Pea-sized Berries Research Articles

Biocontrol of Botrytis cinerea as Influenced by Grapevine Growth Stages and Environmental Conditions.

The growth of four commercial biocontrol agents (BCAs: Bacillus amyloliquefaciens (BAD), Aureobasidium pullulans (APD), Metschnikowia fructicola (MFN), and Trichoderma atroviride (TAS)) was evaluated using turbidimetric assays on artificial substrates mimicking the chemical berry composition at four stages: pea-sized berries, veraison, softening, and ripe berries. The response of BCA growth differed among BCAs. Subsequently, the BCAs' population size was assessed after 1 to 13 days of incubation on the substrate mimicking ripe berries at 15 to 35 °C. The population size of BAD increased with temperatures, while that of MFN decreased; the population sizes of APD and TAS showed bell-shaped patterns with lower growth at 15 or 35 °C. Finally, the BCAs were applied to ripe berries and then incubated at 15 to 30 °C. After 1 to 13 days, the berries were inoculated with B. cinerea and incubated for 7 days, after which the BCA control efficacy was assessed. The highest control was observed at 25 °C for BAD and APD, at 15 to 20 °C for MFN, and at 25 to 30 °C for TAS. The results confirm that the plant substrates and temperature affect the population size of the BCA following application; temperature also affects the preventative efficacy of BCA against B. cinerea.

Early yield prediction in different grapevine varieties using computer vision and machine learning

Yield assessment is a highly relevant task for the wine industry. The goal of this work was to develop a new algorithm for early yield prediction in different grapevine varieties using computer vision and machine learning. Vines from six grapevine (Vitis vinifera L.) varieties were photographed using a mobile platform in a commercial vineyard at pea-size berry stage. A SegNet architecture was employed to detect the visible berries and canopy features. All features were used to train support vector regression (SVR) models for predicting number of actual berries and yield. Regarding the berries’ detection step, a F1-score average of 0.72 and coefficients of determination (R2) above 0.92 were achieved for all varieties between the number of estimated and the number of actual visible berries. The method yielded average values for root mean squared error (RMSE) of 195 berries, normalized RMSE (NRMSE) of 23.83% and R2 of 0.79 between the number of estimated and the number of actual berries per vine using the leave-one-out cross validation method. In terms of yield forecast, the correlation between the actual yield and its estimated value yielded R2 between 0.54 and 0.87 among different varieties and NRMSE between 16.47% and 39.17% while the global model (including all varieties) had a R2 equal to 0.83 and NRMSE of 29.77%. The number of actual berries and yield per vine can be predicted up to 60 days prior to harvest in several grapevine varieties using the new algorithm.

Indole-3-butyric acid, an alternative to GA3 for bunch quality enhancing of table grape Vitis vinifera L. cv. Superior Seedless

Gibberellic acid (GA3) is the most widely used plant growth regulator to thin out bunches and increase berry size in seedless table grapes, but there is evidence of its negative effects, including loss of fertility and malformations of the rachis. This study analyses the effects of applying the auxin indole-3-butyric acid (IBA), as a novel alternative, on fruit yield, bunch structure, anatomy and postharvest quality of cv. Superior Seedless. The application of IBA and GA3 at different phenological stages (15 cm shoot length, full bloom, fruit set and pea-size berry) and doses (2, 20 and 50 ppm) were compared in a two-growing season experiment. Spraying IBA at full bloom or fruit set, improved bunch weight by increasing the size and weight of the berries, correlating with the promotion of rachis vascular tissues. Bunches treated with IBA retained a greater number of berries at harvest without generating compactness, since the elongation of the rachis internodes and lateral shoulders were also promoted. In addition, IBA augmented postharvest quality of bunches by reducing rachis browning and increasing berry firmness. These results suggest that the use of IBA is a beneficial technology to improve bunch structure and quality in seedless grapes. Highlights IBA effects applied at different dosages and phenological stages was evaluated. IBA at full bloom and fruit set improved bunch and berry weight and berry size. The number of berries per bunch increased with IBA at full bloom and fruit set. IBA increased lateral rachis internode and lateral rachis length via promotion of vascular tissues. IBA increased postharvest quality, reduced rachis browning and increased of berry firmness.

