Borbála Bálo

GRA.LE.D. (GRApevine LEaf Digitalization) Software for the Detection and Graphic Reconstruction of Ampelometric Differences between Vitis leaves

Raster graphic ampelometric software was not exclusively developed for the estimation of leaf area, but also for the characterization of grapevine (Viti vinifera L.) leaves. The software was written in C++ programming language, using the C++ Builder 2007 for Windows 95-XP and Linux operation systems. It handles desktop-scanned images. On the image analysed with the GRA.LE.D., the user has to determine 11 points. These points are then connected and the distances between them calculated. The GRA.LE.D. software supports standard ampelometric measurements such as leaf area, angles between the veins and lengths of the veins. These measurements are recorded by the software and exported into plain ASCII text files for single or multiple samples. Twenty-two biometric data points of each leaf are identified by the GRA.LE.D. It presents the opportunity to statistically analyse experimental data, allows comparison of cultivars and enables graphic reconstruction of leaves using the Microsoft Excel Chart Wizard. The GRA. LE.D. was thoroughly calibrated and compared to other widely used instruments and methods such as photo-gravimetry, LiCor Li3100, WinDIAS2.0 and ImageTool. By comparison, the GRA.LE.D. presented the most accurate measurements of leaf area, but the LiCor Li3100 and the WinDIAS2.0 were faster, while the photo-gravimetric method proved to be the most time-consuming. The WinDIAS2.0 instrument was the least reliable. The GRA.LE.D. is uncomplicated, user-friendly, accurate, consistent, reliable and has wide practical application.

Stability of ampelometric characteristics of Vitis vinifera L. cv. 'Syrah' and 'Sauvignon blanc" leaves: impact of within-vineyard variability and pruning method/bud load.

Historically, grapevine (Vitis vinifera L.) leaf characterisation has been a driving force in the identification of cultivars. In this study, ampelometric (foliometric) analysis was done on leaf samples collected from hand-pruned, mechanically pruned and minimally pruned ‘Sauvignon blanc’ and ‘Syrah’ vines to estimate the impact of within-vineyard variability and a change in bud load on the stability of leaf properties. The results showed that within-vineyard variability of ampelometric characteristics was high within a cultivar, irrespective of bud load. In terms of the O.I.V. coding system, zero to four class differences were observed between minimum and maximum values of each characteristic. The value of variability of each characteristic was different between the three levels of bud load and the two cultivars. With respect to bud load, the number of shoots per vine had a significant effect on the characteristics of the leaf laminae. Single leaf area and lengths of veins changed significantly for both cultivars, irrespective of treatment, while angle between veins proved to be a stable characteristic. A large number of biometric data can be recorded on a single leaf; the data measured on several leaves, however, are not necessarily unique for a specific cultivar. The leaf characteristics analysed in this study can be divided into two groups according to the response to a change in bud load, i.e. stable (angles between the veins, depths of sinuses) and variable (length of the veins, length of the petiole, single leaf area). The variable characteristics are not recommended to be used in cultivar identification, unless the pruning method/bud load is known.

Damage of Grapevine Leaf Photosynthesis by UV-B (280–320 nm) Radiation in Two Cultivars of Vitis Vinifera

Recent increase in solar UV-B (280–320 nm) radiation on the surface of the Earth is a potential damage for all living organisms. In plants, an important site of damage is the photosynthetic electron transport, mainly Photosystem (PS) II, the pigment-protein complex embedded in the thylakoid membrane of chloroplasts. PS II electron transport is impaired by UV-B irradiation and the D1 and D2 protein subunits of PS II reaction centre are degraded as a consequence of this functional damage [1, 2].

Examination of biogenic amines in grapevine musts originating from vineyards treated with different viticultural practices

ABSTRACT Viticultural practices as defoliation (DF) and cluster tipping (CT) (hereinafter referred to as the abbreviation) are often used for crop regulation to enhance quality. Reduced yield can be accompanied not only with more favourable sugar-acid composition but also with changes of other chemical compounds in the berries, for example, biogenic amines as well. The latter play a significant role in human health. The experiment has been carried out at three different growing sites of Hungary in 2014. DF was done at full bloom, CT occurred when the berry reached pea size. Berry sampling for biogenic amine analysis was carried out several times during the ripening period. In our trial, we examined the effect of the above-mentioned treatments, the sites and the sampling dates on the amount of berries’ biogenic amine content. We concluded that DF and CT changed the amount of each type of amines in the berries. According to our measurements the treatments and the site did affect the amount and composition of biogenic amines, but the sampling time not. The treatments were most effective in the case of histamine which is crucial for triggering allergic reactions.

Bois noir affects the yield and wine quality of Vitis vinifera L. cv. ‘Chardonnay’

The Bois noir (BN) disease induced by ‘Candidatus Phytoplasma solani’ (CPs) is common in European vineyards. Its damage has not been fully investigated, especially with regards to wine attributes. The impact of BN on yield, berry composition and wine characteristics of Vitis vinifera L. cv. ‘Chardonnay’ was therefore comprehensively characterized in a 3-year field experiment in Hungary, Eger winegrowing region. Additionally, the bindweed-related tuf-b1 genotype was identified to be involved in the BN pathosystem in the experimental vineyard. Infection of CPs tuf-b1 genotype resulted in severe yield loss, the average decrease in number of bunches and total yield per vine was 56.7% and 68.4%, respectively. Analyses of wines produced from grapes of BN infected vines revealed decreased alcohol, epicatechin and iron contents; and increased organic acids, titratable acidity, catechin and calcium contents. Sensory evaluation of these wines confirmed unfavourable characteristics, i.e. higher acidity, bitterness, and usually pinkish discolouration. Negative impact on berry composition and wine quality were pronounced in the vintage with favourable weather conditions for grapevine production, whereas the negative effects of BN infection were less prominent, even masked, in the vintages with unfavourable weather (wet and cool). To reduce BN-caused damage, the need for improved preventative and curative measures for BN disease is highlighted.