North American Vitis Species Research Articles

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.

SNPs Associated with Foliar Phylloxera Tolerance in Hybrid Grape Populations Carrying Introgression from Muscadinia

Leaf-feeding phylloxera decreases the photosynthetic activity of a grape plant, leading to decreasing number of fruit buds. In addition, phylloxera larvae emerging from the leaf galls may colonize the roots, negatively affecting the growth of the grape plant. In this study, we evaluated host tolerance of three grapevine hybrid populations obtained from crossing of the same maternal grapevine M. no. 31-77-10 with interspecific hybrids carrying introgressions from Muscadinia and other North American Vitis species against leaf-feeding grape phylloxera. Combining genotyping data of the populations obtained with 12,734 SNPs and their resistance phenotypes evaluated in the laboratory experiment, we performed an association study. As the result of GWAS, nine SNPs with the lowest significant p-values were discovered in the whole sample of 139 hybrids as associated with variation of the scores ‘the percentage of infested leaves’ and ‘intensity of gall formation’. Three of the SNPs on LG 7 were located in the same chromosome interval where a major QTL (RDV6) for root phylloxera resistance was reported from Muscadine background. Two SNPs on LG 8 were detected within the gene, encoding E3 ubiquitin-protein ligase UPL4 involved in apoptosis. SNPs detected on LG 13 and LG 18 may overlap with the previously reported QTLs for phylloxera resistance inherited from V. cinerea.

Genetic analysis reveals an east-west divide within North American Vitis species that mirrors their resistance to Pierce's disease.

Pierce's disease (PD) caused by the bacterium Xylella fastidiosa is a deadly disease of grapevines. This study used 20 SSR markers to genotype 326 accessions of grape species collected from the southeastern and southwestern United States, Mexico and Costa Rica. Two hundred sixty-six of these accessions, and an additional 12 PD resistant hybrid cultivars developed from southeastern US grape species, were evaluated for PD resistance. Disease resistance was evaluated by quantifying the level of bacteria in stems and measuring PD symptoms on the canes and leaves. Both Bayesian clustering and principal coordinate analyses identified two groups with an east-west divide: group 1 consisted of grape species from the southeastern US and Mexico, and group 2 consisted of accessions collected from the southwestern US and Mexico. The Sierra Madre Oriental mountain range appeared to be a phylogeographic barrier. The state of Texas was identified as a potential hybridization zone. The hierarchal STRUCTURE analysis on each group showed clustering of unique grape species. An east-west divide was also observed for PD resistance. With the exception of Vitis candicans and V. cinerea accessions collected from Mexico, all other grape species as well as the resistant southeastern hybrid cultivars were susceptible to the disease. Southwestern US grape accessions from drier desert regions showed stronger resistance to the disease. Strong PD resistance was observed within three distinct genetic clusters of V. arizonica which is adapted to drier environments and hybridizes freely with other species across its wide range.

The genome sequence of the grape phylloxera provides insights into the evolution, adaptation, and invasion routes of an iconic pest

BackgroundAlthough native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors such as pathogens and climate change. Limited understanding of the insect genetics resulted in successive outbreaks across the globe when rootstocks failed. Here we report the 294-Mb genome of D. vitifoliae as a basic tool to understand host plant manipulation, nutritional endosymbiosis, and enhance global viticulture.ResultsUsing a combination of genome, RNA, and population resequencing, we found grape phylloxera showed high duplication rates since its common ancestor with aphids, but similarity in most metabolic genes, despite lacking obligate nutritional symbioses and feeding from parenchyma. Similarly, no enrichment occurred in development genes in relation to viviparity. However, phylloxera evolved > 2700 unique genes that resemble putative effectors and are active during feeding. Population sequencing revealed the global invasion began from the upper Mississippi River in North America, spread to Europe and from there to the rest of the world.ConclusionsThe grape phylloxera genome reveals genetic architecture relative to the evolution of nutritional endosymbiosis, viviparity, and herbivory. The extraordinary expansion in effector genes also suggests novel adaptations to plant feeding and how insects induce complex plant phenotypes, for instance galls. Finally, our understanding of the origin of this invasive species and its genome provide genetics resources to alleviate rootstock bottlenecks restricting the advancement of viticulture.