Development of downy mildew in grape bunches of susceptible and resistant cultivars: infection pathways and limited systemic spread

Background and Aims Plasmopara viticola development in bunches of two grapevine cultivars, the resistant Divico and the susceptible Chasselas, was studied by using microscopy and molecular detection to investigate tissue susceptibility and the extent of colonisation. Methods and Results Bunches were inoculated with P. viticola at four phenological stages, and the development of downy mildew was recorded. Visible symptoms were evident after the first three inoculation stages for Chasselas. Inoculation at inflorescence swelling resulted in the desiccation of the inflorescence and at the end of flowering led to desiccation of parts of the bunches with some berries developing normally until ripening. After inoculation of pea-sized berries, brown rot symptoms appeared, whereas no infections were observed after inoculation at veraison. Histological and molecular examination showed that downy mildew invaded almost all bunch tissues but required an active stomata as an infection site. Mycelium and haustoria, however, were never observed in the vascular tissues. For Divico, inoculation at early stages of development resulted in sparse infections with limited colonisation. Conclusion Downy mildew systemic development occurs only between adjacent tissues meaning that as the stomata lose function the severity of the infection is reduced. Significance of the Study Limited infection justifies the maintenance of a fungicide control program for the resistant cultivar Divico.

Deep learning and computer vision for assessing the number of actual berries in commercial vineyards

The number of berries is one of the most relevant yield components that drives grape production in viticulture. The goal of this work was to estimate the number of actual berries per grapevine using computer vision and deep learning in commercial vineyards. Images from the visible range (RGB) were acquired from a set of 96 grapevines (Vitis vinifera L.) at pea-size berry stage using a red, green and blue camera (RGB). At harvest, the number of berries and per vine was manually assessed as the ground-truth values. The algorithm involved computer vision to detect berries in the images and to extract canopy features, in order to gain information about canopy occlusion. These were used by the machine learning regression models built to estimate the number of actual berries per vine. A SegNet architecture was used to segment individual berries and several canopy related features. Four datasets were created combining the number of estimated visible berries and different canopy features. Three different regression models were tested on the four datasets. The best results were achieved with support vector regression (SVR) on a dataset including six canopy features. This method yielded a root mean squared error (RMSE) of 205 berries, a normalised root mean squared error (NRMSE) of 24.99% and a coefficient of determination (R2) of 0.83 between the number of estimated and the number of actual berries per vine. The results show that the number of actual berries in grapevines can be assessed with high accuracy up to 60 days prior to grape harvest, using the developed algorithm based on computer vision and deep learning.

Effect of Seawater Irrigation on the Sugars, Organic Acids, and Volatiles in ‘Reliance’ Grape

Ongoing climate change in recent decades exacerbated the decline in agricultural water use, and seawater irrigation could feasibly alleviate the shortage of water resources, which restricts viticulture in some countries. However, studies on the effects of seawater irrigation on grape volatiles are limited. Herein, ‘Reliance’ grapevines were irrigated with diluted seawater (10% concentrations) in the field since the pea-size berry stage (S1), stage EL 32 (S2), and the pre-veraison period (S3) every seven days. Results showed irrigation with seawater significantly increased the sugar content and decreased the organic acids when compared with the control berries. Seawater irrigation did not induce secondary soil salinization, and it enhanced the volatiles in the fatty acid and isoprene pathways without affecting the amino acid pathway aroma. More terpenes were found in seawater-treated berries, including citronellol, β-myrcene, α-terpineol, and trans-rose oxide. Gene profiling by RT-qPCR analysis revealed that VvLOXA could be the primary gene in C6 volatile biosynthesis altered by the seawater. Moreover, seawater irrigation during the pea-size period had the best effect on fruit quality. This work adds to our understanding of the effect of seawater irrigation on grape aroma quality and provides a sufficient basis for the utilization of seawater in vineyards.

