Risposta fisiologica, produttiva e qualitativa del vitigno Aglianico (Vitis vinifera L.) alla cimatura tardiva applicata in combinazione con diversi livelli di irrigazione

Negli ultimi anni sta crescendo l'interesse per la definizione di nuove strategie di gestione del vigneto che permettano l'adattamento della viticoltura mediterranea ai cambiamenti climatici. Questi ultimi stanno infatti, in modo sempre più evidente, avendo un impatto negativo su diversi parametri qualitativi delle uve alla raccolta. Uno di questi effetti è l'accelerazione dell'accumulo dei solidi solubili nell'uva durante la maturazione, laddove la sintesi dei composti polifenolici risulta invece meno influenzata. Questo si sta traducendo in uno sbilanciamento fra il contenuto di zuccheri e polifenoli a favore dei primi, fenomeno che è conosciuto come disaccoppiamento fra la maturazione tecnologica e la maturazione fenolica. Questo a sua volta porta alla produzione di vini molto alcolici ma che sono insoddisfacenti dal punto di vista del profilo fenolico e sensoriale. Fra le strategie proposte per rallentare l'accumulo dei solidi solubili, la cimatura tardiva è stata riportata essere molto promettente, in particolare sul vitigno Aglianico, che è il vitigno oggetto di studio di questa tesi. Però è stato altresì mostrato in altri studi come l'efficacia di questo tipo di intervento vari in base a diversi fattori ambientali e fisiologici e, tra questi, lo stato idrico della pianta sembrerebbe svolgere un ruolo importante nella modulazione di questi effetti della cimatura tardiva. Lo scopo di questa tesi era di studiare gli effetti dell'interazione tra la cimatura tardiva e l'irrigazione in post-invaiatura sulle performance fisiologiche, produttive e qualitative del vitigno Aglianico. Inoltre, con questo lavoro di tesi ci si propone di studiare gli effetti carry-over dell'applicazione delle cimature e delle irrigazioni sulle componenti della produzione negli anni successivi alla loro applicazione. È stato pertanto svolto un esperimento che prevedeva l'applicazione di nove trattamenti imposti quando le uve avevano raggiunto i 12 °Brix e questi consistevano in tre livelli di cimatura combinati con tre livelli di irrigazione applicati per quattro anni consecutivi. I tre livelli di cimatura consistevano in un trattamento non cimato, un trattamento cimato ad una intensità intermedia (riduzione dell'area fogliare del 36%) e un trattamento che prevedeva un livello di cimatura più intenso (riduzione dell'area fogliare del 58%). I tre trattamenti irrigui prevedevano un trattamento non irrigato, un trattamento con una restituzione del 50% del fabbisogno idrico (calcolato come ETc al netto delle piogge), e infine un trattamento che prevedeva la restituzione del 100% del fabbisogno idrico. I risultati hanno mostrato come le cimature tardive inducano effetti dipendenti dall'intensità della loro applicazione. È stato infatti osservato che quando queste sono di lieve intensità si assiste ad un incremento del contenuto di solidi solubili alla raccolta, mentre le cimature di maggiore intensità inducono una significativa riduzione del contenuto in solidi solubili alla raccolta. Le 3 irrigazioni hanno mostrato in generale di favorire l'accumulo di solidi solubili negli acini. Sono stati però riscontrati diversi effetti interazione fra i diversi trattamenti sperimentali e l'anno di applicazione. Le cimature intense hanno portato inoltre ad un abbassamento della produzione negli anni successivi all'applicazione dei trattamenti. L'irrigazione per contro ha mitigato gli effetti negativi sulla produzione causati dalle cimature intense e in parte ha mitigato anche l'effetto negativo che la siccità dell'annata ha indotto sulla produzione dell'anno successivo. Inoltre, è stato evidenziato che anche il contenuto polifenolico delle uve è stato influenzato dagli interventi di cimatura e di irrigazione mostrando anche diverse interazioni tra i fattori. In particolare, i risultati suggeriscono che le cimature molto intense possono causare un ritardo nella maturazione fenolica delle uve. In generale, i risultati di questo lavoro di tesi forniscono informazioni che possono aiutare a chiarire gli effetti complessi che le interazioni fra gestione in verde della chioma, stato idrico della pianta e parametri ambientali hanno sulle perfomance produttive e qualitative dell'Aglianico

Morphological and Genetic Clonal Diversity within the ‘Greco Bianco’ Grapevine (Vitis vinifera L.) Variety

