110R Rootstock Research Articles

Investigation of Rooting Performance of Some Grapevine Rootstocks with Aeroponic Method

In the study, the aeroponic system examined the rooting performances of three grapevine rootstocks (110R, 1103 Paulsen, 5BB) commonly used in Türkiye. IBA was applied to grapevine cuttings to encourage rooting. Grapevine cuttings taken during the winter dormancy period were placed in the aeroponic system after the necessary pretreatments. Significant improvements were observed in root length, root number, and rooting rate during the rooting process of cuttings placed in the aeroponic system. No diseases or pests were observed during the rooting period in the daily checks. As a result of the study, the highest root length was 17.77 cm in 110R rootstock, while the lowest was 7.1 cm in 1103P rootstock. The highest rooting rate was 76.67% in a 25 ppm IBA application in 1103P rootstock and 73.33% in a 100 ppm IBA application. The lowest rooting was 10% in 110R rootstock at 100 ppm IBA application dose and in the control group. The study's results revealed the positive effects of aeroponic systems in increasing rooting performance. The advantages offered by these systems are essential in terms of sustainability and efficiency in agriculture. Considering global challenges such as climate change and the reduction of agricultural areas, aeroponic systems are expected to find wider applications in the future.

Rootstock Influences Growth, Yield, Berry Physiochemical and Quality Wine Produced from Cabernet Sauvignon Grown in the Pune Region

The experiment was conducted to study the effect of rootstock on growth, yield, quality, and sensory evaluation of wine made from ‘Cabernet Sauvignon’ grapes. Among the rootstock’s, pruning weight was significantly higher in vines grafted on 110R rootstock. Days for buds sprout and days to veraison was early in Gravasec grafted rootstocks, while early days to harvest in Gravasec and SO4 rootstocks. Cabernet Sauvignon vines grafted on 110R rootstock recorded significantly higher fruit yield than other rootstocks studied. Wine composition like volatile acid, total acids and ethanol was higher in vines grafted on 140RU; malic acids in 1103P and colour intensity in SO4 grafted vines. The wine sensory attributes were also positively influenced using different rootstocks, wine prepared from Cabernet Sauvignon grapes grafted on 1103P recorded the highest overall wine quality which was followed by Fercal rootstock.

Effects of different rootstocks on the growth and yield characteristics of Papazkarası (Vitis vinifera L.)

Rootstocks, which are becoming increasingly important in viticulture, influence the growth, yield, and grape quality of the grafted variety. Therefore, understanding the resistance characteristics of rootstocks to phylloxera, nematodes, environmental conditions, and abiotic and biotic stresses is crucial. Selecting a rootstock that is appropriate for the region where the vineyard will be established optimizes grape quality. The aim of this research is to determine the performance of the cv. Papazkarası on different rootstocks. For this purpose, an experiment was established at Irem Çamlica Viticulture and Winery Co. vineyard in Kırklareli province. Ten-year-old Papazkarası vines grafted onto 1103P, 110R, and 420A rootstocks were used as plant material. To determine the growth of the vines, parameters such as shoot elongation rate (cm/week), shoot length changings (cm), pruning wood weight (PW) (kg/vine), vigor (g), puissance, number of buds per square meter (number), balanced pruning buds number (number/vine), vegetative growth (VG), Ravaz Index (RI), Partridge Index (PI), and yield (kg/vine) were examined. Additionally, to determine cluster characteristics, cluster width and length (cm), weight (g), and the volume of gappy and spaceless clusters (cm³) were measured. The results of the research indicated that the 1103P rootstock had the lowest yield, puissance, RI, PI, and VG values; moderate values for PW, vigor, number of shoots, number of berries per cluster, and cluster length; and the highest values for cluster weight, the volume of gappy and spaceless clusters. The 110R rootstock was found to be more balanced compared to other rootstocks, with the highest values for vigor, RI, and PI; average values for yield, puissance, and VG; and the lowest values for PW, number of shoots, number of berries per cluster, cluster length, weight, and the volume of gappy and spaceless clusters. The 420A rootstock had the highest values for yield, PW, VG, number of shoots, number of berries per cluster, and cluster width and length; average values for RI, PI, cluster weight, and the volume of gappy and spaceless clusters; and the lowest value for one-year-old cane weight. In conclusion, based on the characteristics outlined, a selection can be made from these rootstocks according to cultivation purposes, but other rootstocks should also be investigated.