EARLY LEAF REMOVAL AS STRATEGY TO REDUCE BOTRYTIS BUNCH ROT ON CHARDONNAY GRAPEVINE IN HIGH ALTITUDE REGION OF SANTA CATARINA STATE

The objective of this work is to compare different periods of leaf removal in the control of this disease in Chardonnay grown in high altitude regions of Santa Catarina - Brazil. The experiments were conducted in São Joaquim city, in 2018 and 2019 growing seasons. The treatments consisted of leaf removal at the phenological stages of full bloom, buckshot berries, pea-sized berries, veraison, and the control treatment, in which the plants without leaf removal. Epidemiological variables were calculated from: beginning of symptom appearance; times to reach maximum disease incidence and severity; maximum disease incidence and severity; and areas under the incidence and severity disease progress curves. The results of the present work show the importance of early leaf removal of Chardonnay in management of B. cinerea, it is recommended to be carried out at the phenological stages of full bloom, buckshot berries and pea-sized berries, as it provides a reduction in the maximum severity of B. cinerea and a reduction of AUSDPC. The rate of disease progression demonstrated that B. cinerea infection and development was faster in plants not submitted to leaf removal. The management of early leaf removal is efficient to prevent the development of B. cinerea in Chardonnay.

A szálvesszőgyűrűzés hatása a bogyóhéj fenolos koncentrációjára három csemegeszőlőfajta esetében

The effect of cane girdling on grape skin phenolic composition and concentration was examined on three Hungarian table grape varieties, i.e. noir-skinned 'Esther', rose-skinned 'Lidi', and blanc-skinned 'Fanny'. Girdling was conducted at the BBCH 75 phenological growth stage (pea-sized berries). A significant increase was observed in anthocyanin-glycosides in the treated berry skins irrespective of the cultivar. Other phenolic substances (gallic acid, trans-resveratrol, (+)-catechin, quercetin-3-glucuronide) were less sensitive to the treatment, but noticeable differences were found between the genotypes.

Yield components detection and image-based indicators for non-invasive grapevine yield prediction at different phenological phases

Forecasting vineyard yield with accuracy is one of the most important trends of research in viticulture today. Conventional methods for yield forecasting are manual, require a lot of labour and resources and are often destructive. Recently, image-analysis approaches have been explored to address this issue. Many of these approaches encompass cameras deployed on ground platforms that collect images in proximal range, on-the-go. As the platform moves, yield components and other image-based indicators are detected and counted to perform yield estimations. However, in most situations, when image acquisition is done in non-disturbed canopies, a high fraction of yield components is occluded. The present work’s goal is twofold. Firstly, to evaluate yield components’ visibility in natural conditions throughout the grapevine’s phenological stages. Secondly, to explore single bunch images taken in lab conditions to obtain the best visible bunch attributes to use as yield indicators.In three vineyard plots of red (Syrah) and white varieties (Arinto and Encruzado), several canopy 1 m segments were imaged using the robotic platform Vinbot. Images were collected from winter bud stage until harvest and yield components were counted in the images as well as in the field. At pea-sized berries, veraison and full maturation stages, a bunch sample was collected and brought to lab conditions for detailed assessments at a bunch scale.At early stages, all varieties showed good visibility of spurs and shoots, however, the number of shoots was only highly and significantly correlated with the yield for the variety Syrah. Inflorescence and bunch occlusion reached high percentages, above 50 %. In lab conditions, among the several bunch attributes studied, bunch volume and bunch projected area showed the highest correlation coefficients with yield. In field conditions, using non-defoliated vines, the bunch projected area of visible bunches presented high and significant correlation coefficients with yield, regardless of the fruit’s occlusion.Our results show that counting yield components with image analysis in non-defoliated vines may be insufficient for accurate yield estimation. On the other hand, using bunch projected area as a predictor can be the best option to achieve that goal, even with high levels of occlusion.

