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[EN] The performance of snake melon [Cucumis melo var. flexuosus (L.)] in organic farming was studied under high biotic and salt stress conditions. Soilborne diseases (mainly caused by Macrophomina phaseolina and Neocosmospora falciformis), combined with virus incidence [Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV), and Tomato leaf curl New Delhi virus (ToLCNDV)] and Podosphaera xanthii attacks, reduced yield by more than 50%. Snake melon susceptibility to M. phaseolina and Monosporascus cannonballus was proved in pathogenicity tests, while it showed some degree of resistance to Neocosmospora keratoplastica and N. falciformis. On the contrary, salt stress had a minor impact, although a synergic effect was detected: yield losses caused by biotic stress increased dramatically when combined with salt stress. Under biotic stress, grafting onto the melon F(1)Pat81 and wild Cucumis rootstocks consistently reduced plant mortality in different agroecological conditions, with a better performance compared to classic Cucurbita commercial hybrids. Yield was even improved under saline conditions in grafted plants. A negative effect was detected, though, on consumer acceptability, especially with the use of Cucurbita rootstocks. Cucumis F(1)Pat81 rootstock minimized this side effect, which was probably related to changes in the profile of sugars, acids, and volatiles. Grafting affected sugars and organic acid contents, with this effect being more accentuated with the use of Cucurbita rootstocks than with Cucumis. In fact, the latter had a higher impact on the volatile organic compound profile than on sugar and acid profile, which may have resulted in a lower effect on consumer perception. The use of Cucumis rootstocks seems to be a strategy to enable organic farming production of snake melon targeted to high-quality markets in order to promote the cultivation of this neglected crop., This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades, cofunded with FEDER funds [project nos. AGL2017-85563-C2-1-R and RTA2017-00061-C03-03 (INIA)], and by PROMETEO project 2017/078 (to promote excellence groups) by the Conselleria d'Educacio, Investigacio, Cultura i Esports (Generalitat Valenciana). AF-L is a recipient of a predoctoral fellowship from Generalitat Valenciana.

[EN] Grapevine is grown as a grafted plant, mainly using phylloxera-resistant rootstocks obtained when this aphid destroyed European vineyards, and the use of a reduced number of rootstocks in each production area is common. This indicates that the genetic variability that is being used could be insufficient to tackle new stress constraints. Changes that will be produced as a consequence of climate change are promoting the development of new rootstocks and the study, in a deeper manner, of those already in use, mainly in relation to drought stress. In this work, we have studied 40 rootstock accessions, including clones of common rootstocks, others developed later, some recovered from old abandoned fields and other, resprouted rootstocks. From these accessions, 19 unique SSR profiles were obtained and chlorotypes were assigned, as no information was available for them in the VIVC database, thus generating new knowledge. Genetic variability was analysed in the 110 Ritcher, 140 Ruggieri and 1103¿Paulsen rootstocks (derived from Vitis berlandieri and Vitis rupestris), commonly used in the countries of greater wine production (Spain, France and Italy), and in the 19 rootstocks with unique profiles. As expected, higher variability was found in the latter. Fortunately, variability was also found in the small sample of which reflects there is variability among the three more-commonly-used rootstocks despite they are half and/or full sibs. Considering all the germplasm analysed, the relationships found agree with a recent report stating that some genotypes had been erroneously assigned, previously, and show that another genotype may not be correct. Variability was also found in clones of several rootstocks, with considerable variability in some of them, including two rootstocks rescued from old abandoned vineyards. This result suggests the possibility of evaluating these materials for other traits. Finally, evaluation of osmotic-stress tolerance was carried out in in vitro culture, using media containing PEG. Micropropagated plants of one rootstock classified as drought-resistant, another reported as sensitive and two others whose classification in the field is variable were used. The results indicate that this methodology can be useful in breeding programmes, to screen the variability in osmotic-stress tolerance among clones and to study root architecture and plasticity., The study was supported by the projects CGL2015-70843-R, MINECO co-funded with FEDER funds, and AGCOOP_D/2018/007, funded by FEADER, MAPA and Conselleria d'Agricultura, Desenvolupament Rural, Emergencia Climatica i Transicio Ecologica (Generalitat Valenciana). The authors thank the owners of nurseries and other members of the viticulture sector (see Table S1) for supplying the different accessions required to carry out this work and A. Frances who collaborated in the evaluation of osmotic stress tolerance.

