Auxin treatment of pre‐veraison grape (Vitis vinifera L.) berries both delays ripening and increases the synchronicity of sugar accumulation

Background and Aims: Pre‐veraison auxin treatments can delay grape berry ripening, but there is little information about their effects on berry development and wine composition. The aim of this study was to further investigate these effects and explore the practical implications of delaying ripening. Methods and Results: Treatment of pre‐veraison Vitis vinifera L. cv. Shiraz berries with 1‐naphthaleneacetic acid (NAA) significantly delayed ripening as measured by the accumulation of total soluble solids (TSS) and anthocyanins. The onset of the post‐veraison phase of berry size increase was delayed in NAA‐treated fruit, but these fruit were significantly larger than Control fruit at harvest. NAA‐treatments significantly increased the synchronicity of berry sugar accumulation. GC‐MS analysis of wine headspace volatiles showed significant, but largely small, differences in the concentration of 19 compounds. No significant difference in sensory properties was found between replicate small‐scale wine lots made from Control and NAA‐treated fruit. Conclusions: Auxin treatment delayed berry ripening, increased the synchronicity of sugar accumulation between berries, increased berry size and changed the levels of some volatile compounds, but did not affect wine sensory properties. Significance of the Study: We propose that NAA sprays might be used to delay grape berry ripening and increase the synchronicity of sugar accumulation, and therefore ripening, without deleterious effects on wine quality. This may be useful in controlling winery intake and fruit composition.     

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico

BACKGROUND: The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep‐red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high‐performance liquid chromatography. RESULTS: The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time‐independent process, whereas the concentration of peonidin increased linearly with time. Peonidin‐O‐acetyl‐glucoside was transferred from skin more slowly than petunidin‐O‐acetyl‐glucoside and malvidin‐O‐acetyl‐glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one‐tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION: Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance. Copyright © 2011 Society of Chemical Industry     

Influence of partial rootzone drying on the composition and accumulation of anthocyanins in grape berries (Vitis vinifera cv. Cabernet Sauvignon)

Background and Aims: The aim of the study was to investigate anthocyanin composition and accumulation in grape berries in response to the partial rootzone drying (PRD) irrigation technique.
Method and Results: The experiment was on Vitis vinifera cv. Cabernet Sauvignon, wherein PRD had a 40% water deficit relative to the control treatment. PRD decreased berry weight compared with the control, but did not influence total anthocyanin concentration. A significant increase in glucosides of delphinidin, cyanidin, petunidin and peonidin was found in response to PRD from the onset of anthocyanin accumulation (veraison), while malvidin-glucosides were unaffected by the irrigation treatment. The PRD treatment did not cause changes in the proportions of acetyl-, 3- p -coumaroyl- and monoglucoside anthocyanins. Wines produced from the treatments showed no difference in total monomeric anthocyanin, but relative increases (15%) in wine colour density, total tannin and polymeric pigment occurred in response to the PRD treatment. The anthocyanin composition of the wines reflected the response shown in the grapes, where the relative contribution of non-malvidin anthocyanins to total anthocyanins was significantly increased in wines from the PRD treatment.
Conclusions: The differences in anthocyanin composition observed in response to PRD could not be accounted for by changes in bunch microclimate, and most likely reflect differences in the methylation step of anthocyanin synthesis.
Significance of the Study: The observed changes in anthocyanin composition under the PRD irrigation system have not been previously reported in response to water deficit, and may reflect a unique response to within-vine signalling induced by PRD.     

Spatio‐temporal dynamics of grape anthocyanin accumulation in a Tempranillo vineyard monitored by proximal sensing