Effects of leaf removal on grape cluster architecture and control of Botrytis bunch rot in Sauvignon Blanc grapevines in Southern Brazil

Management practices, such as leaf removal, can affect grape cluster architecture and the microclimate around the cluster, which influences the development of Botrytis bunch rot disease. The timing of leaf removal among five different phenological stages was investigated as a tool for managing grape cluster architecture-related variables and for managing Botrytis bunch rot of Sauvignon Blanc grapevines. A commercial vineyard located in São Joaquim municipality, in the highland region of Santa Catarina State, Southern Brazil, was assessed in a randomized complete block design during the 2015 and 2016 growing seasons. The treatments consisted of leaf removal of four basal leaves around clusters at the phenological stages of full bloom, buckshot berries, pea-sized berries, veraison, and 15 days after veraison. At harvest, cluster architecture variables (cluster length, cluster mass, rachis mass, number of berries, berry mass, and cluster compactness index) and Botrytis bunch rot incidence and severity were assessed weekly from the first appearance of symptoms to harvest. Disease progress curves were constructed and compared to several epidemiological parameters. There was no significant effect of the removal of four basal leaves on the cluster architecture-related variables (cluster and berry masses, number of berries, and cluster compactness index); however, reduced the intensity of Botrytis bunch rot. Leaf removal carried out before veraison significantly reduced (P < 0.05) the incidence, severity, AUDIPC, and AUDSPC of Botrytis cinerea in Sauvignon Blanc when compared with those of vines without leaf removal. Early leaf removal at the phenological stages of full bloom, buckshot berries, and pea-sized berries reduced the severity of B. cinerea infection and showed in the phenological stage of full bloom the lowest values for AUDSPC of 199.26 and 171.30 in the 2015 and 2016 growing seasons, respectively. The results of this study suggest that leaf removal carried out before veraison during the phenological stages of full bloom, buckshot berries, or pea-sized berries should be recommended for Sauvignon Blanc cultivar production to reduce Botrytis bunch rot in the highland regions of Santa Catarina State, Southern Brazil.

Phenolic composition of wine from 'Cabernet Sauvignon' grapes subjected to leaf removal at different timing in Southern Brazil

Abstract: The objective of this work was to evaluate the phenolic composition of wine from 'Cabernet Sauvignon' (Vitis vinifera) grapes subjected to leaf removal management at different timing, in a high-altitude region. The experiment was carried out in the 2015 and 2016 vintages, in a vineyard located in the municipality of São Joaquim, in the state of Santa Catarina, Brazil. The treatments consisted of different periods of leaf removal in the clusters, at five phenological stages ‒ full bloom, buckshot berries, pea-sized berries, veraison, and 15 days after veraison ‒, and of a control without leaf removal. At harvest, 50 kg of each treatment were collected for winemaking. The contents of gallic acid, catechin, p-coumaric acid, vanillic acid, resveratrol, quercetin, rutin, and kaempferol were evaluated. The results showed the importance of leaf removal before veraison, to obtain wine with a higher concentration of phenolic compounds, which favors wine quality. The leaf removal management promotes the increase of gallic acid, vanillic acid, p-coumaric acid, resveratrol, quercetin, and kaempferol in wine. The early leaf removal before veraison results in increases in vanillic acid, p-coumaric acid, resveratrol, quercetin, and kaempferol. The wine made from grapes not subjected to leaf removal shows higher values of catechin and rutin.

Agronomic performance of 'Cabernet Sauvignon' with leaf removal management in a high-altitude region of Southern Brazil

