Characterization of the largest relic Eurasian wild grapevine reservoir in Southern Iberian Peninsula

Wild grapevine is becoming a threatened species in the Iberian Peninsula due to human impacts. The aim of this work was to carry out a holistic study for six years of the largest wild grapevine population found up to date in SW Iberian Peninsula. This population has 115 vines. Ampelographic and soil characteristics have been studied. Evaluation of its environment has also been studied by describing the main parasitic species and natural enemies of pests. The ability of this plant material for its micropropagation and storage in slow-growth conditions has been tested. Microvinification resulted in a wine with good acidity and medium color intensity, two interesting characteristics under a warm climatology. Finally, the identification of private alleles in this wild population, absent in other locations from the Northern and Southern Iberian territories, is a very valuable feature and confirms the importance of establishing conservation programs. The population here studied is genetically unique and potentially useful for commercial rootstocks and cultivars breeding that would improve viticulture and enology. Additional key words: ecology; genetic analysis; ex situ conservation; sanitary status; Vitis vinifera subsp. sylvestris. Abbreviations used: DC (dark condition); ELISA (enzyme linked immusorbent assay); F (fixation index); He (expected heterozygosity); Ho (observed heterozygosity); I (information index); K (number of populations); Na (number of alleles); NC (normal condition); Ne (effective number of alleles); SSR (simple sequence repeat). Authors’ contributions: Conceived and designed the experiments: RAG, MC, MAL, JLG and RO. Acquisition, analysis or interpretation of data: RAG, MC, ML, MAL, AG, CAO, AP, HB, JLG and RO. Drafting of the ms and contributed reagents/materials/analysis tools: RAG, MC, JLG and RO. Statistycal analysis: RAG, MC and RO. Obtaining funding: RO. Administrative, technical or material support: ML. Citation: Arroyo-García, R.; Cantos, M.; Lara, M.; López, M. A.; Gallardo, A.; Ocete, C. A.; Pérez, M. A.; Bánáti, H.; García, J. L.; Ocete, R. (2016). Characterization of the largest relic Eurasian wild grapevine reservoir in Southern Iberian Peninsula. Spanish Journal of Agricultural Research, Volume 14, Issue 3, e0708. http://dx.doi.org/10.5424/sjar/2016143-8929. Supplementary material (Table S1) accompanies the paper on SJAR’s website. Received: 3 Nov 2015. Accepted: 14 Jul 2016. Copyright © 2016 INIA. This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial (by-nc) Spain 3.0 Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Funding: COST Action FA1003: “East-West collaboration for grapevine diversity exploration and mobilization of adaptive traits for breeding”. Competing interests: The authors have declared that no competing interests exist. Correspondence should be addressed to José Luis García: jlgarcia@irnase.csic.es.


Introduction
Grapevine is currently considered the most important fruit crop all over the world (De Mattia et al., 2008), with about 8 million hectares planted but it is seriously affected by the genetic erosion.For example, in Andalusia, only 5 cultivars (Palomino fino, Pedro Ximénez, Jaén, Muscat of Alexandria and Zalema), out of the 119 described in the region in 1807 by Clemente-2 2010), including research on its genetic structure.Furthermore, to indicate those measures carried out for in situ conservation, considering the relevance of this wild genetic resource for the future of the crop and their current scarcity (Arroyo-García & Revilla, 2013).

Localization and in situ characterization
Wild grapevine population nuclei were mapped by a GPS receiver along Rivera de Huelva course.Accessions were assessed at flowering time (May), to determine the sex of the plants.Pollen samples from flowers were obtained by brushing the mature anthers from 10 male and 10 female vines.Grains were introduced in DPX (Fluka) and observed under optical microscope Olympus BX 61 in order to study the morphological structure of the grains.
The phenological development of the vines was followed twice per month from 2005 to 2011.The main ampelographic descriptors were evaluated following the OIV (2009) systematic list on a sample of 25 vines of each sex.