: Grapevine (Vitis vinifera L.) has been propagated vegetatively for hundreds of years. Therefore, plants tend to accumulate somatic mutations that can result in an intra-varietal diversity capable of generating distinct clones. Although it is common that winemakers request specific clones or selections for planting new vineyards, relatively limited information is available on the extent, degree, and morphological impact of the clonal diversity in traditional, highly valued grapevine varieties within production areas protected by geographical denomination of origin. Here, we present a morphological and genetic investigation of the intra-varietal diversity in 'Greco Bianco', the grapevine variety used to produce the DOCG and PDO "Greco di Tufo" wine. Seventeen clones from different farms (all within the allowed production area) were phenotypically characterized using ampelographic and ampelometric traits. The clones were also genotyped with Simple Sequence Repeats (SSR) and retrotransposon-based DNA markers (REMAP). The morphological analysis indicated a uniformity in the qualitatively scored traits, and a limited variability for the quantitative traits of the bunch and of the berry composition. The molecular markers also depicted variability among clones, which was more evident with the use of REMAPs. The comparison of the discriminatory information of the three analyses indicated that they provided different estimates of the level of diversity. The evaluation described herein of the clonal variability has implications for the management and protection of clonal selections in 'Greco Bianco' and prompts for further multidisciplinary investigations on its possible role in winemaking

Biodegradable mulching spray for weed control in the cultivation of containerized ornamental shrubs

Abstract Background Weed control represents a major issue in plant cultivation in containers. Manual weed control is very expensive and the use of chemical herbicide or plastic mulch films has a large environmental impact. The aim of this study was to test the efficacy of an experimental biodegradable chitosan-based mulching spray in controlling weed growth in containers. This research also studied the effect of this mulch on the growth of Viburnum lucidum Mill. plants to test for possible phytotoxic effects. Results The study compared a total of six treatments derived from three types of weed control (no weed control; herbicide, oxadiazon; mulching spray) applied in containers either filled only with the sterile substrate or filled with the sterile substrate and then artificially inoculated with seeds of the weed species [Sonchus asper (L.) Hill subsp. asper and Epilobium montanum L.]. The mulch controlled the weeds effectively for more than 2 months after its application even under severe weed infestation. The mulching spray controlled the emergence of S. asper more efficiently than E. montanum plants, probably because the latter has a stronger capacity to penetrate the mulch film during emergence. Conclusions Three months after its application, the mulch started to degrade and this allowed some weeds to emerge in the containers, but, in general, the mulch performed better than the herbicide. The chitosan-based mulch did not have any negative effective on the growth of V. lucidum plants

A method for using monthly average temperatures in phenology models for grapevine (Vitis vinifera L.)

In recent years, there have been increasing efforts to link phenology models with seasonal climate predictions in so-called Decision Support Systems (DSS) to tailor crop management strategies. However, temporal discrepancies between phenology models with temperature data gathered on a daily basis and seasonal forecasting systems providing predictability on monthly scales have limited their use. In this work, we present a novel methodology to use monthly average temperature data in phenology models. Briefly stated, we modelled the timing of the appearance of specific grapevine phenological phases using monthly average temperatures. To do so, we computed the cumulative thermal time (Sf) and the number of effective days per month (effd). The effd is the number of days in a month on which temperatures would be above the minimum value for development (Tb). The calculation of effd is obtained from a normal probability distribution function derived from historical weather records. We tested the methodology on four experimental plots located in different European countries with contrasting weather conditions and for four different grapevine cultivars. The root mean square deviation (RMSD) ranged from 4 to 7 days for all the phenological phases considered, at all the different sites, and for all the cultivars. Furthermore, the bias of observed vs predicted comparisons was not significantly different when using either monthly mean or daily temperature values to model phenology. This new methodology, therefore, provides an easy and robust way to incorporate monthly temperature data into grapevine phenology models.info:eu-repo/semantics/publishedVersio

Diversity in Morphometric, Pomological, and Fruit-Quality Traits of Apricot (Prunus armeniaca) Traditional Varieties: Implications for Landrace Differentiation at Regional Scale

Traditional crop varieties are receiving increasing attention in sustainable agriculture, conservation genetics, and plant science because they offer significant and largely unexplored diversity. The DNA profiling of landraces is being applied to numerous crops, yet a detailed knowledge of morphological diversity is often needed to increase the efficiency of both the conservation and exploitation of local germplasm. In this work, morphological, pomological, and fruit-quality traits (16 qualitative and 16 quantitative) were collected from 44 traditional apricot landraces cultivated in Campania, the Italian region with the highest number of traditional varieties. The aim was to assess varietal diversity and to highlight possible trends and phenotypes that may have driven the morphological differentiation. All traits were polymorphic, and each variety had a distinctive phenotype. The qualitative and quantitative traits provided different classifications of the varieties. Nonetheless, the Factorial Analysis of Mixed data indicated that, for both categories of variables, the fruit traits were the most influential for landrace classification. Interestingly, some easily discernible color phenotypes of the fruits mostly contributed to the discrimination of the analyzed apricot germplasm. We conclude that these specific, commercially relevant features of the fruit were important drivers of the differentiation of the cultivated apricot material at regional scale

Diversity in Morphometric, Pomological, and Fruit-Quality Traits of Apricot (<i>Prunus armeniaca</i>) Traditional Varieties: Implications for Landrace Differentiation at Regional Scale

