Genetic diversity in forest populations from conservation units in the Atlantic Rainforest in northeast Brazil

Abstract

Fragmentation leads to changes in the size and dynamics of forest populations. Studies of genetic diversity support strategies for preserving the genetic resources, and the data to date for the Atlantic Forest in northeast Brazil is scarce. Thus, the objective of this study was to evaluate the genetic diversity of Protium heptaphyllum (Burseraceae) tree species in three populations. We sampled 64 individuals in this study, for which seven primers used generated 90 loci, with 93% being polymorphic. The average number of alleles was 1.59, the effective number of alleles was 1.34, Nei's genetic diversity was 0.20, and the Shannon index was 0.30. AMOVA indicated higher genetic variation among individuals within populations than among populations. Bayesian analysis revealed the existence of two distinct genetic groups, in which the MAC (Macaíba) population was the most differentiated. Genetic bottleneck tests indicated that all populations presented significant reductions in the population size. In situ conservation strategies must be adequately maintained considering the current isolation of studied populations, the genetic bottleneck, and the low average genetic diversity detected. Also, further recovery of degraded areas in the vicinity and ex situ conservation are recommended.

Does the faxinal system help to maintain the genetic diversity of Curitiba prismatica (D.Legrand) Salywon & Landrum?

“…Polymorphism, which is considered an important measure of diversity, was different among populations and these results were lower than that observed for other tree species in the Atlantic Forest biome, such as Hancornia speciosa Gomes (Apocynaceae), with an approximate polymorphism of 81.00% based on a study of 105 individuals (Fajardo et al, 2018), and Protium heptaphyllum (Aubl.) Marchand (Burseraceae), with polymorphism of 93.00% for 64 individuals (Freire et al, 2019). In the present study we found that the managed areas have high levels of genetic diversity, thus contributing to the maintenance of the species over time.…”

“…They can provide information on genetic diversity indices, allele and genotypic frequencies, gene flow, effective population size, fixation index, genetic distance, and genetic bottlenecks (Brandão et al, 2015;Costa et al, 2015). ISSRs cannot differentiate heterozygous from homozygous individuals, they have been used in studies of intra-and interpopulation genetic diversity, as well as in analyses of genetic structure Fajardo et al, 2018;Laakili et al, 2018;Bocanegra-González et al, 2019;Freire et al, 2019).…”

SELECTION OF ISSR MOLECULAR PRIMERS FOR STUDIES OF GENETIC DIVERSITY IN Handroanthus impetiginosus (MART. EX DC.) MATTOS

“…The pairs of individuals with the highest values of genetic identity were 13 and 15 (0.87), 17 and 19 (0.85) and 5 and 10 (0.84), which were grouped into distinct clusters, suggesting that these individuals have greater genetic similarity to each other. In the dendrogram, from a cutoff point of 0.70 of Nei's (1978) genetic identity, it is possible to identify 10 groups: G1 (1, 2, 3, 4, 5, 8 and 10); G2 (14 and 16); G3 (17, 19, 21, 23 and 24); G4 (28 and 29); G5 (20); G6 (25 and 27); G7 (26); G8 (6, 7, 9, 11, 12, 13 and 15); G9 (18 and 22) and G10 (30 The Nei's (1978) diversity index for the study population was He = 0.35 ± 0.15, while the Shannon index (I) was 0.52 ± 0.18, which can be considered low to intermediate, when compared to the results obtained in studies with the same markers for other forest species (RAJASEKHARAN et al, 2017;FREIRE et al, 2019;LOPES;COSTA;ARRIEL, 2020).…”

Conservation of Manilkara salzmannii in an Atlantic Forest fragment through the study of fruits and seeds

“…Further research is necessary, such as analyzing the acceleration of seed germination via studies of dormancy breakage. Freire et al (2019), in a study of Protium heptaphyllum in the same fragment, observed low genetic diversity of the population. This suggests the need for further investigations and effective conservation actions in fragmented landscapes, where ecological relationships and genetic resources must be maintained.…”