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Effects of different winter pruning times on table grape vines performance and starch reserves to face climate changes
Abstract
In the context of climate change, in which some extreme weather and climate events have increased in frequency and intensity because of global warming, adaptive techniques in viticulture have become necessary to reduce the resulting negative impacts. This study on four table grape cultivars has evaluated the effects of different winter pruning treatments (time of pruning) on phenology, fruit composition and starch content in canes and ≥two-year-old wood. By shifting the pruning time from leaf fall up to budbreak (BBCH 08), a neutral response on yield and berry quality parameters (TSS, TA and pH) was observed for the 4 cultivars. Late pruning treatments resulted in shorter shoot lengths and delayed phenological stages for the early ripening cultivars. The partitioning of starch between canes and older wood was almost similar, although lower in canes, with average values of 13% and a significant reduction at budbreak in order to release soluble sugars for the initial vegetative growth. Starch was mainly located in newly formed xylem, i.e., in the parenchymatic rays where amyloplasts are located, whereas a smaller amount of starch was visible in the other tissues (phloem, cortex). The possibility of a late pruning until over budbreak can be considered a practice to avoid some late spring frost risks, often occurring in viticultural areas. Thus, a ‘precise’ application of winter pruning into a global warming viticulture context could have potential benefits, performing a cost-effective tool management without negative (or very limited for early cultivars) effects on yield and quality of table grapes.
... The growing degree day (GDD) or heat unit approach provides a reliable methodology to express the impact of temperature on growth and development in cropping systems (Hoogenboom 2000;Parthasarathi et al. 2013;Molitor et al. 2014;Piña-Rey et al. 2021). It can also provide guidance for determining suitable viticulture regions, cultivars (based on ripening time), and vineyard management such as pruning (Parker et al. 2013Ferrara et al. 2022). Cultivars with late bud burst, that can skip frost damage in colder regions, and early ripening cultivars, that ripen before the onset of heat waves or the rainy season, are considered suitable for good quality grape cultivation (Schrader et al. 2019;"OSU Extension Service", n.d.). ...
... Shortening of the growing season from bud burst to harvest maturity, loss of bud fertility, flower abortion, earlier bud burst, blooming, fruiting, starch metabolism, and maturity have already been reported as phenological shifts in the different viticultural regions across the world (Craufurd, and Wheeler 2009;Tao et al. 2013;Figueiredo et al. 2015;Merrill et al. 2020;Ferrara et al. 2022). For instance, phenological shifts of 10-24 days have been noticed in south-west Germany during the 40-year period 1975 to 2015 (Koch and Oehl 2018). ...
... Thus, accounting for a genotype specific approach with varying temperature can further reduce the variability in accumulated heat units for the key phenophases. In addition to GDD for phenological timings and phenophase durations, it would be interesting in future studies to calculate the GDD for the phyllochron, i.e., the thermal time between the two successive unfolded leaves (Ferrara et al. 2022) on these cultivars in this region and its relationship with grapevine physiology and fruit quality attributes to better understand vine growth and development. ...
... The growing degree day (GDD) or heat unit approach provides a reliable methodology to express the impact of temperature on growth and development in cropping systems (Hoogenboom 2000;Parthasarathi et al. 2013;Molitor et al. 2014;Piña-Rey et al. 2021). It can also provide guidance for determining suitable viticulture regions, cultivars (based on ripening time), and vineyard management such as pruning (Parker et al. 2013Ferrara et al. 2022). Cultivars with late bud burst, that can skip frost damage in colder regions, and early ripening cultivars, that ripen before the onset of heat waves or the rainy season, are considered suitable for good quality grape cultivation (Schrader et al. 2019;"OSU Extension Service", n.d.). ...
... Shortening of the growing season from bud burst to harvest maturity, loss of bud fertility, flower abortion, earlier bud burst, blooming, fruiting, starch metabolism, and maturity have already been reported as phenological shifts in the different viticultural regions across the world (Craufurd, and Wheeler 2009;Tao et al. 2013;Figueiredo et al. 2015;Merrill et al. 2020;Ferrara et al. 2022). For instance, phenological shifts of 10-24 days have been noticed in south-west Germany during the 40-year period 1975 to 2015 (Koch and Oehl 2018). ...
... Thus, accounting for a genotype specific approach with varying temperature can further reduce the variability in accumulated heat units for the key phenophases. In addition to GDD for phenological timings and phenophase durations, it would be interesting in future studies to calculate the GDD for the phyllochron, i.e., the thermal time between the two successive unfolded leaves (Ferrara et al. 2022) on these cultivars in this region and its relationship with grapevine physiology and fruit quality attributes to better understand vine growth and development. ...
Progressive warming of the grape growing regions has reduced the land capability for sustainable grapevine production and the geographical distribution of grapes. Bud burst, blooming, berry set, veraison, and harvest are the key phenological stages of grapevine, and are crucial for managing vineyard activities. The objective of this study was to evaluate the effect of seasonal temperature variability on the timing of key phenological stages of table grape cultivars in a new emerging viticulture region, i.e., the Pothwar region of Pakistan. Phenological stages of four table grape cultivars were recorded during two consecutive growing seasons at two locations. All phenological stages were attained earlier for the relatively warmer location, i.e., Chakwal. Similarly, the length of the growing season from bud burst to harvest was 15 to 21 days longer for the 2020 growing season than for the 2019 growing season, which corresponds to the inter-annual temperature variability. Moreover, the grapevine cultivars showed a distinct response for each growth phase; cv. Perlette matured earlier while cv. NARC Black was the last to ripen. Despite the large variability in the length of the active growing period from bud burst to harvest, accumulated growing degree days (GDD) varied only in a narrow range, i.e., 1510-1557 for cv. Perlette, 1641-1683 for cv. King's Ruby, 1744-1770 for cv. Sugraone, and 1869-1906 for cv. NARC Black. This implies that seasonal temperature variability using GDD is a better indicator for the phenology of table grape cultivars compared to regular time. It is clear from the results from this study that the variation in phenological responses of table grape cultivars due to temperature differences necessitates genotype and site-specific vineyard management.
... In the context of climate change, the observed increase in average surface temperatures causes an acceleration of plant phenology progression, exposing vulnerable green bud structures to a higher risk of late frost damage (Alikadic et al., 2019;Masson-Delmotte et al., 2021). In the context of some extreme weather and climate events have increased in frequency and intensity due to global warming, adaptive techniques in viticulture have become necessary to mitigate the resulting negative impacts (Ferrara et al., 2022). The adaptation and resistance of the grapevine to low temperatures during the dormancy period involve the realization of processes of accumulation and dynamics of biochemical compounds in tissues, with direct implications for protecting them against the destructive action of intracellular freezing (Holzapfel et al., 2010;Mohamed et al., 2012;Babajamali et al., 2022;Monteiro et al., 2022). ...
... An important role is played by starch, which, through the hydrolysis process starting in January, leads to the formation of soluble sugars with a cellular protective function due to the promotion of water retention through osmotic means, thereby lowering the cryoscopic point of cellular sap (Zapata et al., 2004;Lebon et al., 2008). Several studies indicate that during winter, grapevine roots contain rich reserves of starch and sugars, with starch being present in all tissues of the bark and wood (annual or multiannual), actively contributing to the dynamics of carbohydrates in grapevine shoots (Caprara & Pezzi, 2013;Liu and Sherif, 2019;Călugăr et al., 2022;Ferrara et al., 2022;Costea et al., 2023). The larger the reserves of carbohydrates accumulated in the wood, the better the wood maturation, and the plant becomes more resistant to low temperatures during the dormancy period (Cichi et al., 2016;Călugăr et al., 2019;Horiuchi et al., 2021). ...
The adaptation and resistance of the vine to low temperatures during the dormancy involves the realization of processes of accumulation and dynamics of some biochemical compounds in the tissues. In this study, between November and March (2022-2023), the dynamics of carbohydrates (soluble sugars and starch) was monitored at 10 days in the annual and multiannual vine wood in the 'Cabernet Sauvignon', 'Fetească neagră' and 'Merlot' from the Banu Mărăcine wine-growing center (plateau-type area, slightly leached reddish-brown soil) and Șimnicu de Sus wine-growing area (slope-type area, medium eroded reddish-brown soil). Regarding the carbohydrate content during the dormancy, significant differences between the two viticultural areas were highlighted only concerning the content of soluble sugars (%) in multiannual wood for the 'Merlot' and 'Cabernet Sauvignon'. As for the starch content (%) in annual woody shoots and in multiannual wood, no statistically significant differences were observed either between the studied cultivars or between the two areas.
... Most studies investigated the effect of late winter pruning (post-budbreak) compared to pruning performed during the dormancy period. However, other studies have observed different effects, for both wine and table grapes, even for pruning during other phenological stages: for instance, from late leaf fall (Williams et al., 2023), at various stages during dormancy (Ahmed et al., 2017), to vine bleeding (Deloire & Pellegrino, 2022;Ferrara et al., 2022). Pruning time can also influence must composition. ...