Response of selected scion and rootstock grape (<i>Vitis </i>spp.) genotypes to induced drought stress

Climate change is expected to elevate drought frequency, straining agricultural freshwater resources. Developing drought-tolerant grapevine varieties is crucial. This study examined grape scion and rootstock genotypes under well-watered (WW) and induced-drought (ID) conditions. ID treatment reduced vine length by 11.34-35.15%, with Vitis parviflora, 110R, and Male Hybrid rootstocks showing superior growth. Root length increased under ID, indicating an adaptive moisture-seeking response. The ID treatment led to substantial reduction in leaf count and average leaf area, especially in Flame Seedless (27.71 and 19.07 cm2, respectively). Drought stress elevated chlorophyll a:b ratio, affecting chlorophyll degradation in different genotypes. Significant variations were observed in leaf and root iron (Fe) and zinc (Zn) contents. Enzyme activities particularly peroxidase and polyphenol oxidase especially rose under drought, particularly in V. parviflora (3.39 μM guaiacol min-1 mg-1 protein and 1.33EU/ml/min respectively) likely to be contributing in drought tolerance mechanism. Principal component analysis (PCA) highlighted impact of traits on genotypes, emphasizing V. parviflora, Male Hybrid and Pusa Navrang as superior drought stress tolerant genotypes. Genotype clustering confirmed distinct groupings, while, correlation analysis unveiled intricate trait interactions.

The effect of plant growth regulator bacteria on micro propagation of grapevine rootstock with three different rooting abilities

In the study, 3 American rootstocks (110 R, 1103 P and 5 BB) with low, medium, and high rooting ability were used, 2 different bacterial isolates Bacillus cereus (ZE-7) and Pseudomonas putida (ZE-12) and their binary combination and the bottom of the cuttings. It was aimed to determine the effect of bacteria on rooting by treating the rooting part. During the rooting stage, hormone-free MS medium was treated with PGPRs, and in addition, hormone-free MS medium containing 1 mgl-1 IBA was used to determine the effects of PGPRs strains. At the end of the study, the root ratio of the explants was maintained; root length, number of roots, root fresh weight, root dry weight, shoot length, shoot fresh weight, and shoot dry weight data were examined. It was determined that PGPR applications generally gave higher values than control and IBA applications. Among the rootstocks, it was determined that they gave the best results in terms of root development. The highest values were obtained in the 5BB rootstock, and the lowest values were generally obtained in the 110R rootstock. Shoot development values varied according to the rootstocks and applications. In terms of the effects of the applications on root development, the highest rooting rate was 72.03%, the highest root number ratio was 1.95 on average, and the highest root fresh weight was 39.75 mg from the Bacillus Cereus application; Additionally, the highest root dry weight was obtained from B.cereus+P.putida application with 13.06 mg. The research highlighted this feature of 5 BB rootstock, which is considered among the easily rooting rootstocks, with its PGPR effect. 110 R, which is known as a difficult rooting rootstock and has high resistance to drought and active lime, which are the biggest threats today, showed a lower rooting rate, but when the values were examined, it was above the control and IBA applications.

Clonal Preselection in Grape (Vitis vinifera L.) Varieties of Ekşi Kara and Gök Üzüm

Ekşi Kara (functional female flowers) and Gök Üzüm (hermaphroditic flowers) are the two most important autochthonous varieties of middle Anatolia. This clone selection study started with mass-selection in producer vineyards consisting of approximately 5000 vines by The International Organization of Vine and Wine (OIV) clonal selection procedure. Two-years genetic and sanitation were examined visually in population and 220 clone candidates were ampelography and fertilization biology and bud fertility determined for Ekşi Kara variety. The clone candidates were ranked at the level of sums, with weighted grading of three-year yield, growth, and quality records. Sanitation analyses of the superior clones were made. 17 clones in the Ekşi Kara grape variety were selected according to their superior scores in genetic selection and sanitation analyses. Eleven clones were selected by mass selection from Gök Üzüm carried out in a single location, and 2 clones were selected with genetic selection scores and health tests. Grapevine fleck virus (GfKV) was the most common ( 29%) in the samples tested, Grapevine leafroll-associated virus 1+3 (GLRaV-1 + 3,  26%), Grapevine virus A (GVA, 12%), Grapevine leafroll associated virus-2 (GLRaV-2,  3%), Arabis mosaic virus (ArMV) / Grapevine fanleaf virus (GFLV) ( 1%) are fallowed with indicated percentage. Although virus and bacterial infections are common in the vineyards, enough healthy clones were selected. 17 Ekşi Kara and 2 Gök Üzüm clones selected as pollinators were grafted onto the 110R rootstock for clone comparison in homogeneous conditions, and a "Clone Comparison Vineyard" was established in Selçuk University.