Analysis of soil
Soil samples were obtained at rooting depths (0-30 cm).The organic matter present in the soil was determined by the Walkley and Black´s (1934) method, organic carbon concentration by dichromate oxidation (Nelson & Sommers, 1982) and calcium carbonate by using a Bernard calcimeter (Álvarez-Iglesias et al., 2003).The pH of the soils was determined in saturated paste extract (1:2.5 v/v) with a portable pH-meter and electrode system (Crison pH/mV p-506, Spain), calibrated in the field.
Samples were dried at 50 ºC for 48 h.Dried soil samples were ground and homogenized by sieving through nylon nets of 2 mm mesh in order to remove large stones and dead material and then ground again to <60 µm.Soil samples of 2 mm fraction were analyzed for size particle distribution by the hydrometer method (Gee & Bauder, 1986), Kjeldahl-N by the method described by Hesse (1971) and available P by the method of Olsen et al. (1954).The extraction was made according to Lindsay & Norvell (1978).Available metals (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S and Zn) of all samples were measured by inductively coupled plasma (ICP) spectroscopy (Advantage de Thermo, Beverly, MA, USA) (Walinga et al., 1995).(Arnold, 2002).This is a hermaphrodite subspecies developed along the domestication process, where most of the table grape, raisin or wine producing cultivars are included (This et al., 2006).
The Eurasian wild grapevine, as the rest of Vitis species are lianae which take the bushes or trees of the surrounding vegetation as supporters.Probably the Iberian Peninsula was the westernmost refuge for wild grapevines during Quaternary glacial periods (Lehmann & Böhm, 2011).According to the literature (Laguna, 1566;Clemente-y-Rubio, 1807), wild grapevines were very common in Spain until middle 19 th century.On the other hand, it is necessary to underline that these vines had their genetic contribution to the Iberian cultivars which were included in the proles occidentalis (Negrul, 1938).According to DNA microsatellite analysis, Iberian wild vines have provided the chlorotype 'A' to autochthonous cultivars (Arroyo-Garcia et al., 2006), probably by hybridization from Phoenician age to present with imported hermaphrodite plants.A 4% of hybrid specimens between both subspecies were found in Spanish natural habitats (De Andrés et al., 2012).Wild grapevine constitutes an interesting phytogenetic resource for cultivars and rootstocks breeding in order to cope the consequences of climatic change and the possible appearance of new pests and diseases (Mackey, 2009).
Canalization of rivers, dam and levee constructions, forestry and horticulture exploitations of floodplain forests, cleaning of riverbanks and the continuous extension of the road network resulted in direct eradications of wild grapevine populations throughout Europe (Arnold, 2002).Other indirect repercussions, derived from the importation of North American diseases and pests such as powdery and downy mildews and Phylloxera, led to the current status of the wild grapevine as a threatened taxon in the European territory (Thorsell & Sigaty, 1997), and hence in the Iberian Peninsula (Ocete et al., 1999).
Preliminary studies on the localization and ecology of this Vitaceae were carried out in Ossa-Morena mountain range and surrounding areas of Portugal and Spain (Ocete et al., 1999(Ocete et al., , 2002)).The sources of Rivera de Huelva River are located on the Spanish side of these mountains, in the Extremadura region (Badajoz province).The banks of the river are poorly preserved due to aforementioned human impacts, highlighting the construction from 1940 to 1979 of four dams along its channel to supply drinking water to Seville metropolitan area.
The aim of the present paper was to study from a holistic point of view the largest wild grapevine population found up to date in the Mediterranean area of the Iberian Peninsula (Ocete et al., 1999;Cunha et al., 3 Characterization of the largest relic wild grapevine reservoir in SW Iberian Peninsula kg of bunches were obtained.The use of the grape destemmer reduced the sample to 8.79 kg.After destalking, berries were pressed by hand, obtaining 1,788 mL of must.The alcoholic fermentation with maceration and daily removing was developed by wild yeasts, at 20 ºC, along 10 days and monitored by density measures.References of the official analytic methods used from OIV (2015) and data obtained are shown in Table 1.