Several studies have already highlighted how late pruning, conducted after bud break, can result in a delay in phenology and, consequently, in ripening. However, the effects of pruning periods on vegetative and productive parameters are less well known. The aim of this study was to evaluate the effect of pruning periods on ripening kinetics, grape composition at harvest and yield parameters, considering the grapevine cultivar and year. The experimentation was conducted from 2011 to 2013 in two of the main Italian wine-growing areas: Franciacorta, in Northern Italy, and Montefalco, in Central Italy. In Franciacorta: Chardonnay and Pinot Noir were considered while in Montefalco, the varieties included were Sauvignon Blanc, Grechetto di Orvieto, Sagrantino, and Sangiovese. Six different pruning periods were compared: at leaf fall (NOV), during dormancy (DEC, JAN, FEB), in the pre-bud break period (MAR) and late, post-bud break (APR). Results obtained showed that the effects of the pruning period are clear and sufficiently replicable only considering pre-bud brake pruning (APR). The observation of the ripening kinetics highlighted in fact a delay in grape ripening for APR in both contexts as well as a lower values for the sugar-acidity ratio at harvest. In terms of grape yield, a moderately negative effect of APR was observed in Montefalco, while a more severe effect was observed in Franciacorta. This analysis gives a comprehensive understanding of the effects of pruning timing on grape yield and composition, providing viticulturists with transversally applicable information, useful for an aware management of the vineyard.
... Since 1926, Alexandrov andMakarevskaia, cited by Stoev, 1979, found that in winter the roots of the vine contain rich reserves of starch and sugar and the starch fills all the tissues of the bark and wood, representing one of the first works on the dynamics of carbohydrates in vines shoots. These researches were continued by Costea et al., 2010;Ferrara et al., 2022. The better the maturation of the wood, the greater the reserves of substances accumulated in the wood, the plant being more resistant to low temperatures in winter (Dejeu, 2005). ...
The state of endodormancy in the vine as an adaptation reaction to unfavourable temperature conditions, has a complex character and is the result of multiple biochemical and physiological processes that take place at the level of the tissues of the vine shoots. In this study, the adaptation and response reactions of Merlot, Cabernet Sauvignon and Feteasca neagra grapevine varieties to the temperatures during the dormant season in the Banu Maracine wine growing centre are monitored, by following the evolution of some biochemical compounds involved in these mechanisms: evolution of free water (%), bound water (%), total water (%) and total dry matter (SUT %), as well as the evolution of carbohydrates (soluble sugar and starch) in annual and multiannual vine wood. A grouping of the analyzed varieties is made according to the storage potential of carbohydrates under the different conditions of minimum temperatures.
... Recent studies have shown that the type and time of pruning can delay the phenological maturity and photosynthetic capacity of the vine (Ren et al., 2022), reflecting on growth, yield (Gambetta et al., 2020) and fruit quality (Perez-Navarro et al., 2021) from Vitis vinifera L. cv. 'Malbec' (Ferrara et al., 2022;Morgani et al., 2022), 'Merlot' (Falginella et al., 2022;Vuerich et al., 2021;Allegro et al., 2020), 'Bobal' and ' Tempranillo' (Buesa et al., 2020), and Pinot Noir (Frioni et al., 2019). ...
The pruning time for Vitis vinifera sp. is determined by environmental factors that affect the level of hormones in the plant and, consequently, control metabolic changes. Inducing meristematic activity and altering the phenology of the vine. However, a drastic reduction in the yield of excessively pruned vines has been observed with potential effects not only for the current season but also for subsequent seasons, due to the decrease in the plant's reserves. Thus, this review provides a comprehensive discussion on how pruning time affects the phenology of vines grown in a semi-arid climate, highlighting how environmental factors regulate vine growth in regions with a semi-arid climate, and which strategies can be used for cultivation in this region. Estimating the best pruning time encourages better practices and timely actions to improve vine productivity and grape quality. Therefore, this study provides important information for planning grapevine cultivation at different pruning times.
... Such forecasting of grapevine developmental stages allows for a more precise preparation of vineyard activities. It can also provide guidance for selecting suitable cultivars, determining regional suitability for grapes production, and optimizing vineyard management (Parker et al. 2013Zapata et al. 2017;Ferrara et al. 2022). Developing grapevine phenology models under varying environmental conditions is crucial to adapt viticulture to the rising climatic challenge. ...
Phenological shifts are one of the most visible signs of climatic variability and change in the biosphere. However, modeling plant phenological responses has always been a key challenge due to climatic variability and plant adaptation. Grapevine is a phenologically sensitive crop and, thus, its developmental stages are affected by the increase in temperature. The goal of this study was to develop a temperature-based grapevine phenology model (GPM) for predicting key developmental stages for different table grape cultivars for a non-traditional viticulture zone in south Asia. Experiments were conducted in two vineyards at two locations (Chakwal and Islamabad) in the Pothawar region of Pakistan during the 2019 and 2020 growing seasons for four cultivars including Perlette, King’s Ruby, Sugraone and NARC Black. Detailed phenological observations were obtained starting in January until harvest of the grapes. The Mitscherlich monomolecular equation was used to develop the phenology model for table grapes. There was a strong non-linear correlation between the Eichhorn and Lorenz phenological (ELP) scale and growing degree days (GDD) for all cultivars with coefficient of determinations (R2) ranging from 0.90 to 0.94. The results for model development indicated that GPM was able to predict phenological stages with high skill scores, i.e., a root mean square (RMSE) of 2.14 to 2.78 and mean absolute error (MAE) of 1.86 to 2.26 days. The prediction variability of the model for the onset timings of phenological stages was up to 3 days. The results also reveal that the phenology model based on GDD approach provides an efficient planning tool for viticulture industry in different grape growing regions. The proposed methodology, being a simpler one, can be easily applied to other regions and cultivars as a predictor for grapevine phenology.
... On the contrary, preliminary results by Duchemin et al. [165] on raspberries indicate a 20-32% yield reduction in AV systems compared to raspberries protected by plastic coverages; however, fruit quality remains the same. Similarly, Ferrara et al. [166] found that vine yields under solar panels were slightly reduced (−10 to −15%) compared to vines grown under the full sun in Northern Italy (Veneto region) over three seasons of field experimentation. However, a recent trial in a Primitivo vineyard in the Puglia region found that AV vines yielded more than full-sun vines [Ferrara p.c.]. ...
Feeding nine billion people by 2050 will be a challenge due to climate change. There is a significant portion of abandoned and unused marginal lands across the nation and in the Puglia region, in Southern Italy. Innovative techniques and practices in the frame of climate-smart agriculture can help rehabilitate marginal lands into productive and profitable areas. The objective of this study was to systematically review the literature on marginal areas in Puglia, responding to the lack of information in this context and evaluate their revitalization potential. We systematically reviewed the literature on unused/marginal areas and identified related studies dealing with different types of marginal areas and their potential for sustainable rural development. Marginal areas in Puglia represent a range of historical rural landscapes that support biodiversity, the economy, and ecological services. However, the analysis of the current situation in Puglia’s marginal areas indicates a lack of infrastructure and scarce resources, which led to land abandonment and the migration of local residents, resulting in the deterioration of the ecological system. Therefore, establishing a sustainable policy is crucial for preserving the local heritage and economy of the region. However, policymakers should carefully study the challenges and opportunities arising from local contexts before embarking on ambitious place-based innovation strategies. The analysis indicates that both biophysical and socio-economic factors are strategic elements for improving the revitalization potential of marginal areas for sustainable development. This review provides useful information regarding the revitalization potential of marginal areas for food, feed, and non-food production, which is crucial in the implementation of a sustainable development strategy for rural communities in Puglia but can also be applied to similar areas in other countries. However, the success of the sustainable development strategy in Puglia’s marginal areas should consider the vital function of farmers’ self-organization and social capital as key factors in the adoption of agricultural innovations for the revitalization of these areas.
... Recent studies have shown that the growing season can delay phenological maturity, and affect yield components, crop coe cients, and total evapotranspiration in Vitis vinifera L. cv. 'Malbec' (Ferrara et al., 2022;Morgani et al., 2022), 'Merlot' (Allegro et al., 2020), 'Bobal' and 'Tempranillo' (Buesa et al., 2020), and Pinot Noir (Frioni et al., 2019). In contrast, Falginella et al. (2022) reported that yield and qualitative parameters are not affected by different growing seasons in hot climate regions. ...
This study aimed to investigate the impacts of the growing season on the physiological performance, phenological cycle, and yield of grapevines grown in a semiarid climate. Thus, we established a field experiment in two growing seasons using cultivars with intermediate cycles (BRS Magna and BRS Núbia), and early cycles (BRS Violeta) in Bom Jesus, Piauí, Brazil. Our results suggest that vines cultivated during the second season (September-December) anticipated the phenology from sprouting to berry maturation (BBCH01-BBCH89) of all studied cultivars. The vines cultivated in the 2nd season had an average duration of 109 days after pruning. The growing season within each cultivar level showed that the 2nd season was the best for all studied cultivars. In all cases, plants from the second growing season showed higher rates of CO2 assimilation, transpiration, stomatal conductance, leaf temperature, and the relationship between internal, and external CO 2 concentrations (Ci/Ca ratio). BRS Magna had the highest production (3563.5 kg/plant), the highest number of berries per bunch (34.5), longitudinal diameter (35.1 mm), and transverse diameter, universal of the berry (15.3 mm), fruit mass (61.83 g), berries (2.4 g), and total soluble solids (14.9 °Brix). Principal component analysis (PCA) showed that the studied cultivars differed from each other, highlighting alterations in the analyzed variables as affected by growing season. Our findings provide relevant information for the growing season, and behavior of vine cultivars to be used as a basis for viticulture cultivation in semiarid environments.
