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The Queensferry Crossing opened in 2017 to enhance the resilience for road vehicles crossing the Firth of Forth outside Edinburgh, Scotland. The M90 carriageway consists of two lanes of traffic in each direction and hard shoulders. The three-tower, cable-stayed structure extends for 2.7 km, including approach viaducts. Structural health monitoring was specified by the employer in the construction works including 2184 physical sensors, which is believed to be the world's largest bridge monitoring system. This paper describes the monitoring and its uses thus far. A load test was conducted in 2020, comparing the sensor data favourably to the design. The monitoring is now integral to the operation of the bridge for measurement of structural performance and the management of the route. Automated reports give analysis of fixed periods of time and further detail for specific triggered events in occurrences of high load, abnormal load movements and extreme weather. The user interface includes a threshold alert system informing of the need for specific inspection and maintenance regimes. Route management in winter and extreme weather response is enhanced with the inclusion of sensor data. Monitoring data are also being used for research at various universities, each of which is described in brief.

PremiseThere is considerable variation in leaf lobing and leaf size, including among grapevines, some of the most well-studied leaves. We examined the relationship between leaf lobing and leaf size across grapevine populations which varied in extent of leaf lobing.MethodsWe used homologous landmarking techniques to measure 2,632 leaves across two years in 476 unique, genetically distinct grapevines from 5 biparental crosses which vary primarily in the extent of lobing. We determined to what extent leaf area could explain variation in lobing, vein length, and vein to blade ratio.ResultsAlthough lobing was the primary source of variation in shape across the leaves we measured, leaf area varied only slightly as a function of lobing. Rather, leaf area increases as a function of total major vein length, total branching vein length, and decreases as a function of vein to blade ratio. These relationships are stronger for more highly lobed leaves, with the residuals for each model differing as a function of distal lobing.ConclusionsFor a given leaf area, more highly lobed leaves have longer veins and higher vein to blade ratios, allowing them to maintain similar leaf areas despite increased lobing. These findings show how more highly lobed leaves may compensate for what would otherwise result in a reduced leaf area, allowing for increased photosynthetic capacity through similar leaf size.

SummaryAnnual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning (1995 to 1999) and end (2017 to 2020) of the lifetime of a vineyard initially planted in 1991 and removed in 2021. X-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits. Modeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay of later rings, consistently shortening ring width throughout the lifetime of the vine. Ravaz index, juice pH, photosynthetic assimilation and transpiration rates, and instantaneous water use efficiency are correlated with scion trunk radius. Ultimately, our research indicates that rootstocks modulate secondary growth over years, altering physiology and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species.

PremiseGrapevine leaves have diverse shapes and sizes. Their shape and size is known to be influenced by many factors including genetics, vine phytosanitary status, environment, leaf and vine age, and node position on the shoot. In order to determine the importance of grapevine leaf shape and size to canopy temperature, we examined the relationship in five seedling populations grown in a vineyard in California, USA.MethodsAll of the populations had one parent with compound leaves of the Vitis piasezkii type and each population had a different second parent with non-compound leaves. In previous work, we measured leaf shape and size using 21 homologous landmarks. Here, we paired these morphology data with measurements taken using an infrared thermometer to measure the temperature of the canopy. By recording time of sampling and canopy temperature, we were able to determine which vines were cooler or hotter than expected, using a linear model.ResultsWe established a relationship between leaf size and canopy temperature: vines with larger leaves were cooler than expected. In contrast, leaf shape was not strongly correlated with variation in temperature.ConclusionsUltimately, these findings indicate that vines with larger leaves may contribute to the reduction of overall vine canopy temperature, but further work is needed to determine if this is due to variation in leaf size, differences in the openness of the canopy, or other related traits.

Geographical distribution and diversity of current plant species have been strongly shaped by climatic oscillations during the Quaternary. Analysing the resulting divergence among species and differentiation within species is crucial to understand the evolution of taxa like the Vitis genus, which provides very useful genetic resources for grapevine improvement and might reveal original recolonization patterns due to growth habit and dispersal mode. Here, we studied the genetic structure in natural populations of three species from eastern North America: Vitis aestivalis, V. cinerea and V. riparia using different marker types. Vitis aestivalis and V. cinerea showed higher diversity than V. riparia. The two former species are less differentiated, confirming an earlier divergence of V. riparia. V. aestivalis and V. riparia exhibited different genetic groups on both sides of the Appalachian Mountains that could mirror different recolonization routes from southern refugia. Genetic structure was stronger in V. cinerea, for which two varieties (var. berlandieri and var. cinerea) are morphologically recognized. Our results confirm this distinction and suggest the existence of three other lineages within var. cinerea. These discontinuities appear linked to adaptation of var. berlandieri to dry and limy areas of Texas and partially to the Mississippi River Valley. Rapid range expansions from refugia upon climate warming are also suggested by the low linkage disequilibrium values observed. Furthermore, large variation for downy mildew resistance was observed in the three species. Our findings appeared consistent with the vegetation history of eastern North America.