Genetic analysis
Since wild grapevines are mostly dioecious while cultivated are generally hermaphrodites we have only used male plants for the genetic analysis as they cannot be escapes from cultivated fields nor the result of pollination between wild and cultivated plants.A sample of 63 male accessions were analyzed (Table 2) and compared with a published genotype data, corresponding to Spanish wild grapevine populations (De Andrés et al., 2012).

Sanitary status
Roots were unearthed up to 40-50 cm of depth to observe possible symptoms caused by subterranean phytophagous and pathogens.Samples of fine roots were observed under binocular to detect possible damages caused by Phylloxera (Daktulosphaira vitifoliae Fitch) (Homoptera, Phylloxeridae), root-knot nematodes and rot fungi.
The detection of possible symptoms caused by phytophagous arthropods, insects and mites, and diseases was carried out in spring and summer, every 15 days along the six years of this investigation, on shoots, leaves and bunches of 100 vines, situated up to 3 m height.In the case of mites 50 leaves/vine were observed to evaluate the intensity of infestation.
Special attention was paid to try to find mealybugs because some of them are vectors of virus, as Planococcus citri (Risso) (Hemiptera, Pseudococcidae) that transmits Grapevine leafroll virus.For this task, 25 vines exhibiting a perimeter higher than 20 cm were debarked from 2009 to 2012 to find the hemipteran.
The degree of infestation/infection caused by mites was evaluated according to the procedures of Ocete et al. (2007) and OIV (2009) in the case of both kinds of mildews.To detect the possible presence of Grapevine fan leaf, Grapevine leafroll and Grapevine fleck viruses, 10 samples from the oldest female and male vines were taken in June 2010.ELISA tests were performed using the Bioreba kit systems.
Together with phytophagous sampling, natural predatory species of Chrysopidae and Coccinelidae were identified.On the other hand, to investigate mite species found inside erinea, 25 available leaves with erinea were randomly chosen from ten individuals in July.The leaves were put in a chamber at 4 ºC for 20 min to slow down the activity of the predatory mites.Immediately after, erinea were studied under the binocular to pick up natural enemies of this mite in action.The Berlese-Tullgren funnel was also used to extract the mites from the erinea.Predatory specimens of Colomerus vitis (Pagenstecher) (Acari, Eriophyidae) were separated and introduced into tubes with ethanol (70%) with 2 drops of glycerin.Mites were cleared in lactic acid and mounted on Heinze-PVA medium.Observations were made using an interference contrast microscope.Generic nomenclature for the Phytoseiidae follows the criteria proposed by Chant & Mc-Murtry (1994) for Typhlodrominae and those referred by De Moraes et al. (1986) for Amblyseiinae.

Microvinification
For microvinification berries from 3 available vines were harvested on 26th September 2012.In total, 10.55After disinfection, the explants were placed individually in sterile test tubes (25 × 150 mm) with 8 mL of "VID" medium (Sarimento et al., 1992) with 0.13 µmol/L indolebutyric acid (IBA) and 0.32 µmol/L benzylaminopurine (BA) with 0.6% agar, pH 5.7.Each tube was covered with a plastic cap, sealed with parafilm and placed in a growth chamber at 23±2ºC, 30 µmol/m 2 •s of light intensity and 16 h of photoperiod.Adaptation to outside conditions was carried out according to Cantos et al. (1998).
Conservation in germplasm banks.Sixty explants from the in vitro cultures were chosen and cultivated in the same conditions described above.After 15 days, 30 of these explants were cultured at the same conditions (NC) and the other 30 were placed in a fridge at 4 ºC and darkness to slow the growth (DC).After two and six months, 15 explants of each condition were taken and micropropagated again (1 cm and 1 bud) in De Wit tubes with 8 mL of the same medium and cultured at NC conditions of light and temperature.After 30 days the survival, stem length, bud (nodes), lateral shoots and root numbers, and rooting percentages were recorded in all situations considered.
Allele size and total number of alleles were determined for each SSR (Simple Sequence Repeat).Putative alleles were indicated by their estimated size in bp.Genetic diversity was estimated using the following statistics: number of alleles (Na); mean number of alleles per locus; effective number of alleles (Ne); observed heterozygosity (Ho); expected heterozygosity (He) (Nei, 1973); and fixation index (F), also called inbreeding coefficient.All those statistics were calculated using GenAlex software version 6.0 (Peakall & Smouse, 2006) and the Excel Microsatellite Toolkit (Park, 2001).
Bayesian clustering was applied on the SSR genotype data using the software package STRUCTURE, vers.2.1 (Falush et al., 2003).Analyses were performed with the total collection (63 unique genotypes).Only accessions with ancestry values superior to 0.7 were included in each population analyses.Admixture model and correlated allelic frequencies were used to analyze the dataset without prior population information.Ten simulations per K value were performed for each number of populations (K) (set from 1 to 10).Burn-in period and Monte Carlo Markov Chain length were set up to 100,000 and 300,000, respectively in each run.To assess the best K-value supported by the data we calculated the second order change of the likelihood function divided by the standard deviation of the likelihood (ΔK) (Evanno et al., 2005).

