ResumoA castanha-do-brasil pertence à família Lecythidaceae e é uma espécie nativa da Floresta Amazônica com elevado potencial econômico. O presente estudo objetivou avaliar a diversidade genética de AbstractGenetic diversity among Bertholletia excelsa Bonpl genotypes using ISSR molecular markers. The Brazil nut belongs to Lecythidaceae family and is a native species from the Amazon rainforest with high economic potential. This study aimed to evaluate the genetic diversity among Bertholletia excelsa Bonpl genotypes and with naturally occurring in the northern State of Mato Grosso, with ISSR molecular marker. Therefore, we characterized 37 genotypes through eight primers, with a total of 52 amplified loci in all genotypes, being 46 polymorphic. The number of fragments amplified by primer ranged from 5 [Di(AG) 8 were the most divergent and can be used as parents for hybrid formation in the improvement programs. It is recommended to in situ conservation of analyzed genotypes.

ABSTRACT. Several species within the genus 10365-10375 (2015) genetic diversity in breeding programs. These latter species could also be domesticated or improved to produce commercial products. Using 13 simple sequence repeat loci, the population structure and genetic diversity of T. speciosum and T. subincanum natural populations in the Juruena National Park, Mato Grosso State, Brazil, was studied. We sampled all individuals of each species (N = 25) present inside a designated research area established by the Program for Research on Biodiversity. The average number of alleles per locus was 5 for T. speciosum and 6.69 for T. subincanum, with average PIC values above 0.5 in both species. All evaluated individuals varied genetically. Seeds from the individuals analyzed will be useful for the development of germplasm banks and for establishment of breeding programs.

ABSTRACT. Forest fragmentation reduces the effective size of natural populations, isolates individuals in the landscape, and, consequently, changes species' mating systems by increasing the degree of relatedness between individuals and inbreeding. Investigating the impact of habitat degradation on forest fragments helps to assess the genetic and ecological consequences of these changes, and allows the development of effective and sustainable conservation strategies to manage the genetic resources of species living in degraded landscapes. The aim of the present study was to assess the genetic diversity of fragmented Theobroma speciosum populations using microsatellite markers. Three urban forest fragments were selected in the municipality of Alta Floresta, Mato Grosso State, Brazil, namely C/E park, J park, and Zoo Botanical park. Seventy-five individuals (25 in each fragment) were sampled by collecting their leaves for genomic DNA extraction. Polymerase chain reaction amplifications were performed using nine polymorphic simple sequence repeat primers, which amplified 84 alleles. The mean expected heterozygosity was 0.970, and it was always higher than the observed heterozygosity. Analysis of molecular variance revealed that most variability occurred within populations (64%) rather than between them (36%). The Structure software and an unweighted pair group method with arithmetic mean dendrogram revealed three distinct groups, showing that individuals were allocated to their correct populations. Genotype number 3 from C/E park, number 45 from J park, and number 51 from Zoo Botanical park could be used as stock plants in breeding programs, because they were the most dissimilar within the populations studied. The high genetic diversity levels detected in all three populations studied emphasize the importance of protecting this species in its natural habitat.

ABSTRACT. Cajazeira (Spondias mombin L.), of the family Anacardiaceae, is a species of fruit tree found in the Amazon region with fruits that have excellent prospects for commercial use. We aimed to evaluate the genetic diversity within and among natural populations of S. mombin, with natural occurrence in northern Mato Grosso State, by using inter-simple sequence repeat (ISSR) markers. Overall, 126 individuals were evaluated from three populations located Alta Floresta (AFL) 42, Marcelândia (MAR) 41, and Nova Bandeirantes (NBA) 43. The individuals were genotyped with 14 ISSR primers, which amplified 99 fragments. All markers, with the exception of DiGA3'A, presented a polymorphic information content above 0.25, and thus, are Analysis of molecular variance showed that 77.38% of the total genetic variation is found within populations while 22.62% is found among populations. AFL and NBA are genetically the most similar populations and also the closest "Structure" revealed genetic diversity among the genotypes of each population. As there is genetic variability in both populations, and there are no genetically identical individuals, both populations can be a source of genotypes for germplasm banks and for future commercial fruitful plantations S. mombin.