Effect of PGR and Chemicals on Shelf Life, Bunch and Berry Quality Parameters of Sudhakar Seedless Grapes (Vitis vinifera L.)

The experiment was conducted on Sudhakar Seedless vines grafted on 110-R rootstock were selected for this study. The experiment was designed in randomized block design (RBD) having five treatments with four replications were carried out at MRDBS Nashik during 2020-2021. Pre-harvest application of treatments (Chitosan at 10 ppm, Naphthalene acetic acid at 100 ppm, activated Potassium salt @ 2.0 g/ liter, Salicylic acid at 2.0 ml/liter and Potassium Schoenite @ 2.0 g/liter along with untreated vines were applied at veraison stage of berry development. Application of Chitosan @ 10 ppm resulted in to the increase berry size and berry quality along with less Number of rotten berries in physiological loss in weight. Followed by the application of Naphthalene acetic acid at 100 ppm recorded less Number of rotten in this study. However, the lowest physiological loss of weight (%) were recorded with the application of Naphthalene acetic acid. The increasing dose of Naphthalene acetic acid resulted into decrease in pre- harvest berry drop. In grapevines, Application of salicylic acid significantly increase in berry weight, bunch weight, Total Soluble Solids /acidity ratio as compare to untreated vines. Biochemical composition of berries was influenced by the application of Activated potassium salt at different concentration. The application of Potassium schoenite in grapevines were found effective for increasing TSS of Sudhakar seedless grapes.

The Effect of Rootstock on the Activity of Key Enzymes in Acid Metabolism and the Expression of Related Genes in ‘Cabernet Sauvignon’ Grapes

The types and contents of organic acids in wine grapes determine wine quality. To explore the effects of different rootstocks on the acid metabolism of ‘Cabernet Sauvignon’ grapes, various perennial rootstock–scion combinations were used as experimental materials. High-performance liquid chromatography (HPLC) was used to determine citric acid, tartaric acid, and malic acid contents during fruit development. Succinic acid and oxalic acid contents and the activity of related enzymes were measured using spectrophotometry. The expression levels of related genes were measured using a real-time fluorescence quantitative method. The results showed that all four rootstock types significantly reduced oxalic acid and citric acid contents in the grapes, while increasing succinic acid content to varying degrees. Employing 110R, SO4, and Kangzhen3 rootstocks increased tartaric acid and malic acid contents. Enzyme activity analysis revealed that 110R, SO4, and Kangzhen3 rootstocks increased the NAD-MDH enzyme activity, which positively correlated with malic acid content. Simultaneously, these rootstocks reduced the NADP-ME enzyme activity level. NAD-MDH and PEPC gene expression levels were higher in ‘Cabernet Sauvignon’ grapes grafted with 110R, SO4, and Kangan3 rootstocks compared to control self-rooted seedlings. Grafting these three rootstocks enhanced malic acid accumulation in ‘Cabernet Sauvignon’ grapes.

CHARACTERIZATION THE INFLUENCE OF THE ROOTSTOCKS SO4, 44-53M, 110R AND FERCAL ON THE VOLATILE COMPOSITION OF RED WINES FROM THE HYBRID VARIETIES STORGOZIA (THREE HARVESTS) AND RUBIN (TWO HARVESTS) IN THE CONDITIONS OF CENTRAL NORTHERN BULGARIA

