Different susceptibility of European grapevine cultivars for downy mildew

Downy mildew, caused by the obligately biotrophic peronosporomycete Plasmopara viticola, is one of the most destructive of grapevine diseases that occurs worldwide. The classical cultivars of Vitis vinifera, up to date utmost important for wine and table grape production, are all susceptible to P. viticola, resulting in severe epidemics under warm and humid conditions. The aim of our present study was to characterize the susceptibility to infection by P. viticola among different grapevine cultivars grown in European vineyards in comparison to resistant Vitis species. For this purpose we inoculated leaf discs, leaves and whole plants of eight V. vinifera cultivars considered to be susceptible ('Albariño' [Clone1, Clone2 and Clone3], 'Tempranillo', 'Touriga Nacional', 'Riesling', 'Pinot Noir', 'Pinot Blanc', 'Müller-Thurgau' and 'Cabernet Sauvignon') with P. viticola under controlled conditions. Four Vitis genotypes with a distinct degree of resistance to P. viticola (V. riparia, V. rupestris, V. amurensis and the hybrid Vitis x vinifera 'Solaris') were used as resistant and partially resistant references. To assess the degree of susceptibility we scored the disease incidence and severity visually and microscopically analyzed the course of host tissue colonization by the pathogen. The microscopical studies indicated even slight differences in the infection rate, the course of host tissue colonization and the parasitation i.e. haustoria formation, among the V. vinifera cultivars. The obtained data were suitable for statistical analysis that showed significant differences in the assessed parameters among the V. vinifera cultivars. The principal component analysis (PCA) of the data revealed three groups of susceptibility:genotypes which are little susceptible, e.g. 'Cabernet Sauvignon', 'Pinot Blanc', 'Pinot Noir', 'Müller-Thurgau' and 'Riesling';a second group formed by those genotypes which are very susceptible, i.e. the two clones of 'Albariño' (the most susceptible of all) and 'Tempranillo'; anda third group comprising the genotypes used as resistant and partially resistant references (V. riparia, V. rupestris, V. amurensis and the hybrid Vitis x vinifera 'Solaris').Within the first group 'Cabernet Sauvignon' formed a subgroup indicating a very low susceptibility to P. viticola. In this work, for the first time the visual assessment of disease incidence and severity with a microscopical analysis of infection intensity, colonization of host tissue and parasitation to discriminate differences in susceptibility of European V. vinifera cultivars for P. viticola was combined.

Variation in Sensitivity of Different Grapevine Genotypes to Erysiphe necator Growing under Unfavourable Climatic Conditions

This paper reports the susceptibility to powdery mildew of 41 grapevine genotypes growing in the north and northwest of Spain over a three-year period. Although the humid climate of these vine-growing areas is not particularly favourable to the development of this disease, serious damages appears in some years when dry weather alternates with times of some rain. All the examined genotypes belonged to the collection of the Misión Biológica de Galicia (CSIC) (Pontevedra, Galicia, Spain). The incidence and severity of powdery mildew were determined on leaves three weeks after the onset of flowering and on clusters at harvest. The values for both variables were smaller than those recorded for other fungal diseases, although great differences in susceptibility between the different genotypes were observed. The most susceptible was Castañal (recently included in the Spanish Registry of Commercial Varieties), a genotype native to the O Rosal subzone of the Rias Baixas denomination of origin area. The present results could help viticulturalists grow different grapevine genotypes more successfully in regions with climatic conditions similar to those where the study was undertaken

Evaluation of foliar resistance to downy mildew in different cv. Albariño clones

Resistance to downy mildew was studied in different Vitis vinifera L. cv. Albariño clones belonging to the collection of the Mision Biológica de Galicia, CSIC (Spain). V. riparia, V. vinifera cv. Solaris and V. vinifera cv. Müller-Thurgau were used as controls. Plants were inoculated with Plasmospora viticola in the laboratory using the leaf disc, whole leaf and whole plant techniques. The results were compared with those obtained in the field for the same Albariño clones. The most susceptible group of clones included MBG-2, MBG-14, MBG-12 and MBG-9, while MBG-13, MBG-3 and MBG-6 formed the most resistant group. The remaining clones showed intermediate resistance. These results coincide with observations made in the field. The resistance observed in MBG-12 could have been generated from in vitro culture, because this induces changes in the downy mildew resistance.

La caracterización molecular y ampelográfica de clones de "Albariño", "Savagnin Blanc" y "Caíño Blanco" (Vitis vinifera L.) demuestra que son cultivares diferentes

The grapevine cultivar "Albariño" is one of the oldest grown in the vine-growing areas of North-Western Spain and Northern Portugal. Since recognition of Origin Denomination status for the Rías Baixas region (the coast of Western Galicia, Spain) in 1987, the economic importance of this cultivar has increased, and its grapes are now among the most expensive in Spain. The area occupied by "Albariño" vines in this region is increasing every year, and the wines made from its grapes are gaining international recognition. These events, plus the fact that "Albariño" was little known outside its traditional growing area, have led to speculation about its origin and the existence of synonyms. Misnames of "Albariño" have included "Savagnin Blanc" and "Caíño Blanco". The present work compares "Albariño", "Savagnin Blanc" and "Caíño Blanco" ampelographically (i.e., it compares shoot, leaf, grape cluster, berry and seed characteristics) and molecularly using microsatellite markers. The results show that they are in fact three different cultivars providing a complete description. For "Caíño Blanco", there is little previously reported information.El "Albariño" es uno de los cultivares más antiguos de la zona vitícola del Noroeste de España y norte de Portugal. Desde la aprobación en el año 1987 de la Denominación de Origen Rías Baixas, este cultivar es el de mayor valor económico de esta zona vitícola, y su uva alcanza uno de los precios más elevados de España. Su superficie de cultivo, dentro de esta Denominación de Origen, se multiplica año tras año, y sus vinos adquieren fama internacional. Todo ello, unido a que era un cultivar poco conocido fuera de esta pequeña zona vitícola española, ha llevado a la aparición en los últimos años de diversas especulaciones sobre su origen, y a la atribución de diferentes sinonimias. Entre los nombres erróneamente atribuidos al "Albariño" se encuentran "Savagnin Blanc" y "Caíño Blanco". En el presente trabajo se hace un estudio comparativo de los tres cultivares a nivel ampelográfico (brote, hoja, racimo, baya, semilla) y a nivel molecular por medio de marcadores microsatélite. Los resultados demuestran que "Albariño", "Savagnin Blanc" y "Caíño Blanco" son cultivares distintos, proporcionando una completa descripción de cada uno. De uno de ellos, "Caíño Blanco", existe muy poca información previa