Ecology and Genetics of Natural Populations of North American Vitis Species Used as Rootstocks in European Grapevine Breeding Programs.

Three North American Vitis species (V. riparia, V. berlandieri, V. rupestris) became widely used in rootstock breeding programs following the expansion of North American pests and diseases introduced in vineyards of the world during the 19th century. When they escape, they become feral in the most dynamic parts of Mediterranean floodplains. To better understand this ongoing process, we studied the ecology of Vitis species in their native sympatric range. We analyzed in deep 61 plots of 710 m2 containing Vitaceae species along 216 km of the Buffalo River and adjacent plateaus (Arkansas, United States). We investigated the populations structure and genetics of the Vitis complex (i.e., possible hybrids and the Vitis species) and the sharing of habitats with other Vitaceae (Muscadinia rotundifolia and Parthenocissus quinquefolia). Vitaceae share space according to their life strategies and microhabitat along ecological gradients. The plateau niche seems optimal for V. berlandieri and V. aestivalis. V. berlandieri is also found in alluvial zones. The most erosive parts of the river are colonized by V. rupestris, whereas the first terraces include most of the M. rotundifolia populations. Vitis riparia and Parthenocissus live in the largest range of forest habitats, from plateaus to alluvial forests, and from the forest floor to the canopy, with the highest densities along the river. Interestingly, natural hybridization can occur, but establishment success is rare and limited to alluvial forests. In their native range, these populations are controlled by biotic and abiotic conditions. In Europe, the biotic relations among species are different. Our study shows that V. riparia and its hybrids could be the best candidates for a large scale invasion.

VitisGDB: The Multifunctional Database for Grapevine Breeding and Genetics

VitisGDB: The Multifunctional Database for Grapevine Breeding and Genetics

Single and multiple phenotype QTL analyses of downy mildew resistance in interspecific grapevines

Key messageDowny mildew resistance across days post-inoculation, experiments, and years in two interspecific grapevine F1 families was investigated using linear mixed models and Bayesian networks, and five new QTL were identified.Breeding grapevines for downy mildew disease resistance has traditionally relied on qualitative gene resistance, which can be overcome by pathogen evolution. Analyzing two interspecific F1 families, both having ancestry derived from Vitis vinifera and wild North American Vitis species, across 2 years and multiple experiments, we found multiple loci associated with downy mildew sporulation and hypersensitive response in both families using a single phenotype model. The loci explained between 7 and 17% of the variance for either phenotype, suggesting a complex genetic architecture for these traits in the two families studied. For two loci, we used RNA-Seq to detect differentially transcribed genes and found that the candidate genes at these loci were likely not NBS-LRR genes. Additionally, using a multiple phenotype Bayesian network analysis, we found effects between the leaf trichome density, hypersensitive response, and sporulation phenotypes. Moderate–high heritabilities were found for all three phenotypes, suggesting that selection for downy mildew resistance is an achievable goal by breeding for either physical- or non-physical-based resistance mechanisms, with the combination of the two possibly providing durable resistance.

High-throughput sequencing data clarify evolutionary relationships among North American Vitis species and improve identification in USDA Vitis germplasm collections.

Grapes are one of the most economically important berry crops worldwide, with the vast majority of production derived from the domesticated Eurasian species Vitis vinifera. Expansion of production into new areas, development of new cultivars, and concerns about adapting grapevines for changing climates necessitate the use of wild grapevine species in breeding programs. Diversity within Vitis has long been a topic of study; however, questions remain regarding relationships between species. Furthermore, the identity of some living accessions is unclear. This study generated 11,020 single nucleotide polymorphism (SNP) markers for more than 300 accessions in the USDA-ARS grape germplasm repository using genotyping-by-sequencing. Resulting data sets were used to reconstruct evolutionary relationships among several North American and Eurasian Vitis species, and to suggest taxonomic labels for previously unidentified and misidentified germplasm accessions based on genetic distance. Maximum likelihood analyses of SNP data support the monophyly of Vitis, subg. Vitis, a Eurasian subg. Vitis clade, and a North American subg. Vitis clade. Data delineate species groups within North America. In addition, analysis of genetic distance suggested taxonomic identities for 20 previously unidentified Vitis accessions and for 28 putatively misidentified accessions. This work advances understanding of Vitis evolutionary relationships and provides the foundation for ongoing germplasm enhancement. It supports conservation and breeding efforts by contributing to a growing genetic framework for identifying novel genetic variation and for incorporating new, unsampled populations into the germplasm repository system.