Ex situ conservation
Micropropagation.From cuttings of the considered population, uninodal explants, 1 cm length were prepared.The explants were disinfected by the following steps: a) washing with water and detergent, gently rinsing with distilled water; b) immersion in 70% ethanol for 45 s; c) immersion in a solution of 45% sodium hypochlorite (3.5 % active chlorine) with some drops of Tween-20 (20 min at 30 ºC with stirring); d) gently rinsing with distilled, sterilized water.

5
Characterization of the largest relic wild grapevine reservoir in SW Iberian Peninsula considered as medium level (Báscones, 2004).Soil was very poor in available phosphorous.Concentration of available potassium was also very low if compared to the 200 mg/kg of available potassium of normal agricultural soils (Pérez de Mora et al., 2006).Because the percentage of CaCO 3 was very low, the available calcium levels were also low.On the contrary, available magnesium concentration, 274 mg/kg (Table 3), showed higher contents that those considered normal ranging from 180 mg/kg (González et al., 2003), to 120 mg/kg (Báscones, 2004).Na level was within normal values and Fe concentration was slightly high.
Other microelements considered as toxic above certain thresholds as Ba, Cd, Cu, Mn, Pb, S and Zn presented normal values (Table 3).

Sanitary status
On roots, no symptoms of infestation or infection attributable to Phylloxera, root-not nematodes or mycelium of rot fungi were detected.
In the vine leaves, damages caused by mites, concretely by the Erineum strain of Colomerus vitis were very frequent in all the vines progressively developing from March to the end of July.The percentage of leaves affected varied usually between 10 to 20%.Symptoms of the presence of Calepitrimerus vitis (Nalepa) (Acari, Eriophyidae) were scarcer, developing from March up to the beginning of June, and affecting from 3 to 18% of the leaves.
Small spots of infestation caused by larvae and adults of Haltica ampelophaga Guérin and Méneville (Coleoptera, Chrysomelidae) were very occasionally found on leaves.Several shoots and leaves showed bites caused by Decticus albifrons (Fabricius) (Ortopthera, Tettigonidae) and Ephipiger ephipiger Fiebig (Ortopthera, Tettigonidae).In June 2012, a very dry year, several specimens of Doctiosaurus maroccanus (Thunberg) (Ortopthera, Acrididae) were also detected in the external part of the gallery forest, but there was no evidence of feeding on vines.On the other hand, some small colonies of Aphis gossypii Glover (Hemiptera, Aphididae) were present only on 7 vines between middle of May to the end of June.
About the origin of the fungal diseases it is necessary to remark that in the surrounding area where this study was carried out there are not vineyards, only some cottages and ancient buildings with very isolated vines.The nearest wine producing area is about 40 km far from the studied zone.The presence of symptoms caused by Erysiphe necator (Schweinitz) Burrill was common in most of the vines, mainly on leaves and shoot axes, affecting between 10-21% of the leaves and around a 15% in male individuals than in female plants.Female flowers had reflexed stamens while all the male flowers found corresponded to type I (fully developed stamens, no gynoecium).
Young shoots had low intensity of anthocyanin coloration.Mature leaves were bigger in female plants and mainly wedge-shaped while in male plants leaves were more frequently pentagonal.The male grain of pollen is tricolporate, quite similar to that belonging to hermaphrodite cultivars, and the female one is a unaperturate ovoid sac.
Only female plants had berries.All the berries were small, rounded and reddish.The seed morphology is subspherical with a small beak.Wide/length ratio is higher than in the cultivated varieties.