[EN] Drought stress is one of the major threats to agriculture and concomitantly to food production. Tomato is one of the most important industrial crops, but its tolerance to water scarcity is very low. Traditional plant breeding has a limited margin to minimize this water requirement. In order to design novel biotechnological approaches to cope with this problem, we have screened a plant cDNA library from the halotolerant crop sugar beet (Beta vulgaris L.) for genes able to confer drought/osmotic stress tolerance to the yeast model system upon overexpression. We have identified the gene that encodes BvHb2, a class 2 non-symbiotic hemoglobin, which is present as a single copy in the sugar beet genome, expressed mainly in leaves and regulated by light and abiotic stress. We have evaluated its biotechnological potential in the model plant Arabidopsis thaliana and found that BvHb2 is able to confer drought and osmotic stress tolerance. We also generated transgenic lines of tomato (Solanum lycopersicum) overexpressing BvHb2 and found that the resulting plants are more resistant to drought-induce withering. In addition, transgenic lines overexpressing BvHb2 exhibit increased levels of iron content in leaves. Here, we show that class 2 non-symbiotic plant hemoglobins are targets to generate novel biotechnological crops tolerant to abiotic stress. The fact that these proteins are conserved in plants opens the possibility for using Non-GMO approaches, such as classical breeding, molecular breeding, or novel breeding techniques to increase drought tolerance using this protein as a target., This project was funded by the project PAID-00-10 "Introduccion De Genes Relacionados Con La Tolerancia A Estres Hidrico Y Oxidativo En Distintos Materiales Que Presentan Caracteristicas Utiles Para Su Uso Como Patrones De Plantas Horticolas De Interes Agronomico". (Ref. 2726) from the Universitat Politecnica de Valencia.

[EN] Pot experiments were carried out to characterize the response of two Cucumis metuliferus accessions against (a)virulent Meloidogyne arenaria, M. incognita or M. javanica populations, to Mi1.2 gene and to determine the compatibility and the effect on physicochemical properties of cantaloupe melon. In addition, histopathological studies were conducted. Plants were inoculated in 200 cm3 -pots with 1 J2 cm-3 24 of soil containing sterilized sand a week after transplanting and maintained in a growth chamber at 25 ºC for 40 days. The susceptible cucumber cv. Dasher II or melon cv. Paloma were included for comparison. The number of egg masses and number of eggs per plant were assessed, and the reproduction index (RI) was calculated as the percentage of eggs produced on the C. metuliferus accessions respect those produced on the susceptible cultivars. The compatibility and fruit quality was assessed grafting three scions (two of Charentais type) and one of type Piel de Sapo under commercial greenhouse conditions. The resistance level of both C. metuliferus accessions ranged from highly (RI < 1%) to resistant (1% ¿RI ¿ 10%) irrespective of Meloidogyne populations. Melon plants grafted onto C. metuliferus accession BGV11135 grew as selfgrafted plants and did not modify negatively fruit quality traits. Giant cells induced by RKN on C. metuliferus were mostly poor developed compared to those on cucumber. Furthermore, necrotic areas surrounding the nematode were observed. C. metuliferus accession BGV11135 could be a promising melon rootstock to manage Meloidogyne spp. irrespective of its (a)virulent Mi1.2 condition without melon fruit quality reduction., This work was supported by AGL2013-49040-C2-1-R, and AGL2014-53398-C2-2-R projects from the Spanish Ministry of Economy, Industry and Competitiveness, and cofounded with FEDER Funds. The authors would like to thank Semillas Fito for providing melon cv. Paloma, Dr Christine Vos (Scientia Terrae Research Institute) for her English revision and critical comments of the manuscript and Dr Nuria Escudero (Universitat Politecnica de Catalunya) for her support and critical comments on the manuscript.

