ABSTRACT. Brazil is considered one of the domestication centers of cassava (Manihot esculenta), containing a large part of the biological diversity and traditional knowledge of the species. The aim of the present study was to evaluate the genetic diversity of cassava landraces grown by farmers in the north of Mato Grosso State, Brazil, using inter simple sequence repeat (ISSR) molecular markers. The study was carried out in the municipality of Alta Floresta, MT, on farms located in two rural areas. Seventeen cassava landraces were selected. The DNA was extracted and polymerase chain reaction amplifications were performed using 15 ISSR primers. Genetic similarity estimates were calculated using Jaccard's index and the generated matrix was used for clustering the genotypes by using UPGMA and Tocher's methods. The 15 ISSR primers amplified 120 fragments, revealing 61.67% polymorphism. The polymorphism information content ranged from 0.04 to 0.61, averaging 0.39. The most similar genotypes were AF5 and AF8, whereas the least similar were AF1 and AF16. The UPGMA clustering method formed five groups. Group I included twelve landraces, Group II contained two, and the other groups contained one landrace each. Tocher's method resulted in six groups: 12 landraces clustered in one group, and the other groups each contained one landrace. The ISSR markers proved efficient in revealing genetic diversity among the cassava landraces. The landraces grown by farmers in the two rural areas of Alta Floresta have a great variability and, thus, can be exploited in programs for breeding and preservation of the species.

ABSTRACT. Hymenaea courbaril L. is a tropical tree species with economic and medicinal potential largely used in programs for the recovery of degraded areas. The use of molecular markers in genetic studies can 2 V.D. Rocha et al. Genetics and Molecular Research 16 (3): gmr16039706 help in the definition of forest restoration strategies. This study was conducted to analyze the genetic diversity among H. courbaril ('jatobá') genotypes naturally occurring in the north of Mato Grosso State, Brazil, using ISSR markers, aiming to contribute to the development of seed collection and seedling production strategies. Twenty-four H. courbaril individuals were sampled by collecting leaves for DNA extraction by the CTAB method. The individuals were genotyped using 14 ISSR primers, resulting in the amplification of 87 bands in total, 65 of which were polymorphic. The ISSR markers presented average polymorphism information content of 0.44. Dissimilarity values based on the Jaccard coefficient ranged from 0.12 to 0.52. The most divergent individuals were 3 and 22, whereas 14 and 19 were the most genetically similar. The UPGMA and Tocher clustering methods indicated the formation of four distinct groups, revealing genetic variability among the 24 H. courbaril genotypes. Therefore, all the evaluated genotypes can be used for seed collection and seedling production, but the most divergent individuals should be prioritized.

Abstract:The species Spondias mombin, is native to the Amazonian region. Since these trees' cultivation is incipient, their exploitation is done through extraction techniques. The aim of the present study was to assess the genetic divergences between S. mombin genotypes and to quantify the relative contribution from 12 morphological traits of the species' fruits and seeds, as well as to collect data able to subsidize future research on the species conservation and domestication. 60 genotypes were assessed in total, and ten fruits of each genotype were analyzed. Eight descriptors were used for fruit characterization, namely: fruit mass, pulp weight, volume, length, width, thickness, total soluble solids content and hydrogenionic potential. The seed descriptors were mass, length, width and thickness. The data were assessed through the principal components and groupings by applying the UPGMA and Tocher methods. They were analyzed in the GENES software, based on the dissimilarity matrix (Euclidean distance average). The analysis applied to the principal components showed that the first three components explained 83 % accumulated variation. The main traits contributing to the genotype discrimination were fruit width, fruit pulp weight, pH, seed length and thickness, and the most responsive traits to S. mombin genotype selection. The features fruit mass, seed width, fruit thickness, fruit volume, fruit length, seed mass and total soluble solid content presented the smallest contribution to diversity. The grouping methods UPGMA and Tocher evidenced genetic divergence between the analyzed genotypes. Genotypes 37 and 41 were more divergent than the others, what makes them promising for crossings in future genetic enhancement programs focused on the species' domestication. Rev. Biol. Trop. 65 (4): 1337-1346. Epub 2017 December 01.

Resumo Este estudo objetivou caracterizar a morfoanatomia, histoquímica e fitoquímica dos órgãos vegetativos de Hymenea courbaril, visando detectar estruturas secretoras ou células secretoras que armazenam metabólitos secundários, cujas atribuições conferem potencial medicinal à espécie. A coleta do material vegetal foi realizada em indivíduos nativos de H. courbaril no município de Alta Floresta, MT. O material botânico (folíolos e caule) foi fixado, foram realizadas secções transversais e paradérmicas nos órgãos, montadas em lâminas histológicas e o material fresco foi submetido a testes histoquímicos e fitoquímicos. Foram detectados canais de secreção no folíolo e caule de H. courbaril, a caracterização fito-histoquímica deu positivo para metabólitos secundários como taninos, esteroides, flavonoides, compostos fenólicos, lipídios, saponinas e glicosídeos, a presença destes compostos pode conferir à espécie atividades biológicas importantes no tratamento de diversos tipos de doenças. Além disso, tais substâncias desempenham um importante papel ecológico de manutenção e continuidade da espécie na natureza, como mecanismos contra a herbivoria e a desidratação.