Analysis of soil
The results of soil analysis are shown in Table 3.According to the percentages of fine sand, silt and clay the soil studied is classified as sandy loam (Haplic Fluvisol).The pH was 7.29, classified as neutral.Electrical conductivity was only 0.052 mS/cm, very low in relation to levels considered normal (< 4 mS/cm) (Báscones, 2004).Level of organic matter was normal and, in consequence, also C and N contents, with a C/N rate of 10.7  et al., 2012) and La Minilla allowed to find out that the high number of private alleles presented in La Minilla population is similar to the number found in the Northern and Southern wild populations (Table 2).This result pointed out that some alleles in these populations are not present in the other Spanish populations.The mean number of alleles between the different populations ranged from 6.3 to 9.1.The number of effective alleles (Ne) ranged between 3.4 and 4.6.The information index (I) ranged from 1.3 to 1.7; Ho ranged between 0.608 and 0.687, whereas the values of He were slightly higher, ranging between 0.636 and 0.766.The fixation index (F) showed values ranging from 0.012 to 0.121, supporting the existence of inbreeding depression in some wild grape populations.
Population structure between wild grapevine populations from the Iberian Peninsula.The genetic structure analysis included Northern and Southern Spain wild grapevine populations (218 samples) and the wild accessions from La Minilla (63 samples).The choice of a fixed number of populations (K) is arbitrary, each of them characterized by a set of allele frequencies at each locus.Individuals in the sample are probabilistically assigned to genetic groups or jointly to one or more groups.Consequently, we performed an analysis where K varied from 1 to 10.This analysis showed a large increase of likelihood from K=1 to K=3 and smaller increases from K=3 to K=10.Using the methodology of Evanno et al. (2005), this result supports K=3 as the most likely number of genetic groups, which corresponds to wild individuals from Northern, Southern and La Minilla populations (Fig. 1).Then, it may be supposed that La Minilla genetic group comprise a unique population that could be the result of fragmentation due to the recent human alteration of the habitat.

Ex situ conservation
Micropropagation.The in vitro response of the explants obtained directly from the field individuals is indicated in Table 4.After 30 days of in vitro culture, the 64.9% of the explants formed stem and leaf with good growth (averages of 5.5 cm length stem, 9.2 nudes and 1.6 of lateral shoots), and 97.8% of rooting, with an average of 3.5 roots per plant with 7.3 cm of mean length with a very good aspect.In consequence, the acclimation to outside conditions was 80%. of bunches.Oil spots on leaves together with other damages on shoot axes and bunches caused by downy mildew (Plasmopara viticola (Berkeley and Curtis) Berlease and de Toni), were also frequent mainly in those vines situated in the shadiest places of the gallery forest, where the level of infection on leaves reached 17% and around 9% on bunches.Symptoms caused by Botrytis cinerea Pearson were not found any year.
Regarding the possible virus infections, all the ELISA tests were negative for Grapevine leafroll, Grapevine fan leaf and Grapevine fleck viruses.No symptoms were detected in the wild vines.