A gas chromatographic (GC-FID) study to characterize the influence of SO4, 44-53M, 110R and Fercal rootstocks on the volatile composition of red wines from the hybrid varieties Storgozia (harvests: 2017, 2018 and 2019) and Rubin (harvests: 2017 and 2019) under the soil and climatic conditions of Central Northern Bulgaria was conducted. The 110R rootstock in Storgozia has been shown to generate the highest total volatile content (756.10 mg/dm3) in 2017 harvest. 110R also affected the higher alcohols content of Storgozia. It generated the highest content of this indicator (713.00 mg/dm3) again in wines from the 2017 harvest. Regarding the content of esters, aldehydes and terpenes no significant differences were observed between the experimental variants of wines from this grapevine variety. In the case of Rubin wines, a very high final total volatile content was proved at rootstock 44-53M (1717.24 mg/dm3), harvest 2019. The highest concentration of higher alcohols in the 2017 harvest was identified for SO4, while in Rubin - the 2019 harvest, 110R generated the highest presence of higher alcohols. This fraction in both harvests was mainly represented by 2-methyl-1-butanol and 3-methyl-1-butanol. The esters were dominated by ethyl acetate and propyl acetate. In both harvests, the highest total terpene content was found in the wines from SO4 rootstock. The conducted research was evidence of the significant influence of different rootstocks on the volatile composition of wines from hybrid grapevine varieties in the conditions of Central Northern Bulgaria.

HiFi chromosome-scale diploid assemblies of the grape rootstocks 110R, Kober 5BB, and 101–14 Mgt

Cultivated grapevines are commonly grafted on closely related species to cope with specific biotic and abiotic stress conditions. The three North American Vitis species V. riparia, V. rupestris, and V. berlandieri, are the main species used for breeding grape rootstocks. Here, we report the diploid chromosome-scale assembly of three widely used rootstocks derived from these species: Richter 110 (110R), Kober 5BB, and 101–14 Millardet et de Grasset (Mgt). Draft genomes of the three hybrids were assembled using PacBio HiFi sequences at an average coverage of 53.1 X-fold. Using the tool suite HaploSync, we reconstructed the two sets of nineteen chromosome-scale pseudomolecules for each genome with an average haploid genome size of 494.5 Mbp. Residual haplotype switches were resolved using shared-haplotype information. These three reference genomes represent a valuable resource for studying the genetic basis of grape adaption to biotic and abiotic stresses, and designing trait-associated markers for rootstock breeding programs.

The Effects of Ortho Silicone Applications on the Acclimatization Process of Grapevine Rootstocks

Micropropagation is a tool for large-scale reproduction of planting material for viticulture sustainability. Successful micropropagation depends on the continued productivity of plantlets during the acclimatization phase. Due to high humidity in the culture container and free water in the environment, it causes rapid water loss and drying of plantlets with watery stems and leaves, poorly developed cuticle, large intercellular space, and incomplete stomata. Acclimatization of in vitro grown plantlets is often difficult. Silicon is gaining in importance as a useful tool in coping with multiple stress factors in different plant species, due to its contribution to the formation of the cuticle of plants, its mechanical resistance to biotic and abiotic stress, and its contribution to the flow of water through stomata and plant surfaces. In this study, the effects of 500 and 1000 µL ortho silicon applications at the acclimatization stage on in vitro propagated plantlets of 41B, 110R and Fercal grapevine rootstocks were evaluated by examining their survival rates. In the in vitro propagation process, rooting rates were listed as Fercal (64%) and 110R (32%) and 41B (28%) according to rootstocks, while root numbers were listed as Fercal (11.8), 41B (8.5), 110R (3.6). Genotypic differences were determined in the effects of silicon on plantlets in the acclimation process. In 110R and Fercal control plantlets, all plantlets were lost during acclimatization. Of the plantlets treated with 1000 µL SiO2, 110R 66% Fercal 88% and in 41B, the control, 500 and 1000 µL SiO2 applied plantlets survived 100%, 66% and 66%, respectively. 1000 µL SiO2 dose was more effective on survival rates than 500 µL applications. In subsequent studies, it was found that 1000 µL SiO2 applications could be used for practical success in grapevine genotypes that had problems in acclimatization and in other in vitro propagation studies.