Microscopic bud dissection can be used to assess grapevine bud fruitfulness prior to winter pruning and long before actual bud fruitfulness can be measured in the vineyard the following spring. Bud dissections should be performed by qualified and trained personnel because inflorescence primordia are difficult to distinguish in some varieties. In the Puglia region, Southeastern Italy, in 2018 and 2019, potential fruitfulness using bud dissection and actual fruitfulness observed in the vineyard were compared for seventeen table grape varieties. The percentage of fertile buds, the number of inflorescence primordia (IP) per node, and the incidence of primary bud necrosis (PBN) were detected with bud dissection to be used either for managing winter pruning or for predicting yield during the successive season. The data were successively compared with fertile buds and actual bud fruitfulness observed in the vineyard during spring. The table grape varieties examined had similar values of fertile buds and fruitfulness both with bud dissection and in the vineyard. The application of longitudinal sections in bud dissections can be an alternative approach (or can be integrated into traditional cross sections) to distinguish IP in some difficult varieties, but the two techniques can be used together for more repeatable results. The bud dissection technique (with both cross and longitudinal sections) can provide useful insights for viticulturist to help guide winter pruning (intensity of pruning and number of canes) and to predict potential yield.
This study aimed to investigate the possible existence of reproducible aromatic red wine styles, focusing on fresh fruit aromas and mature fruit aromas (i.e., with dark, jammy fruit characteristics) and taking into account both vintage and vineyard.The study was performed on Australian Shiraz and Cabernet‑Sauvignon from three different meso-climate areas and two consecutive vintages. Sequential harvests were carried out based on the plateau of the physiological indicator berry sugar accumulation (mg/berry) in order to obtain fresh fruit and mature fruit wine sensory profiles. There was a predictable aromatic sequence during grape ripening at each of these two distinct maturity stages regardless of grape genotype (variety) and environment (vineyard and vintage). The post-plateau period of berry sugar accumulation was found to be crucial for the evolution of wine aromatic profiles. During this period, wine aromatic and phenolic maturity were uncoupled from technological maturity (i.e., berry sugar concentration). Dimethyl sulfide was found to be the most relevant wine aromatic marker for differentiating the fresh fruit and mature fruit stages irrespective of the variety. Specific cultivar markers with potential sensory contribution were also identified; for example, (Z)‐3‐hexenol, a possible contributor to the aromatic freshness of Shiraz wines from the fresh fruit stage. The evolution of terpenoids appeared to be separate from the dynamics of berry ripening post plateau of fruit sugar accumulation. On the other hand, ester composition was significantly altered during the same ripening period in Shiraz and Cabernet‑Sauvignon wines with a marked grape genotype effect. The results showed that yeast metabolism was also affected by berry ripening evolution from the plateau of berry sugar accumulation onwards.
Cover crops are increasingly adopted in viticulture to enhance soil quality and balance the vegetative and reproductive growth of vines. Nevertheless, this sustainable practice has been only recently used for table grape viticulture, with results often contrasting. The aim of this study was to assess the effect of a fescue (Festucaarundinacea Schreb.) cover crop on soil quality, yield, and grape qualitative parameters in a table grape vineyard (cv “Italia”) located in southern Italy, comparing results with the conventional tillage. Soil organic carbon (C), total nitrogen (N), microbial biomass C (MBC), β-glucosidase (BGLU) and alkaline phosphomonoesterase (APME) activities were assessed during three growing seasons (2012–2014) and three phenological stages. The trend of soil chemical and microbiological properties was jointly influenced by the soil management system, growing season and phenological stage. Compared to conventional tillage, cover crops increased, on average, soil organic C, total N, MBC, BGLU and APME by 136%, 93%, 112%, 100% and 62%, respectively. Slight or no effects of cover crops were observed on grape quality and yield, except for 2012 (the driest season), when a yield reduction occurred. This study reveals that cover crops strongly enhance soil quality in the short-term, with potential advantages for grape production in the long-term.
Climate change impacts viticulture with even stronger effects on sparkling wines. Innovative cultural practices represent effective short-term solutions. Among these, postponement of winter pruning later than budburst delayed both vegetative and reproductive cycles as well as technological maturity of several varieties from different wine regions. This research aims to assess the impact of delayed winter pruning on grapevine performance as a function of training system.
The trial was carried out in a Pinot Noir vineyard sited at 385 m asl in Central Italy. Delayed winter pruning was performed when unpruned canes had shoots showing three unfolded leaves (BBCH 13) and compared to standard winter pruning within two separate experiments focused on: i) cane pruning, and ii) spur pruning. Grapevine phenology, vegetative growth, fruit ripening kinetics and productivity of selected vines were assessed over three years. Delayed winter pruning postponed budburst by 20 and 31 days in Guyot and spur pruned cordons, respectively; then, differences diminished over time showing a maximum delay of 17 days at bloom and 7–10 days at harvest. Despite a decrease in yield (ranging from −35 to −47% in cane and spur pruning, respectively), delayed winter pruning increased titratable acidity (40–89%) and reduced sugars (721%) as compared to control vines. Although effects of delayed pruning were stronger in spur pruned vines, delayed winter pruning was effective also on cane-pruned vines, therefore adapting to varieties marked by low basal-node fruitfulness
Bud dormancy and cold hardiness are critical adaptations for surviving winter cold stress for temperate perennial plant species. In grapevine, acquisition of cold hardiness requires dormancy induction in the early winter and careful maintenance of dormancy state throughout winter. With sufficient exposure to low, non-freezing temperatures (chilling requirement), grapevine buds transition between early (endodormant) and late winter (ecodormant) states. The objective of this study was to uncover the relationship between fulfilment of the chilling requirement and the effects of various temperatures on loss of cold hardiness (deacclimation). The relationship between chilling requirement and temperature as it affects the rate of deacclimation (k deacc) was examined for dormant cuttings of Vitis vinifera, V. aestivalis, V. amurensis and V. riparia. The effect of temperature on k deacc was exponential at low and logarithmic at high temperatures. Deacclimation rates also increased in magnitude as chilling accumulated demonstrating a change in deacclimation potential (Ψ deacc), following a logarithmic response. The combination of Ψ deacc and k deacc indicates genotype-specific thermal efficiency for deacclimation and growth in Vitis that may be overlooked by simple growing degree-day computations. The Ψ deacc and k deacc parameters are genotype-specific and will greatly increase the refinement of models predicting effects of climate change on phenology. Deacclimation rates represent a quantitative determinant of dormancy transition and budbreak in grapevine and will assist researchers in selecting germplasm for differences in chilling requirement and thermal efficiency.
Aims: Under global warming, the desynchrony between technology maturity and phenolic maturity of wine grapes is a worthy concern. Late winter pruning (LWP) has been proved to be an effective way to delay the grape phenological stages. The aim of this study was to evaluate the effects of LWP at different phenological stages (based on Baillod & Baggiolini system) on the delay of the grape ripening, on vine yield components as well as on berry composition, among others, the anthocyanin to sugar ratio.
Methods and results: The two-year (2015 and 2016) trial was conducted in Rioja wine region (North of Spain) on Maturana vines and in each year, four pruning treatments were carried out taking apical buds/shoots as reference: (1) winter pruning at stage A (WPA; dormant bud); (2) LWP at stage C (LWPC; green shoot tip) in 2015 and at stage F (LWPF; inflorescence clearly visible) in 2016; (3) LWP at stage G (LWPG; inflorescences separated); (4) LWP at stage H (LWPH; flowers separated). LWPC failed to delay the late phenological stages and did not exert important influence on vine yield and berry composition. LWPG and LWPH succeeded to delay all the phenological stages of grapes to a great extent and created a considerably cooler and longer ripening period compared to WPA. Vine yield was not affected by LWPF and was reduced significantly (averagely by 41%) by LWPG. LWPH lead to great losses in yield (averagely by 67%), especially in 2015. LWPG did not change the fruit composition while LWPH increased the ratio of anthocyanin to sugar and helped to maintain a relatively high level of acidity in berries.
Conclusions: The primary cause of the decline in production seems to be the losses of flowers and/or the reduction in fruit set percentage in the current season, instead of the losses in inflorescences within buds in the previous season. For Maturana grapes, LWP after the stage F would reduce the vine yield and could be applied as an alternative to the time consuming cluster thinning to meet the needs of yield control. Delaying the winter pruning to stage H could improve the fruit quality in spite of the greater risk of botrytis and a serious decline in production.
