Eva Choer

Divergência genética entre populações de cebola com base em marcadores morfológicos

Bulbs of 16 acessions from Onion Gene Bank of Embrapa Clima Temperado were evaluated for weight, diameter, length, skin color, shape, uniformity, and post harvest conservation in Pelotas, RS, Brazil. The objective of this work was to estimate genetic divergence in onion populations. The obtained data were submitted to principal component and cluster analysis. There was genetic variability for evaluated traits. Acessions were separated in three clusters. One cluster had 13 populations including all landraces and cultivars with brown skin color; the second cluster had the landrace with violet bulbs; and the third cluster had the two cultivars with white bulbs. Skin color, weight and post harvest of bulbs showed the highest contribution to divergence among acessions.

Eficiência de coeficientes de similaridade em genótipos de feijão mediante marcadores RAPD

O objetivo deste trabalho foi avaliar a eficiencia de coeficientes de similaridade em genotipos de feijao por meio de marcadores RAPD. A eficiencia dos coeficientes de similaridade de Jaccard, Sorensen-Dice, Russel e Rao, Ochiai, Coincidencia Simples, Rogers e Tanimoto, Hamann, Kulczynski 2, Yule e Phi no agrupamento de 35 cultivares locais e comerciais de feijao foi analisada com base em 104 marcadores RAPD. Os coeficientes foram comparados por dendrogramas, pela eficiencia da projecao no espaco bidimensional e por grupos formados pelo metodo de otimizacao de Tocher. Os diferentes coeficientes de similaridade apresentaram variacao quanto a eficiencia de projecao no espaco bidimensional e quanto ao numero de grupos formados pelo metodo de otimizacao de Tocher. Os coeficientes de Russel e Rao e de Yule sao os mais discordantes, e os coeficientes de Sorensen-Dice, Ochiai e Kulczynski 2 sao mais eficientes que os demais. O coeficiente de Russel e Rao nao tem a capacidade de agrupar as cultivares em seus respectivos centros de domesticacao.

Diversidade genética em cultivares locais e comerciais de feijão baseada em marcadores RAPD

Abstract – The objective of this work was to characterize the genetic diversity within and amongcultivars and landraces of common bean from RAPD markers analysis, and to evaluate the capacity ofthis markers in clustering common bean genotypes according to domestication centers and seed color.Thirty five common bean genotypes including 13 commercial cultivars and 22 landraces, from State ofRio Grande do Sul, Brazil, were evaluated. Genetic distances were calculated using Sorensen-Dice’ssimilarity coefficient, displayed in a dendrogram. RAPD markers were efficient in separating cultivarsand landraces according to domestication centers, but not according to seed color. Mesoamericancommercial cultivars and landraces have been clustered in different groups. A high degree of similaritywas observed among cultivars in use in Rio Grande do Sul.Index terms: Phaseolus vulgaris , genetic variation, cluster analysis. (1) Aceito para publicacao em 18 de agosto de 2003.Extraido da tese de doutorado apresentada pelo primeiro autora Universidade Federal de Pelotas (UFPel), Pelotas, RS.

Characterization of potato genotypes using molecular markers

The objective of this work was to characterize 27 potato genotypes, using molecular markers. Polyacrylamide gel electrophoresis, RAPD techniques and isozymes of esterase, phosphoglucomutase and soluble proteins were analyzed in tubers, and isocitrate dehydrogenase, aspartate transaminase, phosphoglucomutase and peroxidase, in leaves. Eighteen primers were tested and four were chosen, kits OPX (01, 04 and 09) and OPY (07), to analyze RAPD markers in leaf extracts. Similarity and cluster analysis were conducted using Jaccard coefficient and the unweighted pair-group method using arithmetic average. Despite the differences detected in the analysis of proteins and isozymes in the tubers, as well as of isozymes in the leaves, the characterization of all genotypes through gel electrophoresis was not possible, while RAPD markers were efficient to characterize all the 27 genotypes.

Caracterização de cultivares de pessegueiro e de nectarineira por marcadores moleculares

In species with a narrow genetic basis, such as peach and nectarine (Prunus persica (L.) Batsch), the utilization of molecular markers in cultivar characterization is very important, besides the potential of use for protection. Gel electrophoresis and RAPD techniques were used to characterize peach cultivars Granada, Esmeralda, Jade, Eldorado, Riograndense, Capdeboscq, Aldrighi, Precocinho, Diamante, Turmalina, Maciel, BR-1, Pepita, Coral, Chinoca, Marfim, Chiripa, Della Nona and Planalto and nectarine cultivars Dulce and Anita. Isoenzymes of 6-phosphogluconate dehydrogenase and acid phosphatase in pollen, peroxidase, phosphoglucoisomerase, aspartate transaminase and isocitrate dehydrogenase in leaves, malate dehydrogenase, leucine aminopeptidase and phosphoglucomutase in pollen and leaves were analyzed. Fifty primers were tested and eleven were used to analyze RAPD markers in leaf extracts. Similarity and cluster analysis were conducted using Jaccard coefficient and the unweighted pair group method with arithmetic average. Despite the differences detected in malate dehydrogenase in peach and nectarine pollen and leaves, the low polymorphism presented by the other systems did not allow the characterization of all cultivars through gel electrophoresis. RAPD markers, associated or not to isoenzyme analysis, were efficient to characterize peach and nectarine cultivars.

Reciclagem de agarose em laboratórios de biologia molecular

In molecular biology laboratories, the agarose gel electrophoresis is used on a daily basis in order to separate nucleic acid molecules. The agarose is a polimere of elevated cost. The goal of the present work consisted in the optimization of a protocole of agarose recycling, transforming it, once again, into a powdery material similar to the original, after performing the decontamination of Ethidium bromide, allowing its reuse in analitycal electrophoresis. The process, originally proposed by PALACIOS et al. (2000) receveid modifications and consisted in balancing the agarose in water, drying and milling it. The recycled agarose resembled the original, presenting slightly bigger and darker granules. The recycled agarose was avaliable for imediate use, being storegeable at room temperature, for wide periods of time and taking up very few space. It is fit for the manufacturing of analytical gels of the widest brand of concentrations and buffer compositions. Besides, recycling also contributes to the diminution of solid waste disposed in the enviroment and results in significant reduction of costs. The manufaturing of gels took place in a similar way as with the original product, not recquiring any aditional procedure. The recycled gels showed similar performance in electrophoresis and allowed and adequate resolution of bands.

BRS Eliza: cultivar de batata para mesa, com película lisa e resistência à pinta-preta e à requeima

BRS Eliza is a tablestock potato cultivar released in 2001, by Embrapa Clima Temperado, Pelotas, Brazil. It is adequate for puree and salad. Maturity is medium early. Tubers are oval shaped, yellow and smooth skin, low sensitivity to greening, yellow clear flesh and shallow eyes. BRS Eliza did not show physiological defects on the tubers. Has a good field resistance to late (Phytophthora infestans) and early blight (Alternaria solani), and medium resistance to main viroses. BRS Eliza is susceptible to black leg (Erwinia carotovora). It produces a high percentage of commercial tubers. Must be marketed immediately after harvesting. It requires accurate seed management in storage.