Root Architecture and Development of American Grape Rootstocks Grafted with Foxy Grapes (Vitis labrusca L.) Cultivars

One of the important factors affecting rootstock performance in grafted grapevine production is root structure and its ability for different soil. In the present study, foxy grape varieties registered for the first time in the Black Sea Region in Turkey by the selection, and several American grape rootstocks were bench grafted. In this study; it is aimed to examine the root architecture of foxy grape grafted saplings for their root architecture and the development of rootstocks. In the experiment ‘Rizessi’, ‘Çeliksu’, ‘Ülkemiz’ and ‘Rizellim’ foxy grape cultivars grafted on 140Ru, SO4 and 110R rootstocks. WinRhizo root analysis program (Regent Instrument Inc. Canada, ver.2013) was used to determine rootstocks' architecture and development of grafted vine saplings. Roots prepared for scanning were placed on the scanning part of the device and transferred to the computer context. Root length and mean root diameter are two of the essential features that reveal the root architecture of rootstocks. In the study, root length (cm), root surface area (cm2), root diameter (mm), root volume (cm3), root tip number (piece), root branching number (piece), and root intersection number (piece) were determined. Total root length was determined between 330.05 - 595.40 cm ('Rizellim'/SO4 and 'Çeliksu'/140Ru) and mean root diameter of 2.04 - 3.13 mm ('Çeliksu'/140Ru and 'Rizessi'/110R). Negative relationships were found between root length and mean root diameter. Among the rootstocks, the highest root surface area was 399.67 cm2, root volume was 29.32 m3, the number of root tips was 1605.75, the number of root forks was 5421.89, and the number of root crossing was 671.61 on 110R rootstock. In all combinations obtained as a result of the study, it was determined that the rootstocks showed good root development and were in harmony with the new foxy grape cultivars.

Mitigating Grapevine Red Blotch Virus Impact on Final Wine Composition

Grapevine red blotch virus (GRBV), the causative agent of red blotch disease, causes significant decreases in sugar and anthocyanin accumulation in grapes, suggesting a delay in ripening events. Two mitigation strategies were investigated to alleviate the impact of GRBV on wine composition. Wines were made from Cabernet Sauvignon (CS) (Vitis vinifera) grapevines, grafted onto 110R and 420A rootstocks, in 2016 and 2017. A delayed harvest and chaptalization of diseased grapes were employed to decrease chemical and sensory impacts on wines caused by GRBV. Extending the ripening of the diseased fruit produced wines that were overall higher in aroma compounds such as esters and terpenes and alcohol-related (hot and alcohol) sensory attributes compared to wines made from diseased fruit harvested at the same time as healthy fruit. In 2016 only, a longer hangtime of GRBV infected fruit resulted in wines with increased anthocyanin concentrations compared to wines made from GRBV diseased fruit that was harvested at the same time as healthy fruit. Chaptalization of the diseased grapes in 2017 produced wines chemically more similar to wines made from healthy fruit. However, this was not supported by sensory analysis, potentially due to high alcohol content masking aroma characteristics.

Regulated Deficit Irrigation and Its Effects on Yield and Quality of Vitis vinifera L., Touriga Francesa in a Hot Climate Area (Douro Region, Portugal)

Under a climate change scenario, vineyards will experience serious challenges in the future. In an attempt to overcome such difficulties, this experiment offers a study on the effect of regulated deficit irrigation as a method for short-term adaptation to climate change in cv. Touriga Francesa, grafted into the rootstock 110R in the Douro region during a three-year period. Water stress on the plant and its effects on canopy, production, and quality of musts were analyzed. Rainfed vines (R0) were compared to three deficit irrigation regimes as a function of estimated crop evapotranspiration (ETc): R25 (25% ETc), R50 (50% ETc), and R75 (75% ETc). Water was applied on a weekly basis whenever predawn water potential showed moderate water stress until 15 days prior to harvest. The results suggest that rainfed plants under these circumstances suffered, in general, a negative impact on vine performance, while moderate water stress had more favorable effects on fruit composition, as well as in yield. Nonetheless, further studies should be conducted as irrigation did not show consistent effects on yield or berry composition.

Impact of Rootstock and Season on Red Blotch Disease Expression in Cabernet Sauvignon (V. vinifera).

Grapevine red blotch virus (GRBV), the causative agent of grapevine red blotch disease, is widespread across the United States and causes a delay in ripening events in grapes. This study evaluates the effects of GRBV on Cabernet Sauvignon grape berry composition, grafted on two different rootstocks (110R and 420A) in two seasons (2016 and 2017). Total soluble solids, acidity, and anthocyanin concentrations were monitored through ripening and at harvest. Phenolic and volatile compounds were also analyzed at harvest to determine genotypic and environmental influences on disease outcome. Sugar accumulation through ripening was lower in diseased fruit (RB (+)) than healthy fruit across rootstock and season. GRBV impact was larger in 2016 than 2017, indicating a seasonal effect on disease expression. In general, anthocyanin levels and volatile compound accumulation was lower in RB (+) fruit than healthy fruit. Total phenolic composition and tannin content was higher in RB (+) fruit than healthy fruit in only 110R rootstock. Overall, GRBV impacted Cabernet Sauvignon grape composition crafted on rootstock 110R more than those crafted on rootstock 420A.