Background and Aims: The spatio‐temporal variability of phenol grape composition in a vineyard can be characterised by using precision viticulture tools. Characterising anthocyanin variation in grapes requires a large number of observations, which can be done by using proximal sensors in the field. This study characterises the dynamics of spatial‐temporal variability in fruit anthocyanin content at different stages from veraison to harvest using a newly available non‐destructive fluorescence method. Methods and Results: The study was conducted in a Tempranillo (Vitis vinifera L.) vineyard (Navarra, Spain) during the 2010 season. A handheld, non‐destructive fluorescence‐based proximal sensor was used to monitor the anthocyanins of the berries at six different times between veraison and harvest. The fluorescence‐based anthocyanin indices were significantly correlated with the anthocyanin contents in berries (R² ranged from 0.74 to 0.78). The variability of the anthocyanin content decreased during the ripening period, reaching a minimum at harvest. Although the mean anthocyanin content of fruit increased from veraison until mid‐September, when a fairly stable value was reached that remained constant until harvest, spatial patterns within the vineyard changed over the whole ripening period. The spatial correlations between the anthocyanin content at each monitoring date and harvest time revealed that larger similarities in the spatial distribution of anthocyanins occurred at veraison and 10 days before harvest. Conclusions: Grape anthocyanins accumulated from veraison until around 1 month before harvest, whereas their spatial pattern within the vineyard changed throughout the whole ripening period. Significance of the Study: Knowledge of the spatial‐temporal variation of the anthocyanin content within a vineyard may assist decision making regarding sampling and vineyard management, especially if vineyard segmentation is employed.     

Elevated temperature decouples anthocyanins and sugars in berries of Shiraz and Cabernet Franc

Background and Aim: We tested the hypothesis that elevated temperature decouples anthocyanins and total soluble solids (TSS) in developing berries and explored the effects of fruit load and water supply on the putative decoupling. Methods and Results: We established three 2² factorial experiments where two thermal regimes (elevated temperature, control) where combined with varieties (Shiraz, Cabernet Franc), fruit loads (bunch removal, control) or water regimes (irrigated, water deficit). The relationship between anthocyanins and TSS had a lag phase where TSS increased with no change in anthocyanins and an approximately linear phase where both traits increased in parallel for TSS > 11.4°Brix. Mean residuals in the linear phase were 0.065 mg/g in controls compared with ?0.064 mg/g in the heated treatment, hence demonstrating the thermal decoupling of anthocyanins and TSS across varieties fruit loads and water regimes (P < 0.0001). Delayed onset of anthocyanin accumulation at elevated temperature explained the decoupling. Water deficit increased the anthocyanin : TSS ratio. Conclusion: Elevated temperature decoupled anthocyanins and sugars in berries by a relative shift in onset rather than rate of accumulation of these berry components. Significance of the Study: Warming trends are likely to disrupt the anthocyanin : sugar ratio in berries with consequences for colour : alcohol balance in red wines. Water deficit established shortly before veraison could partially restore these ratios.     

Original article: Anthocyanin profile in Monastrell grapes in six different areas from Denomination of Origen Jumilla during ripening stage

The aim of our research has been to investigate the pattern of accumulation of anthocyanins in the skin of Monastrell variety and to establish if the fingerprint of this cultivar changed in six different areas from Denomination of Origen Jumilla during ripening stage in two consecutive seasons (2007 and 2008). The results show that the anthocyanin profile for Monastrell variety is maintained: it could be observed a higher proportion of non‐acylated anthocyanins, a higher proportion of coumarylated than acetyl derivatives and a higher proportion of trihydroxylated than dihydroxylated anthocyanins. During ripening period, in all zones studied, we observed the same trends: increasing of cyanidin, peonidin and malvidin‐3‐glucoside and decreasing of the other two monoglucosides (delphinidin and petunidin). Slightly quantitative differences were observed for the different zones in the 2 years studied, leading to the conclusion that edaphoclimatic factors also influence the accumulation of anthocyanin compounds.     

Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development

The flavan-3-ol and proanthocyanidin composition of both seeds and skin of Vitis vinifera L. cv. Shiraz grapes was determined by reversed-phase HPLC after acetone extraction and acid-catalysis in the presence of excess phloroglucinol. Samples were taken at weekly intervals from fruit-set until commercial harvest. The main period of proanthocyanidin accumulation in grape seeds occurred immediately after fruit-set with maximum levels observed around veraison. Over two seasons there was variation in both the timing and content of proanthocyanidins in seeds. In skin, proanthocyanidin accumulation occurred from fruit set until 1–2 weeks after veraison. Proanthocyanidin subunit composition was different in seeds and skin and changed during berry development but the mean degree of polymerisation of the tannin polymers in skins was higher than in the seeds at all stages of berry development. Proanthocyanidin levels in both seeds and skin decreased between veraison and harvest. Additional proanthocyanidin subunits were released when the residues remaining after acetone extraction were subjected to direct acid-catalysis in the presence of phloroglucinol. In the seeds, these accounted for much of the post-veraison decrease, but not in grape skin. At harvest, 75% of extractable berry proanthocyanidin was in the seeds. Accumulation of proanthocyanidins in the seeds appears to be independent of that in the skins, but in both tissues synthesis occurs early in berry development and maximum levels are reached around veraison.     