Abstract: The objective of this work was to compare the effect of different times of leaf removal on the vegetative-productive efficiency and on the chemical and physical characteristics of 'Cabernet Sauvignon' clusters in a high-altitude region of the state of Santa Catarina, Brazil. The experiment was conducted in the 2015 and 2016 vintages, in a commercial vineyard, located in the municipality of São Joaquim, in the state of Santa Catarina, at 1,230-m altitude. The treatments consisted of different times leaf removal in the cluster zone, in the following phenological stages: full bloom, buckshot berries, pea-sized berries, veraison, and 15 days after veraison, besides a control without leaf removal. The evaluated variables were subjected to the analysis of variance and compared with the Scott-Knott test, at 5% probability. In a high-altitude region, leaf removal provides more adequate indices for plant vegetative:yield balance. It also increases yield when performed during the pea-sized berry and veraison stages, increases the fertility index when performed during the pea-sized berry stage, and improves the chemical composition of 'Cabernet Sauvignon' grape when performed up to the pea-sized berry stage. The obtained results show the importance of early leaf removal to obtain must with potential for the production of quality wines.

Association of Botryosphaeriaceae grapevine trunk disease fungi with the reproductive structures of Vitis vinifera

Several species belonging to the Botryosphaeriaceae were isolated from grapevine ( Vitis vinifera ) tissue other than wood during a survey of two vineyards planted to cultivars ‘Chardonnay’ and ‘Shiraz’ in the Hunter Valley, New South Wales, Australia over the 2007/08 and 2008/09 growing seasons. A total of 188 isolates corresponding to nine different species of Diplodia, Dothiorella and Neofusicoccum anamorphs were isolated from dormant buds, flowers, pea-sized berries and mature berries prior to harvest in addition to 142 isolates from the trunks of the same vines. Furthermore, the occurrence of Dothiorella viticola, Diplodia mutila and Neofusicoccum australe is reported here for the first time from grapevines in the Hunter Valley. These findings may provide important information for the management and spread of Botryosphaeriaceae in vineyards where they are considered serious wood-invading pathogens. Botryosphaeriaceae are occasionally found on bunches, however, until now they have not directly been related to bunch rots. Control strategies for trunk diseases caused by Botryosphaeriaceae are currently limited to remedial surgery and wound protection. These strategies do not consider other grapevine tissue as potential inoculum sources for infection of Botryosphaeriaceae in the vineyard.

Composition of Sauvignon blanc Grapes as Affected by Pre-veraison Canopy Manipulation and Ripeness Level

The implications of pre-veraison canopy management and ripeness level (19°B and 21°B) on microclimate and grape and must composition were determined on intensively micro-sprinkler irrigated Vitis vinifera L. cv. Sauvignon blanc/110 Richter vines, grown on a vertical trellis in the Breede River Valley of South Africa. Rows were east-west orientated and vines spaced 2.75 m x 1.5 m. Spurs were spaced approximately 15 cm apart. Canopy management consisted of different combinations of seasonal practices (suckering, shoot positioning, topping, leaf thinning) during the pre-veraison growth period (just after budding to pea size berry) in order to accommodate foliage and to improve the canopy microclimate. Treatments that included leaf thinning improved the light conditions in the canopy without a noticeable effect on other microclimate parameters as well as bunch and berry sap temperature. The must pH remained relatively stable, with an increase in ripeness level from 19°B to 21°B, whereas the rest of the measured grape composition components followed a decreasing pattern during this period. Treatments that included leaf thinning tended to increase titratable acidity and decrease pH at both ripeness levels. Additional leaf thinning (up to the lower half of the canopy at pea size) increased the glucose and fructose concentrations without changing their ratio. It also decreased the malic acid concentrations of the berries, whereas the free-amino-nitrogen content of the must was stimulated. Furthermore, leaf thinning in general increased the monoterpene content (fruity aroma) and apparently enhanced the 2-methoxy-3-isobutylpyrazine content (grassy/green pepper aroma), thereby increasing the total measured aroma profile. Both palate and flavour profiles were therefore changed by applying pre-veraison seasonal canopy management. The data emphasised the importance of the correct timing and application of canopy management. This seemed to be of great significance in the realisation of an improved grape composition, even for S. blanc subjected to a relatively hot terroir.

