890 research outputs found
Study and parentage analysis of old Albanian grapevine cultivars by ampelography and microsatellite markers
The number of old grapevine cultivars in Albania, originated in the country or introduced over many centuries and adapted to the conditions of the country, is huge. Because numerous cases of homonymy and synonymy exist, the interest for variety recognition is high. Investigation of these cultivars aptitudes is related to identification of desired characteristics and their utilization. In the framework of COST Action FA1003, trueness to type assessment of 13 old Albanian cultivars was undertaken including morphologic description and genetic fingerprinting. Parentage relationships were studied as well. The selected cultivars are of interest for their antiquity, for high production and distinctive organoleptic features. The ampelographic study of these cultivars supported confirmation of the results obtained by genetic profile comparison with seven SSR-marker databases and the European Vitis Database. In summary 12 unique genotypes, four parent-offspring relationships and one full parentage were found
The "missing link" 'Blaue Zimmettraube' reveals that 'Blauer Portugieser' and 'Blaufränkisch' originated in Lower Styria
Parent offspring analysis already revealed genetic relationships for 'Blauer Portugieser' and 'Blaufränkisch', sharing at each locus one allele with 'Grüner Silvaner' and 'Weisser Heunisch', respectively. The missing second progenitor of 'Blauer Portugieser' and 'Blaufränkisch' is a recently rediscovered black grapevine, called 'Blaue Zimmettraube'. It was found in the largest German wine growing area Rheinhessen. The same cultivar was detected as a single vine in Friuli, Italy and named Sbulzìna. The 'Blaue Zimmettraube', bearing female flowers, and thus the female parent in the crosses, was cultivated in the 19th century in Lower Styria together with 'Grüner Silvaner' and 'Weisser Heunisch'. Because the 'Blaue Zimmettraube' did not exist in Austria and red wine production was fairly rare in that country before 1800, it is suspected that the cradle of 'Blauer Portugieser' and 'Blaufränkisch' is in Lower Styria. Furthermore, according to chlorotype analysis, it turned out that 'Blauer Gänsfüsser' is the male parent of 'Blaue Zimmettraube' and thus the 'Blaue Zimmettraube' represents a veritable "missing link". To prove the genetic relationships the nine GrapeGen06-markers and additional forty microsatellite markers were applied. Likelihood analysis with allele frequencies of 22 SSR-markers from 772 cultivars revealed a very high degree of probability that the proposed parents are consistent, due to rare alleles inherited from 'Blaue Zimmettraube'. To investigate on the geographical origin of 'Blauer Portugieser' and 'Blaufränkisch' historical Austrian and Styrian references were consulted
Pre-selectable integer quantum conductance of electrochemically fabricated silver point contacts
The controlled fabrication of well-ordered atomic-scale metallic contacts is
of great interest: it is expected that the experimentally observed high
percentage of point contacts with a conductance at non-integer multiples of the
conductance quantum G_0 = 2e^2/h in simple metals is correlated to defects
resulting from the fabrication process. Here we demonstrate a combined
electrochemical deposition and annealing method which allows the controlled
fabrication of point contacts with pre-selectable integer quantum conductance.
The resulting conductance measurements on silver point contacts are compared
with tight-binding-like conductance calculations of modeled idealized junction
geometries between two silver crystals with a predefined number of contact
atoms
A view into American grapevine history: Vitis vinifera cv. 'SĂ©millon' is an ancestor of 'Catawba' and 'Concord'
The Vitis vinifera background of 'Catawba' and 'Concord' was investigated by using SSR analysis: 'SĂ©millon' was shown to be an ancestor of 'Catawba', while the wild parent remains unknown. 'Concord' was confirmed to be an offspring of 'Catawba' and another unknown wild parent. Since these two important American varieties most likely resulted from random natural crosses and successful selection, the original, wild growing wild donors remain unknown
Deepening inside the homonyms of 'Wildbacher' by means of SSR markers
Sixteen accessions of the grapevine cultivar 'Wildbacher' coming from different European repositories and from Styrian and Italian private vineyards were analysed by genetic fingerprinting with SSR markers. Five different molecular profiles were found, confirming that the name 'Wildbacher' is commonly used as a homonym. Several new genotypes could be linked to the previous list of the 'Wildbacher' family. In particular, in Italian commercial vineyards two main 'Wildbacher' varieties defined by A and B genetic profiles were found. They correspond to the two reference genotypes from Styria, 'Wildbacher Blau' ('Blauer Wildbacher)' and 'Wildbacher Spätblau'. In both countries 'Wildbacher Blau' represents the most spread and better performing type and it is earlier ripening compared to 'Wildbacher Spätblau'. They were morphologically and genetically very similar to each other and they shared at least one allele at each of the 11 SSR loci analyzed for cultivar identification. Three different other 'Wildbacher' genotypes from a German collection were identified as individual cultivars. While 'Rotblättriger' (genotype C) and 'Frühblau' from Germany (genotype D) showed some genetic similarity with A and B genotypes, E 'Wildbacher', coming from Hungary, proved to have a distinct genetic profile. Close relationship to the key variety (for the development of European diversity) 'Heunisch' is indicated by sharing one allele at all loci investigated so far. There exist some indications that the second parent is an extinct wild vine. Evaluation of morphological parameters resulted in some differences among all five genotypes.
Calculation of the Infrared Intensity of Crystalline Systems. A Comparison of Three Strategies Based on Berry Phase, Wannier Function, and Coupled-Perturbed Kohn–Sham Methods
Three
alternative strategies for the calculation of the IR intensity
of crystalline systems, as determined by Born charges, have been implemented
in the Crystal code, using a Gaussian type basis set. One
uses the Berry phase (BP) algorithm to compute the dipole moment;
another does so, instead, through well localized crystalline orbitals
(Wannier functions, WF); and the third is based on a coupled perturbed
Hartree–Fock or Kohn–Sham procedure (CP). In WF and
BP, the derivative of the dipole moment with respect to the atomic
coordinates is evaluated numerically, whereas in CP it is analytical.
In the three cases, very different numerical schemes are utilized,
so that the equivalence of the obtained IR intensities is not ensured
a priori but instead is the result of the high numerical accuracy
of the many computational steps involved. The main aspects of the
three schemes are briefly recalled, and the dependence of the results
on the computational parameters (number of k points
in reciprocal space, tolerances for the truncation of the Coulomb
and exchange series, and so on) is documented. It is shown that in
standard computational conditions the three schemes produce IR intensities
that differ by less than 1%; this difference can be reduced by an
order of magnitude by acting on the parameters that control the accuracy
of the calculation. A large unit cell system (80 atoms per cell) is
used to document the relative cost of the three schemes. Within the
current implementation the BP strategy, despite its seminumerical
nature, is the most efficient choice. That is because it is the oldest
implementation, and it is based on the simplest of the three algorithms.
Thus, parallelism and other schemes for improving efficiency have,
so far, been implemented to a lesser degree in the other two cases
In-situ Mössbauer Spectroscopy with MIMOS II at Rio Tinto, Spain
The Rio Tinto, located in southwest Spain, exhibits a nearly constant, acidic pHvalue along its course. Due to the formation of sulfate minerals, Rio Tinto is considered a potential analogue site for sulfate-rich regions on Mars, in particular at the landing site of the Mars Exploration Rover Opportunity, where the ferric sulfate mineral jarosite was identified with Opportunity's Mössbauer spectrometer. Primary and secondary mineralogy was investigated in situ with portable Raman and Mössbauer spectrometers at four different Rio Tinto sampling sites. The two techniques analyse different sample portions due to their specific field of view and sampling depth and provide complementary mineralogical information
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