Effects of partial rootzone drying on yield, ripening and berry ABA in potted Tempranillo grapevines with split roots

Our objective was to investigate whether grape berry growth and colour development is associated with variation in abscisic acid (ABA) levels during ripening under an irrigation regime of partial rootzone drying (PRD). The study was carried out using container‐grown Tempranillo grapevines (established as fruit‐bearing cuttings) with a split root system (occupying two contiguous pots) and grown under controlled conditions. Three irrigation treatments were imposed – a control (well watered), and two forms of deficit irrigation, viz. partial rootzone drying (PRD), and sustained deficit irrigation (SDI). Under SDI, a given volume of irrigation water was applied uniformly and simultaneously to both sides of the split roots of each vine. Under the PRD regime, the same total volume of irrigation was applied, but as separate allocations to each side of the split root system in turn, and alternating on a 10‐day cycle. Because both deficit treatments received the same total amount of irrigation water (about 50% of the volume applied to controls), we were able to distinguish between the effects of deficit irrigation per se, versus any specific impact PRD might be having on vine performance. Outcomes were as follows. Compared to well‐watered control vines, yield per plant, and weight per bunch were both reduced significantly under SDI, but were sustained close to control values under the PRD regime. SDI and PRD thus differed significantly in their respective impacts on vine performance, and comparing just these two forms of deficit irrigation, PRD resulted in greater yield, higher bunch weight, bigger leaf area and increased berry weight compared with the SDI treatment. Moreover, PRD also induced greater accumulation of skin anthocyanins at harvest, compared to SDI. Berry ABA concentration increased continuously throughout veraison, achieving a maximum at the end of this period. The increase of berry ABA concentration was earlier and faster in PRD than in SDI, which exhibited only a slight increase in berry ABA by the end of veraison. These distinctive responses to PRD compared to SDI imply that the alternating wet‐dry cycles of PRD, rather than simply a deficit irrigation, as in SDI, had a distinctive effect on growth, ripening and berry composition. Our data imply that these different responses might be related to ABA physiology, and especially to ABA levels in berries during ripening.     

Preparation of novel distinct highly aromatic liquors using fruit distillates

This work describes the preparation of aromatised liquors using deodorised and concentrated fruit distillates. The raw spirits were improved by making a partial deodorisation, using activated charcoal, followed by concentration, using a distiller. The liquors were prepared by a maceration process. The procedure is exemplified using fig distillates to prepare myrtle berry liquors. The acidity, copper, polyphenol and anthocyanin indexes and volatile and anthocyanin profiles were monitored in each preparation step. The concentration process increased the ethanol proof to 75% v/v and decreased the acidity and the copper content. The partial deodorisation decreased the levels of high molecular weight volatiles, while the content of lower molecular weight compounds that contribute to flavour was maintained. Delphinidin‐3‐O‐glucoside, cyanidin‐3‐O‐glucoside, petunidin‐3‐O‐glucoside and malvidin‐3‐O‐glucoside were the major anthocyanins.     

High‐pressure recovery of anthocyanins from grape skin pomace (Vitis vinifera cv. Teran) at moderate temperature

The objective was to evaluate the influences of the high hydrostatic pressure extraction parameters on the recovery of anthocyanins from the grape skin pomace extracts (Vitis vinifera cv. Teran) under moderate temperatures. Studied parameters were: solvents (methanol and ethanol); solvent concentrations (30, 50, and 70%); pressures (300, 400, and 500 MPa); times (3, 6.5, 10 min); and temperatures (22, 26, 30 °C). Predominant anthocyanins in all extracts were malvidins (malvidin‐3‐glucoside as the main compound) representing 55.77% of overall anthocyanin content. The type of solvent did not significantly influence anthocyanin extraction yield, while decreased solvent concentration (increased solvent‐to‐water ratio) significantly improved extraction of anthocyanins. Increase of pressure enhanced extraction yield of the anthocyanins but temperature showed stronger impact on the anthocyanins recovery. This investigation evidenced that the best conditions for HHPE of anthocyanins from grape pomace were extraction time 3.39 min, extraction temperature 29.48 °C, pressure 268.44 MPa and solvent concentration 70%.