Toward the elucidation of cytoplasmic diversity in North American grape breeding programs

Plants have an intriguing tripartite genetic system: Nuclear genome × Mitochondria × Plastids and their interactions may impact germplasm breeding. In grapevine, the study of cytoplasmic genomes has been limited, and their role with respect to grapevine germplasm diversity has yet to be elucidated. In the present study, the results of an analysis of the cytoplasmic diversity among 6073 individuals (comprising cultivars, interspecific hybrids and segregating progenies) are presented. Genotyping by sequencing (GBS) was used to elucidate plastid and mitochondrial DNA sequences, and results were analyzed using multivariate techniques. Single nucleotide polymorphism (SNP) effects were annotated in reference to plastid and mitochondrial genome sequences. The cytoplasmic diversity identified was structured according to synthetic domestication groups (wine and raisin/table grape types) and interspecific-hybridization-driven groups with introgression from North American Vitis species, identifying five cytoplasmic groups and four major clusters. Fifty-two SNP markers were used to describe the diversity of the germplasm. Ten organelle genes showed distinct SNP annotations and effect predictions, of which six were chloroplast-derived and three were mitochondrial genes, in addition to one mitochondrial SNP affecting a nonannotated open reading frame. The results suggest that the application of GBS will aid in the study of cytoplasmic genomes in grapevine, which will enable further studies on the role of cytoplasmic genomes in grapevine germplasm, and then allow the exploitation of these sources of diversity in breeding.

Climatic Niche Characterization of 13 North AmericanVitisSpecies

Climate change models predict that sites suitable for vineyards will shift over the next 50 years. In part through rootstocks and hybrid scions bred from North American Vitis species, cultivated grapevines can thrive in a variety of environments. However, relatively little is known about the range of climatic conditions under which natural populations of native North American Vitis species occur. In this study, we use geographic information system data to describe the climatic niches of 13 North American Vitis species that are distributed east of the Rocky Mountains and to compare climatic niches in a phylogenetic context. We extracted bioclimatic data from thousands of locality points and performed univariate and multivariate statistical analyses for each Vitis species. We then used these data to determine if phylogenetic relatedness was associated with similarities or differences in climatic niches. Finally, we performed Maxent modeling and multivariate environmental similarity surfaces analysis to identify suitable climate space for each species throughout the United States. Our results indicate Vitis species occur under a wide range of climatic conditions, including warm and wet (V. shuttleworthii), warm and dry (V. mustangensis), cold and wet (V. labrusca), and cold and dry (V. riparia) climates. Some clades within Vitis exhibit similarities in their climatic niches (niche conservatism), while others include species with notably different climatic niches (niche divergence). Additionally, we identify novel geographic locations where some species could potentially flourish. These data provide valuable insights into the abiotic environments occupied by natural populations of North American grapevines and may be useful in the development of rootstock genotypes to suit specific climates now and in the future.

Discriminating Spectral Signatures Among and Within Two Closely Related Grapevine Species

Several North American Vitis species are used to breed scions and rootstocks, including V. riparia and V. rupestris. However, the degree to which Vitis species can be distinguished using remote sensing is not well known. Here we explore whether two North American Vitis species and genotypes growing in a common garden can be discriminated with leaf and canopy hyperspectral reflectance factor data (350-2500 nm) using independent t-test and derivative analysis. Foliar properties and spectral indices of the grapevines were evaluated with analysis of the variance (ANOVA) and pair-wise Bonferroni adjusted t-tests. The results showed that V. riparia and V. rupestris can be distinguished at the leaf level spectra of visible, near- and infrared spectral regions. At the canopy level, genotypes were spectrally discriminated with limited success. The Photochemical Reflectance Index (PRI) demonstrated the highest potential not only to differentiate two species, but also two genotype pair groups within V. rupestris. This finding was also true for the PRI calculated with simulated EO-1 Hyperion data. These capacities to distinguish Vitis species, and to a lesser extent genotypes, using spectral signatures have important applications in remote monitoring of vineyards for plants health and also for locating wild Vitis populations for future crop improvement efforts.