SummaryAnnual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning and end of the lifetime of the vineyard.X-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits.Modeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay thereafter, consistently shortening ring width throughout the lifetime of the vine. The ratio of yield to vegetative growth, juice pH, photosynthetic assimilation and transpiration rates, and stomatal conductance are correlated with scion trunk radius.Rootstocks modulate secondary growth over years, altering hydraulic conductance, physiology, and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species.

Macro and micro nutrient accumulation affects all stages of plant growth and development. When nutrient deficiencies or excesses occur, normal plant growth is altered resulting in symptoms such as leaf chlorosis, plant stunting or death. In grapes, few genomic regions associated with nutrient accumulation or deficiencies have been identified. Our study evaluated micro and macro nutrient concentrations in Vitis vinifera L. to identify associated SNPs using an association approach with genotype by sequencing data. Nutrient concentrations and foliar symptoms (leaf chlorosis and stunting) were compared among 249 F1 Vitis vinifera individuals in 2015 and 2016. Foliar symptoms were consistent (≥90%) between years and correlated with changes in nutrient concentrations of magnesium (r = 0.65 and r = 0.38 in 2015 and 2016, respectively), aluminum (r = 0.24 and r = 0.49), iron (r = 0.21 and r = 0.49), and sodium (r = 0.32 and r = 0.21). Single nucleotide polymorphisms associated with symptoms, sodium, and magnesium were detected on each chromosome with the exception of 5, 7 and 17 depending on the trait and genome used for analyses explaining up to 40% of the observed variation. Symptoms and magnesium concentration were primarily associated with SNPs on chromosome 3, while SNPs associated with increased sodium content were primarily found on chromosomes 11 and 18. Mean concentrations for each nutrient varied between years in the population between symptomatic and asymptomatic plants, but relative relationships were mostly consistent. These data suggest a complex relationship among foliar symptoms and micro and macro nutrients accumulating in grapevines.

This chapter examines the risks faced by human rights defenders who have been affected by Colombia’s armed conflict as well as in other spaces of social contestation, taking into account the country’s recent peace process and the protection infrastructure presently available. Drawing upon the experiences of campesino (small farmers), indigenous and Afro-Colombian communities, the chapter argues for the need to move beyond individual protection measures to the protection of collectives and communities. Communities involved in the defence of their territories are concerned not only about the loss of their lands, but the loss of their identities, histories and ways of life. Strategies to protect themselves include the creation of community-based organisations and support networks, the formation of neutral zones, the reliance on cultural institutions such as the Indigenous Guard, and the welcoming of international accompaniment. Secondly, it critically analyses the workings of the National Protection Unit (Unidad Nacional de Proteccion, UNP), the Colombian protection mechanism for human rights defenders at risk. Defenders highlight the inadequacies of the measures provided to them, including their intrusiveness, inappropriateness and over-emphasis on physical security. Finally, the chapter examines the significance of impunity. State complicity with perpetrators and the failure to prevent and investigate attacks have resulted in deep distrust amongst human rights defenders of state authorities. Defenders highlight the need to address these deep-rooted, structural problems for genuine protection to exist.

In this contribution, we use field-based hyperspectral imaging (HSI) and partial least squares regression (PLSR) to estimate early indicators of grapevine physiological indicators, and analyze identified significant spectral regions for fast and accurate plant health monitoring. HSI and physiological measurements were carried out at two commercial vineyards in California, USA. The PLSR models were developed between reflectance spectra extracted from hyperspectral images and four vine physiological parameters, including stomatal conductance (G s ) photosynthetic CO 2 rate (A), intercellular CO 2 concentration (Ci) and transpiration rate (E). The results demonstrate PLSR models to predict physiological parameters ( $\mathrm{R}^{2}\geq 0.6$ ), and the best model was found for $\mathrm{G}_{\mathrm{s}}\ (\mathrm{R}^{2}=0.7)$ . The identified significant spectral regions overlap with most commonly used remote sensing stress indicator, suggesting that HSI coupled with PLSR has great potential for upscaling and broader agricultural applications.

‘Concord’, the most well-known juice grape with a parentage of the North American grape species Vitis labrusca L., possesses a special ‘foxy’ aroma predominantly resulted from the accumulation of methyl anthranilate (MA) in berries. This aroma, however, is often perceived as an undesirable attribute by wine consumers and rarely noticeable in the common table and wine grape species V. vinifera. Here we discovered homology-induced promoter indels as a major genetic mechanism for species-specific regulation of a key ‘foxy’ aroma gene, anthraniloyl-CoA:methanol acyltransferase (AMAT), that is responsible for MA biosynthesis. We found the absence of a 426-bp and/or a 42-bp sequence in AMAT promoters highly associated with high levels of AMAT expression and MA accumulation in ‘Concord’ and other V. labrusca-derived grapes. These promoter variants, all with direct and inverted repeats, were further confirmed in more than 1,300 Vitis germplasm. Moreover, functional impact of these indels was validated in transgenic Arabidopsis. Superimposed on the promoter regulation, large structural changes including exonic insertion of a retrotransposon were present at the AMAT locus in some V. vinifera grapes. Elucidation of the AMAT genetic regulation advances our understanding of the ‘foxy’ aroma trait and makes it genetically trackable and amenable in grapevine breeding.