Background Somatic embryogenesis is the preferred method for cell to plant regeneration in Vitis vinifera L. However, low frequencies of plant embryo conversion are commonly found. In a previous work we obtained from cut-seeds of a grapevine infected with the Grapevine leafroll associated viruses 1 and 3 (GLRaV-1 and GLRaV-3), high rates of direct regeneration, embryo plant conversion and sanitation. The aim of this study is to evaluate the usefulness of this procedure for regeneration of other grapevine varieties which include some infected with one to three common grapevine viruses (GLRaV-3, Grapevine fanleaf virus (GFLV) and Grapevine fleck virus (GFkV)). As grapevine is highly heterozygous, it was necessary to select from among the virus-free plants those that regenerated from mother tissues around the embryo, (true-to-type). Results Somatic embryogenesis and plant regeneration were achieved in a first experiment, using cut-seeds from the 14 grapevine varieties Airén, Cabernet Franc, Cabernet Sauvignon, Mencía, Merlot, Monastrell, Petit Verdot, Pinot Blanc (infected by GFLV and GFkV), Pinot Gris, Pinot Meunier, Pinot Noir, Syrah, Tempranillo (infected by GFLV), and Verdil. All regenerated plants were confirmed to be free of GFkV whereas at least 68% sanitation was obtained for GFLV. The SSR profiles of the virus-free plants showed, in both varieties, around 10% regeneration from mother tissue (the same genetic make-up as the mother plant). In a second experiment, this procedure was used to sanitize the varieties Cabernet Franc, Godello, Merlot and Valencí Blanc infected by GLRaV-3, GFkV and/or GFLV. Conclusions Cut-seeds can be used as explants for embryogenesis induction and plant conversion in a broad range of grapevine varieties. The high regeneration rates obtained with this procedure facilitate the posterior selection of true-to-type virus-free plants. A sanitation rate of 100% was obtained for GFkV as this virus is not seed-transmitted. However, the presence of GLRaV-3 and GFLV in some of the regenerated plants showed that both viruses are seed-transmitted. The regeneration of true-to-type virus-free plants from all infected varieties indicates that this methodology may represent an alternative procedure for virus cleaning in grapevine. Electronic supplementary material The online version of this article (10.1186/s12870-017-1159-3) contains supplementary material, which is available to authorized users.

In vitro culture represents a tool for the ex situ conservation of a high number of sanitised plants in a reduced space. However, the culture media and/or other growing conditions need to be optimised to minimising plant growth and storage cost. Growth on MW medium was evaluated in the commercial cultivars ‘Airen’, ‘Bobal’, ‘Chardonnay’, ‘Garnacha Blanca’, ‘Moscatel de Alejandria’, ‘Moscatel de Grano Menudo’, ‘Pedro Ximenez’, ‘Pinot Blanc’, ‘Pinot Gris’, ‘Sauvignon Blanc’, and ‘Tempranillo’; the minor cultivars ‘Chelva’, ‘Valenci Negre’, ‘Valenci Blanc’, and ‘Verdil’; and the endangered cv. ‘Esclafacherre’. Different growth rates were observed among cultivars: those with faster growth need to be subcultured every 1.5–2.0 months; those with the slowest growth every 3.5–4.0 months. The effect of halving the sucrose in MW reduced the growth of the cultivars that grew faster without compromising survival. When IBA was removed from MW, growth was also reduced in some cultivars. Therefore, small modific...

In horticulture, grafting is a popular technique used to combine positive traits from two different plants. This is achieved by joining the plant top part (scion) onto a rootstock which contains the stem and roots. Despite its wide use, the biological mechanisms driving rootstock-induced alterations of the scion phenotype remain largely unknown. Given that epigenetics plays a crucial role during distance signalling in plants, we studied the genome-wide changes induced by DNA methylation in eggplant (Solanum melongena) plants grafted onto two interspecific rootstocks used to increase scion vigour. As a control, we compared any epigenetic effect found in such grafts to patterns detected in self-grafted plants. We found that vigour was associated with a specific change in scion gene expression and a genome-wide hypomethylation in CHH context. Interestingly, this hypomethylation correlated with the down-regulation of younger and potentially more active LTR retrotransposons (LTR-TEs), suggesting that graft-induced epigenetic modifications are associated to both physiological and molecular phenotypes in grafted plants. We propose that rootstocks can promote vigour by reducing DNA methylation in the scion genome, following similar principles found in some heterotic hybrids.

