The initial rationale for studying grape training systems centred primarily on the response of yield to canopy management. The environmental conditions thus differed between the two vintages. Mathematical formula for calculating the growing degree days (GDD base 10 ☌) was also used, and the results showed cumulative growing degree days between véraison and harvest was 858.64 GDD in 2013, lower than 785.87 GDD in 2012. Rain began in 2012 at 29 DAV but gradually reduced until 43 DAV. No rain fell at harvest in 2013, but some rain fell during the final stage of berry ripening (34–45 DAV). Post-véraison rainfall was higher in 2013 than 2012 (mainly during 10–20 DAV). 2013 had many more days than 2012 with lower temperatures for 10–50 DAV (days after version). The daily maximum temperature exceeded 35 ☌ for most of this stage, which thus significantly accumulated heat in 2013. The average daily temperature during the first ten days after véraison was higher for the 2013 than the 2012 vintage ( Figure 1). The vineyard in the present study was in a wine-producing region of China with unique ecological conditions, a semi-humid climate, and high rainfall during the berry-ripening stage. The influence of training systems in unfavourable climatic regions, such as wet areas, on grape diseases and anthocyanin profiles in the skins of Cabernet Sauvignon grapes ( Vitis vinifera L.), however, has not been well studied. Vine training systems can influence vine performance, such as vine size, canopy density, grape maturity, and berry quality. The accumulation and metabolism of anthocyanins in grape skins are complex physiological and biochemical processes, and anthocyanin content depend on climatic and geographical factors, cultural practices, and grape cultivars. They accumulate after véraison via the phenylpropanoid biosynthetic pathway in the grape skin, where they serve a wide range of biological functions such as protection against solar exposure and ultraviolet radiation, free-radical scavenging and anti-oxidative capacity, defence against a variety of pathogens, attraction of predators for seed dispersal, and the newly proposed modulation of signalling cascades. Anthocyanins are important parameters of wine quality and directly influence the organoleptic characteristics of wines, such as colour and astringency. In summary, VSP was the best training system for Cabernet Sauvignon to accumulate relatively stable individual anthocyanins in this wet region of China and potentially in other rainy regions.Īnthocyanins, a class of phenolic compounds important in wine production, contribute most of the orange, pink, red, blue, and purple colours to grapes and their wines. With regard to the ratios of 3′5′/3′-substituted, methoxylated/non-methoxylated and acylated/non-acylated anthocyanins, the significantly higher levels were also shown in VSP system. Generally, VSP benefited the most, contributing to significantly highest levels of total individual anthocyanins, and major anthocyanin, including malvidin-3- O-glucoside and malvidin-3- O-(6- O-acetyl)-glucoside, and the grapes obtained from VSP presented significantly highest proportion of 3′5′-substituted anthocyanins. With regard to the effect of training systems, 4AK grapes had the lowest concentrations of total anthocyanins and individual anthocyanins, SG and VSP differed according to the different vintages, and showed highest concentration of total individual anthocyanins in 20, respectively. A wet vintage of 2013 had more accumulation of 3′5′-substituted and acylated anthocyanins, including malvidin-3- O-(6- O-acetyl)-glucoside, malvidin-3- O-glucoside, and petunidin-3- O-( cis-6- O-coumaryl)-glucoside, etc. PLS-DA (Partial Least Squares-Discriminant) analysis showed that the relatively dry vintage could well discriminate three training systems, but the wet vintage was not. Three training systems had no impact on berry maturity. SG and VSP had lower disease infections of leaves and berries, especially in the mid- and final stage of berry ripening. 4AK was the most productive system in comparison to SG and VSP. Cabernet Sauvignon in the 20 growing seasons in a wet region of central China. We evaluated the influence of three training systems, Single Guyot (SG), Spur-pruned Vertical Shoot-Positioned (VSP), and Four-Arm Kniffin (4AK), on the performance of grapes and vines of Vitis vinifera L. Grapevine training systems determine the suitability for grape varieties in a specific growing region.
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