic similarity among varieties originating from the same geographical region. Approximately 200 loci were identified with divergent markers (FST ≥ 0.80) within annotated exons, many of which were linked to important traits like phenotypic adaptability and environmental responsiveness. These findings offer valuable opportunities for grapevine breeding initiatives.
Additionally, the genetic variability of 35 PRIMITIVO clones from Apulia, including selected and certified clones propagated over several years, was examined using genotyping-by-sequencing. A total of 38,387 filtered SNPs were analyzed, and pairwise identity-by-state (IBS) analysis showed high variability (IBS < 0.75) among the clones. Genetic diversity analysis revealed three main groups, differentiated by geographic origin. Clones from Gioia del Colle were further divided into two distinct clusters, corresponding to variation in grape-related traits. The FST analysis identified numerous loci associated with stress responses and developmental traits, including genes involved in stress regulation, as well as adaptation to environmental conditions such as glutamate receptors and auxin and ethylene signaling.
A broader analysis of five emblematic Apulian grapevine varieties (NEGRAMARO, MALVASIA NERA, PRIMITIVO, MINUTOLO, and UVA DI TROIA) using the GBS approach uncovered significant intra- and inter-varietal genetic variation. Key genes related to secondary metabolism, stress resilience, and berry quality were identified, including WRKY transcription factors and enzymes that influence wine flavor, aroma, and pigmentation. Several SNP loci were validated for varietal traceability, essential for maintaining wine authenticity and marketability. These findings not only contribute to the conservation of viticultural biodiversity but also support sustainable wine production strategies, ensuring the competitiveness of Apulian wines in the global market.
The research highlights the importance of preserving and utilizing intra-varietal variability, which is essential for the sustainability and adaptability of viticulture, especially in the context of changing environmental conditions
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
EVALUATION OF MINOR APULIAN OLIVE GENOTYPES FOR RESISTANCE TO XYLELLA FASTIDIOSA
No full textThe spread of olive quick decline syndrome (OQDS) caused by the bacterium
Xylella fastidiosa subsp. pauca is threatening Apulia's olive resources,
damaging the regional economy and landscape heritage. To reduce the impact
of the disease, a breeding program has been launched in 2017 aimed at
identifying new sources of resistance to expand the range of varieties that
can be used in the infected areas, together with the resistant varieties
“Leccino” and "FS17". One hundred olive samples, including 19 unknown
accessions from free pollination of Cv. Simone and 81 minor local
cultivars, were grown in the epidemic-affected areas in Apulia and tested
for resistance in a three-block randomized scheme field trial by
artificially infecting them with an X. fastidiosa strain. All cultivars
were genotyped in advance with 10 SSR markers to identify synonyms and
homonyms. Genotypes were evaluated for symptomatology, colony forming units
(cfu)/ml, and Cq value after 4 (2021), 5 (2022), and 6 (2023) years postinoculation
by Real-Time PCR assay. Molecular data were used to investigate
the genetic relationships between the resistant genotypes to provide clues
to start new olive breeding programs. The first results identified some
promising genotypes which show low symptoms, low number of cfu, and high Cq
values which indicate a potential resistance to the disease, comparable to
that of Leccino. The investigation will be continued to consolidate these
results
APULIAN OLIVE GERMPLASM AS POTENTIAL SOURCES OF RESISTANCE TO XYLELLA FASTIDIOSA
No full textThe olive tree (Olea europaea subsp. europaea var. europaea) represents the
cornerstone crop of Apulian economic system based on the production of oil
and table olives. During the last years, the high genetic variability of
Apulia's olive germplasm is being exposed to a risk of genetic erosion due
to social, economic, and climatic changes. In addition, since 2013, the
spread of the gram-negative bacterium Xylella fastidiosa subsp. pauca,
which is responsible for the olive tree rapid decline syndrome (OQDS), has
menaced Apulia's olive biodiversity, damaging the regional economy and
landscape heritage.
To reduce the impact of Xylella fastidiosa, breeding programs have been
started to identify agronomically interesting traits and new sources of
tolerance or resistance.
So far, two cultivars "Leccino" and "FS17" (also known as "Favolosa")
showed resistance to X. fastidiosa in contrast to the susceptible cultivars
"Cellina di Nardò" and "Ogliarola salentina". In addition, recent studies
have shown a moderate tolerance in "Frantoio," "Toscanina," "Termite di
Bitetto," "Maiatica," "Dolce di Cassano," "Oliastro," "Nociara," and
"Nocellara Etnea."
This study aims to investigate the variability of interactions with
X. fastidiosa of a large panel of Apulian olive genotypes.
Sixty olive samples (50 cultivars and 10 unknown genotypes) were grown up
in an experimental field, following a randomized block with 5 replicates,
located in the west part of the infected area in province of Lecce, and
they were inoculated with X. fastidiosa. Monitoring of colony-forming units
(CFU) by RealTime-PCR assay allowed to identify a different behavior of the
genotypes to the infection, based on the Cq values. A preliminary subset of
most promising tolerant genotypes (PT) including both cultivars and
unknown, was identified and characterized by molecular analysis with a set
of 10 SSR markers. The allelic profiles were compared with the molecular
profiles deposited in the Di.S.S.P.A database consisting of about 600 olive
genotypes widespread in the Mediterranean basin. Lynch and Ritland Method
(LRM), Neighbor-joining and STRUCTURE analysis allowed to highlight cases
of synonymy and homonymy, evaluate the genetic relationships between
unknown olive genotypes and cultivars, and investigate the genetic
structure of this Apulian olive germplasm
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
Genome Scan Analysis for Advancing Knowledge and Conservation Strategies of Primitivo Clones (Vitis vinifera L.)
Get PDFThe success of the Primitivo variety underscores the critical need for the managing of clone genetic conservation, utilization, and improvement. By combining genomic and environmental data, breeders can better predict the performance of varieties, thereby improving breeding efficiency and enabling more targeted development of high-quality grapevine cultivars. In this study, 35 Primitivo clones were analysed, including selected and certified clones that have been propagated over several years in Apulia. Genetic variability among the Primitivo clones was assessed through genotyping by sequencing. Using 38,387 filtered SNPs, pairwise identity-by-state (IBS) analysis demonstrated the uniqueness of the 35 clones (IBS 0.50) identified numerous loci putatively associated with stress responses and developmental traits, including genes involved in key plant biological processes, stress response regulation, and adaptation to environmental conditions such as glutamate receptors, auxin, and ethylene signalling
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