Mealybugs cause economic loss to vineyards through physical damage, fouling fruit and leaves with honeydew, and the transmission of viruses. Planococcus ficus is one of several mealybug species in vineyards, and one that causes economic damage over a relatively large global range. To develop novel management tools, host resistance to P. ficus, which has not previously been identified for any grape cultivars, was studied. Ten grape lines (species, cultivars, and rootstocks) were evaluated for P. ficus resistance across two separate potted plant assays. Significant differences were detected among cultivars and rootstocks in the recorded number of P. ficus juveniles, adults, and egg sacs. Cabernet Sauvignon and Chardonnay were two of the most favorable grape cultivars for mealybug population growth, whereas rootstocks IAC 572, 10-17A, and RS-3 all demonstrated some level of resistance. Southern fire ant (Solenopsis xyloni) was positively associated with mealybug populations, but did not have a negative effect on the observed presence of other arthropod species including potential predators.

Grape growers use rootstocks to provide protection against pests and pathogens and to modulate viticulture performance such as shoot growth. Our study examined two grapevine scion varieties (‘Chardonnay’ and ‘Cabernet Sauvignon’) grafted to 15 different rootstocks and determined the effect of rootstocks on eight traits important to viticulture. We assessed the vines across five years and identified both year and variety as contributing strongly to trait variation. The effect of rootstock was relatively consistent across years and varieties, explaining between 8.99% and 9.78% of the variation in growth-related traits including yield, pruning weight, berry weight, and Ravaz index (yield to pruning weight ratio). Increases in yield due to rootstock were generally the result of increases in berry weight, likely due to increased water uptake by vines grafted to a particular rootstock. We demonstrated a greater than 50% increase in yield, pruning weight, or Ravaz index by choosing the optimal rootstock, indicating that rootstock choice is crucial for grape growers looking to improve vine performance.

Grapevine (Vitis vinifera) teinturier cultivars are characterized by their typical reddish leaves and red-fleshed berries due to ectopic anthocyanin formation. Wines of these varieties have economic importance as they can be used for blending to enhance the color of red wines. The unique and heritable mutation has been known for a long time but the underlying genetic mechanism still is not yet understood. Here we describe the association of the red-fleshed berry phenotype with a 408 bp repetitive DNA element in the promoter of the VvmybA1 gene (grapevine color enhancer, GCE). Three different clones of &lsquo, Teinturier&rsquo, were discovered with two, three and five allelic GCE repeats (MybA1t2, MybA1t3 and MybA1t5). All three clones are periclinal chimeras, these clones share the same L1 layer, but have distinct L2 layers with different quantities of GCE repeats. Quantitative real time PCR and HPLC analysis of leaf and berry samples showed that the GCE repeat number strongly correlates with an increase of the expression of VvmybA1 itself and the VvUFGT gene regulated by it and the anthocyanin content. A model is proposed based on autoregulation of VvmybA1t to explain the red phenotype which is similar to that of red-fleshed apples. This study presents results about the generation and modes of action of three MybA1t alleles responsible for the red-fleshed berry phenotype of teinturier grapevines.

The shoot structure of cultivated grapevine Vitis vinifera L. typically exhibits a three-node modular repetitive pattern, two sequential leaf-opposed tendrils followed by a tendril-free node. In this study, we investigated the molecular basis of this pattern by characterizing differentially expressed genes in 10 bulk samples of young tendril tissue from two grapevine populations showing segregation of mutant or wild-type shoot/tendril phyllotaxy. One population was the selfed progeny and the other one, an outcrossed progeny of a Vitis hybrid, ‘Roger’s Red’. We analyzed 13 375 expressed genes and carried out in-depth analyses of 324 of them, which were differentially expressed with a minimum of 1.5-fold changes between the mutant and wild-type bulk samples in both selfed and cross populations. A significant portion of these genes were direct cis-binding targets of 14 transcription factor families that were themselves differentially expressed. Network-based dependency analysis further revealed that most of the significantly rewired connections among the 10 most connected hub genes involved at least one transcription factor. TCP3 and MYB12, which were known important for plant-form development, were among these transcription factors. More importantly, TCP3 and MYB12 were found in this study to be involved in regulating the lignin gene PRX52, which is important to plant-form development. A further support evidence for the roles of TCP3-MYB12-PRX52 in contributing to tendril phyllotaxy was the findings of two other lignin-related genes uniquely expressed in the mutant phyllotaxy background. Genetic analysis suggests an explanation for differing arrangements of tendrils on grapevine plants, with implications for grape production. Grapevines are unique in that their tendrils, which are usually modified leaves, are also the starting point for the bunches of flowers that will later become fruits. Thus, an understanding of how tendril development is controlled may provide insights into grape production. An international team led by Gan-Yuan Zhong of the USDA-Agricultural Research Service, Geneva, USA, studied a population of grape plants, some of which displayed a normal grapevine tendril arrangment relative to the leaves, and some of which showed alternative arrangements. By comparing the genes that differed in activity between the two types of grapevine, they identified key components in the genetic control of this complex trait.