Significance and impact of the study: The outcomes of this research open a door for the winegrowers to realize the yield control in a simple way. Also, for those who only pursue wines of top quality (regardless of production), a very late winter pruning might provide them with high-quality grapes. Moreover, as can be seen obviously from our results, viticulturists could postpone the budburst date to whatever extent they wish thus reducing the risk of spring frost injury to zero, though this point is not our focus in the study.
The use of mulches in vineyards and orchards is a traditional agricultural practice used with the aim of saving moisture, reducing weed growth and improving organic matter content in the soil. In table grape vineyards trained to overhead system in Puglia region (Southeastern Italy), plastic sheets covering the canopy are often used to either advance ripening or delay harvest. In this environment, the living mulches could contribute to the modification of the microclimate around the canopy below the plastic sheets. This condition has an influence on the climatic demand and on both the vegetative and productive activities, mainly in stages with a high evapotranspiration. However, the presence of living mulches could increase the demand of available water and nutrient resources and this could cause a lower yield. The aim of this study was to acquire a suitable knowledge to manage irrigation and verify the influences of living mulches on the vine by using wireless sensor networks to measure the vapor pressure deficit, soil water potential and content.
The influence of pruning date on yield control and ripening rate of spur-pruned Sangiovese grapevines was investigated over two years (2013 and 2014). Winter pruning was applied on 1 or 4 Feb (mid dormancy); 1 or 5 March (late dormancy); 2 or 7 April (bud swell); 2 or 7 May (flowers closely pressed together); and 1 or 6 June (40 to 50% of flower caps fallen), respectively. Vine yield and fruit composition at harvest were not affected by shifting from the standard pruning dates of mid and late dormancy to the bud swell stage. In contrast, the number of inflorescences in compound buds was significantly reduced for vines pruned in early May. No inflorescences were retained on vines pruned at the beginning of June. Early May pruning reduced fruit set and berry weight and slowed fruit ripening compared to the other pruning dates. At harvest, must soluble solids and titratable acidity were 1.6 Brix lower and 1.8 g/L higher, respectively, for the May treatment compared to the standard pruning dates. The early May pruning dates also achieved higher total anthocyanins and phenolic concentrations than the standard pruning dates, indicating that this technique can potentially decouple the accumulation dynamics of these components. Further studies are needed to better calibrate winter pruning date for managing yield and berry maturation rate. © 2016 by the American Society for Enology and Viticulture. All rights reserved.
Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning (LWP) can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP) or late and very late winter pruning (LWP, VLWP) performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER) were followed throughout the season. Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs. 34 in SWP), highest maximum NCER/leaf area (+37% as compared to SWP) and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly cluster thinning. This preliminary study indicates that proper winter pruning date should be timed so as not to exceed the stage of two unfolded leaves.
The horticultural market is characterized by an increasing demand of fresh extra-seasonal products and of early- or late-ripening fruits, both achieving a better economic income. In table grapes, the ripening period can be extended by selecting new varieties or by applying cultural techniques apt to force the plant growth under unfavorable climatic conditions or to protect the foliage and fruits from meteorological adversities. The harvest date may be advanced by inducing a praecocious budbreak. This is obtained by managing the vineyard as a protected cultivation, that is, by covering the roof and the lateral belts of vineyard with transparent plastic films, which allow a high fraction of solar radiation to pass through and then are able to retain a good portion of energy by limiting the convective and radiative thermal dispersions. Hence, the air temperature increases and induces a faster accumulation of growing degree days which, in turn, stimulate an earlier vine budbreak. The plastic covering is affixed on the vineyard at the end of winter; the earlier the covering, the earlier the budbreak. This latter can be advanced by 10 to 40 days depending on the covering date, the grape cultivar and the climatic characteristics of growing environment. The maximum effect can be obtained by covering the vineyard 50 days before natural vine budbreak in open field; however, the advancing effect could be partially lost during the following phenological phases, when the internal thermal regime is too high respect to the requirements of the reproductive and photosynthetic processes. The plastic film optical properties greatly influence the canopy development and the qualitative traits of the grape clusters. This type of protected cultivation has proved to be particularly suitable for early-maturing cultivars and seedless grapes; these latter, in particular, may improve the berry quality, and any case, avoid the competition of seeded varieties with bigger and savoury berries. The harvest date may be delayed by protecting the ripening clusters from meteorological adversities. This technique profits from the good preservability on vine which characterizes the grapevine cluster and improves this trait by protecting the berry sanitary status during ripening. In fact, starting from veraison, berry skin turns thinner and juice turns sweeter, thus berry becomes more sensitive to fungal attacks, especially after the wetting caused by the late summer rains. To preserve the crop, the vineyard roof in covered with plastic films. Under the best conditions, which are with healthy grapes and low rainy season, the berry integrity may be guarantied for a long period, and the harvest may be delayed by 3 months, without reducing yield and berry carpometric characteristics. For best results, it is very important to maintain berry hydration and turgidity as long as possible, since the grape freshness is the goal to achieve and the attribute which distinguishes this product from that coming from the cold storage. The protected cultivation to delay harvest is particularly convenient for late seeded cultivars, especially for grapes having an appropriate skin thickness, abundant pruine and a big berry with a relatively low surface: volume ratio, which are all traits helping to limit berry transpiration and thus favors its final hydration status.
Endodormancy (ED) and cold hardiness (CH) are two strategies utilized by grapevine (Vitis vinifera L.) buds to survive unfavorable winter conditions. Each phenomenon is triggered by different environmental cues—ED by short-day (SD) photoperiod and cold hardiness (CH) by low temperatures. In grapevine buds, CH occurs mainly via the supercooling of intracellular water, a phenomenon associated with the low temperature exotherm (LTE). The seasonal dynamics of ED and CH were studied on grapevines buds by determining the BR 50 (time required to reach 50 % of bud break under forced conditions) and the LTE, which measure the depth of ED and the level of CH, respectively. Overlapping BR 50 and LTE curves revealed that CH began to develop in late April, when buds were fully endodormant and daily mean temperatures had started to drop below 14 °C, suggesting that ED is a prerequisite for the acquisition of full CH. Increase in starch content and thickening of the cell wall (CW) of meristematic cells which occurs in dormant buds could be involved in structural and metabolic changes that favor CH subsequent acquisition. Interestingly, the thickening of the CW and the synthesis of starch which are associated with ED were induced by a SD-photoperiod, while the hydrolysis of starch, the accumulation of soluble sugars, and the up-regulation of dehydrin genes, which are associated with CH, were induced by low temperatures. Overall, the results indicate that structural, metabolic, and transcriptional changes that occur during ED in grapevine buds are necessary for the further development of CH.
Seasonal dynamics of total non-structural carbohydrates (TNC) in relation to the leaf-fruit ratio were measured over five years at different grapevine phenological stages in one- and two-year-old canes, trunks and roots of the cultivar 'Chasselas' (Vitis vinifera L.). Carbohydrates were mainly stored as starch in different parts of the grapevine during the growing season. Soluble carbohydrates represented only a small part (< 7% of dry weight, DW) of the TNC. In the roots and trunks, the starch content fluctuated during the growing season, reaching the lowest values between budbreak and flowering depending on the year, and the highest values between harvest and leaf fall. The soluble sugar content increased in the trunks and the two-year-old canes during the winter period with the decrease in temperatures. A negative correlation was established between the average air temperature recorded during the seven days before sample collection for carbohydrate analysis, and soluble carbohydrate content in the trunks and two-year-old canes. The leaffruit ratio (source-sink), expressed by the "light-exposed leaf area-kg -1 fruit", not only substantially influenced the soluble sugar content in berries but also the starch and TNC concentrations in the trunks and roots at harvest. Higher leaf-fruit ratios resulted in increased starch and TNC concentrations in the trunks and roots, which attained the maximum values when the leaf-fruit ratio neared 2.0 m 2 of light-exposed leaf area-kg -1 fruit. Canopy height and leaf area had no predominant influence on the soluble sugars, starch contents, or TNC in the permanent vine parts.
Seasonal dynamics of reserve nitrogen (N) over five years and nonstructural carbohydrates over three years were monitored at six vine phenological stages in one-, two-, or older than two-year-old wood fractions of minimally (MP) and severely pruned (VSP) Riesling (Vitis vinifera L.) under cool-climate conditions. Levels of reserve nitrogen were highest in all woody fractions and both pruning systems at leaf fall, dormancy, and budbreak and lowest at bloom, bunch closure, and veraison. In general, N-concentrations were lower in older wood fractions. The magnitude of N-mobilization between budbreak and bunch closure and N-replenishment after veraison was higher for MP vines than for VSP vines and correlated with leaf area formation and leaf area loss, respectively. During the observation period, MP attained higher concentrations of N at most sampling dates in all wood fractions as compared with the VSP system, with the greatest differences in 2002 and 2003. Over a five-year period, N-concentration at veraison declined in both systems, which may have been related to the long-term trend in seasonal plant water status. Changes in dry matter and total nonstructural carbohydrates (TNC) in different wood fractions followed a similar general pattern as changes in N, but mobilization and replenishment occurred at earlier phenological stages. Concentrations in glucose, fructose, and sucrose decreased to almost the lowest values during the season at budbreak and increased again before leaf fall, whereas starch degradation occurred after budbreak and its re-formation between bunch closure and veraison. Minimum TNC concentration, usually observed between full bloom and bunch closure, increased with age of the woody fraction but decreased over the three seasons for all fractions and both systems. With the exception of 2001, MP had slightly lower concentrations in TNC and its component sugars for most sampling dates.