Timing of leaf removal modifies chemical and phenolic composition of Sauvignon Blanc wine

The objective of this work was to evaluate the effect of different defoliation times on the chemical and phenolic composition of Sauvignon Blanc wine in high altitude regions of Santa Catarina - Brazil. The experiment was conducted in the 2015 and 2016 seasons, in a vineyard located in the city of Sao Joaquim – Santa Catarina State. The defoliation was carried out during phenological stages: full bloom, berries pepper-corn size, pea-sized berries, veraison, 15 days after veraison and control without leaf removal. During harvest, severity of Botrytis cinerea was assessed by visual evaluation through a diagrammatic scale. For the wine samples from each season, total acidity (meq L−1 ), pH, total polyphenol content (mg L−1 of gallic acid) and color (Abs 420nm) were performed. For the wines of the 2015 harvest, phenolic compounds were analyzed: gallic acid, catechin, vanillic acid, P-coumaric acid and rutin. The chemical composition of Sauvignon Blanc wine was affected as a result of leaf removal timing, defoliation carried out in full bloom, berries pepper-corn size and pea-sized berries reduced total acidity and increased pH of the wines in both seasons. For wine color, in both seasons, it was found a greater yellow coloration in wines originated from grapes where the plants were not defoliated. The increase of yellow coloration is due to the oxidation of catechins and epicatechins, which is related to the increase of botrytis bunch rot. In the 2015 season there were no influence of leaf removal timing in total polyphenols, however, in the 2016, the defoliation performed in full bloom resulted in lower polyphenols contents. Wines from non-defoliated plants presented higher values of catechin, rutin, P-coumaric acid and gallic acid, related to yellow coloration of wines and greater susceptibility to darkening and oxidation. For vanillic acid, wines from non-defoliated plants have the lowest values, this compound is important in wine preservation. Leaf removal is an important management technique in high altitude regions of Santa Catarina - Brazil, it improves wine chemical composition, and if carried out during the stages of full bloom, pepper corn berries and pea-sized berries can reduce the severity of Botrytis bunch rot; and avoid the formation of phenolic compounds related to the processes of oxidation and darkening.

Soil Management in the Breede River Valley Wine Grape Region, South Africa. 1. Cover Crop Performance and Weed Control

Eight cover crop treatments were applied for 12 consecutive years on a medium-textured soil in a vineyard near Robertson (33˚50’S, 19˚54’E). A treatment with full surface straw mulch and full surface post-emergence chemical control applied from just before grapevine bud break to harvest (BB), and one with no cover crop combined with BB, were also applied. The control consisted of mechanical control in the work row and post-emergence chemical control in the vine row applied from bud break to harvest. Rotating Triticale v. Usgen 18 (triticale) and Vicia dasycarpa Ten. (vetch) did not improve the dry matter production (DMP) of either species. Average DMP decreased as follows: triticale > Secale cereale L. v. Henog (rye)/Vicia faba L. v. Fiord (faba bean) mixture > triticale/vetch biennial rotation > triticale/vetch annual rotation > vetch. Triticale (BB) resulted in total winter weed suppression from 1995 to 1996 and from 2001 to 2004. Total weed control from bud break to the pea size berry stage of the grapevines was achieved with straw mulch (BB), triticale (BB), rye/faba bean mixture (BB) and triticale/vetch rotated biennially (BB) from 2001 to 2003. For triticale combined with full surface post-emergence chemical control applied from grapevine berry set (AB), and for triticale/vetch rotated annually (BB), this was restricted to 2001 and 2003. From the pea size berry stage to harvest, straw mulch (BB), triticale (BB), vetch (BB), rye/faba bean mixture (BB) and triticale (AB) reduced the weed stand significantly in comparison to the control.

