1,721,118 research outputs found
Fruit thinning and quality: Exploring new chemical solutions
No full textApple fruit thinning is still an essential technique despite the fact that the apple fruit industry is continuously evolving in terms of new cultivars, new high-density planting orchards and training system. Also, in the last years new chemical thinners have been put on the market requiring specific protocols to reduce the risk for the grower and gain the desired results. Specific working groups formed at international and national level have been trying to face these changes, but the apple industry is a dynamic sector and the research does not always satisfy the productive chain and the market demands. The difficulty to respond in a timely manner to the industry are dependent upon the fact that fruit thinning is a difficult technique, and, in some circumstances, the obtained results are unsatisfactory. Fruit thinning is strongly related to both the meteorological conditions occurring at the thinner application time and the tree-side physiological state. Moreover, the ongoing climate change further increases the complexity of the overall thinning scenario. A possible improvement of the research on fruit thinning should be achieved with a better coordination among the existing working groups in order to exchange information on the new molecules and the new cultivars placed on the market to set up timely strategies in the different cultivation areas. All this should be organized and supported by the availability of structural fund policy from both institutional agency and the whole productive chain
Hierarchy and strategy: how do they affect thinning response?
No full textIn the apple, the reproductive structures are formed by corymbs carrying a central flower (that originates the fruit king) blooming first, and 4-6 lateral flowers that bloom according to a time sequence, originating the lateral fruitlets. In a normal climatic course, the king fruit grows before and at a higher rate (high hierarchy situation), thus exerting a competition for the assimilation of nutrients towards lateral fruitlets and the other growing organs (i.e., shoots and leaves). In some situations, however, these differences in growth are not so marked and both the central and lateral fruitlets grow at the same rate thus, bearing similar sizes (low hierarchy situation). In the first case, the king fruit has a low tendency to abscise and the lateral fruits are characterized by higher natural abscission, while in the second situation the probability of abscission of both the king and laterals fruitlets are similar, thus affecting also the efficacy of the chemicals thinners used. In some circumstances, a consistent reduction of the fruit load is required to meet the commercial standard fruit requirement and different chemical thinning agents can be sprayed in a sequence, especially on cultivars considered “difficult to thin”. This technique is named “strategy” in the practice
Plant bioregulators: do we still need them?
No full textPlant growth regulators (PGRs) are substances able to interfere with the plant’s hormone system controlling several physiological processes in trees. Since the discovery of plant hormones, the use of PGRs have offered the possibility to control different production steps, from the nursery to open-field. Even in a period characterized by a certain reticence towards agrochemicals, the research on the use of PGRs is still ongoing and the main chemical industries have introduced new molecules on the market. Traditional PGRs are finding new interesting uses and the new ones can represent a solution to the increasingly pressing demands coming from growers. In addition, these compounds might represent an additional tool to help solving problems linked to climate changes that afflict various physiological processes of plants (fulfillment of the chilling requirements, fruit skin colour, fruit load) managing to balance canopy growth and fruiting. In this contribution some examples on the use of PGRs are reported, focusing in particular on the latest formulations that have appeared on the market in recent years. It has to be kept in mind that the PGRs, although being an important tool, must be considered just an option among the portfolio available to the grower for improving quantity and quality of fruit production and that a proper use of PGRs requires a deep understanding of the physiological mechanism of the process to obtain the desired effects avoiding the collateral side-effects
Modelling metamitron-induced fruit drop as related to photoinhibition stress, dosage and number of applications in 'Golden Delicious'
No full textResearch was carried out in Emilia-Romagna region in a 'Golden Delicious' orchard to assess the thinning efficacy of metamitron (commercial name Brevis®) applied either as a single or double application. The choice to perform one or two applications depends upon several factors such as the blooming abundance, the fruit load and the climatic conditions from bloom/fruit set until the time of the treatment. Several models, based upon either the carbon uptake or the stress induced by the thinning agent, can be used to decide both the dosage and time of application. The thinning trials carried out a few years ago were used in the present research to model fluorescence data in order to assess their potential in predicting the thinning efficacy in single and double applications of Brevis®. Considerations were raised regarding the predictions about the need for a second application and, eventually, its dosage based on the new models prompted out in the present study
Dealing with plant bioregulators in Italy: From the introduction to now
No full textPlant bioregulators (PBRs) are natural or synthetic substances able to interfere with the plant's hormone system controlling important physiological processes in trees. The discovery of plant hormones (auxins, gibberellins, cytokinins, ethylene and abscisic acid) and the research and development of PBRs has been always an evolving process. PBRs research started in 1930s, when the natural auxin indoleacetic acid (IAA) was discovered, and the first Italian experience began in the late 1940s, when auxin-like compounds as indolebutyric acid (IBA), α-naphthalenacetic acid (1-NAA) and its amide (NAAm) found practical uses. Gibberellic acid (GA3) was isolated in the 1950s and identified a decade later. In Italy, Berelex (GA3) was tested as fruit-setting agent, while Regulex (GA4-7) was tested in the 1980s for apple fruit skin russeting control. The study on GA metabolism allowed to understand the action of "growth retardants", whose research began in the mid-1960s with chlormequat (CCC) and daminozide (SADH), in the 1980s with paclobutrazol, and, finally, in 2003 with prohexadione-Ca. Zeatin, the first cytokinin, was discovered at the beginning of the 1960s. Nowadays, 6-benzyladenine (6-BA) is widely used as thinning agent on pomefruit and the mixture with GA4+7 allows to control fruit shape elongation in apple. In the 1960s, ethylene was recognized as gaseous hormone for fruit ripening control. Ethylene releasing compounds were used for enhancing fruit coloration in table grape, as a mechanical harvesting aid, and as a thinning agent for stonefruit. The study on ethylene biosynthesis recently led to find inhibitors of its action (aminoetoxyvinylglycine, ReTain) and perception (1-methylcyclopropene, SmartFresh). Abscisic acid (ABA) induces fruit abscission, stomatal closure and fruit ripening and colour enhancement. A commercial formulation (ProTone) has been recently used in table grapes. Other growth substances have been also shown to regulate physiological processes in trees: brassinosteroids, polyamines, jasmonates, and strigolactones, the latter being a new class of hormones regulating plantmycorrhizal interactions and playing a role in controlling apical dominance. As a conclusive remark, PBRs represent an important tool, although they must be considered as part of a larger portfolio of options for the grower to control vigour and improving cropping
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
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