Resumo -O objetivo deste trabalho foi comparar diferentes técnicas multivariadas na caracterização de 35 genótipos de gergelim mediante 769 marcadores RAPD. As distâncias genéticas foram obtidas pelo complemento aritmético do coeficiente de Jaccard e agrupadas pelos métodos hierárquicos do vizinho mais próximo, do vizinho mais distante, das médias aritméticas não ponderadas (UPGMA), do método de otimização de Tocher e análises de coordenadas principais. O agrupamento dos genótipos foi alterado em função dos diferentes méto-dos usados. Adotando-se a mesma distância genética (0,36) como valor de corte, diferenciaram-se quatro grupos no método do vizinho mais próximo, 13 para o vizinho mais distante, 11 no UPGMA e quatro no Tocher. Entre os métodos hierárquicos, o UPGMA apresentou o melhor ajuste das distâncias originais e estimadas (CCC = 0,89). As análises das coordenadas principais confirmaram a baixa diversidade existente entre os genótipos. A maior divergência ocorreu entre as cultivares Seridó 1 e Arawaca 4, e a menor, entre os genótipos VCR-101 e GP-3314. As três primeiras coordenadas principais contabilizaram 35,13% do total da variabilidade, e 18 autovalores foram necessários para explicar 81% da variação genética. Os métodos UPGMA, de otimização de Tocher, e as análises de coordenadas principais são complementares na formação dos grupos.Termos para indexação: Sesamum indicum, análise de agrupamento, coordenadas principais. Multivariate techniques for the determination of genetic diversity in sesame using RAPD markersAbstract -The objective of this work was to compare different multivariate techniques in the characterization of 35 sesame genotypes using 769 RAPD makers. Genetic distances were obtained from the arithmetic complement of the Jaccard coefficient, and were evaluated by single linkage, complete linkage and unweighted arithmetic average (UPGMA) agglomerative methods, Tocher optimization method and principal coordinate analysis. The clustering structure was altered by the different methods. Adopting the same genetic distance (0.36) as value of cut, four groups were discriminated in single linkage, 13 in complete linkage and 11 in UPGMA; the Tocher's optimization methods formed four groups. Among the hierarchical clustering methods, UPGMA showed the best adjust for estimated and originals distances (CCC = 0.89). Principal coordinates analyses confirmed the low diversity among genotypes. The highest divergence occurred between Seridó 1 and Arawaca 4 cultivars, and the minor, between VCR-101 and GP-3314 genotypes. The three first principal coordinates responded for 35.13% of the variability, and 18 autovalues were necessary to explain 81% of the genetic variation. UPGMA, Tochers' optimization and the principal coordinates analyses are complementary in the clusters formation.

The purpose of this study was to use a historical series of exsiccates as a documentary source, aiming to retrieving information on species of Urticaceae Juss. The study approached the collections of exsiccates belonging to herbaria of the Royal Botanic Gardens (K), Kew, England; Muséum National d’Histoire Naturelle (P), Paris, France; and New York Botanical Garden (NY), New York, USA, also printed sources and manuscripts. We analyzed more than 2800 exsiccates, comprising the period between 1783 and 2003. From the information labels of the exsiccates, it was possible to obtain the use and common name of the Urticaceae species. A total of thirteen species with register of use were find in the labels, six genera of Urticaceae: five species of Pourouma Aubl., three of Cecropia Loefl., two of Urera Gaudich., one of Boehmeria Jacq., one of Coussapoa Aubl., one of Laportea Gaudich. Five categories of usage were identify: (1) animal feeding; (2) human feeding; (3) medicinal; (4) fiber and (5) fuel. The analysis of the labels registers pointed to be efficient to raise information related to Urticaceae species, and combined to the research of printed sources and manuscripts provide more details to the data. Furthermore, adding information to the review of the collections history in Brazil. It is necessary to establish initiatives which facilitate the access to documents associated to exsiccates, like the manuscripts of collectors, for continuing the advances in the retrieval of knowledge registered.