Microvinification
Analysis of the microvinification is shown in Table 1.The experimental wine resulted with medium concentration of alcohol, similar to that obtained with traditional cultivars from the region.The total acidity was relatively high, and consequently the pH value was much lower than that obtained with traditional Andalusian cultivars.It is a very important characteristic to highlight, because it would need no addition of tartaric acid to give stability.The volatile acidity was slightly high due to the absence of potassium metabisulphite addition.The color intensity is medium for a red wine due to the irregular degree of maturation of the berries, but it was not possible to delay the harvest due to heavy incidence of berry-consuming birds.The concentration of methanol is correct, and fulfills Spanish legislation, that allows up to 400 mg/L.The dry extract is normal for a red wine and the total polyphenols index measured at 280 nm is also normal.

Genetic analysis
Genetic diversity of the wild populations.The results of the genetic diversity analysis, according to DNA microsatellite genotyping are shown in Table 2.These 7 Characterization of the largest relic wild grapevine reservoir in SW Iberian Peninsula of lateral shoots per plants although higher in the NC culture, showed no significant differences between treatments (Table 5).
Rooting percentage was 100% for both culture conditions independently of the storage period.Mean number of roots was similar for all the conditions except for NC after 2 months that was higher (Table 5).

Discussion
According to the literature already revised in the Introduction section, this is the largest population found Conservation in germplasm banks.Survival rate of explants was high after 2 months for both normal (NC) and dark cold room (DC) conditions.Although DC treatment showed more survival rate than NC cultures the difference was not significative, ranging from 80 to 100%.After 6 months of culture, survival rate fell to 40% both for NC and DC treatment (Table 5).
The DC treatments reduced the explants growth compared to NC cultures (Table 5).No great differences were observed between 2 or 6 months of culture in DC conditions.In standard conditions, 6 months of culture resulted in lower growth, both in terms of stem length and number of buds (Table 5).The mean number 8 century (De Herrera, 1513) up to the sixties of the 20 th century, until synthesis pesticides became routinely used (Hidalgo, 2002).
As in the rest of the Andalusian populations, Colomerus vitis (Pagenstecher) (Acari, Eryophidae) is present on all the vines sampled while infestations by Calepitrimerus vitis are less frequent (Ocete et al., 2007).Probably, these monophagous species were imported from natural habitats to first vineyards during the domestication process started around 8,000 B.P in the Caucasian region (Ocete et al., 2007).
On the contrary, damages caused by downy and powdery mildews were imported from American grapevine species along 19 th and 20 th centuries.
This population conserves a wide diversity of natural enemies of pests, as is frequent in other populations found in Andalusia region (Ferragut et al., 2008).The neuropteran Chrysoperla carnea is very common in the Western area of the Iberian Peninsula, covered mainly by oak tree species, feeding on aphids, white flies and mites (Marín & Montserrat, 1987).This neuropteran has also been found feeding on the same arthropods that live on wild grapevine populations (Ferragut et al., 2008).About coleopterans, the two species of ladybirds found are common in natural flora (Cardoso & Gomes, 1986) and crops (Ripollés, 1990;Down et al., 2000) of the Iberian Peninsula.
In the case of Phytoseiidae species, its distribution varies with the location of the wild grapevine populations through different European regions, according to the very scarce literature existing on this subject (Gallardo, 2005).Therefore, along the Rhine´s flood plains in Germany and France, the most frequent predators were Euseius finlandicus (Oudemans), Neuseiulella tiliarum (Oudemans), Typhlodromus tiliae (Oudemans), Phytoseius sp.(Ocete et al., 2000).T. phialatus can also be found in most of the Spanish Guarantees of Origin (Villaronga et al., 1991) and on spontaneous flora situated around several French vineyards (Tixier et al., 2000).P. persimilis is common in the Iberian Peninsula in natural habitats and different agroecosystems (García-Mari et al., 1987) and also on wild grapevine species from USA (Karban et al., 1995).It constitutes a trading species used in biological control of in the Mediterranean area of the Iberian Peninsula (Ocete et al., 2002;Cunha et al., 2004), where the distribution of this grapevine subspecies is highly fragmented.This natural riparian habitat has been intensely modified by man along the history.A proof of it is the presence of a Roman aqueduct ruins inside the location studied in the present paper.