Twenty-year-old "Chemlali" olive trees trained to vase and rainfed were investigated in either "on" (2004) or "off" (2003) year. A randomized block design with three blocks and three treatments was used and each experimental plot consisted of nine olive trees. Three treatments were applied: (1) rainfed conditions (RF, used as control treatment); (2) irrigation with well water (WW); and (3) irrigation with treated wastewater (TWW). Irrigation with TWW led to a significant increase of root N, P, Ca, Zn, Mn, Na, and Cl concentrations, in particular in the on-year. Data showed significant differences, between the two years, for the concentration of the mineral elements in the roots, with general lower values in the on-year, probably as a consequence of nutrients movement upward in the tree. Fruit N, P, K, Zn, Mn, and Cl contents were significantly higher in TWW irrigated trees with respect to both RF and WW trees, whereas similar values for Ca, Mg, Na, and Cl contents were measured for WW and TWW irrigated trees. The irrigation with TWW allowed to reuse problematic waters and to save nutrients inputs in the olive orchard thus moving towards a more sustainable management of olive orchards in countries where water is the major limiting factor for agriculture.
Background and AimsRegulated deficit irrigation (RDI) and bunch thinning are two viticultural practices applied worldwide. There is limited knowledge, however, about their combined effects on carbohydrate dynamics and accumulation. We evaluated during year 3 and 4 of the experiment the effect of 4 consecutive years of RDI and bunch thinning on carbohydrate status, vegetative and reproductive variables. Methods and ResultsFrom 2006/07 to 2009/10, we imposed four levels of water supply [100, 60, 38 and 25% of reference evapotranspiration (ETo)] and two crop loads (100 and 50% of the bunches). We compared shoot length, flowers per inflorescence and yield in 2009/10. We also measured pruning mass and the concentration of non-structural carbohydrates in dormant wood in the winters of 2009 and 2010. Starch concentration in the trunk was reduced by severe water deficit (25 and 38% ETo) and improved by bunch thinning. Pruning mass, shoot length, flowers per inflorescence and yield were affected in vines with water applied at 25 and 38% of ETo. Conclusions
Severe water stress and high crop load reduced trunk starch concentration with no interaction between both factors, whereas the concentration of total non-structural carbohydrate was not affected. Vegetative growth and yield were reduced after 4 years of severe water stress. Significance of the StudyWe provide evidence that starch concentration and carbon partitioning can be manipulated through common viticultural practices, such as irrigation and crop load.
Humic acids are the most active components of soil organic matter and have been shown to have an hormone-like activity thus stimulating plant growth. The objective of this work was to verify the quantitative and qualitative yield responses of the table grape cv. Italia after the application of a humic acid at various phenological stages. The humic acid used in this study has been extracted from a clay soil of the Apulia region and was applied at a concentration of 100 mg L-1 in four different times: pre-bloom (I), full-bloom (II), fruit set (III) and veraison (IV) and in two years, 2007 and 2008. The following parameters were measured at harvesting: berry size, °Brix, pH and titratable acidity. Finally, the °Brix/titratable acidity ratio has been calculated. Soil Plant Analysis Development (SPAD) readings were performed every 30 days up to harvesting time on the leaves of the middle shoots. No statistical differences were observed between the two years for all the parameters examined. The humic acid applied at full-bloom (II) induced a significant increase of berry size (width and weight) and a significant improvement of the other quality parameters (titratable acidity and °Brix/titratable acidity) with respect to the control. This study confirmed that humic acids, if applied at full-bloom, can induce significant increase of qualitative and quantitative parameters in table grape and can find a positive application in an organic and sustainable viticulture.
The effect of the number of RAPD fragments on the estimation of genetic distances has been studied on 10 genotypes (Vitis
vinifera) using 320 primers. A total number of 1683 scorable bands was obtained but only polymorphic bands (932) were considered
in this work. The variation of the genetic distances, in relation to an increasing number of bands, was evaluated through
a bootstrap sampling procedure. The mean coefficient of variation (CV) of the genetic distances decreased as the number of
bands increased. A CV of 10% was obtained with about 100–150 bands while a CV of 5% with a large number of bands (400–500
and over). To reduce the cost and the time of the analyses, primers with different levels of polymorphism were compared. Genetic
distance matrices, based on different numbers of bands and primer polymorphism, were highly correlated with the genetic distance
matrix of the whole data set when they were determined with a large number of RAPD fragments, either from high or low polymorphic
primers. The effect of the number of bands on the estimation of genetic distances was evaluated also through the variation
of the pattern of aggregation among genotypes (cluster analysis). Stable clusterings were detected when a large number of
polymorphic bands (400 and over) was used. Some rearrangements of the genotypes in the dendrograms was observed as the number
of bands decreased; below 100–150 bands the clusterings were completely rearranged.
Late ripening berry dehydration is an important phenomenon that occurs through grape berry water loss due to the alteration of the fruit water budget when transpiration and potential water back flow to the plant exceed the import of water into the berry through the phloem and xylem. Berry shrivelling can have a significant economic impact, reducing yields by ≥25 % with consequences on berry composition and the resulting wine. Its occurrence and consequences are expected to increase due to predicted climate change, shifting grape development and ripening into warmer periods (i.e., heat waves and drought events).
The quality of wine grapes depends on the balance between primary and secondary metabolites. Unlike many perennial crops that accumulate starch in the fruits before ripening, the non-climacteric grapes ripe with no previous carbon reserves. Based on the assumption that fruit carbon sink is limiting metabolite accumulation in grapes, bunch thinning is performed to limit plant Sink/Source (S/S). We studied the effects of severe bunch thinning on the accumulation of primary metabolites and on four families of glycosylated aroma precursors (GAPs) at the arrest of fruit phloem unloading of two white grape Vitis vinifera cvs. At plant level, crop reduction resulted in significant losses of metabolites to be accumulated in the fruits: i.e. up to 72% for sugars, 75% for organic acids and GAPs. Nevertheless, S/S manipulation could not modify the balance between GAPs and primary metabolites or increase the concentration in GAPs in the physiologically ripe grape.
Climate is the main factor affecting grape and wine quality in Mediterranean viticulture. Global warming provokes an increase in the accumulation of soluble solids in grapes, together with a lower content of anthocyanins and acidity. This result in stuck and sluggish fermentations causing economic losses in the winery. Climate adaptation strategies are essential to minimize the detrimental effects of global warming on grape and wine quality. This review summarized the effect of viticultural techniques to delay grapevine ripening with emphasis on canopy management and we overviewed the effects of high temperatures on grape and wine quality. Some viticultural techniques such as severe shoot trimming, minimal pruning, late winter pruning and apical leaf removal may delay grapevine ripening close to 15 days. Forcing regrowth is the most interesting technique since it allows to delay grape ripening at least of two months which can be essential in warm grapevine production areas.
Background and Aims
Climate change is advancing grapevine phenology, decoupling berry technological and phenolic maturity. The aim of this study was to assess the usefulness of late winter pruning for delaying grape ripening.
Methods and Results
In two Bobal and Tempranillo vineyards located in eastern Spain, vines pruned at dormancy were compared with a delayed winter pruning (late pruning) carried out just before the basal buds burst (BBCH 05). In both cultivars, late pruning delayed grape ripening, resulting in grapes with higher anthocyanin concentration for similar TSS at harvest. In general, the resulting wines had a higher colour intensity and lower hue angle. These effects were more noticeable in Tempranillo, an earlier ripening cultivar, than in Bobal. Despite late pruning improving vine water status, the yield was steadily reduced by 10%.
Conclusions
Late pruning is a useful strategy for delaying grape ripening, thus adapting grapevine production to climate change. The small detrimental effects on yield and compression of pruning dates within a few days may limit the application of this practice.
Significance of the Study
Delaying winter pruning can be used to improve grape and wine composition when facing changes in the meteorological conditions experienced during berry ripening.