Practical applications

Due to increased interest for the use of cheap winery byproducts as a source of expensive polyphenols for functional food production, skins from grape pomace became valuable raw material. Therefore, there is a need to evaluate the influence of HHPE innovative extraction technology on its nutritive value during processing. Optimizing parameters for polyphenolic recovery from grape pomace is directly related with nutritional value and economics of food engineering during industrial processing. Obtained results showed that the HHPE under lower temperatures is suitable for the extraction process of anthocyanins from grape skin pomace, but more research is needed to identify other food‐grade solvents with their corresponding concentrations that are useful for the extraction assisted with high hydrostatic pressure.     

The effect of bunch shading on berry development and flavonoid accumulation in Shiraz grapes

Opaque boxes were applied to bunches of Shiraz grapes prior to flowering to determine the effect of sunlight on berry development and accumulation of flavonoids. The boxes were designed to maintain airflow while excluding light and thus to minimise changes in temperature and humidity. There was no significant effect of shading on sugar accumulation and in two of the three seasons studied there was no effect on berry weight. Chlorophyll concentration was much lower in the shaded fruit, which appeared pale yellow until veraison. The fruit coloured normally in the shaded bunches and in two of the three seasons there was no significant change in anthocyanin content. Expression of the gene encoding UDP-glucose flavonoid-3-O-glucosyl transferase (UFGT), a key gene in anthocyanin synthesis, increased after veraison and was similar in both shaded and exposed fruit. Anthocyanin composition was altered in the shaded fruit, which had a greater proportion of the dioxygenated anthocyanins, the glucosides of cyanidin and peonidin. Shading had no significant effect on the levels of condensed tannins in the skin or seeds of ripe fruit. Shading significantly reduced the levels of flavonols in the grape skin. In the exposed fruit, flavonol concentration was highest around flowering then declined as the berries grew, but there was an increase in flavonols per berry during ripening. When the boxes were applied before flowering, shaded fruit had much lower levels of flavonols throughout berry development and at harvest the level of flavonols were less than 10% of that in exposed fruit. A gene encoding flavonol synthase (FLS) was expressed at flowering and during ripening in exposed grapes but its expression was greatly reduced in shaded fruit. The results indicate that shading had little effect on berry development and ripening, including accumulation of anthocyanins and tannins, but significantly decreased flavonol synthesis.     

Canopy microclimate and berry composition: The effect of bunch exposure on the phenolic composition of Vitis vinifera L cv. Shiraz grape berries

Studies on the effect of light exposure on specific phenolic compounds of berries from Shiraz vines grown in a hot climate are reported. Berries that had developed on bunches receiving high levels of ambient light generally had the highest relative levels of quercetin-3-glucoside and a lower proportion of their malvidin anthocyanins as the coumarate derivative, compared to berries that had developed on bunches in shaded canopy conditions. The response of total anthocyanin levels to treatment conditions was variable and depended on the degree of bunch shading and the resultant berry temperature. It appears that a high degree of bunch exposure in hot climates is not conducive to optimal anthocyanin accumulation in berries. The interactive effects of light and temperature on berry phenolic content and concentration are discussed.     

Rootstock and salinity effects on rates of berry maturation, ion accumulation and colour development in Shiraz grapes

Shiraz grapevines on either their own roots, or on the rootstocks Ramsey, 1103 Paulsen, 140 Ruggeri or 101–14, were grown at two separate sites within the Murray‐Darling viticultural region with similar irrigation regimes but with an irrigation water salinity of either 0.43 dS/m (low salinity site) or 2.3 dS/m (high salinity site). Rootstock effects on grape berry development, ion concentrations, soluble solids and acidity were followed during one season. Wines were also made and compared using spectral analysis and sensory evaluation. Rootstock effects that were common across both sites were (1) a close relationship between K+and soluble solids accumulation in developing grape berries which commenced at the onset of veraison and was indicative of a link between K+and sucrose transport in the phloem, and (2), higher wine K+, pH and colour hue for all rootstocks with one exception, namely 101–14 at high salinity where 101–14 responded similarly to own roots. Juice K+, pH and loss of K+from juice during winemaking were highest for grapes from the high salinity site. Mean berry weight was smaller and the range in berry size across rootstocks was narrower at the saline site. The narrower range in berry sizes may have contributed to fewer rootstock effects on wine spectral characteristics at high salinity. There was no effect of rootstock on CO₂ assimilation rate or stomatal conductance at either site, although intrinsic leaf‐based water‐use efficiency measured as A/g was 50% higher at the saline site. All treatments exhibited berry shrivel at maturity, but the extent was smaller at high salinity. Slower development of berry colour during veraison was observed on some rootstocks, for example 101–14, and while unrelated to canopy size per se, a higher leaf‐to‐fruit ratio for 101–14 may have been a factor. Slower berry colour development during veraison had no bearing on the colour density of wine made from the harvested grapes.     