The evaluation of the ampelographic characters is very similar to that described for other Andalusian wild grapevines (Ocete et al., 2007).The sexual structure of female and male flowers is similar to the rest of the Spanish populations (Ocete et al., 1999).the female pollen grain featured an unaperturate ovoid sac as described by Gallardo et al. (2009) in other Andalusian populations.Only female plants had berries, like in the case of the Spanish populations (Ocete et al., 1999).Their seed typologies are close to the wild grapevine seeds described by Terral et al. (2010).
Wild grapevine is sensitive to Phylloxera under artificial laboratory conditions.The absence of symptoms on roots in the wild ecosystems from the Iberian Peninsula to the Caucasian region seems to be due to soil flooding several months each year.This edaphic condition could also determinate the absence of symptoms caused by species belonging to Meloidogyne and some root rot fungal species, as reported by Ocete et al. (2007).
The very scarce infestation caused by the coleopteran H. ampelophaga constitutes the first citation of this species in wild populations from Portugal to the Republic of Georgia.This coleopteran had an important incidence on Spanish vineyards from, at least, the 16 th  et al., 2011a).The color intensity is lower than those obtained in microvinifications using wild grapevines from Cádiz province (Ocete et al., 2007) and Sardinia (Lovicu et al., 2009), where the values were 12 and 14 respectively (Table 1).According to the microvinification analysis (Table 1) it is a young wine, which according to absorbance data at different wavelengths, has as color components yellow (30.58%), red (58.56%) and violet (10.51%), being then very well balanced.
Precise detection and quantification of genetic variation is prerequisite for the successful conservation and exploitation of plant genetic resources.The results of the genetic analysis showed that La Minilla still harbors a number of wild grapevine accessions with low levels of heterozygosity (He).Similar result has been observed in wild grapevine populations analyzed in Morocco, Sardinia, Portugal, France or Italy (Di Vecchi-Staraz et al., 2009;Cunha et al., 2010;Zecca et al., 2010;Zinelabidine et al., 2010).However, we have detected that the observed heterozygosity (Ho) was not significantly lower (p≤0.05)than expected heterozygosity (He) in La Minilla populations, in parallel with the estimation of F values close to zero (Table 2).Since F values near 0 indicate random mating, the F values found for La Minilla wild populations are consistent with a random mating population status.At the same time, the relative lower genetic diversity in this population may be due to the sample size, because a positive correlation of number of alleles with sample size is expected (De Andrés et al., 2012).However, the identification of private alleles in each wild population is valuable and confirms the importance to establish a conservation program of new wild populations from La Minilla.The analysis of the genetic structure reveals three main genetic groups corresponding to Northern, Southern Spain and La Minilla populations.These genetic groups showed very high average probability of assignment to their own cluster, in agreement with the hypothesis that they are genetically distinct.The specific alleles present in each wild population strongly support the importance of conservation of this wild germplasm.
There does not exist any legislation on the preservation of wild grapevines in Andalusia nor in Spain and in consequence this subspecies is not provided in the mandatory previous studies of environmental impact required for public works.Thus, in the case of this population 35 vines were completely destroyed during the cited period of re-building of the bridge.It is necessary to start an active program to stop the constant and alarming loss of wild grapevines in the region claimed by Ocete et al. (2007), including a legal figure of preservation and to start programs for in situ protection and restoration of Tetrannychiide, mainly to control Tetranychus urticae (Koch), as it occurs in Andalusian greenhouses (García-Mari, 1994).Despite E. stipulatus was found in a short number of erinea, this is probably the most representative Phytoseidae on traditional Mediterranean crops.This mite, together with other species of the same genus, such as T. phialatus, T. rhenanoides and T. phialatus, control Panonychus ulmi (Koch) (Acari, Tetranychidae) on pear and apple tree orchards from Northeastern Spain (Sarasúa et al., 2000).