Volatile Compounds from Grape Skin, Juice and Wine from Five Interspecific Hybrid Grape Cultivars Grown in Québec (Canada) for Wine Production.

Developed from crosses between Vitis vinifera and North American Vitis species, interspecific hybrid grape varieties are becoming economically significant in northern areas, where they are now extensively grown for wine production. However, the varietal differences between interspecific hybrids are not well defined, nor are the relationships between hybrid grape and wine composition, which causes significant drawbacks in the development of viticulture and winemaking of northern wines. In an effort to increase our understanding of interspecific hybrids, we have characterized the free volatile compounds profiles of berries (juice and skin) and wines of five red hybrid varieties (Frontenac, Marquette, Maréchal Foch, Sabrevois and St. Croix) grown in Québec (Canada), using GC-MS(TOF)-SPME. In grapes and wines, significantly higher levels of C6 and other fatty acid degradation products (FADP) were found in Frontenac, Maréchal Foch and Marquette. Terpenes were primarily located in the skin, with Marquette showing the highest level for these compounds. Both the level of terpenes and the level of FADP in grape were strongly correlated with their respective levels in wine, as demonstrated by the redundancy analyses. Nonanal, (E,Z)-2,6-nonadienal, β-damascenone, ethyl octanoate and isoamyl acetate showed the highest OAVs in the wines of the studied varieties.

SEQUENCE ANALYSIS OF LOCI RPV10 AND RPV3 FOR RESISTANCE AGAINST GRAPEVINE DOWNY MILDEW (PLASMOPARA VITICOLA)

The oomycete Plasmopara viticola is one of the most important pathogens of grapevine (Vitis vinifera L.). All traditional European cultivars used for wine production are highly susceptible. Therefore a great quantity of fungicides is necessary to enable high quality production of grapes. Newly bred resistant cultivars generated via marker-assisted selection (MAS) are a major contribution toward reducing fungicide applications for more sustainable viticulture. Identification of specific markers linked to resistance loci is crucial to facilitate high throughput screening in a breeding program. Many North American Vitis species carry resistance genes due to co-evolution with Plasmopara viticola. Some Asian Vitis species also exhibit such resistances although their evolutionary origin is not yet understood. Among others, the two loci Rpv3 (American origin, e.g., ?Regent?) and Rpv10 (Asian origin, e.g., ?Solaris?) have been identified in earlier studies. Analysis of the genomic DNA sequence of ?Solaris? at the Rpv10 locus and ?Villard Blanc? at the Rpv3 locus revealed several candidate genes which might be responsible for the expression of resistance against Plasmopara viticola. These candidates include six genes with protein domains similar to resistance proteins known from other plant species. The aim of the study is the elucidation of the cellular defense mechanisms and the development of gene-linked markers for high throughput screening in grapevine breeding.

THE INTERACTION OF ELSINOË AMPELINA WITH VITIS VINIFERA

Grapevine anthracnose caused by Elsinoe ampelina (de Bary) Shear is a disease of European origin that reduces crop quality and quantity. Vitis vinifera L. is susceptible to this disease, whereas some American grapevine species are resistant. In this study, we compared the interaction of E. ampelina with V. vinifera and a North American Vitis species by using trypan blue to stain both the fungal cells and the dead plant cells at the site of the hypersensitive response (HR). At 2 days post inoculation (dpi) on V. vinifera leaves, small collapsed epidermal cells on the leaf surface were observed, and typical lesions were observed at 7 dpi. Rapidly growing hyphae were observed at 2 dpi within unstained (live) cells. At 7 dpi, deeply stained plant cells were observed in the central part of the lesions, whereas the fungal hyphae were observed in the peripheral area of the lesions surrounded by unstained leaf cells. By contrast, in the interaction of E. ampelina with a resistant North American Vitis species, the HR was observed as early as 2 dpi, and almost all the hyphae were included within the area of stained leaf cells. These observations suggest that the absence of the HR in V. vinifera might be one of the causes for its susceptibility to E. ampelina.