The impact of cluster thinning on fertility and berry and wine composition of 'Blauer Portugieser' (&lt;i&gt;Vitis vinifera L.&lt;/i&gt;) grapevine variety

&lt;p&gt;&lt;strong&gt;Aim&lt;/strong&gt;: Two different yield reductions based on cluster thinning (CT) were performed to determine their impact on vine growth, yield, and grape and wine composition of 'Blauer Portugieser' grapevine variety.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods and results&lt;/strong&gt;: Two levels of cluster thinning (limited CT1 – 20-30 % and severe CT2 – 40-50 % cluster reduction) were applied at the pea-size berry (BBCH 75) phenological stage in 2007, 2008 and 2011. The potential impact of CT was determined by measurements of vine growth and fertility potential, berry weight, berry colour, soluble solids content, titratable acidity, pH and total phenolics. Additionally, for the first time, individual phenolic compounds were identified and quantified in berry skin and wine by HPLC-MS. In general, CT of 'Blauer Portugieser' significantly decreased titratable acidity in grape and wine, and increased pH and chromatic parameters in grape and alcohol content and volatile acidity in wine. A significant decrease in yield per vine (of 0.92 kg of grape/vine), together with an increase in soluble solids (of 2.8 °Brix) in grape and pH and total extract content in wine was only observed in severe CT (CT2). Furthermore, CT2 significantly increased the content of total anthocyanins, flavonols and hydroxycinnamic acids, but not total flavanols, in grape and wine. CT2 significantly increased the content and proportion of &lt;em&gt;p&lt;/em&gt;-coumaroyl pentose in grape and wine, catechin in grape, epicatechin in wine, quercetin-3-glucuronide (the main flavonol in 'Blauer Portugieser') in grape and wine, the content of myricetin-3-glucoside in grape, and the content of 3-glucosides of laricitrin, myricetin and quercetin in wine. Finally, CT2 increased the content and the proportion of 3-glucosides of delphinidin, petunidin and peonidin but decreased the proportion of malvidin-3-glucoside in grape and wine.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;: A significant impact on yield and grape and wine composition was observed, particularly in the CT2 treatment, in which the yield loss was compensated by higher contents of soluble solids in grape, alcohol in wine, and phenolic compounds in grape and wine.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Significance and impact of the study&lt;/strong&gt;: The present study is the first report on the impact of different levels of cluster thinning on yield and grape and wine composition of 'Blauer Portugieser' variety. Grape and wine composition has been evaluated with an emphasis on a detailed profile of individual and total phenolic contents. The results are undoubtedly useful for winegrowers, who, until now, lacked technological guidelines to optimize 'Blauer Portugieser' yield and wine quality.&lt;/p&gt;

Suppression of the D-class MADS-box AGL11 gene triggers seedlessness in fleshy fruits

Seedlessness, one of the most desired traits in fleshy fruits, can be obtained altering solely AGL11 gene, a D -class MADS-box. Opposite to overlapping functions described for ovule identity. AGAMOUS like-11 (AGL11) is a D-class MADS-box gene that determines ovule identity in model species. In grapevine, VviAGL11 has been proposed as the main candidate gene responsible for seedlessness because ovules develop into seeds after fertilization. Here, we demonstrate that AGL11 has a direct role in the determination of the seedless phenotype. In grapevine, broad expression analysis revealed very low expression levels of the seedless allele compared to the seeded allele at the pea-size berry stage. Heterozygous genotypes have lower transcript accumulation than expected considering the diploid nature of grapevine, thereby revealing that the dominant phenotype previously described for seedlessness is based on its expression level. In a seeded somatic variant of Sultanina (Thompson Seedless) that has well-developed seeds, Sultanine Monococco, structural differences were identified in the regulatory region of VviAGL11. These differences affect transcript accumulation levels and explain the phenotypic differences between the two varieties. Functional experiments in tomato demonstrated that SlyAGL11 gene silencing produces seedless fruits and that the degree of seed development is proportional to transcript accumulation levels. Furthermore, the genes involved in seed coat development, SlyVPE1 and SlyVPE2 in tomato and VviVPE in grapevine, that are putatively controlled by SlyAGL11 and VviAGL11, respectively, are expressed at lower levels in silenced tomato lines and in seedless grapevine genotypes. In conclusion, this work provides evidence that the D-class MADS-box AGL11 plays a major and direct role in seed development in fleshy fruits, providing a valuable tool for further analysis of fruit development.