Vignoles? is a valuable component of the wine grape cultivar portfolio in the eastern United States. Because it is relatively winter hardy, ?Vignoles? is grown in such diverse locations as New York, Missouri, Indiana, Ohio, Pennsylvania, Illinois, Nebraska and Michigan. However, Vignoles has tight clusters prone to bunch rot, and losses up to one third of the crop are possible. Despite consumer demand for Vignoles, its production is limited by bunch rot susceptibility associated with compact cluster architecture. Our goal is to select a loose-clustered clone of ?Vignoles? that will contribute to an integrated approach to disease control. Following gamma radiation, irradiated buds and non-irradiated controls were bench grafted onto 3309C rootstock. A total of 2,336 vines, including 30 non-mutagenized ?Vignoles? control vines, were planted in 2007 (500 vines) and in 2008 (1,839 vines). The experimental vineyard is located at the Cornell Lake Erie Research and Extension Laboratory (Portland, New York) in the Lake Erie shore grape and wine production region. Vines were cultivated in grow tubes and drip irrigated to promote rapid vine establishment and growth. The vines were trained to a bilateral cordon, spur pruned, and cultivated following standard practices for hybrid wine grape cultivars in western New York, including fertilization and weed, pest, and disease management. Many clones planted in 2007 fruited in 2008, but fruit was dropped to encourage vegetative establishment. The generation of new clones and the establishment of the vineyard are complete. The second stage of the project is evaluation of cluster looseness and bunch rot susceptibility. A pyramidal selection approach for cluster compactness is being followed, using berries per centimeter as a measure of cluster compactness. We have identified several clones with looser clusters than control, non-mutagenized ?Vignoles? vines.

Grapevine seedlings initially display spiral phyllotaxy of true leaves, then undergo a shift to alternate phyllotaxy with the production of the first lateral meristems (typically tendrils). The node at which the shift from spiral to alternate phyllotaxy occurs varies from about the 4th to about the 12th node on the vine. To investigate the genetic control of the transition from spiral phyllotaxy to alternate phyllotaxy, a population segregating for this trait was developed and screened. The population derived from four female parents and six male parents crossed in a Design 2 mating array (all female parents crossed to all male parents). The female parents were the pistillate flowered rootstock varieties 1613 Couderc, 93-5 Couderc (California clone), Vitis rupestris 187G, and Fercal. The male parents were staminate flowered grape rootstock germplasm, species, and species hybrid selections with diverse backgrounds, including accessions from the USDA ARS National Clonal Germplasm Repository, Davis, California (denoted with DVIT accession numbers): IAC 572, Vitis labrusca Y137 DVIT 1392, Vitis hybrid Y93 DVIT 1519, Vitis hybrid Q126 DVIT 1456, Vitis hybrid Q130 DVIT 1466, and Vitis hybrid R127 DVIT 1490. The species background of the male parents includes V. labrusca, V. mustangensis, V. riparia, V. tiliifolia, and V. rupestris. Seedlings from controlled crosses were grown in individual pots in a greenhouse with artificial illumination to provide 24 h day length. The node number of the first observed lateral meristem was recorded; the goal was 50 seedlings per population for each of 24 populations, although some populations showed poor seed germination. Male and female parents differ from one another at P =0.01, with male parents falling into three groups and female parents into two groups based on the mean node of phyllotaxy shift in their seedlings. Narrow sense heritability of the first tendril bearing node is estimated at 0.23 based on breeding value of male parents and at 0.45 based on breeding value of female parents.

Anthocyanins are considered an excellent source of antioxidant phytochemicals for health benefits. The majority of wine, table and raisin grapes have anthocyanins only in their colored skin. Anthocyanin content of grapes would be increased if their flesh also contained anthocyanins. C33-30, a seedless female flowered table grape with red skin and clear flesh berries was hybridized with the ?Rubired? wine grape, which has black skin and red flesh berries. The F1 progeny segregated in a 3 colored:1 white skin and 1 red:1 clear flesh ratio for colored berries. The seedling expressing the highest level of anthocyanin in the flesh and skin was similar to ?Rubired?. Seven modified backcross families were created by crossing red flesh seeded F1 selections with seedless red skin table or white skin raisin grapes. Skin color segregated as a single dominant gene as expected. One red flesh parent was heterozygous for skin color and the rest were homozygous. Only seedlings with colored skin had red flesh. Flesh color segregated as a 1 red:1 clear in three of the families or in a 2:1 ratio or higher in four families. One red flesh parent produced an abnormally high percentage (>80%) of red flesh seedlings. Leaf color in the leaf disk assay correlated well with flesh color in the F1 family. Seedlings that developed 0 to 20% anthocyanin in the leaf disk assay had clear flesh with white, red or black skin (32% of BC1 population). However 19% of red flesh seedlings would have been discarded using this selection criterion. Part of this discrepancy is due to the fact that leaves taken too early in their development from greenhouse grown plants did not develop anthocyanin.