Rootstock Effect on Volatile Composition of Albariño Wines

Background: Rootstock is a viticultural practice used to combat the devastating Phylloxera vitifoliae (Fitch). Additionally, it is well-known that wine aroma composition depends mainly on variety, viticulture management and winemaking; therefore, rootstocks can affect to berry quality. This study evaluated the influence of nine rootstocks (110R, SO4, 196-17C, Riparia G, 161-49C, 420A, Gravesac, 3309C and 41B) on volatile composition of Albariño wine in two consecutive vintages. Material and Methods: Volatile compounds belonging to eight groups (alcohols, C6-compounds, ethyl esters+acetates, terpenes + C13-norisoprenoids, volatile phenols, volatile acids, lactones and carbonyl compounds) were determined in Albariño wines by GC–MS, during 2009 and 2010 vintages. Results: Rootstock 110R had a positive influence on Albariño wines, increasing total volatile concentration, due mainly to 2-phenylethanol, decanoic and hexanoic acids, ethyl esters and acetates, and C13-norisoprenoids. However, the higher contribution of volatile fatty acids to Albariño wine was shown when grapevines were grafted onto SO4. Conclusions: This work provides new information about the impact of rootstocks on Albariño wine volatile composition, where 110R had a positive influence on Albariño wines under the edaphoclimatic conditions of Salnés Valley (Galicia, Spain).

On the Applicability of Chitosan Oligomers-Amino Acid Conjugate Complexes as Eco-Friendly Fungicides against Grapevine Trunk Pathogens

In a context in which the incidence and severity of grapevine fungal diseases is increasing as a result of both climate change and modern management culture practices, reducing the excessive use of phytosanitary products in viticulture represents a major challenge. Specifically, grapevine trunk diseases (GTDs), caused by several complexes of wood decay or xylem-inhabiting fungi, pose a major challenge to vineyard sustainability. In this study, the efficacy of chitosan oligomers (COS)–amino acid conjugate complexes against three fungal species belonging to the Botryosphaeriaceae family (Neofusicoccum parvum, Diplodia seriata, and Botryosphaeria dothidea) was investigated both in vitro and in planta. In vitro tests led to EC50 and EC90 effective concentrations in the 254.6−448.5 and 672.1−1498.5 µg·mL−1 range, respectively, depending on the amino acid involved in the conjugate complex (viz. cysteine, glycine, proline or tyrosine) and on the pathogen assayed. A synergistic effect between COS and the amino acids was observed against D. seriata and B. dothidea (synergy factors of up to 2.5 and 2.8, respectively, according to Wadley’s method). The formulations based on COS and on the conjugate complex that showed the best inhibition rates, COS−tyrosine, were further investigated in a greenhouse trial on grafted vines of two varieties (”Tempranillo” on 775P and “Garnacha” on 110R rootstock), artificially inoculated with the mentioned three Botryosphaeriaceae species. The in planta bioassay revealed that the chosen formulations induced a significant decrease in disease severity against N. parvum and B. dothidea. In summary, the reported conjugate complexes may be promising enough to be worthy of additional examination in larger field trials.

Effect of rootstocks on growth parameters of red globe grapevines (Vitis vinifera L.)

The present investigation was conducted for two years (2018-19 and 2019-20) to study the effect of rootstocks (Dogridge, 110R, 140Ru, Salt Creek and own roots of Red Globe) on growth parameters of Red Globe grapevines. The vigour and growth parameters such as pruning weight was found maximum on vines grafted on Dogridge rootstocks while minimum days to sprout and cane maturity was recorded in own rooted Red Globe vines. Number of canes/vine, shoot length, shoot diameter, leaf area and stock: scion ratio varied significantly among the rootstocks and were found maximum in vines grafted on Dogridge rootstock followed by Salt Creek and 110R rootstocks. The present study revealed that Red Globe grapevines grafted on Dogridge followed by Salt Creek rootstock proved better for growth parameters but in terms of growth period Red Globe own rooted vines was early to sprout and took minimum days for cane maturity over the vines grafted on rootstocks.