Época de desfolha e sua influência no desempenho vitícola da uva ‘Sauvignon Blanc’ em região de elevada altitude

A videira caracteriza-se como uma espécie exigente em tratos culturais, e para se alcançarem condições ótimas no momento da colheita, é fundamental que as técnicas de manejo sejam adequadas às características de cada região. A desfolha, nesse sentido, tem sido uma importante ferramenta de manejo do dossel vegetativo, podendo melhorar a composição química dos cachos e aumentar a eficiência produtiva da videira. O objetivo deste trabalho foi avaliar o manejo da desfolha em diferentes estádios fenológicos, sobre a eficiência produtiva e na composição química dos cachos da variedade Sauvignon Blanc cultivada em regiões de altitude. O experimento foi conduzido nas safras 2015 e 2016, em um vinhedo localizado no município de São Joaquim, SC (28°17’39”S e 49°55’56”W, 1230m). Os tratamentos consistiram em diferentes épocas de desfolhas, realizadas na região dos cachos nos estádios fenológicos: plena florada, grão chumbinho, grão ervilha, virada de cor das bagas, 15 dias após a virada de cor e sem desfolha (testemunha). Os dados foram submetidos à análise de variância (ANOVA) e comparados pelo Teste Scott-Knott a 5% de probabilidade de erro. Observou-se que a desfolha realizada até o estádio fenológico virada de cor propicia incremento no índice de fertilidade. O manejo da desfolha realizado nos estádios fenológicos grão ervilha e virada de cor apresentaram as maiores produtividades em relação aos demais estádios fenológicos e plantas não submetidas ao manejo da desfolha. Além disso, o manejo da desfolha melhorou a maturação tecnológica e fenólica da uva Sauvignon Blanc quando realizada nos estádios fenológicos grão chumbinho e grão ervilha, nas duas safras avaliadas. Os resultados deste trabalho evidenciam a importância no manejo da desfolha para obtenção de um mosto com potencial para elaboração de vinhos finos de qualidade, principalmente quando realizados entre os estádios fenológicos de grão chumbinho e grão ervilha. Portanto, a desfolha da videira Sauvignon Blanc em regiões de altitude deve ser considerada uma prática de manejo indispensável ao vitivinicultor

Influence of differing nitrogen nutrition on polyamines and non-structural carbohydrates during different developmental stages of grapevines (c.v. White Riesling).

Polyamines (PA) are triggered by external inducers (hormones, fertilization, nutrients etc.). In triggered systems, the level of free PAs increase before the onset of cell division. PAs are high dur- onset of development as compared with other stages of development. During a fertilisa- tion experiment with amounts of N and timing, non-structural carbohydrates and PAs were determined in leaves, and developing Leaves: PAs were lowest in the unfertilized plots; fertilization showed no differentiated effects. PA-concentrations peaked after full bloom and fell to 50% of the starting value at the stage pea-sized berries. Shoots: belonging to the leaves with the same plastochron-index showed a similar behaviour like PA in leaves. Stems: Putrescine (Put) and Spermidine (Spd) show a clear time course. Put decreases until fully developed and after- wards a slight increase until pea sized berries. Spd behaves nearly inverse: peak at increasing of the flowers and a minimum at fruit set. Berries: all four tested PAs show a clear pattern of their time course. Agmatine (Agm) is highest at 27 May (five to six leaves unfolded), lowest at 5 June and peaking again at fully developed (24 June). At fruit set concentrations are as low as at 5 June (flowers are growing). Put is high at five to six leaves unfolded, decreases continuously until fully developed and a maximum at fruit set. Spd shows a maximum at are grow- ing and reaches a minimum at fruit set. Spd has nearly constant concentrations through five to six leaves unfolded until are fully developed in all fertilizer variants. At fruit set is a maxi- mum. peaks at fully developed, decreases to fruit set and increases again at pea sized berries. Treatments show a differentiation; highest values are found with the plot 90/60. A direct connection to the carbohydrate metabolism could not detected during this experiment.