Manipulating the leaf area to fruit mass ratio alters the synchrony of total soluble solids accumulation and titratable acidity of grape berries

Abstract

Background and Aims This study investigated: (i) the importance of changing the leaf area: fruit mass ratio (LA : FM) by crop removal and/or shoot trimming on total soluble solids (TSS) concentration and content, pH, titratable acidity (TA) and berry mass; (ii) the extent to which changes in LA : FM ratio altered the synchrony TSS : TA ratio; and (iii) whether the responses were consistent for Pinot Noir and Sauvignon Blanc. Methods and Results Vertical shoot positioned–trained vines were trimmed shortly after fruitset or at veraison to six or 12 main leaves per shoot and crop thinned by removing 0, 50 or 75% of the bunches. TSS and pH, TA and fresh berry mass were measured weekly from pre‐veraison to harvest. TSS concentration accumulation in berries was slowed with shoot trimming and accelerated by crop removal, with crop removal having a greater effect. Trimming shoots at fruitset in combination with no crop removal resulted in the greatest delay in veraison (the start of TSS accumulation) and slowest rate of TSS accumulation. TSS content mirrored TSS concentration for LA : FM manipulations at fruitset but fewer differences were detected for LA : FM changes at veraison. In contrast, TA and pH were largely unaffected. Conclusions Changes to the LA : FM ratio via crop removal or shoot trimming modified berry TSS accumulation but not TA. Such desynchronisation was consistent for both cultivars. Significance of the Study Crop and/or leaf removal represent valuable means to manipulate the time to achieve target fruit TSS concentration and TA. The similar responses of the two cultivars indicate that LA : FM manipulation could potentially have common responses for different cultivars. The desynchronisation of berry components highlights the need to consider each berry component individually and in a dynamic manner by sampling throughout the ripening phase.

Effect of shoot topping intensity on 'Cabernet Franc' grapevine maturity in high-altitude region

“…For example, the results of the present study are in agreement with those obtained with 'Pinot Noir', in which reductions of the leaf area up to 50% caused a decrease in the accumulation of soluble solids, but no alteration in the acid content (Parker et al, 2015). However, in studies conducted with 'Syrah' (Leão et al, 2016) and 'Sauvignon Blanc' (Šuklje et al, 2013) grapevines, subjected to reductions of 12 and 44% in the total leaf area, respectively, no differences were observed in the concentration of SS.…”

“…The different levels of shoot topping resulted in a linear decrease of the soluble solids content in 'Cabernet Franc' grape berries in the different intensities of shoot topping, in both cycles evaluated (Figure 1 The higher the intensity of shoot topping, the lower the accumulation of soluble solids, which leads to the inference that the reduction in the ratio of leaf area to fruit caused a decrease in the carbohydrate supply to the berries (Parker et al, 2015). In addition, one can take into account the hypothesis that the remaining leaves were not able to increase the photosynthetic activity of plants that received the treatments (Vasconcelos & Castagnoli, 2000).…”

Hierarchical modelling partitions variation in vineyard fruit maturity for optimal sampling

“…Thus much attention in recent years has been devoted to precision farming systems to, at one level, document the variation and at the next, to apply site‐specific treatments to constrain diversity of productivity and composition (Bramley n.d.). In our system we obtained satisfactory estimates of the population mean through a random selection of vines within defined biomass zones for which a simple, field‐oriented procedure has been proposed (Bramley n.d., Ledesma and Carpena , Parker et al ). Other systems have been proposed, but not assessed by us, include ‘structured‐random’ (Wulfsohn et al , Vega et al ), ‘grid’ (Taylor et al , Baluja et al ), ‘staggered linear‐transect’ (Rigamonti et al ), ‘transects, normal to landscape trends’ (Austin and Heyligers , Burbidge ) and ‘grid within spatial variograms’ (Fortin et al , McBratney and Pringle ).…”

“…It appears sensible to combine recommendations from other researchers with our findings: sample from the mid‐cane/cordon (Belvini et al , Lefort et al ), and use grab sampling and a random grid (Vega et al ). Similarly, it may be that further efficiencies may be gained in circumstances where repeated samples are collected to determine date of harvest using linear regression (Considine and Frankish , Parker et al ). In such circumstances the sample size for each time of sampling may be reduced but this has not been considered as a part of this study.…”

Characterization of rhizosphere bacterial community and berry quality of Hutai No.8 (Vitis vinifera L.) with different ages, and their relations

“…Generally, grape quality is distinguished by a number of factors, such as berry maturity, vineyard productivity, plant vigor, health, floor and canopy management, rootstock, growing environment, tree-ages, and so on. [7][8][9][10][11][12][13] Like other living plants, grapevine roots both release many kinds of substances into the soil and absorb moisture, mineral salts and other nutrients from the soil. Plant rhizosphere, where material exchange occurs between roots and soil, is the soil nearest to the plant root system.…”