Background: The grafting of watermelons (Citrullus lanatus) is a common technique that increases yield under stressful soil conditions. The most common rootstocks for watermelons are Cucurbita hybrids. However, they often have a negative impact on fruit quality. Exploiting novel Citrullus germplasm such as citron melon (Citrullus lanatus var. citroides) is an alternative to avoid these quality problems.; Results: Citron melon has been validated as watermelon rootstock, comparing its effects on watermelon quality to those of Cucurbita hybrids. Larger fruits with thicker rinds were observed in fruits from plants grafted onto both citron and Cucurbita rootstocks. The citron melon had no significant effect on flesh sugars or acid profiles compared to non-grafted watermelons, except for an increase in glucose and malic acid content, which also occurred in the Cucurbita rootstocks. The aroma profile of fruits produced on citron melon was similar to that of the non-grafted and self-grafted controls. The citron rootstock did not display the increased levels of (Z)-6-nonen-1-ol (a compound associated with pumpkin-like odors) found in fruits produced with Cucurbita hybrids.; Conclusion: The low impact of citron melon rootstock on fruit quality, along with the enhanced resistance against nematodes, make the citron a promising alternative to Cucurbita rootstocks. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

We identified a single plant in a grow out of the eggplant (Solanum melongena L.) variety ‘Black Beauty’ bearing green fruit. ‘Black Beauty’ normally produces violet/black pigmented fruit attributed to anthocyanin accumulation. We selected the green-fruited true-breeding genotype E13GB42 from the S2 generation obtained from selfing of the S0 green-fruited color mutant. Characterization of 12 simple sequence repeat (SSR) markers, eight fruit morphological attributes and fruit yield support E13GB42 arising as a spontaneous mutant of ‘Black Beauty’. With the exception of fruit calyx prickliness, E13GB42 was not significantly different from ‘Black Beauty’ for fruit morphological attributes and yield. E13GB42 exhibited an SSR marker profile identical to that of ‘Black Beauty’ but polymorphic with that of eight violet/black-fruited modern eggplant hybrids, older open-pollinated varieties and landraces. Transcript levels of key anthocyanin biosynthetic genes (Chs, Dfr, and Ans) and regulatory genes (MybC, Myc, and Wd) were significantly lower in the green-fruited E13GB42 mutant in comparison with the black-fruited variety ‘Black Beauty’ at various stages of fruit development ranging from small post-anthesis fruit to full-size marketable fruit. Progeny obtained from selfing of the original mutant and reciprocal crosses with ‘Black Beauty’ produced violet, green, and green with violet striped color classes that together were not compatible with one or two gene inheritance models, suggesting that the mutation responsible for the E13GB42 phenotype influences multiple genetic factors that control fruit pigmentation.