Phenolic contents and compositions in skins of red wine grape cultivars among various genetic backgrounds and originations.

In order to analyze and compare the phenolic characteristics of red wine grapes with diverse genetic backgrounds, skin phenolics among 21 different cultivars belonging to Vitis vinifera L., East Asian and North American Vitis species and hybrids, as well as 2 varieties of muscadine grapes were estimated by HPLC-MS/MS. There were 45 anthocyanins, 28 flavonols, 8 flavan-3-ols, 9 cinnamic acids, 5 benzoic acids, 5 ellagic acids and 2 stilbenes detected in all the samples. Total contents of each phenolic type varied significantly among the different grape cultivars investigated. There was also a large variability in the phenolic compositions of different grape groups. The differences in anthocyanin composition were obvious between V. vinifera and non-V. vinifera grapes and also between the grapes originating from Eurasia and North America. Quercetin-3-glucuronide and quercetin-3-glucoside were marker flavonol compounds for Euvitis grape skins. Flavan-3-ol monomers were dominant in the skins of muscadine and non-V. amurensis East Asian grapes, whereas polymers were more common in V. vinifera and North American grapes. The muscadine grapes were very rich in flavonols, flavan-3-ols and ellagic acids. Via principal component analysis, these grape cultivars were clustered into three groups according to their characteristic phenolic content and composition.

Variation in recombination rates across Vitis species

Recombination rate data are presented for three populations of grape based on framework genetic linkage maps developed with simple-sequence repeat markers. These linkage maps were constructed from different Vitis species and represent three genetic backgrounds. The first population is pure Vitis vinifera, derived from a cross of the European cultivars Riesling and Cabernet Sauvignon. The second is an interspecific cross between two commercially used rootstock cultivars of different North American Vitis species parentage, Ramsey (Vitis champinii) and Riparia Gloire (Vitis riparia). The third population, D8909-15 (Vitis rupestris × (Vitis arizonica/Vitis girdiana form)) × F8909-17 (V. rupestris × (V. arizonica/Vitis candicans form)), is an F1 from two half-sibs. Genome-wide and chromosome-wide recombination rates varied across the three populations and among the six Vitis parents. Global recombination rates in the parents of the third F1 population, with a complex Vitis background, were significantly reduced. In the first and third populations, the recombination rate was significantly greater in the male parent. Specific genome locations with frequent heterogeneity in recombination were identified, suggesting that recombination rates are not equal across the Vitis genome. The identification of regions with suppressed or high recombination will aid grape breeders and geneticists who rely on recombination events to introgress disease resistance genes from the genomes of wild Vitis species, develop fine-scale genetic maps, and clone disease resistance genes.

Inheritance of Gall Formation Relative to Phylloxera Resistance Levels in Hybrid Grapevines

Grape phylloxera is an insect pest of grapevines and is controlled by rootstocks bred from resistant North American <i>Vitis</i> species. However, rootstocks with <i>V. vinifera</i> in their parentage, such as the <i>V. vinifera x V. rupestris</i> hybrid AXR#1, have failed. This study is the first to examine the inheritance of resistance to tuberosity and nodosity formation separately. F₂ progeny from a remake of AXR#1 were screened with B type phylloxera originally collected from AXR#1 roots. Transgressive segregation was observed in the progeny for all measures of resistance and its inverse, susceptibility: number of nodosities, number of tuberosities, number of adults on tuberosities, and age to first reproduction. These metrics were used to define resistance and susceptibility and to separate progeny into the two phenotypic classes for chi-square analyses of segregation ratios based on one and two locus models. Segregation of nodosity formation using all definitions fit a 1:7 phenotypic distribution; thus, at least two loci are involved. Segregation of tuberosity formation and numbers of adults varied depending on the resistance definition that was applied; it is unclear whether one or two genes control tuberosity formation. In each case the resistant class was recessive. Due to the different distributions best fit by the two phenotypes, these results suggest that separate mechanisms control nodosity and tuberosity formation.