Variability of the stomata among 'Albariño' (Vitis vinifera L.) clones and its relationship with susceptibility to downy mildew

Research Note

Reconciling multiple societal objectives in cross-scale marine governance: Solomon Islands’ engagement in the Coral Triangle Initiative

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Environmental governance aims to reconcile an expanding set of societal objectives at ever-larger scales despite the challenges that remain in integrating conservation and development at smaller scales. We interrogate Solomon Islands’ engagement in the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security to contribute new insight on the scalar politics of multi-level marine governance. We show how regional objectives are re-interpreted and prioritized as they translate into national policy and practice. Our data suggest that enhanced coordination of finances and activities, integration of objectives in shared protocols and priority geographies, and a subtle shift in power relations between the state, donors, and implementation partners have resulted from processes of re-scaling. We discuss important procedural adjustments in cross-level and cross-scale governance across jurisdictional, institutional, and sectoral scales. We also reflect on the changing role of national governments in shifts toward large-scale, multi-national initiatives.LE acknowledges funding from the Australian Research Council Centre of Excellence for Coral Reef Studies. PJC and DB undertook this work as part of the CGIAR Research Program on Fish Agrifood Systems (FISH). Funding support for this study was provided by an Australian Centre for International Agricultural Research grant (FIS/2012/074)

Complete quantum control of exciton qubits bound to isoelectronic centres

In recent years, impressive demonstrations related to quantum information processing have been realized. The scalability of quantum interactions between arbitrary qubits within an array remains however a significant hurdle to the practical realization of a quantum computer. Among the proposed ideas to achieve fully scalable quantum processing, the use of photons is appealing because they can mediate long-range quantum interactions and could serve as buses to build quantum networks. Quantum dots or nitrogen-vacancy centres in diamond can be coupled to light, but the former system lacks optical homogeneity while the latter suffers from a low dipole moment, rendering their large-scale interconnection challenging. Here, through the complete quantum control of exciton qubits, we demonstrate that nitrogen isoelectronic centres in GaAs combine both the uniformity and predictability of atomic defects and the dipole moment of semiconductor quantum dots. This establishes isoelectronic centres as a promising platform for quantum information processing

Macro- and microscopic leaf characteristics of six grapevine genotypes (Vitis spp.) with different susceptibilities to grapevine downy mildew

This work reports the leaf morphology of six grapevine genotypes, five belonging to Vitis vinifera and one to Vitis riparia. Earlier studies on these genotypes showed different levels of susceptibility to grapevine downy mildew (Plasmopara viticola). The aim of this work was to detect differences between the leaf morphology of these cultivars at the macro- and microscopic levels, and to characterize morphological traits which could be associated with susceptibility and resistance to downy mildew. An ampelographic description of each genotype was used to develop a scheme illustrating the characteristic leaf morphology. The density and morphology of the trichomes and the stomatal index was assessed by means of microscopical techniques. Distinct macro and microscope differences among the genotypes were seen. No clear relation between ampelographic characteristics and susceptibility to downy mildew was observed. The two cultivars that in earlier studies were found to be the least susceptible to downy mildew were the most similar in terms of their spongy mesophyll. Both showed very little or no wax on the abaxial surface of their leaves.

Characterisation and identification of grapevine cultivars (Vitis vinifera L.) from northwestern Spain using microsatellite markers and ampelometric methods

Nine grapevine varieties from northwestern Spain (8 commonly known as types of Caíño and one as Tinta Femia) were characterised by constructing their typical ‘mean leaves’ and by determining their genetic profiles with respect to 6 microsatellite markers. Leaf morphologies were compared and the similarities between the cultivars were determined. Thirty three alleles were detected at the 6 microsatellite loci analysed. The different cultivars were successfully identified by both methods. In combination, the different techniques provide a more complete variety characterisation. Synonymy between these and other Spanish and Portuguese cultivars is discussed.

Memory effect in silicon time-gated single-photon avalanche diodes

We present a comprehensive characterization of the memory effect arising in thin-junction silicon Single-Photon Avalanche Diodes (SPADs) when exposed to strong illumination. This partially unknown afterpulsing-like noise represents the main limiting factor when time-gated acquisitions are exploited to increase the measurement dynamic range of very fast (picosecond scale) and faint (single-photon) optical signals following a strong stray one. We report the dependences of this unwelcome signal-related noise on photon wavelength, detector temperature, and biasing conditions. Our results suggest that this so-called "memory effect" is generated in the deep regions of the detector, well below the depleted region, and its contribution on detector response is visible only when time-gated SPADs are exploited to reject a strong burst of photons