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Establishing a foundation for the identification and initiation of clonal variation in Vitis vinifera
Full text linkCompared to other valuable fruit crops, there is minimal focus on genetic improvement of varietal quality of fruit produced from the world‟s major wine grapes, with current breeding programs focusing on traits such as resistance to biotic or abiotic stresses. To produce the highest quality fruit, viticulturists give attention to the best utilization of existing varieties with relationship to vineyard location and cultural practices. The existence of “clones”, assumed to be natural genetic variants within existing varieties, provides viticulturists with vines and fruit that fit their needs. The overarching goal of this project is to further the understanding of clonal variation of Vitis vinifera. The first objective of this project was to assess the importance of clonal variation to the Washington wine industry and develop a sense of the knowledge and interest in clonal variation among wine consumers. To achieve this, two surveys were conducted and results indicate that clonal variation is important to the industry and consumers, and there is a need for a resource in Washington that could genetically confirm clonal identity. To address the need identified by the survey studies, a new genetic test was investigated as part of the second objective. The method tested in this study yielded similar results as in all past DNA-based studies where varieties could be clearly differentiated, but clonal identification remains a challenge. The final objective of this project focused on developing a lab-based resource for the generation of clones to enable further studies. The Vitis genome has been sequenced and functional genomics studies are being conducted which are expected to reveal the genetic basis of clonal variation. Thus, a need has arisen for an in planta system to test gene function in V. vinifera. A prerequisite for such studies is an efficient regeneration system in Vitis. This has been accomplished using plant material from the dwarf cultivar V. vinifera „Pixie‟, an excellent model Vitis system
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Evaluation of pre-breeding resources for Pyrus spp.
Full text linkIn the U.S. there is an urgent need for dwarfing, precocious, cold tolerant, and disease resistant rootstocks for efficient production of pear (Pyrus communis L.). A key challenge is finding locally acclimated and genetically diverse parental material for breeding desirable rootstocks suitable for pear production in the U.S. To address this genetic resource gap, Pyrus communis L.cultivars, acclimated to the U.S environment, were utilized to develop two types of populations. A traditional population was developed in 2012 and consisted of 132 individuals derived from reciprocal crosses between 'Bartlett', 'D'Anjou', and 'Comice'. A putative mutant population was developed in 2013, utilizing gamma-irradiated pollen, comprising of 49 individuals recovered from crosses between 'Abbé Fetel', 'D'Anjou', 'Bartlett', and 'Comice'. In addition, a genetically diverse set of Pyrus germplasm was sourced from the USDA-ARS Corvallis Germplasm Repository as a pre-breeding resource for Pyrus rootstock development. Progeny from both types of populations were phenotyped for segregation of traits including, branch density, caliper, height, bark type, branch angle, and blind wood. Within the traditional population, ten of the individuals were potentially dwarfing and two individuals exhibited precocity as they flowered within four years after germination. Within the putative mutant population, four individuals were found to be potentially dwarfing. Target Region Amplification Polymorphism (TRAP) molecular markers were used to evaluate the extent of genetic interrelatedness, and diversity, within both types of populations and the germplasm collection. This analysis revealed that individuals in the traditional population formed two distinct groups. The individuals in the putative mutant population exhibited unpredictable grouping, perhaps as a consequence of gamma-irradiation of the pollen or to their true paternal lineage in case of any outcrossing, which is common during hybridization. The USDA germplasm collection separated into two groups, with no clear subgroups, most likely due to the inclusion of a genetically diverse set of individuals. Phenotypic and genetic diversity information generated for these pre-breeding resources is expected to enable appropriate selection of individuals for use as parental material for breeding experiments aimed at developing pear rootstocks for efficient pear production in the United States
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Population structure analysis of parental material in hop and pear breeding programs
Full text linkHops and pears are important agricultural commodities in the United States, particularly in Washington State. Hop, Humulus lupulus, is a cone-bearing plant that produces essential oils and organic acids that contribute to the flavor, aroma, and bitterness of beer. Washington hop production exceeded 205 million) of the United States pear production value, followed by Oregon State and California with 30% and 20%, respectively. To maintain and improve the viability of these industries in Washington State, hop and pear breeding programs must continue to create disease resistant and desirable cultivars using diverse parental material. Evaluating genetic relationships among new parental material for these breeding programs is critical for helping breeders make crosses between diverse v individuals. This thesis presents information on genetic diversity in breeding parents for hops and advanced rootstock selections for pear, and helps to resolve genetic relatedness between genotypes. Genetic relationships among hop parental genotypes used in th
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
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Towards understanding the genetics of pre- and post- harvest traits bitter pit in apple and chilling requirement in pear
Full text linkCrops from the Rosaceae family are very important for Washington agriculture but many factors can decrease yield and quality of the main tree fruit species of this family. One of the biggest problems in apple is bitter pit, a nutritional disorder. The main cause is a calcium deficiency that results in localized cell death which develops into black, corky pits. It is hard to define the stages and the mechanisms behind its development because many different factors influence its occurrence. The genetic and phenotypic characteristics define the generation of the pits, but also agronomical practices can have an important effect. A previous study in the Dhingra lab identified two homologs of a putative bitter bit associated gene (MdPBAG) in apple. These genes have been cloned and sequenced to detect genetic variability among eight commercial cultivars and eight seedlings with differing susceptibility to bitter pit. This genetic analysis was the first step in a larger genomic screen to detect QTLs for bitter pit in apple. Several QTL regions were identified and one of the two MdPBAG homologs was found to be approximately located 1cM apart from a QTL on linkage group 3. The QTL regions were also analyzed to identify candidate genes and their expression was evaluated to determine if they might be involved in the genetic mechanism inducing the disorder. Consumers find pear fruit problematic; 'ripe and ready-to-eat' pears are difficult to source. Many cultivars of pear only start to mature after a cold storage period which switches on the autocatalytic production of ethylene. Previous reports indicate that the gene family ACS seems to have a major function in determining the length of the required cold treatment. In this project, three cultivars, with different chilling requirements were analyzed to identify specific alleles for the genes of the ACS family. New ACS alleles, compared to the previously reported ones, were identified in both Anjou and Comice. In order to advance this study further, a segregating population was created, making reciprocal crosses of the three selected cultivars to create new genetic recombinants with differing cold requirements and to analyze their segregation
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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