香格里拉海拔高度对‘赤霞珠’葡萄果实花色苷的影响

利用高效液相色谱(HPLC)测定香格里拉不同海拔高度‘赤霞珠’果实中各发育阶段主要花色苷成分变化。结果表明,在‘赤霞珠’果实中共检测到10余种花色苷衍生物,主要有矢车菊色素、飞燕草色素、芍药色素、矮牵牛色素和锦葵色素5种。香格里拉地区‘赤霞珠’葡萄花色苷含量在转色初期随海拔升高而增加,尤其在西当试验点较为明显,因为高海拔地区有着较强的光照和辐射,温度较低,有利于花色苷合成。同时表明,在转色期间低海拔试验点的葡萄花色苷含量较高,在成熟期为高海拔试验点花色苷含量较高,影响花色苷合成的因素错综复杂,各种因素之间有交互作用,需进一步研究。     

Shoot thinning effects on seasonal whole‐canopy photosynthesis and vine performance in Vitis vinifera L. cv. Barbera

Background and Aims: While shoot thinning is one of the most widely applied practices in the vineyard as a tool to regulate canopy density and/or crop level, its physiological bases are still fairly obscure and have been poorly investigated. Our aim was to assess seasonal modification of whole‐canopy net CO₂ exchange rate (NCER) in thinned and non‐thinned grapevines, as well as establishing correlations with grape composition. Methods and Results: Potted, mature cv. Barbera vines were thinned (ST) to 10–15 shoots/m over the two trial years and compared with a non‐thinned control (C). The data logged each season included whole‐vine NCER monitored pre‐ and post‐veraison for periods of variable lengths, vine growth, yield components and grape composition. While final leaf area per vine did not differ between treatments, ST showed reduced yield and improved berry colour and must sugar accumulation. In 2009, NCER/vine recovery in ST was 85% of C at verasion, whereas in 2010 full recovery was already reached around bloom. Conclusions: A load of 15 shoots/m maximised canopy efficiency by inducing the fastest recovery of whole‐vine photosynthesis and markedly improved sugar, colour and phenolics. Retaining 10 shoots/m delayed NCER recovery while improving overall grape composition as compared to C. Significance of the Study: Direct assessment of the complex seasonal canopy NCER dynamics triggered by shoot thinning indicates that the source‐sink balance evolves in ST towards a higher supply of assimilates per unit of crop than that available in non‐thinned canopies during the veraison‐to‐harvest period.     

Irrigation of grapevines with saline water at different growth stages: Effects on leaf,wood and juice composition

Background and Aims: This study reports on the effects that timing of saline irrigation has on leaf and wood tissue concentrations of Na⁺ and Cl^– and on juice composition. Methods and Results: Colombard vines on Ramsey rootstock were drip irrigated with saline water during any one of four annual growth stages: pre‐flowering, berry formation, berry ripening and postharvest. At other times, vines were irrigated with non‐saline water as was the control. Salts were annually flushed from the rootzone. Over six seasons, saline irrigation caused five‐ and sevenfold rises, respectively, in the leaf and juice Na⁺ concentrations and two‐ and fourfold rises in respective Cl^‐ concentrations. Saline irrigation raised juice pH and this was associated with a rise in juice Na⁺. Normalising responses for inter‐treatment differences in the seasonal salt load to isolate the effects of timing showed that juice Cl^‐ concentration was most sensitive to saline irrigation during berry formation and juice malate concentration most sensitive to saline irrigation pre‐flowering. Conclusion: Cl^‐ uptake was greatest when saline irrigation was applied early in organ formation, whereas Na⁺ uptake reflected seasonal salt load in irrigation water. Significance of the Study: In vines on the chloride excluding rootstock Ramsey, yield loss under saline irrigation was associated with high concentrations of sodium in the leaf.     