Genetic linkage map of the interspecific grape rootstock cross Ramsey (Vitis champinii) × Riparia Gloire (Vitis riparia)

The first genetic linkage map of grape derived from rootstock parents was constructed using 188 progeny from a cross of Ramsey (Vitis champinii) x Riparia Gloire (V. riparia). Of 354 simple sequence repeat markers tested, 205 were polymorphic for at least one parent, and 57.6% were fully informative. Maps of Ramsey, Riparia Gloire, and the F1 population were created using JoinMap software, following a pseudotestcross strategy. The set of 205 SSRs allowed for the identification of all 19 Vitis linkage groups (2n=38), with a total combined map length of 1,304.7 cM, averaging 6.8 cM between markers. The maternal map consists of 172 markers aligned into 19 linkage groups (1,244.9 cM) while 126 markers on the paternal map cover 18 linkage groups (1,095.5 cM). The expected genome coverage is over 92%. Segregation distortion occurred in the Ramsey, Riparia Gloire, and consensus maps for 10, 13, and 16% of the markers, respectively. These distorted markers clustered primarily on the linkage groups 3, 5, 14 and 17. No genome-wide difference in recombination rate was observed between Ramsey and Riparia Gloire based on 315 common marker intervals. Fifty-four new Vitis-EST-derived SSR markers were mapped, and were distributed evenly across the genome on 16 of the 19 linkage groups. These dense linkage maps of two phenotypically diverse North American Vitis species are valuable tools for studying the genetics of many rootstock traits including nematode resistance, lime and salt tolerance, and ability to induce vigor.

Vine Water Relations, Gas Exchange, and Vegetative Growth of Seventeen Vitis Species Grown under Irrigated and Nonirrigated Conditions in California

A comparison was made among 16 native North American Vitis species and Vitis vinifera L. ('Carignane') grown in the San Joaquin Valley of California with or without irrigation over 2 years. Predawn water potential (ΨPD), predawn leaf osmotic potential (Ψπ), midday leaf (Ψl), and stem water potential (Ψstem), stomatal conductance (gs), net CO2 assimilation rate (A), and intrinsic water use efficiency (WUE) were measured on five dates during the growing season the first year of the study and pruning weights were evaluated both years. Net gas exchange and water potential components taken on the last measurement date in 1992 and pruning weights of the nonirrigated species were less (or more negative for Ψ components) than those of the irrigated vines. The 17 Vitis species were ranked according to their relative drought tolerance based upon their performance without irrigation and when compared to their irrigated cohort. The Vitis species considered most drought tolerant were V. californica, V. champinii, V. doaniana, V. longii, V. girdiana, and V. arizonica. Those six species generally had high values of A, gs, and pruning weights and more favorable vine water status at the end of the study than the other species when grown without irrigation. The drought-induced reductions in the measured parameters also were less for those species when compared to their irrigated cohorts. The least drought tolerant species were, V. berlandieri, V. cinerea, V. lincecumii, V. riparia, and V. solonis. The drought-tolerant rankings were generally associated with the species' native habitat and probable soil water availability.

Evaluation of Vitis Species Found in Selected Locations of Texas and New Mexico

North American Vitis species and hybrids thereof have been the source of rootstocks for V. vinifera for the last century. Collection and evaluation of native Vitis in north-central Texas, western Texas, and New Mexico have been made to determine their current status. Known geographical pockets of grapevines were visited, with specimens taken and identified by comparison to herbarium collections and published descriptions. In locals where more than one species existed, many natural hybrids with varying morphological characteristics have become established. In North Central Texas, two areas were visited. The first was Tarrant, Parker and Wise counties where three grapevine species (V. mustangensis, V. cinerea var. helleri, and V. vulpina) and many hybrids were observed. The second was Wilbarger County where V. acerifolia was found growing in the south while V. ×doaniana was found growing in the north. West Texas was primarily populated with V. acerifolia with the exception of the Silver Falls Canyon area in Crosby County where hybrids of V. acerifolia, V. arizonica and V. riparia were observed. In New Mexico, two areas were visited: San Miquel County (North Central region), where V. acerifolia, V. arizonica, and V. riparia were observed and Eddy County (southern New Mexico) where V. arizonica was observed. A rich diversity of Vitis germplasm appears to remain in these habitats.