Beatriz Marti Emygdio

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.

Atividade de enzimas fermentativas em raízes e nódulos de soja sob condições de hipóxia e pós-hipóxia

This study aimed to evaluate the activity of fermentative enzymes in soybean (Glycine max) roots and nodules under hypoxia and post-hypoxia conditions. The soybean genotypes Fundacep 53 RR and BRS Macota associated with Bradyrhizobium elkanii were grown in 3L pots containing vermiculite as substrate under greenhouse conditions. Root system of plants at the R2 stage was subjected to hypoxia by blocking drainage of the pot, by fitting a second one without holes and flooded with nutrient solution diluted one-third of the original. The flooding of the plants was carried out for eight days and after, the pot without drilling was removed for recovery assessment. Non-waterlogged plants were kept as control. Activities of the fermentation enzymes alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC) and lactate dehydrogenase (LDH) were quantified in roots and nodules collected at 2, 4, 6 and 8 days after flooding or recovery. Data were analyzed by ANOVA and compared by the Tukey test (P ≤ 0,05). Activities of ADH, PDC and LDH were hardly stimulated during flooding, especially in nodules, in both genotypes and decreased with recovery. Fundacep 53 RR responded more effectively to treatment effects.