In red winemaking, the extractability of condensed tannins (CT) can vary considerably even under identical fermentation conditions, and several explanations for this phenomenon have been proposed. Recent work has demonstrated that grape pathogenesis-related proteins (PRPs) may limit retention of CT added to finished wines, but their relevance to CT extractability has not been evaluated. In this work, Vitis vinifera and interspecific hybrids (Vitis ssp.) from both hot and cool climates were vinified under small-scale, controlled conditions. The final CT concentration in wine was well modeled from initial grape tannin and juice protein concentrations using the Freundlich equation (r2= 0.686). In follow-up experiments, separation and pretreatment of juice by bentonite, heating, freezing, or exogenous tannin addition reduced protein concentrations in juices from two grape varieties. The bentonite treatment also led to greater wine CT for one of the varieties, indicating that prefermentation removal of grape p...

Crown gall is a devastating grapevine disease often encountered in vineyards prone to winter cold injury. Agrobacterium vitis, the predominant causal agent of this disease, moves from the roots via xylem sap flow to freeze injury sites where genetic transformations then occur. Crown gall disrupts the grapevine trunk vascular system, which prevents nutrient flow and leads to plant decline and death. Viticultural practices designed to fight this disease are only partially effective, thereby requiring alternatives. Genetic engineering and biological control could be more desirable approaches for disease prevention. Biological control typically involves antagonistic organisms, which are applied to grapevine roots to reduce the concentration of pathogenic Agrobacterium strains. Genetic engineering may prevent infection and tumor formation by modifying grapevines and antagonistic organisms. In the grapevine, this may be achieved by enhancing molecular mechanisms for producing bacterium-specific antimicrobial peptides or preventing transferred deoxyribonucleic acid export, integration, and oncogene expression. Alteration of antagonistic organisms enhances the production of bacteriocins effective against agrobacteria. This article reviews the potential use of biological control options and genetic engineering tools for grapevine crown gall suppression and makes recommendations for further use and research.

Grapevine tendril distribution is a characteristic of varieties and species. We examined the tendril distribution on a population of seedlings from a 161-49C x (V. labrusca x V. mustangensis) hybridization. 16149C is a V. riparia x V. berlandieri hybrid that ordinarily bears tendrils in a discontinuous pattern. Although the V. labrusca x V. mustangensis parent frequently demonstrates more than two tendrils in sequence, it does show nodes without tendrils and as such cannot be described as strictly continuous in its tendril distribution. Grapevine tendrils and clusters (inflorescences) are found at the node opposite a leaf. Cultivars and spe cies exhibit some variation in tendril distribution, the phyllotactic patterning of which nodes have tendrils (or clusters) and which do not. Most Vitis species and cultivars have two nodes with tendrils followed by a node without a tendril (Mullins et al., 1992; Gerrath et al., 1998). This pattern is called intermittent tendril distribution. However, in the North American species V. labrusca and some V. labrusca interspecific hy brids, a tendril is found at every node (continuous tendril distribution). Some interspecific hybrid cultivars have an intermediate tendril distribution, with more than two nodes in a row bearing tendrils, but with occasional tendril-free nodes. Cousins et al. (2005) reported exploratory studies in the genetic control of phyllotactic patterning. Here we report in-depth analysis of a population segregating for tendril distribution patterns.

Lime content is the major difference between Northern American and European vine growing soils. This resulted in significant difficulties in the development of rootstocks for European conditions at the end of the 19th and the beginning of the 20th century. It was only the introduction of Vitis berlandieri as a breeding partner that led to lime-tolerant rootstocks. Despite the importance of V. berlandieri for European viticulture, only a few accessions have so far been exploited for breeding rootstocks. In most cases, these vines were only used because they were available in Europe at that time. The genetic variability of the species is certainly much larger. To preserve and evaluate genetic diversity in V. berlandieri, grape berries from 86 individual vines were collected in September 2005 from a large range of natural stands in Texas, United States. The collection locations were found in 13 counties and across a distribution from N 31° 23' to N 29° 43' and W 100° 2' to W 97° 26'. Vines will be planted in germplasm collections and evaluated for their rooting and grafting ability, their lime tolerance, and other viticultural features. Superior types will then be utilized for rootstock breeding programs.