[EN] The response of two Citrullus amarus accessions, BGV0005164 and BGV0005167, was assessed against different Meloidogyne arenaria, Meloidogyne incognita, and Meloidogyne javanica isolates in pot experiments and against M. incognita in plastic greenhouse. In the pot experiments, plants were inoculated with a second-stage juvenile per cm(3) of sterile sand and maintained in a growth chamber at 25 degrees C for 50 days. The watermelon cv. Sugar Baby was included as a susceptible control for comparison. At the end of the experiments, the number of egg masses and eggs per plant was determined, and the reproduction index was calculated as the percentage of the number of eggs produced in the C. amarus accessions with regard to that produced in the susceptible cv. Sugar Baby. In the plastic greenhouse experiment, the ungrafted watermelon cv. Sugar Baby and watermelons grafted onto each of the C. amarus accessions and onto the watermelon rootstock cv. Robusta were cultivated from May to August 2016 in plots with nematode densities from 46 to 1392 J2 per 250 cm(3) of soil at transplantation. At the end of the experiment, the galling index and the number of eggs per plant were determined, and the reproduction index was calculated. Additionally, the compatibility of the two accessions with the watermelon cv. Sugar Baby and the effect on fruit quality (weight, size, shape, firmness, pH, total soluble solids, and flesh color) were assessed under a hydroponic system in a greenhouse. The commercial rootstocks cv. Cobalt and cv. Robusta were also included. All the Meloidogyne isolates produced less egg masses and eggs per plant on the accessions than on Sugar Baby. Both accessions performed as resistant against M. arenaria, and from highly to moderately resistant to M. incognita and M. javanica in pot experiments. In the plastic greenhouse experiment, both C. amarus accessions performed as resistant to M. incognita. Both C. amarus accessions were compatible with the watermelon cv. Sugar Baby, but only the BGV0005167 accession did not influence the fruit quality. Then, the BGV0005167 accession is a promising rootstock for managing the three tropical root-knot nematode species without influencing watermelon fruit quality., The authors thank MINECO and FEDER for funding projects AGL2013-49040-C2-1-R, AGL2014-53398-C2-2-R-AR, AGL2017-89785-R, and AGL2017-85563-C2-1-R-AR. H. A. Garcia-Mendivil acknowledges CONACYT for suport through a pre-doctoral grant.

[EN] Organogenesis is influenced by factors like genotype, type of explant, culture medium components, and incubation conditions. The influence of ethylene, which can be produced in the culture process, can also be a limiting factor in recalcitrant species like pepper. In this work, bud induction was achieved from cotyledons and hypocotyls-from eight pepper cultivars-on Murashige and Skoog (MS) medium supplemented with 22.2 mu M 6-benzyladenine (6BA) and 5.71 mu M indole-3-acetic acid (IAA), in media with or without silver nitrate (SN) (58.86 mu M), a suppressor of ethylene action. In the SN-supplemented medium, the frequencies of explants with buds and with callus formation were lower in both kinds of explant, but higher numbers of developed shoots were isolated from explants cultured on SN. Bud elongation was better in medium with gibberellic acid (GA(3)) (2.88 mu M) than in medium free of growth regulators or supplemented with 1-aminocyclopropane-1-carboxylic acid (ACC) at 34.5 mu M. However, isolation of shoots was difficult and few plants were recovered. The effect of adding SN following bud induction (at 7 d) and that of dark incubation (the first 7 d of culture) was also assessed in order to improve the previous results. When SN was added after bud induction, similar percentages of bud induction were found for cotyledons (average frequency 89.37% without SN and 94.37% with SN) whereas they doubled in hypocotyls (50% without SN and 87.7% with SN). In addition, in both kinds of explant, the number of developed plants able to be transferred to soil (developed and rooted) was greatly increased by SN. Dark incubation does not seem to improve organogenesis in pepper, and hypocotyl explants clearly represent a better explant choice-with respect to cotyledonary explants-for the pepper cultivars assayed., We thank the COMAV germplasm bank at Universitat Politecnica de Valencia and the Arid Lands Institute for pepper seeds and the Tunisian Ministry of Higher Education and Scientific Research who fund N. Gammoudi's stay.