Biostimulants have recently been used in sustainable agriculture systems to improve plant growth and resilience to biotic and abiotic stress. In this study, foliar (ANEfl) and soil (ANEsl) A. nodosum extract applications were studied to elucidate the impact of different delivery methods on grapevines physiology either under well-watered conditions (WW) or under a water deficit period and a subsequent water recovery (WS). ANEfl increased leaf soluble sugars and photosynthesis of WW vines. Under progressive WS conditions, ANEfl positively impacted leaf gas exchange and water use efficiency (+35 % as compared to untreated vines) at Ψ stem about-0.65 MPa. Photosynthesis was also improved during the re-watering period (+2.7 μmol CO 2 m − 2 s-1) via preserved photochemical efficiency (Fv/Fm +0.19 as compared to untreated vines) and enhanced leaf anatomical and biochemical traits (+8% leaf dry matter and +27.3 mg/g DW of leaf soluble sugars). Contrarily, when soil applied, A. nodosum extracts did not significantly improve vine physiology during the reduced water supply period and only mild effects were detected at re-watering. Results demonstrates that foliar applications of A. nodosum extracts could be an alternative sustainable tool to improve grapevine physiological performances under mild-to-moderate water deficit and to preserve photosystems integrity and vineyard resilience when water limiting conditions get more severe.
Grapevine development comprises different phenological stages from bud break to berry maturation which are mainly temperature and water dependent. Pre bud break, there is a crucial stage called dormancy which can be divided in two periods: endodormancy and ecodormancy. Climate change (increase in average temperatures and drought) may accelerate the onset of bud burst, however with greater heterogeneity, thus increasing the risk of shoot exposure to abiotic and biotic constraints. Obviously, this could lead to yield and quality issues. In this regard, the ability to assess when climatic conditions are suitable for dormancy release and to predict the date of bud break is important.
Background and Aims
Global warming can lead to technological ripening occurring in advance of phenolic maturity for red wine cultivars. This study evaluated the effect of post‐budburst winter pruning on the phenology, yield components, berry composition and phenolic maturity in Vitis vinifera L. cv. Merlot.
Methods and Results
Mechanically pre‐pruned vines followed up with hand pruning during winter (Control) were compared to vines that were mechanically pre‐pruned and followed up with hand pruning after budburst when distal buds developed shoots with either three unfolded leaves (DF3) or eight unfolded leaves (DF8). Late pruning delayed budburst, flowering and, to a lesser extent, veraison. The delays were greater for DF8 than DF3 treatments. Yield decreased by about 40 and 71% in DF3 and DF8 vines, respectively, while sugar accumulation and reduction of TA were delayed by both pruning treatments. The concentration of anthocyanin and tannin and of extractable anthocyanin and tannin (of skin and seeds analysed separately) were not influenced by the DF3 treatment while tannin concentration increased in DF8 berries.
Conclusions
Delaying hand pruning of mechanically pre‐pruned vines until after budburst of distal nodes can delay technological ripening without affecting the concentration of anthocyanin and tannin of berries. Yield, however, is substantially reduced.
Significance of the Study
We verified the feasibility of a cost‐effective technique that can be adopted to counteract the hastening of sugar accumulation and organic acid decline caused by global warming on valuable black grapes.
The effects of animal- and plant-derived protein hydrolysates (PHs), namely casein (Cas), soybean (Soy) and
lupin (Lup), in improving grapevine performance and inducing water stress tolerance were evaluated in the field
on the wine grape cultivar Corvina. PHs were applied every ten days and for three times from fruit-set to bunch
closure by spraying at two concentrations (1.6 and 6.4 g L−1 equivalent to 0.5 and 2.0 kg/ha, respectively);
water treatment was used as control. Overall, data clearly pointed out the effect of biostimulants in enhancing
grapevine yield and quality and in reducing conductance index (IG), with differences in efficiency, depending on
the biostimulant origin and concentration. With regards of yield, Soy and Cas at 6.4 g L−1 reached 5.57 and
5.39 kg/vine, respectively, with an increase of 24 and 21% with respect to the control treatment (4.25 kg/vine).
Total soluble solids content was significantly increased by PHs application, with values ranging from 19.05
(control) up to 22.80 °Brix (Lup at 1.6 g L−1). All PHs significantly ameliorated the total anthocyanin content of
berries with respect of the control (132 g L−1). The best effect was obtained by Cas treatment at the lower dose
with an anthocyanin content of 373 g L−1. Generally, canopy temperature of treated vines remained significantly
higher than untreated control of 1–3 °C degrees. Regarding water stress tolerance, the lowest dose of Soy- and
Cas-PHs showed great ability to reduce the stress index IG (proportional to stomatal conductance). This 5-year
study showed the role of PHs, as natural biostimulants, to ameliorate fruit parameters and reduce water loss and
Soy- and Lup-PHs can be considered for a commercial application.
Late pruning is an emerging cultural technique aimed at deferring ripening kinetics and reducing the negative effects of warming trends on grape maturity. It relies on the inhibition of basal nodes and on the postponement of the progression of phenological stages. As a consequence, late pruning is capable of maintaining at harvest a moderate sugar concentration and an adequate acidity level in grapes. This work was intended to deepen the effects of late pruning, focusing on the intra-vine phenology variability and progression as well as on the interactions existing between the changes in vine balance and the ripening time shift. Two experiments were conducted over two consecutive years in different vineyards located in Abruzzo (central Italy), comparing late pruning (LP) applied when unpruned canes had shoots with two/three leaves already unfolded (phenological stage BBCH 12/13) with standard winter pruning executed at dormancy (WP). LP shifted phenology and led to a significant variability in the development stages detected on shoots arising from the different nodes of the spurs, whereas in WP vines shoots arising from count-nodes developed in syn-chrony. LP successfully delayed ripening, but the outputs of the two experiments were different: LP postponed sugars accumulation and the decrease of acidity in both experiments (-2° Brix and +2.5 g/L at harvest, as an average of the two experiments) though the yield was negatively affected only in the first experiment (-47% as compared to WP). Late spur-pruning confirmed its efficacy in spreading grapes maturity and maintaining higher acidity along with a reduced sugar concentration. The delaying effect seems to be quite independent from the seasonal vine balance given as leaf area-to-fruit ratio. The study provided further clarification of the physiological bases underlying vine response to delayed winter pruning and indicated robustness of its effects regardless environmental conditions and degree of vine balance.
The shift in phenological development is the most conspicuous biological effect of climate change in vineyards worldwide. Associated with the advancement in maturity there has been a compression of the harvest period that places significant pressure on vineyard and winery infrastructure. Our aims were to test the feasibility of using delayed pruning as a tool to delay ripening and decompress maturity, to establish how much pruning can be delayed before compromising yield, and to compare the response of Cabernet Sauvignon and Shiraz.
Global warming is shifting vine phenology, compressing harvests and altering the balance of fruit traits relevant to wine. Our aim was to test late pruning as a tool to delay maturity and to assess carry-over effects from repeated late pruning on phenology, yield components, dynamics of leaf area and berry traits of Shiraz grown in the Barossa Valley of Australia. A trial was established in a commercial vineyard comparing three pruning times during four consecutive seasons: (i) winter (Control), (ii) budburst and (iii) 2–3 leaves emerged. Compared with the Control, TSS in berries of vines pruned at 2–3 leaves reached 12°Be 7 days later in the first three seasons, and 14 days later in the last season; the budburst treatment was intermediate between that of winter and of 2–3 leaves. Yield was unchanged by late pruning in three seasons and increased in one. Leaf area index at harvest in 2–3 leaves was greater or similar than in the Control. Late pruning shifted the onset of anthocyanin accumulation against TSS, increasing the anthocyanin concentration and the anthocyanin-to-sugar ratio in two seasons. Late pruning delayed maturity with neutral or positive effects for yield and berry traits. Carry-over effects on phenology, yield, leaf area and berry traits were negligible. In a context of global warming, delaying pruning to 2–3 leaves can effectively spread the harvest and partially restore the anthocyanin : sugar ratio with no penalty for yield in Barossa Valley Shiraz.
Sangiovese vines mechanically spur-pruned during dormancy in February were subjected to immediate or delayed (post bud-burst) manual finishing to test the potential of a ‘double-pruning’ approach to delay fruit sugar accumulation and limit yield. The treatments were applied in 2014, 2015 and 2016 at BBCH-0 as standard hand finishing on dormant buds (SHF) and as late (LHF) and very late (VLHF) hand finishing at BBCH-14 and BBCH-19, i.e. when the two apical shoots on the mechanically shortened canes were respectively about 10 cm and 20 cm long. While yield per vine was drastically reduced in the VLHF treatment (−43% vs. SHF) due to high incidence of unsprouted (blind) nodes, lower shoot fruitfulness and berries per cluster, yield reduction in LHF was −22% vs. SHF due only to unsprouted nodes incidence. While the fruit ripening profile was not significantly modified in VLHF as compared to SHF, LHF achieved for data pooled over the three seasons a delay in basic fruit composition at harvest as lower total soluble solids and pH and higher acidity which, however, was associated with higher phenolics in comparison to SHF. Overall, LHF proved to be effective at reducing yield per vine to a level that did not require expensive cluster thinning. By reducing berry sugar accumulation, it has the potential to produce wines with lower alcohol and higher phenol content. Noteworthy too is its potential to delay harvest date or increase crop hanging time under specific vineyard conditions.
The Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), is the latest atmospheric reanalysis of the modern satellite era produced by NASA's Global Modeling and Assimilation Office (GMAO). MERRA-2 assimilates observation types not available to its predecessor, MERRA, and includes updates to the Goddard Earth Observing System (GEOS) model and analysis scheme so as to provide a viable ongoing climate analysis beyond MERRA's terminus. While addressing known limitations of MERRA, MERRA-2 is also intended to be a development milestone for a future integrated Earth system analysis (IESA) currently under development at GMAO. This paper provides an overview of the MERRA-2 system and various performance metrics. Among the advances in MERRA-2 relevant to IESA are the assimilation of aerosol observations, several improvements to the representation of the stratosphere including ozone, and improved representations of cryospheric processes. Other improvements in the quality of MERRA-2 compared with MERRA include the reduction of some spurious trends and jumps related to changes in the observing system and reduced biases and imbalances in aspects of the water cycle. Remaining deficiencies are also identified. Production of MERRA-2 began in June 2014 in four processing streams and converged to a single near-real-time stream in mid-2015. MERRA-2 products are accessible online through the NASA Goddard Earth Sciences Data Information Services Center (GES DISC).
Alternate bearing is a typical behavior of various fruit tree crops and is common among olive cultivars (Olea europæa L. var. sativa Hoffm. e Lk.). Since this phenomenon affects yield and consequently oil production, it is a concern for olive oil industry in order to offer a constant olive oil amount each year. A 4-year field experiment was conducted on cv Chemlali olive trees in ‘on’ and ‘off’ years in order to study, under arid conditions, both annual macro-element balance and net photosynthetic activity. Shoots growth was much higher in the ‘off’ year with respect to the ‘on’ one (+11.70 cm vs. +2.60). Net photosynthesis rate was much higher in the ‘off’ year with respect to the ‘on’ year and the highest values were observed at spring, when there is an intense vegetative growth. Differences for the mineral elements were observed between the ‘on’ and ‘off’ years. Nitrogen accumulated in leaves mainly in spring in the ‘off’ year, whereas high N values were detected also at the end of summer in the ‘on’ year. Consequently, N fertilization can be accomplished in February–March and possibly after harvest (November–December) to be used at budburst in the successive season. A difference was found between leaf P concentrations in ‘on’ or ‘off’ years from flowering to fruit-set, with the lowest values in the ‘on’ year, in particular in June–July. A supply of P at autumn–winter and partially in spring–summer in particular in an ‘on’ year would be appropriate. K accumulated in leaves in ‘on’ year from spring to summer, thus a supply of K in January–February, before new vegetation, for trees either in ‘on’ or ‘off’ year can be necessary for supporting and implementing the root system activity and the successive shoot growth (‘off’ year) and fruit development (‘on’ year). These results should be useful to partially reduce, through an appropriate fertilization schedule, the alternate bearing in olive tree.
Insufficient leaf photoassimilation could allow mobilized carbohydrate reserves to contribute to berry sugar accumulation. However, the extent of this contribution during rapid and slow berry sugar accumulation is undefined. The potential effect of leaf-to-fruit ratio and water availability on carbohydrate reserve distribution in potted Tempranillo grapevines was examined during berry maturation. Within each leaf-to-fruit ratio treatment (full and 50% leaves), vines were grown under full or 50% reduced irrigation regimes. Dry biomass development, and the starch and soluble sugar concentrations were determined in the roots, trunks, stems and leaves. Berry sugar and anthocyanin accumulation were also assessed. Under full irrigation, no starch remobilization from roots was observed, regardless of the leaf-to-fruit ratio. Under reduced water supply, starch remobilization from roots was concurrent with rapid berry sugar accumulation, especially in grapevines with low leaf-to-fruit ratio. Soluble sugar accumulation coincided with starch depletion in the roots of grapevines under reduced water availability. When berry sugar accumulation slowed, an increase in carbohydrates was observed in the roots. Sustained water constraints during rapid berry sugar accumulation resulted in a forced reliance on stored carbohydrates to support berry sugar accumulation, but did not significantly alter the tempo of berry sugar and anthocyanin accumulation. A reduced leaf-to-fruit ratio intensified the reliance of fruit sugar accumulation on stored carbohydrates. Besides the importance of post-harvest carbohydrate reserve replenishment when root carbohydrate reserves are depleted during berry maturation, the reserves are also refilled during maturation when berry sugar accumulation slows. This study showed distinctly that root carbohydrate replenishment could already start a few weeks before harvest, and this replenishment could be important when the post-harvest carbon assimilation period is ineffective.
Viticulture is a key socioeconomic sector in Europe. Owing to the strong sensitivity of grapevines to atmospheric factors, climate change may represent an important challenge for this sector. The present study analyses viticultural suitability, yield, phenology, and water and nitrogen stress indices in Europe, for present climates (1980–2005) and future (2041–2070) climate change scenarios (RCP4.5 and RCP8.5). The STICS crop model is coupled with climate, soil and terrain databases, also taking into account CO2 physiological effects, and simulations are validated against observational datasets. A clear agreement between simulated and observed phenology, leaf area index, yield and water and nitrogen stress indices, including the spatial differences throughout Europe, is shown. The projected changes highlight an extension of the climatic suitability for grapevines up to 55ºN, which may represent the emergence of new winemaking regions. Despite strong regional heterogeneity, mean phenological timings (budburst, flowering, veraison and harvest) are projected to undergo significant advancements (e.g. budburst/harvest can be >1 month earlier), with implications also in the corresponding phenophase intervals. Enhanced dryness throughout Europe is also projected, with severe water stress over several regions in Southern regions (e.g. southern Iberia and Italy), locally reducing yield and leaf area. Increased atmospheric CO2 partially offsets dryness effects, promoting yield and leaf area index increases in Central/Northern Europe. Future biomass changes may lead to modifications in nitrogen demands, with higher stress in Northern/Central Europe and weaker stress in Southern Europe. These findings are critical decision support systems for stakeholders from the European winemaking sector.
For a retrospective period of 110 years between 1901 and 2010 (observed data), and for the subsequent future period between 2011 and 2100 we calculated the phenological development (bud burst, harvest ripeness), and in particular the spring frost risk (frost after bud burst), as one important derived variable for grapevine (Vitis vinifera L. cv Riesling) for the whole of Germany. For the future climate we included two different scenarios (RCP8.5, RCP2.6) each of them containing a triple set with minimum, medium and maximum temperature increase. The time period between 1981 and 2010 as the last three decades in the observed data was chosen as reference. In general we found an acceleration of the phenological development (all main phases) mainly beginning in the late 1980s. For the three-decade period between 2031 and 2060 this acceleration will reach 11 ± 3 days in the RCP8.5-scenario. The acceleration for the other stages behaved similarly and results in an earlier harvest ripeness of 13 ± 1 days. Since a warmer spring in general leads to earlier bud burst, but does not reduce the risk of frost events during this period in the same manner, changes in the risk of spring frost damage were relatively small. For the coming decades this risk will not decrease for all traditional German viticultural regions in the RCP8.5-scenarios; on the contrary, our results suggest it is likely to increase. The results showed an increasing spring frost risk not only for the debated "upcoming" potential viticultural areas in eastern Germany, an effect which will partly also reach the southernmost viticultural areas. This effect in northern and eastern Germany is due to earlier bud burst together with the stronger continental influence, but for the southern and western regions of Germany is mainly due to the even earlier bud burst. This could modify the regionally nuanced character of German wines.
Some persimmon growers do not harvest fruits even when late maturing ‘Fuyu’ (Diospyros kaki Thunb.) is damaged with withering of most leaves by a sudden frost. This experiment was conducted to determine the influence of no harvest after frost on storage reserves and tree development the next season. Autumn frost firstly damaged leaves and fruits on 2 November 2012 and 12 November 2013. Some trees were harvested on 12 November 2012 and 15 November 2013, whereas the others were left unharvested. In the unharvested trees, fruit dry weight and contents of soluble sugars, starch, nitrogen, and potassium stopped to increase after the frost damage. There were no significant differences in carbohydrates and the inorganic nutrients in dormant shoots between harvested and unharvested trees. Unharvested trees were not adversely affected in the shoot mortality during winter, number of flower buds as well as the growth of shoots, leaves, and fruits the next season.
The response of grapevine carbohydrate reserves and seasonal growth and development to defruiting at the onset of ripening or complete defoliation at commercial harvest was examined at four sites in two hot, inland regions of New South Wales, Australia. Early defruiting over two consecutive seasons increased total nonstructural carbohydrates (TNC) in the roots, and to a lesser extent in the wood, and resulted in yield increases of up to 60% in the third season when fruit was allowed to remain on the vine until harvest. In contrast, defoliation at harvest caused a decline in TNC concentrations and reduced fruit production by up to 22% following one season of treatment and by 50% following two seasons. The higher yields developed after the two proceeding seasons of early defruiting were associated with depletion of the initially high carbohydrate reserves between budbreak and harvest, and reserve restoration did not take place until after harvest. However, in the lower yielding, previously defoliated vines, carbohydrate reserves were restored before fruit maturity. These findings show that carbon demands of ripening fruit, and photoassimilation capacity after harvest, can both limit the restoration of carbohydrate reserves to preseason levels. Marked differences between sites in the seasonal maxima of nonstructural carbohydrate concentrations in perennial tissues and aspects of floral and vegetative development are attributed to water deficits. The interaction between carbohydrate reserves and fruit and shoot growth suggests a feedback process whereby homeostasis, following environmental or cultural perturbations, is restored to a level determined by the capacity of the grapevine to assimilate and store carbohydrates.