Root-knot nematodes (Meloidogyne species) are serious pests in grape production, especially in warm areas. Rootstocks resistant to root-knot nematodes are used to combat these pests. Nematode resistant rootstocks used in the United States include Freedom, Harmony, Dog Ridge, and Ramsey. The nematode resistance in these varieties is thought to be derived from Vitis mustangensis (all four rootstocks) or V. mustangensis and V. solonis (Freedom and Harmony). Dog Ridge and Ramsey are considered natural V. mustangensis hybrids, while Freedom and Harmony are complex hybrids that include Dog Ridge in their parentage. These rootstocks all apparently owe their resistance to the N allele. Although these rootstocks are resistant to many M. incognita populations, M. arenaria and M. incognita populations have been identified in California that are virulent on these rootstocks, damaging them severely. These "N virulent nematodes" pose a new and significant threat to grape production in the United States. New rootstocks are needed with resistance to the N virulent nematode populations. We have identified several Vitis species that provide resistance to N virulent nematodes and are investigating the genetic control of the resistance. We examined progeny populations from crosses with V. mustangensis and V. mustangensis hybrids. Seedlings were grown in a greenhouse and inoculated with root-knot nematode juveniles once two true leaves were present. Resistance evaluation was by egg mass counting six weeks after inoculation. Resistance to N virulent nematodes was inherited as a single dominant allele and appears to confer resistance both to the N virulent Meloidogyne sp. and N avirulent M. incognita nematodes. The V. mustangensis accessions used in this genetic study are sources of resistance superior to that found in Dog Ridge, Freedom, and Harmony. Vitis mustangensis promises to be a useful source of nematode resistance for use in rootstock breeding.

Wild and loss-of-function alleles of the 5 - O - glucosyltransferase gene responsible for synthesis of diglucoside anthocyanins in Vitis were characterized. The information aids marker development for tracking this gene in grape breeding. Anthocyanins in red grapes are present in two glycosylation states: monoglucoside (3-O-glucoside) and diglucoside (3, 5-di-O-glucoside). While monoglucoside anthocyanins are present in all pigmented grapes, diglucoside anthocyanins are rarely found in the cultivated grape species Vitis vinifera. Biochemically 3-O-glucoside anthocyanins can be converted into 3,5-di-O-glucoside anthocyanins by a 5-O-glucosyltransferase. In this study, we surveyed allelic variation of the 5-O-glucosyltransferase gene (5GT) in 70 V. vinifera ssp. vinifera cultivars, 52 V. vinifera ssp. sylvestris accessions, 23 Vitis hybrid grapes, and 22 accessions of seven other Vitis species. Eighteen 5GT alleles with apparent loss-of-function mutations, including seven premature stop codon mutations and six frameshift indel mutations, were discovered in V. vinifera, but not in the other Vitis species. A total of 36 5GT alleles without apparent loss-of-function mutations (W-type) were identified. These W-type alleles were predominantly present in wild Vitis species, although a few of them were also found in some V. vinifera accessions. We further evaluated some of these 5GT alleles in producing diglucoside anthocyanins by analyzing the content of diglucoside anthocyanins in a set of representative V. vinifera cultivars. Through haplotype network analysis we revealed that V. vinifera ssp. vinifera and its wild progenitor V. vinifera ssp. sylvestris shared many loss-of-function 5GT alleles and extensive divergence of the 5GT alleles was evident within V. vinifera. This work advances our understanding of the genetic diversity of 5GT and provides a molecular basis for future marker-assisted selection for improving this important wine quality trait.

Root-knot nematodes (RKNs) infect many annual and perennial crops and are the most devastating soil-born pests in vineyards. To develop a biotech-based solution for controlling RKNs in grapes, we evaluated the efficacy of plant-derived RNA interference (RNAi) silencing of a conserved RKN effector gene, 16D10, for nematode resistance in transgenic grape hairy roots. Two hairpin-based silencing constructs, containing a stem sequence of 42 bp (pART27-42) or 271 bp (pART27-271) of the 16D10 gene, were transformed into grape hairy roots and compared for their small interfering RNA (siRNA) production and efficacy on suppression of nematode infection. Transgenic hairy root lines carrying either of the two RNAi constructs showed less susceptibility to nematode infection compared with control. Small RNA libraries from four pART27-42 and two pART27-271 hairy root lines were sequenced using an Illumina sequencing technology. The pART27-42 lines produced hundred times more 16D10-specific siRNAs than the pART27-271 lines. On average the 16D10 siRNA population had higher GC content than the 16D10 stem sequences in the RNAi constructs, supporting previous observation that plant dicer-like enzymes prefer GC-rich sequences as substrates for siRNA production. The stems of the 16D10 RNAi constructs were not equally processed into siRNAs. Several hot spots for siRNA production were found in similar positions of the hairpin stems in pART27-42 and pART27-271. Interestingly, stem sequences at the loop terminus produced more siRNAs than those at the stem base. Furthermore, the relative abundance of guide and passenger single-stranded RNAs from putative siRNA duplexes was largely correlated with their 5' end thermodynamic strength. This study demonstrated the feasibility of using a plant-derived RNAi approach for generation of novel nematode resistance in grapes and revealed several interesting molecular characteristics of transgene siRNAs important for optimizing plant RNAi constructs.