Pre‐ or post‐harvest applications of putrescine and low temperature storage affect fruit ripening and quality of ‘Angelino’ plum

BACKGROUND: Plum has a very short storage life. The role of pre‐ or post‐harvest applications of putrescine (PUT) and low temperature storage on fruit ripening and quality was investigated in plum fruit (Prunus salicina Lindl. cv. Angelino). RESULTS: Pre‐ or post‐harvest PUT treatments [(0.1, 1.0 or 2.0 mmol L^?1) + 0.01% Tween‐20 as a surfactant] delayed and suppressed the climacteric ethylene production and respiration rate irrespective of the method used to apply PUT. PUT‐treated fruit following low temperature storage (0 ± 1 °C; 90 ± 5% RH), at the ripe stage exhibited higher fruit firmness and titratable acidity (TA), while soluble solids content (SSC), levels of ascorbic acid, total carotenoids and total antioxidants were lower than in untreated fruit. Fruit both sprayed with PUT and stored in low temperature for 6 weeks, at the ripe stage showed reduced respiration rate, delayed changes in the SSC:TA ratio and levels of total carotenoids compared to post‐harvest PUT application. CONCLUSION: Pre‐harvest application of 2.0 mmol L^?1 PUT 1 week before the anticipated commercial harvest was more effective in delaying plum fruit ripening and can be used to extend the storage (0 ± 1 °C) life of plums for up to 6 weeks with minimum losses in fruit quality. Copyright © 2008 Society of Chemical Industry     

Relationships between seed and berry development of Vitis Vinifera L. cv Shiraz: Developmental changes in seed morphology and phenolic composition

Berries were collected regularly from fruit set to berry maturity from irrigated (Shiraz) grapevines in a Barossa valley vineyard. Seeds were removed for detailed study of physical attributes (weight, moisture, colour) and phenolic composition (seed tannins). Three phases of seed growth and development were discerned: (1) a phase of seed growth characterised by a steady increase in both fresh weight and dry weight, biosynthesis and accumulation of flavan‐3‐ols and tannins, and green appearance; (2) a transition phase where seed fresh weight and dry weight reached a maximum, but with continuing enlargement of the basal end. Accumulation of flavan‐3‐ols and seed tannins also reached a maximum during phase 2, and was accompanied by an onset of tannin oxidation, and yellow appearance; and finally, (3) a phase of seed drying and maturation defined by a decrease in fresh weight due to water export, a sustained oxidation of tannins, and overall brown appearance. These phases in seed development correspond to particular stages in berry development. Seeds reached maximum fresh seed weight and full size at the beginning of berry colouring (veraison), while maximum dry seed weight coincided with maximum berry weight. Changes in seed phenolics were linked to berry development and maturation. Changes in seed coat colour were also related to developmental changes in berry anthocyanins and total skin phenolics, indicating that the external appearance and colour of the seed coat may be used as an additional indicator of overall berry ripeness. A graduated colour chart was developed to provide an objective index of seed coat colour and thus developmental status of seeds and berry.     

Impacts of crop level,soil and irrigation management in grape berries of cv ‘Trincadeira’ (Vitis vinifera L.)

Berry size and crop yield are widely recognized as important factors that contribute to wine quality. The final berry size indirectly affects the phenolic concentration of the wine due to skin surface-to-berry volume ratio. The effects of different irrigation levels, soil management and plant crop level on growth of ‘Trincadeira’ berries were studied. In order to test the influence of different irrigation levels (rainfed, pre-veraison and post-veraison), different soil management (tillage and natural cover crops) and different plant crop levels (8 and 16 clusters per vine), leaf water potential, skin anthocyanin, polyphenols, berry skin and seed fresh weight were measured in fruits. The segregation of berries into three different berry classes: small, medium and large, allowed to identify different levels of contribution of soil management and irrigation level into berry, skin and seeds ratios. As expected, higher water availability due to irrigation and soil tillage management during berry development induced an increase in berry flesh weight and this was more evident in larger berries; however, berry skin and seed fresh weight remained unchanged. Also, anthocyanins did not show significant differences.