[EN] Background: A protocol for the micropropagation of the grape (Vitis vinifera L.) cultivar 'Monastrell' was developed. Initial plant material was obtained from the sanitary selection of grapevine plants performed by real-time RT-PCR to confirm the absence of Grapevine fanleaf virus, Arabis mosaic virus, Grapevine leafroll-associated virus 1, Grapevine leafroll-associated virus 3, and Grapevine fleck virus. Results: The effects of the salt composition (comparing Lloyd and McCown woody plant medium and Murashige and Skoog medium 1/2 macronutrients) and the growth regulator benzylaminopurine (BAP), at 0 and 8.9 mu M, on plant propagation were evaluated using nodes as explants. The most efficient procedure consisted of bud induction in the medium with Lloyd and McCown woody plant salts and 8.9 mu M BAP for 30 d along with elongation in cytokinin-free medium for 60 d, which gave 22 nodes/explant (174 plants/initial plant). A second cycle of propagation in a medium without BAP for another 60 d could give approximately 10,000 nodes, which can be obtained after an additional 2 months of culture. All plants acclimatized after the second cycle of multiplication were successfully transferred to soil. Conclusion: We developed an optimal protocol for V. vinifera cv. 'Monastrell' micropropagation, the first described for this cultivar. (C) 2017 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B. V. All rights reserved., The study was supported by the projects RTA2011-00067-C04, RTA2014-00061-C03, and PRP-CGL2015-70843-R, all co-funded with FEDER Funds. Tania San Pedro has a grant (01/14-FSE-22) supported by the Instituto Valenciano de Investigaciones Agrarias.

The accession Solanum peruvianum PI 126944 has been reported as resistant to different biotic and abiotic stresses. In previous works of the group, advanced generations were derived from two interspecific hybrids, including up to pseudo-F6 generations and backcrosses to the cultivated species of some of the pseudo-Fn generations. Moreover, resistance to Tomato yellow leaf curl virus (TYLCV) and Tomato spotted wilt virus (TSWV) was confirmed in some of the plant materials obtained. Here we describe the development of some advanced backcross generations between the cultivated tomato and S. peruvianum. Three backcross assays were carried out. In the first assay, 16 plants belonging to pseudo-F4, pseudo-F5 and pseudo-F6 generations were backcrossed as male parents to cultivated tomato. Immature seeds from the 408 fruits obtained were platted and 77 plants were regenerated. A total of 21 descendants obtained in the first assay were backcrossed as male parents in the second assay, which allowed the obtaining of 599 fruits and regeneration of 365 plants. The 19 male parents used in the third assay were obtained either in the first or in the second one. Seventeen of them were obtained in the first assay and two in the second. A total of 339 plants were regenerated from 519 fruits. A high number of the plants obtained in these assays has been acclimated. Some plants set fruits with viable seeds.

[EN] Cultivation of Cucumis melo is hampered by soil stresses. Grafting is used to overcome these limitations. Different cucurbits belonging to several genera have been used as rootstocks for melons: Cucurbita, Lagenaria, Luffa, etc. However, negative effects on fruit quality appear in some rootstock-scion combinations. The selection of new resistant rootstocks that do not cause this negative impact in quality is necessary to improve melon cultivation. In this work, we evaluated two rootstocks, closer genetically to melon scions than those usually employed: a) an F1 hybrid between a commercial melon (C. melo subspecies melo var inodorus market class Piel de Sapo) and one exotic accession (C. melo subspecies agrestis var. chinensis) with resistance to Monosporacus cannonballus, the causal agent of melon vine decline, and with a certain level of tolerance to Fusarium oxysporum f sp. melonis race 1.2, that causes Fusarium wilt, and b) an accession of Cucumis metuliferus, highly resistant to M. cannonballus, F. oxysporum 1.2 and evaluated and classified as highly resistant to Meloidogyne spp. in this work. Grafting compatibility of these two selected genotypes with commercial melons was good. All grafted plants displayed higher vigour and earlier flowering than ungrafted plants. Fruits from plants grafted onto C. metuliferus showed similar quality than those from ungrafted/selfgrafted plants. However, fruits from plants grafted onto the F1 (inodorus x chinensis) had in this experiment lower brix degree than the ungrafted controls. The resistance to soil borne pathogens found in C. metuliferus and the good performance regarding plant development and fruit quality of the scions indicate that this species is a promising rootstock for melons., C. Gisbert and B. Pico thanks the Programa Hispano-Brasileno de Cooperacion Universitaria PHBP14/00021. Authors also thank the MINECO projects AGL2013-49040-C2-1-R, and AGL2014-53398-C2-2-R, cofunded with FEDER funds.