Genome-wide association (GWA) genetics is potentially of great interest in grapevine to find much more rapidly and efficiently the main loci (QTLs) and alleles involved in the variation of traits of interest to breeding, compared to searches based on individual segregating progenies. Knowledge of the structure of genetic diversity and linkage disequilibrium (LD) is a necessary prerequisite to design association genetics studies. Vitis vinifera genetic diversity and structure are already well characterized, but LD in this species has not been thoroughly estimated yet. Other Vitis species are a large potential source of resistance to biotic and abiotic stresses for introgression into V. vinifera, but relatively few genetic resources are available in germplasm repositories and the genetic diversity of these species is hardly known. The objectives of the DL-Vitis project (ANR 2009-2011) are to assess genetic structure and linkage disequilibrium in V. vinifera and 3 American species (V. riparia, V. cinerea, V. aestivalis). For V. vinifera, 3 samples of 93 cultivars were defined, based on available SSR data, by minimizing structure and kinship and maximizing genetic distances. An additional sample of 93 accessions of wild V. vinifera (subsp. silvestris) was also defined. For each American species, 150-200 seeds were collected in natura last autumn. Genetic diversity and structure will be assessed this year using SSRs, and a sample of 93 accessions will be defined for each species. Four genomic regions of 2 Mb each were chosen to estimate LD between specific SNPs in ca. 1 gene out of 3 in each sample of 93 individuals described above. Novel estimates of LD taking structure and kinship into account were developed. The first results obtained in V. vinifera in 2 genomic regions showed differences in the rate of LD decay between samples and regions, suggesting past occurrence of differential selection.

Breeding rootstocks for fruit crops is slower than scion breeding in the same species. This is due to the testing requirements of rootstocks that reduce the opportunity for comprehensive first tests on individual plants and to expanding selection criteria for rootstocks. Rootstock breeding is a relatively new discipline of fruit crop improvement and novel functions of rootstocks still are being understood and developed; this increases the requirements of rootstocks without diminishing the testing requirements.

Grapevine (Vitis vinifera L.) is one of our oldest domesticated crops and economically the most important cultivated fruit crop in the world. Cultivated grapes show substantial diversity in fruit color, including: varying shades of black, red, pink, grey, white, and types with pigmented berry flesh. The majority of V. vinifera cultivars only possess anthocyanin pigmentation in the skin of the berry (also known as teinturiers). However, some cultivars possess berries with intensely pigmented flesh as well as skin, which is often also associated with greater pigmentation of vegetative tissues. The genetic control and inheritance of fruit color in grapevine is poorly understood, despite evidence that the primary determination of anthocyanin production appears to be controlled by a single dominant locus in V. vinifera with white fruit being a recessive character. Recently, it has been shown that the presence of Gret1, a Ty3-gypsy-type retro-transposon in the promoter region of a myb-like regulatory gene is present in white-fruited cultivars of V. vinifera and that allelic variation in this gene associates with several qualitative classes of grape fruit color. It has been observed that the red-flesh berry phenotype is similarly controlled by a single dominant locus. Considering the association of variation in VvmybA1 with grape berry skin color, it was hypothesized that DNA sequence variation in VvmybA1 would also be associated with genotypes showing intensely pigmented berry flesh. In this study, we show that allelic variation in VvmybA1 associates with the teinturier phenotype both in a panel of accessions possessing red-flesh as well as in a population of full-sibs segregating for the red-flesh phenotype.

The grapevine shoot has a zone in which leaf-opposed clusters are found at the nodes. Beyond the cluster zone, leaf-opposed tendrils are borne at the nodes in a patterned distribution. Cluster number is a primary yield component and selection programs for increasing yield in grapevine frequently consider cluster number. However, selection for increased cluster number requires direct observation, which is only possible once the vine matures. Clusters and tendrils are developmentally related, so it may be that tendril density (tendrils per node) reflects cluster number. In contrast to cluster number, tendril density can be observed on plants of all ages. The hypothesis that tendril density is related to cluster number was tested here. Cluster numbers and tendril density were assessed on 10 primary shoots each of 180 grapevine (Vitis) accessions. The accessions analyzed are cultivars and wild species collections held in the United States National Plant Germplasm System. The correlation coefficient of the number of clusters and tendril density was calculated using the means of 10 observations per accession. Tendril density was determined by calculating the mean number of tendrils per node in the nodes beyond the cluster zone. Cluster number and tendril density were positively correlated; the correlation coefficient was 0.35. This implies that vines with more tendrils per node also tend to have more clusters. The positive correlation of cluster number and tendril density has implications for grapevine improvement, pointing to the possibility of indirect selection for higher cluster number through selection for higher tendril density. Correlation between juvenile tendril density and mature cluster number is yet to be tested.