Written by a recognized expert, and based on his experience in teaching the subject to students with a variety of educational backgrounds, The Science of Grapevines: Anatomy and Physiology is the only book to comprehensively explore the physiology of the grapevine as it occurs around the world. While other books have focused on the vines of specific regions, the globalization of the wine industry and the resulting increase of lands around the world being used for grapevine cultivation has left a gap in information. This book addresses not only the specific issues and concerns of grapevines from regions around the world, but includes important emerging topics such as global climate change, water relations, temperature effect and more. The truly unique approach of this book is the scientifically-grounded exploration, often applying discoveries in other plant species, of the main physiological processes underlying grapevine form and function, their interactions, developmental and environmental control, and their implications for practical vineyard management. Features: * Focuses on the physiology of the whole plant rather than at the cellular and organ levels providing an understanding of whole-plant function * Comprehensive coverage of role of water relations and temperature impact prepares the reader for changing climate impact * Includes European, North and South American grapes and grape-related industry information providing important insights into implications of differences and similarities.
Background and AimsSpringtime root-zone warming activates mobilisation of the root carbohydrate reserves, a critical source of carbon for early canopy and reproductive development in grapevines following winter dormancy. Seasonal variability in soil temperature during spring may result in inconsistent vegetative growth and fruitset with consequences for berry growth and ripening. Methods and ResultsWe monitored flowering and berry ripening in Shiraz grapevines (Vitis vinifera L.) grown in large temperature-controlled pots. The vines were exposed to a cool, ambient and warm root-zone temperature from budburst to fruitset. Root starch mobilisation after budburst was linearly correlated to the cumulative heat units received by the soil. A warm root-zone temperature also hastened leaf expansion, net positive carbon assimilation, onset of flowering and fruit set, berry enlargement and the onset of veraison. At harvest, berry pH and nitrogen concentration as well as fresh and dry mass were higher for the vines exposed to a warm root-zone while berry acidity was lower. Conclusions
Warm soil temperature in spring stimulated the mobilisation of carbohydrates in the roots and accelerated shoot and reproductive development, resulting in larger berries with lower acidity. Significance of the StudyBecause root-zone temperature is an environmental driver of berry size and composition, models predicting yield and berry composition can be fine-tuned to incorporate this critical parameter.
Three-year-old field-grown 'Concord' (Vitis labruscana Bailey) grapevines were destructively harvested at eight growth stages during 1998 to quantify growth, carbohy- drate distribution, and nutrient concentrations of different organs. The roots were the major storage organ for carbohydrates and nutrients, accounting for 84% of the starch and 75% of nitrogen stored in the vines at the beginning of the season. About 78% of the reserve starch in the vine was used for prebloom root and shoot growth. Early-season fine- root growth was a sink for stored vine nitrogen; however, the fine roots quickly became a nitrogen uptake source, providing at least 84% of the spring growth nitrogen. Total root biomass increased from bloom to leaf fall, but reserve carbohydrates and nutrients lost in the prebloom period did not begin to recover in roots until the end of rapid shoot development in late July. Crop removal at harvest, and a late-season root flush, further increased vegetative carbohydrate and nutrient reserves in the short postharvest period.
Phenological shifts are one of the most conspicuous biological effects of global warming; observational data need benchmarking against experimental data. Grapevine phenology was monitored weekly between budswell and maturity in three factorial field experiments during two seasons. Two thermal regimes (heated vs. control) were combined with two irrigation regimes (experiment 1), two source:sink ratios (experiment 2) and four varieties (experiment 3). Open-top chambers were used to elevate temperature.We present evidence of nonlinearity of thermal effects on phenology that is explained by two complementary factors. Firstly, temperature-driven shifts of sensitive events (e.g. onset of sugar accumulation in berries) moved the timing of subsequent events into cooler conditions, hence dampening warming effects. Secondly, thermal effects on phenology seemed to be modulated by the interplay between resource-driven growth and temperature-driven development; an enhanced thermal effect on berry ripening associated with high source:sink ratio supports this proposition.Measured shifts in maturity were smaller than expected from reported time series analysis. During berry ripening towards maturity, the phenological trajectories of heated and control vines largely overlapped on thermal time scales; differences in phenology between treatments were therefore attributed to actual thermal regimes. We thus conclude that thermal sensitivities from time series (6–9 d °C−1) over-estimate thermal effects on grapevine maturity.
The detailed crop specific descriptions of the phenological growth stages of grapevine are supplementary to the general BBCH-scale. It will be instrumental in standardising the national and international experimentation in viticulture. The phenological development of the grapevine is divided into growth phases (principal growth stages 0–9) and each growth phase is subdivided into growth steps (secondary growth stages 0–9). A two-digit code is attached to each growth stage. The description and coding of the phenological growth stages covers the period between dormancy and leaf fall.
Humic acids (HA) and fulvic acids (FA) of different origin were evaluated for their antimutagenic and/or desmutagenic activity on Vicia faba germinating seeds treated with the mutagen compound maleic hydrazide (MH). Both HA and FA were tested at two different concentrations, 20 and 200 mg L−1, either alone or together with 10 mg L−1 of MH. Two experimental procedures were used to investigate the occurrence and nature of the antimutagenic or desmutagenic activity. In procedure 1, HA or FA and MH were interacted for 24 h and then added to the seeds. In procedure 2, the seeds were first treated with HA or FA for 6 days and then transferred to plates containing the MH solution, so that no interaction occurred between HA or FA and MH outside the seeds. The evaluation of the genotoxic activity was done by counting both micronuclei and aberrant anatelophases in root tip cells. Results obtained by using procedure 1 showed a clear desmutagenic action of HA and FA used at both concentrations, whereas results of procedure 2 indicated no antimutagenic effect of HA or FA. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 513–517, 2000
The aim of this investigation was to assess ice nucleation and frost resistance of two varieties of grapevine (Siegrebbe and Madeleine Angevine) during bud burst under radiative freezing conditions analogous to those during Spring in the UK.
During bud burst, grapevines were almost entirely resistant to freezing during frosts of less than ‐3°C by virtue of their ability to supercool. The risk of frost damage increased significantly as bud development progressed, and once buds had passed growth stage DS3 they became more sensitive to freezing and freezing damage was more extensive. The two varieties did not differ in frost resistance but, because of its earlier developing habit, variety Siegrebbe could be more prone to frost damage in the field.
Buds were more prone to damage after freezing once bud burst had commenced and the damage could not be reversed by acclimating plants for periods of 7 to 21 days at 4°C in an 8 h photoperiod. Such acclimation appeared to predispose frozen buds to more extensive damage.
The effects of delayed winter spur-pruning on yield, yield components and fruit composition of Merlot vines was evaluated within a commercial vineyard in Marlborough, New Zealand. Vines were spur-pruned, trained using vertical shoot positioning, trickle irrigated and grafted to Kober 5BB rootstock. Delaying pruning from July (usual winter pruning time in New Zealand) until up to October (when apical shoots on canes were 5 cm long) resulted in yield increases of up to 93%, 63%, and 82% over the three seasons of experimentation. These yield increases reflected higher average berry weight and in turn bunch weights. The increase in average berry weight was associated with a change in the relative abundance of different berry types. Later pruning increased the proportion of large seeded berries while the proportion of smaller seedless berries and live green ovaries (shot berries) decreased. The delayed pruning may have enhanced fertilisation of flowers and development of seeds by postponing flowering to a time when climatic conditions are more favourable; measurements of shoot lengths support this proposal. By delaying winter pruning until after budburst the development of basal nodes was inhibited, so that budburst on the resulting spurs was also delayed.
The potential anticlastogenic and antitoxic effects of a soil humic acid (HA), a peat HA and a peat fulvic acid (FA) on the mutagen maleic hydrazide (MH) have been investigated in two legume species, Vicia faba and Pisum sativum. Both HAs and FA were tested at two different concentrations, 20 and 200 mg l−1, either alone or after 24-hour interaction with 10 mg l−1 of MH before addition to the legume seeds. Anticlastogenicity, i.e. an antimutagenic action defined as the capacity for minimizing chromosome breakages, was evaluated by counting both micronuclei (MN) and aberrant anatelophases (AAT) in root-tip cells. Length and dry weight of the seedling primary root were measured to test the antitoxic activity of HA and FA on MH. The possible occurrence and extent of adsorption or desorption of MH onto or from HA were also investigated. The two species responded differently to the anticlastogenic tests, with V. faba showing a greater number of MN and AAT anomalies than P. sativum. Peat HA and FA exhibited anticlastogenic and antitoxic activities of similar intensity and greater than those of soil HA. The adsorption capacity of both HAs for MH was small, thus suggesting that adsorption is not a major mechanism responsible for the reduction of clastogenicity and antitoxicity of MH by HA.