Only a few adults of N. litoralis were found in our samples.This species is relatively common on coastal crops, mainly in Middle East (De Moraes et al., 2004).
The results obtained from in vitro propagation meant a very high in vitro precocity of this wild plant material, higher than the cultivated one, which normally needs at least 15 days more of culture to reach similar level of development (Gribaudo et al., 1995;Troncoso et al., 1999).
It is interesting to emphasize that the wild grapevine explants developed contemporarily shoots and roots in the culture medium, giving new plants in only one in vitro culture stage indicating a good balance of nutrients and growth regulators.Thus, the possibility of obtaining complete plants with only one in vitro stage saves time and costs in the propagation process.Lateral shoot formation increases multiplication factor and allows using a complete stem with much more possibilities of survival and development.It was possible to attain healthy self-rooted plants for an adequate adaptation to ex vitro conditions.Thus, following the indicated method for plant transplanting and hardening to outside conditions, an 80% of surviving plant was reached.
Survival is the most important factor to consider in conservation assays as it defines the efficiency of the process.Explant growth was reduced by dark and cold culture but a sufficient number of healthy plants could be obtained after 6 months.In NC conditions the growth, measured by stem length and number of buds formed, decreased slightly after 6 months of culture likely due to medium ageing and nutrient depletion.Nevertheless, the number of lateral shoots per explant did not seem to be affected by any of the storage conditions tested.
From the results of these experiments, a robust, quick and economical method, for the in vitro propagation and conservation of wild grapevine plants was set up.
Only about 20% of berry weight could be transformed into must due to the small berry size (0.8-1 cm of diameter), resulting in a low flesh/berry ratio, and the presence of big pips as in other Iberian regions such as Navarra (Ocete et al., 2011b) and La Rioja (Ocete natural habitats as in the cases of France, Austria, Germany and Hungary.It is necessary to remember that wild grapevine is a species well represented in the Andalusian landscape along millennia.In this territory, the first location of Vitis pollen was found in El Padul bogs (Granada province) belonging to initial Upper Pleistocene phases (Florschütz et al., 1971).Also, pollen remains are very abundant in the survey carried out in the Laguna de Las Madres (Huelva province), dating back to the 4,500 BP (Stevenson, 1985), in an area very close to the actual relic wild grapevine populations located in Doñana National Park, Biosphere Reserve and World Heritage Site (Ocete et al., 2007).
The evolutionary process of plant domestication by humans led to morphological, physiological, behavioral and genetic differentiation of a wide range of species from their wild progenitors (Gerbault et al., 2014).
As a conclusion, those wild resources and traditional varieties could be vital to ensure the future and sustainability of viticulture.They constitute a tremendous source of information and genetic material to be used in cultivar breeding, and to adapt them also to the new challenges of the sector and the market demands.In this work a relic population of wild grapevine has been described.According to genetic analysis results, this is a genetically unique population useful for cultivar improving.

Figure 1 .
Figure 1.Graphical representation of ancestry membership coefficients of all 281 Spanish wild individuals.Each individual is shown as a vertical line divided into segments representing the estimated membership proportions in the three genetic clusters inferred with STRUCTURE.Red color corresponds to Southern wild individuals, green corresponds to La Minilla wild individuals and blue to Northern wild individuals.

Table 1 .
Analysis of the microvinification

Table 2 .
Allelic patterns (means ± SD) and fixation index across wild grapevine populations from Spain and La Minilla population Na: number of alleles; Ne: number of effective alleles; I: information index; He: expected heterozygosity; Ho: observed heterozygosity; F: fixation index 4

Table 3 .
Character fertility and presence of heavy metals on soil of the wild grapevine population of Rivera de Huelva.

Table 4 .
Micropropagation response of explants from Rivera de Huelva after 30 days of culture

Table 5 .
Survival and biometry of stem and root produced by Rivera de Huelva wild grapevine plantlets from normal (NC) and darkness and cold conditions (DC) after 2 and 6 months periods.