Polyacetylenes Bearing Chiral-Substituted Fluorene and Terfluorene Pendant Groups: Synthesis and Properties

The synthesis of the first polyacetylenes bearing chiral fluorene-based pendant groups is described. Poly{9,9-bis[(S)-3,7-dimethyloctyl]fluoren-2-ylacetylene} (PFA1), poly{9,9-bis[(S)-2-methylbutyl]- fluoren-2-ylacetylene} (PFA2), and poly{9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluoren- 2-ylacetylene} (PFA3) have been obtained by Rh(I)-catalyzed polymerization of the corresponding terminal acetylene monomers 2-ethynyl-9,9-bis[(S)-3,7-dimethyloctyl]fluorene (2a), 2-ethynyl-9,9-bis[(S)-2-methylbutyl]fluorene (2b), and 2-ethynyl-9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluorene (10). The effect of the alkyl chain length at the C-9 position of fluorene on the structural and conformational aspects of the polymers PFA1 and PFA2 as well as on their chiroptical properties was studied by XRD, DSC, TGA, GPC, UV-vis, and CD. A more planar conformation of the polyenic backbone of PFA1 with respect to PFA2 can be inferred by a red shift of the ð-ð* transition in the UV-vis spectra. Their photoluminescence properties are those typical of fluorene systems. CD measurements evidenced Cotton effects of opposite signs in correspondence of the backbone absorption region, ascribable to an excess of a screw sense of the helical conformations assumed by the two polymers. PFA3 revealed an amorphous structure and exhibited peculiar thermal stability features (as indicated by TGA and DSC). Its emission spectra interest the violet-blue region and do not show any substantial red shift passing from solution to solid state, thus pointing out an aggregation prevention of terfluorene groups by means of the polyacetylene backbone

Detecting somaclonal variation during micropropagation of vine rootstocks using SSR molecular marker and flow cytometery analysis.

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Detecção de Grapevine vírus A no Vale do Sirigi, Zona da Mata de Pernambuco.

Iniciando-se um levantamento e caracterização de vírus, foram coletados ramos de videira das cvs. Isabel, de cultivos tradicionais, Isabel Precoce, Niágara Rosada e Patrícia em São Vicente Férrer, dos quais foram extraídos RNAs total e analisado com um kit One Step RT-PCR com primers específicos para, Grapevine virus A (GVA), Grapevine virus B, Grapevine fanleaf virus e Grapevine leafroll- associated virus-3

Estimates of genetic parameters and the selection of table grape hybrids in semiarid regions of Brazil.

The objective of this study was to estimate the repeatability coefficients, optimal number of harvests, and genetic gains and to select superior hybrids of table grapes for the development of cultivars adapted to semiarid conditions in Brazil. The mixed model methodology REML/BLUP was used to estimate the variance components and predict the genotypic values. Two hundred table grape hybrids were evaluated during six harvests at the Mandacaru Experimental Field in Embrapa Semiárido, Juazeiro, Bahia, Brazil. The experiment was implemented in the absence of an experimental design, with a single individual of each genotype. Twelve quantitative morphoagronomic variables were evaluated. The repeatability coefficients were as follows: 0.20 (yield), 0.18 (number of bunches), 0.37 (bunch length), 0.30 (bunch width), 0.47 (bunch weight), 0.60 (berry length), 0.68 (bunch diameter), 0.70 (berry weight), 0.14 (soluble solids content) and 0.13 (ratio). The accuracies obtained by performing m repeated measurements revealed that for berry characteristics, only one measurement was sufficient; two measurements were required for the length and weight of the bunch; three measurements were required for the bunch width; four measurements were required for the yield and five measurements for the number of bunches; for the soluble solids content and ratio, seven and six measurements were needed, respectively. Individual genotypic selection allows high genetic gains for bunch and berry traits and satisfactory gains for quality traits. In addition, three superior genotypes (?BRS Tainá?, CPATSA 05.168 and CPATSA 79.100) wereidentified for eight traits simultaneously, with ?BRS Tainá? being identified as an apyrenic cultivar

Multitrait selection in seedless grape hybrids in semiarid regions of Brazil.

The absence of seeds has been one of the most valued traits in grapes (Vitis spp.) for fresh consumption. However, the simultaneous selection of superior genotypes for multiple traits is complex. The objective of this study was to select genotypes of superior seedless table grapes in semiarid regions of Brazil. Multiple traits were considered by using the factor analysis and genotype?ideotype best linear unbiased prediction (FAI-BLUP) selection index. A total of 110 grape progenies from 24 crosses were evaluated for traits of agronomic interest. Each hybrid was represented by a single vine plant, without experimental design or repetition. The mixed-model methodology was used to predict the breeding values. The FAI-BLUP index was used to select superior genotypes based on factor analysis and the genotype?ideotype distance. Four factors explained the 11 characteristics studied, with a variability of 81.84%. Desirable gains were observed for 10 of the 11 traits evaluated. The FAI-BLUP index allowed the selection of superior seedless table grape hybrids, which can be used in the genetic improvement of grapevines. In conclusion, we report the selection of seedless table grape hybrids for our study to advance in the table grape breeding program in Brazilian semiarid regions.On-line

Evaluation of grapevines for resistance to downy mildew (Plasmopara viticola) under greenhouse conditions.

Grapevine downy mildew, caused by the fungus Plasmopara viticola is a disease with a great economic impact on grapevine in the Brazil. The objective of this study was to evaluate resistance to downy mildew in seedless grapevine hybrids and one susceptible cultivar ?Thompson Seedles? using natural infection (cross-contamination) and artificial inoculation method under greenhouse conditions. The experiments were performed at Embrapa Semiarid, Petrolina, Pernambuco, Brazil. The first used natural infection from plants with diseased vines, and the second artificial infection in which plants were sprayed with a spore suspension with a concentration of 105 conidia mL-1. The evaluated variables were final incidence, final severity, area under the curve of disease incidence progression and area under the curve of disease severity progression. All evaluated genotypes showed symptoms of downy mildew. The CPATSA 28.14 genotype presented the lowest values of final severity, final incidence, area under the disease severity progress curve and area under the disease incidence progress curve in both experiments. Therefore, the CPATSA 28.14 genotype was identified as having greater resistance to grapevine downy mildew. Clustering by the unweighted pair grouping method using arithmetic averages (UPGMA) resulted in the separation of the genotypes into three and two similarity groups in Experiments I and II, respectively, indicating low diversity among the grapevine hybrids evaluated.On line

Comparação entre ELISA e RT-PCR na detecção de vírus em parreirais no Nordeste do Brasil.

Resumo apresentado de número 604-1