La fertilita delle gemme in Vitis vinifera L. cv Carm\ue8nere

Il recente interesse verso sistemi di allevamento a potatura corta, maturato da esigenze tecniche ed economiche, ha richiamato l'attenzione sul problema della bassa fertilit\ue0 delle gemme nella zona basale dei tralci. Alcune considerazioni di campagna farebbero, inoltre, pensare che alcuni vitigni usualmente considerati a bassa o bassissima fertilit\ue0 basale non siano, almeno in alcune situazioni, da considerarsi tali. Sono state condotte delle osservazioni durante Ie stagioni vegetative del triennio 2002 su un vigneto adulto della cv Carm\ue8nere, allevato con due diversi sisterni di allevamento, uno a potatura lunga (Doppio capovolto) e l'altro a potatura corta (Cordone speronato) al fine di osservare l'effetto della diversa forma di allevamento sulla fertilit\ue0 delle gemme. I risultati delle osservazioni effettuate hanno messo in evidenza che non \ue8 possibile generalizzare il comportamento di questo vitigno poiche la fertilita dei nodi basali puo variare notevolmente in relazione a fattori tecnici (carica di gemme per ceppo e criteri di potatura, espressione vegetativa indotta, potatura verde) ed ambientali (clima ed orografia del sito di coltivazione

The complex microbial community of withered berries of cv. Corvina as revealed by metagenomic analysis

Corvina is the most important of Verona\u2019s red grape varieties and forms the basis for the production of unique wines, such as Amarone and Recioto of the Valpolicella area (Italy). The distinctive features of such wines are linked to the peculiar winemaking techniques and especially to the post-harvest grape withering process, when the grapes are partially dried in attics for three/four months to concentrate sugars up to about 27% (w/v). Dehydratation increases the concentration of constituent substances in berries, determining also specific expression of grape genes. During this process, grapes are colonized with a complex microbiota to an extent which depends on environmental temperature and humidity. In this study, a whole metagenome sequencing (WMS) approach was used to analyse the microbial consortia present on Corvina berries at the end of the withering process performed in two different conditions (\u201ctraditional\u201d or \u201cfast\u201d). Representative berry samples were collected and washed to avoid grapevine DNA contamination. Bioinformatic analyses, performed on reads and scaffolds, revealed that traditionally withered berries were dominated by Clostridiales and Pseudomonadales, while the fast procedure determined the presence of Enterobacteriales and Lactobacillales. On the contrary, few consistent differences characterized the eukaryotic fraction, dominated by Aspergillus and Penicillium for both samples. Interestingly, the \u201cbinning\u201d procedure revealed 15 most abundant genomes characterizing the two conditions. These results provide insights into the microbial community of Corvina withered berries and reveal relevant variations attributable to environmental withering conditions. Further studies will be performed to determine whether the different microbial compositions could lead to significant chemical variations of the musts, with an impact on the organoleptic properties of wine. This study underlines how novel technologies, like WMS, could open novel perspectives in the knowledge and management of traditional processes as the withering process of Corvina, with an impact on the winemaking of important Italian wines

Criogene extraktionsverfahren bei der weisswein-herstellung

Viene illustrata la tecnica della crioestrazione selettiva, riportando i dati vi varie esperienze

Effetti dello stress idrico e della reidratazione su variet\ue0 di vite innestate su due differenti ibridi portinnesti.

Lo stress idrico \ue8 un fattore critico per alcuni fondamentali processi fisiologici delle piante che si manifesta attraverso la riduzione della fotosintesi e della conduttanza stomatica. L'obiettivo del lavoro \ue8 stato quello di analizzare, utilizzando un sistema aperto LCi e una termocamera a infrarossi, gli effetti di stress idrici e della successiva reidratazione sulla fotosintesi e la conduttanza stomatica nelle variet\ue0 di vite (Vitis vinifera L.) Corvina, Corvinone e Rondinella innestate sui portinnesti Kober 5BB e 140 Ru. e coltivate su due tipi di terreno: franco-argilloso e franco. I risultati hanno mostrato che la variet\ue0 Corvinone innestata su 140 Ru. e allevata su terreno franco-argilloso manteneva valori di fotosintesi e di conduttanza stomatica ancora elevati nonostante le condizioni di stress. " ! ! $%(' !! !! %&

Controllo dell\u2019appassimento delle uve

Rassegna delle tecnologie di appassimento in ambiente termoigrocontrollato delle uve destinate alla produzione di Recioto e Amarone della Valpolicell

Effect of different environmental conditions on berry polyphenols during postharvest dehydration of grapes

Effect of different environmental conditions on berry polyphenols during postharvest dehydration of grape

Effect of various thermo-hygrometric conditions on the withering kinetics of grapes used for the production of “Amarone” and “Recioto wines.

Grapes of Corvina, Corvinone and Rondinella cultivars used for the production of “Amarone” and “Recioto” wines were withered under fixed conditions of temperature (10, 15, 20 and 25 °C) and relative humidity (53%, 75% and 95%) in order to evaluate their withering kinetics in an 80 days time-frame. Withering kinetics were described by means of linear and exponential regression equations. In agreement with basic dehydration theory, withering kinetic rates were found to increase with increasing temperature and with decreasing relative humidity (both above and below the value of the critical moisture). Moisture diffusion coefficients, calculated for each trial condition by solving a simplified equation based on Fick’s second law, varied from 1.63 × 10−13 to 6.34 × 10−12. Withering kinetic rates showed an opposite dependence on temperature and relative humidity as shown by multiple linear regression analysis results. Grape surface/volume ratio affected the withering kinetic rates for values above 3.8 cm−1 and at low relative humidity (53%)