Traditional crop varieties are receiving increasing attention in sustainable agriculture, conservation genetics, and plant science because they offer significant and largely unexplored diversity. The DNA profiling of landraces is being applied to numerous crops, yet a detailed knowledge of morphological diversity is often needed to increase the efficiency of both the conservation and exploitation of local germplasm. In this work, morphological, pomological, and fruit-quality traits (16 qualitative and 16 quantitative) were collected from 44 traditional apricot landraces cultivated in Campania, the Italian region with the highest number of traditional varieties. The aim was to assess varietal diversity and to highlight possible trends and phenotypes that may have driven the morphological differentiation. All traits were polymorphic, and each variety had a distinctive phenotype. The qualitative and quantitative traits provided different classifications of the varieties. Nonetheless, the Factorial Analysis of Mixed data indicated that, for both categories of variables, the fruit traits were the most influential for landrace classification. Interestingly, some easily discernible color phenotypes of the fruits mostly contributed to the discrimination of the analyzed apricot germplasm. We conclude that these specific, commercially relevant features of the fruit were important drivers of the differentiation of the cultivated apricot material at regional scale

Early Canopy Management Practices Differentially Modulate Fruit Set, Fruit Yield, and Berry Composition at Harvest Depending on the Grapevine Cultivar

The size and number of the berries and the rachis length are the main elements that define bunch compactness in grapevine (Vitis vinifera L.). This trait is of scientific and commercial interest because it strongly influences phytosanitary status and quality of the fruits. In this work, we investigated the effect of different canopy management strategies based on apical shoot and/or leaf removal applied at the early stage (pre-bloom) in altering the key determinants of bunch compactness. Specifically, we compared apical defoliation (removal of the first half of the shoot leaves from the top), basal defoliation (removal of the second half), and shoot trimming (removal of the apical half of the shoot) to untreated controls. The work was carried out in two red varieties (&lsquo;Aglianico&rsquo; and &lsquo;Casavecchia&rsquo;) that have contrasting bunch compactness (compact and loose, respectively). We measured relevant morphological traits, photosynthetic rates, fertility, fruit set, bunch architecture, and fruit main compositional parameters. This study demonstrates that the position of the removed shoot leaves along with the shoot trimming differentially modified fruit set, the number of berries per bunch, and berry fresh weight and composition at harvest. Nonetheless, the influence on bunch compactness was limited mainly because of photosynthetic and morphological factors strongly associated with the cultivar

Early Canopy Management Practices Differentially Modulate Fruit Set, Fruit Yield, and Berry Composition at Harvest Depending on the Grapevine Cultivar

The size and number of the berries and the rachis length are the main elements that define bunch compactness in grapevine (Vitis vinifera L.). This trait is of scientific and commercial interest because it strongly influences phytosanitary status and quality of the fruits. In this work, we investigated the effect of different canopy management strategies based on apical shoot and/or leaf removal applied at the early stage (pre-bloom) in altering the key determinants of bunch compactness. Specifically, we compared apical defoliation (removal of the first half of the shoot leaves from the top), basal defoliation (removal of the second half), and shoot trimming (removal of the apical half of the shoot) to untreated controls. The work was carried out in two red varieties (‘Aglianico’ and ‘Casavecchia’) that have contrasting bunch compactness (compact and loose, respectively). We measured relevant morphological traits, photosynthetic rates, fertility, fruit set, bunch architecture, and fruit main compositional parameters. This study demonstrates that the position of the removed shoot leaves along with the shoot trimming differentially modified fruit set, the number of berries per bunch, and berry fresh weight and composition at harvest. Nonetheless, the influence on bunch compactness was limited mainly because of photosynthetic and morphological factors strongly associated with the cultivar

Vegetative, yield, and berry quality response of Aglianico to shoot trimming applied at three stages of berry ripening

The rise in air temperature due to climate change is causing an increase in the sugar accumulation rate in grape berries, resulting in increased wine alcohol concentrations. Postveraison leaf area removal (defolia-tion, shoot-trimming) is a suitable canopy management strategy to slow carbohydrate accumulation in the berries. However, in late-ripening cultivars, the phenological stage between veraison onset and harvest can be very long. Therefore, it can be hypothesized that the specific timing when leaf area removal is applied during the phenological stage can affect carbohydrate accumulation in the berries and berry composition. A two-year experiment was designed to compare the responses of Aglianico grapevines, a late-maturing cultivar, to shoot-trimming applied at three different stages of berry ripening. The experimental design included: (a) three trimming treatments applied at total soluble solids of 6, 12, and 18 Brix, respectively; and (b) a control treatment (untrimmed vines). Independent of the application timing, shoot-trimming decreased berry total soluble solids at harvest below that of control vines, but the later the shoot-trimming was applied, the lower berry total soluble solids was at harvest. Shoot-trimming did not affect other berry parameters. These results confirm that, at least for late-maturing cultivars, the timing of application of late shoot-trimming plays a key role in modulating the intensity of the effects of this management practice on berry composition