[EN] Introduction. Interest in grafting onto rootstocks resistant to soil-borne pathogens has risen since the phasing-out of methyl bromide, an efficient soil disinfectant. In this study, we have evaluated the putative effect of rootstock¿scion combinations on pepper fruit nutritional quality in relation to grafting, an effect that is sometimes overlooked. Materials and methods. As the scions, we used two representative sweet pepper cultivars, `Almuden¿ and `Coyote¿, and as rootstocks `Foc¿ and `Charlot¿, both resistant to Phytophthora capsici and Meloidogyne incognita. Dry matter, soluble solids, proteins, phenolics, and vitamin C content, as well as eight minerals (P, K, Ca, Mg, Na, Fe, Cu, and Zn) were measured in fruits from non-grafted, self-grafted, and grafted plants. Results and discussion. Differences in the fruit composition were found, depending on the genotype, rootstock, or rootstock¿scion combination. The main effects were as follows. Higher values of ¿Brix, phenolics, P, Mg, and Na were found in the fruit of `Coyote¿ whereas the vitamin C and Fe levels were higher in `Almuden¿ fruit. The dry matter, protein, and K concentrations were higher in the fruit from grafted plants with respect to the values from non-grafted plants, especially in the fruit from plants grafted onto `Charlot¿ and `Foc¿ rootstocks (increases of 11.8%, 17.6%, and 9.6%, respectively; when average values of the four combinations of these rootstocks). Fruit from `Almuden¿ and `Coyote¿ plants grafted onto the rootstock `Foc¿ had lower ¿Brix values (about one degree less than the control) and lower values of phenolics were also obtained when used this rootstock (14.4% less than for the control). On the other hand, the P concentration was higher in the fruit of `Coyote¿ grafted onto `Charlot¿ (17.2% higher than for the control). This combination also exhibited the highest fruit K concentration (226.70 mg 100 g¿1 fresh weight). Conclusion. From a nutritional point of view it is important to evaluate and select the best rootstock¿scion combinations: in our assay, this was `Charlot¿¿`Coyote¿ the fruit of which showed the highest ¿Brix and K, P, and protein concentrations., This work was funded by the Fundacion Agroalimed (supported by the Valencian regional government - the Comunidad Valenciana). We thank Dr. David Walker for the revision of the written English in the manuscript

[EN] Genetic variability is needed to face environmental changes and pathogen constrains. In addition, the search for intravarietal variability contributes to the avoidance of genetic erosion, preserving clones that are adapted to particular conditions. Variability is also important to diversify grapevine-derived products. In this work, we have analyzed the genetic variability of `Muscat germplasm¿ including samples from neglected vineyards from Alicante and Valencia provinces, accessions of the germplasm collections of `Colección de Vides de El Encín¿ (Alcalá de Henares, Madrid) and `La Casa de las Vides¿ (Agullent, Valencia), accessions supplied by nurseries of Valencia province, and `Muscat of Alexandria¿ clones selected using differential ampelographic characteristics in selection programs (La Marina, Alicante). Fifteen microsatellites (SSRs) were used to study intervarietal variability. The SSR fingerprinting allowed the identification of some accessions, variants, and synonymies. Amplified Fragment Length Polymorphisms (AFLPs) markers and Microsatellite-AFLPs were used to determine the variability attended in `Muscat of Alexandria¿ accessions. A CAPs (Cleaved Amplified Polymorphic Sequences) marker, recently developed for the discrimination of `Muscat¿ flavor genotypes using the SNP1822 G>T, was assessed and showed that all the analyzed accessions were `Muscat¿ flavored. The variation found among the analyzed germplasm is very interesting because variants within `Muscat of Alexandria¿, `Muscat Italia¿, and `Muscat d¿Istambul¿ have been identified. In addition, intravarietal genetic variation was found among the analyzed accessions in `Muscat of Alexandria¿ from selection programs., MINECO and FEDER Funds (project CGL2015-70843-R); Conselleria d'Agricultura, Pesca i Alimentacio, Generalitat Valenciana, Spain (project 2007TAHALI00073)