Secondary Bud Gas Exchange, Growth, and Fruitfulness of Vitis vinifera L. cultivars, ‘Grenache’ and ‘Cabernet Sauvignon’ Grown on the Texas High Plains

In 2017, the grape and wine industry had an overall economic impact of $13.1 billion within the state of Texas. The majority of grapes grown in Texas are produced within the Texas High Plains American Viticultural Area (AVA). However, vineyards within the Texas High Plains AVA are subject to late spring frosts which can potentially diminish fruit quality, and reduce crop production. To assist in planning and production efforts, Texas High Plains AVA grape growers require information regarding vine secondary bud growth and fruitfulness. Therefore, the objectives of this experiment were to compare the growth and fruitfulness of shoots grown from primary and secondary buds ofVitis viniferaL. ‘Grenache’ and ‘Cabernet Sauvignon’ vines grafted to 110R rootstocks. Vines were planted in an experimental vineyard in 2008. Each year over two consecutive growing seasons (2016 – 2017) vines were exposed to the following treatments: primary bud growth intact, and following bud break allowing primary bud shoot growth to reach 15.0 cm in length then removing primary bud shoots (forcing growth from secondary buds). Gas exchange, growth, fruitfulness, and fruit total soluble solid data were collected each year. Collected data followed similar trends each growing season. Hence, data from each growing season were pooled. Gas exchange data indicate leaves from primary shoots had lower photosynthetic rates, and stomatal conductance when compared to leaves grown on secondary shoots. In addition, ‘Grenache’ leaves had greater gas exchange when compared to ‘Cabernet Sauvignon’ leaves. Pruning weights, vine yield, cluster mass, and total soluble solids were greater for shoots grown from primary buds. ‘Cabernet Sauvignon’ vines had greater pruning weights, but ‘Grenache’ vines had greater crop load (Ravaz Index) and cluster mass. Yield and total soluble solids did not differ between grape cultivars, but the number of clusters from each vine, and berry mass varied with cultivar and bud treatment. In the late spring frost-prone Texas High Plains AVA, cultivar selection continues to be a critical factor for vineyard success. Results indicate decreased yields from all vines with shoot growth only from secondary buds. However, even though ‘Grenache’ and ‘Cabernet Sauvignon’ vines responded differently to bud treatments (‘Cabernet Sauvignon’ vines generally produced a greater number of smaller clusters when compared to ‘Grenache’ vines), for each cultivar overall yield was similar across all bud treatments. Therefore, Texas High Plains AVA and other grape producers now have additional information that may assist them when making critical vineyard management choices.

How Do Novel M-Rootstock (Vitis Spp.) Genotypes Cope with Drought?

Most of the vineyards around the world are in areas characterized by seasonal drought, where water deficits and high temperatures represent severe constraints on the regular grapevine growth cycle. Although grapevines are well adapted to arid and semi-arid environments, water stress can cause physiological changes, from mild to irreversible. Screening of available Vitis spp. genetic diversity for new rootstock breeding programs has been proposed as a way for which new viticulture challenges may be faced. In 2014, novel genotypes (M-rootstocks) were released from the University of Milan. In this work, the behavior of M1, M3 and M4 in response to decreasing water availabilities (80%, 50% and 20% soil water content, SWC) was investigated at the physiological and gene expression levels, evaluating gas exchange, stem water potential and transcript abundances of key genes related to ABA (abscisic acid) biosynthesis (VvZEP, VvNCED1 and VvNCED2) and signaling (VvPP2C4, VvSnRK2.6 and VvABF2), and comparing them to those of cuttings of nine commercial rootstocks widely used in viticulture. M-rootstocks showed a change at physiological levels in severe water-stressed conditions (20% soil water content, SWC), reducing the stomatal conductance and stem water potential, but maintaining high photosynthetic activity. Water use efficiency was high in water-limiting conditions. The transcriptional changes were observed at 50% SWC, with an increment of transcripts of VvNCED1 and VvNCED2 genes. M-rootstocks showed similar behavior to 1103P and 110R rootstocks, two highly tolerant commercial genotypes. These rootstocks adopted a tolerant strategy to face water-stressed conditions.