Breeders of woody perennials seek to shorten the time from propagation to flowering and the turnover time between generations. Grapevines usually flower and fruit no earlier than their third season. Onset of flowering occurs when anlagen, undifferentiated primordia arising from axillary and terminal bud meristems, begin to develop into inflorescences as well as tendrils. This occurs in response to hormonal stimuli; high levels of gibberellins in juvenile tissue favor vegetative growth, whereas increased cytokinin levels in physiologically mature tissue favor reproductive growth. We modified a method developed for Vitis vinifera for use on grape rootstock seedlings. Exogenous applications of chlormequat and N-benzyl-9-(2-tetrahydropyranyl) adenine (PBA, a cytokinin) were used induce precocious flowering by increasing the cytokinin:gibberellin ratio, triggering anlagen to develop into inflorescences on physiologically juvenile vines. The optimum treatment was a single application of 3000 micromolar chlormequat and 250 micromolar PBA, followed by 10 subsequent daily applications of PBA alone. Lower concentrations of treatments resulted in a loss of efficacy, and higher treatment concentrations and/or longer durations resulted in phytotoxicity. Abnormalities in flower and leaf morphology were observed with all treatments. Grape rootstock seedlings are dioecious and staminate vines were more responsive to the treatments than pistillate vines. We did not observe production of hermaphroditic flowers on staminate vines. Pollen collected from flowering staminate seedlings was successfully used in crosses that produced fruit and viable seeds. The ability to induce precocious flowering in juvenile grape seedlings has many applications in grape breeding and genetic research.

Development of rootstocks resistant to root-knot nematodes (Meloidogyne spp.) is a priority in grape breeding. The N allele, present in Harmony and Freedom rootstocks, confers resistance to N-avirulent strains of Meloidogyne. Extensive planting of rootstocks containing N has led to the development of N-virulent nematode strains, prompting a search for new resistance alleles. A seedling population derived from Vitis nesbittiana Comeaux was evaluated to investigate the genetic control of nematode resistance in this species. Hybridization with easily propagated rootstock selections will be required to utilize nematode resistance found in V. nesbittiana, a native of Mexico. The female parent of the population was 161-49C, a V. riparia × V. berlandieri hybrid rootstock. 161-49C does not contribute nematode resistance to its progeny. The male parent was V. nesbittiana DVIT 2236.12, an accession held in the U.S. National Plant Germplasm system. Nematode resistance of the 161-49C × V. nesbittiana DVIT 2236.12 population was assessed in greenhouse pot culture. Seedling roots were stained in an eosin-Y solution six weeks after inoculation with 1500 N-virulent M. arenaria juveniles. Resistance classes of seedlings were determined by assessing the degree of galling and number of egg masses per root system. Segregation in the seedling population was consistent with a 1:1 ratio of resistance to susceptibility, indicating that the V. nesbittiana accession is heterozygous for a dominant allele conferring resistance to N-virulent root-knot nematodes. The genetic relationship between this allele and the N allele has yet to be determined.

The grapevine shoot consists of nodes without clusters (inflorescences) basal to a zone in which leaf-opposed clusters are found at the nodes. Beyond the cluster zone leaf-opposed tendrils are borne at the nodes. The numbers and possible relationship of basal nodes and clusters are important in grapevine breeding and improvement. Basal node number influences cluster placement within the canopy, which relates to light penetration to the fruit and fruit maturation and to application of cultural practices, including harvest and cluster treatments. Cluster number is a primary yield component. Basal node and clusters numbers were counted on ten primary shoots each of forty grapevine (Vitis) accessions. The accessions analyzed are cultivars and wild species collections held in the United States National Plant Germplasm System. The correlation coefficient of the number of basal nodes and number of clusters was calculated using the means of the ten observations per accession. Basal node and clusters numbers were negatively correlated; the correlation coefficient was -0.763, which is significant (P

The grape Vitis champinii Planchon is one source of nematode resistance in grape rootstocks. Several selections valued for their resistance to the root-knot nematode (Meloidogyne incognita), a serious pest of grape production, are used as rootstocks and in rootstock variety development. However, V. champinii-based rootstock varieties are faulted for their excess vigor and susceptibility to other root pests. Root-knot nematode populations with the ability to damage important V. champinii-based rootstocks have been identified and may become more common. Other V. champinii accessions might be sources of nematode resistance genes with different specificities or might have more suitable horticultural characteristics than V. champinii varieties in commercial use. Nine V. champinii accessions from the National Clonal Germplasm Repository, Davis, Calif., and a V. champinii rootstock variety were screened for resistance to M. incognita. Resistance was assessed by counting eggs produced per root system. Eight of ten V. champinii accessions did not support nematode reproduction. Susceptible accessions supported lower nematode reproduction than susceptible V. vinifera control varieties. Progeny testing from crosses of resistant and susceptible accessions suggests that a dominant and a recessive gene may condition root-knot nematode resistance.