Genetic diversity in natural populations of Hancornia speciosa Gomes: Implications for conservation of genetic resources

Abstract

The continuing fragmentation of forests has been a threat to the maintenance of genetic resources. Genetic diversity is fundamental to the survival of species in natural environments in the long term, as well as being the basis for genetic improvement. The objective of this study was to evaluate the genetic diversity in natural populations of Hancornia speciosa and to contribute to the development of conservation strategies. We sampled 105 individuals of H. speciosa, distributed in seven populations. The ISSR (Inter-Simple Sequence Repeat) markers provided 70 loci, of which 81% were polymorphic. The mean genetic diversity of Nei (h) was 0.19, and the Shannon index (I) was 0.27. The h and I diversity indices ranged respectively from 0.16 to 0.24 in the PAD (Parque das Dunas) population and from 0.21 to 0.29 in MAC (Macaíba) population. Resulting from a Bayesian analysis, the genotypes were divided into four groups (K = 4). The allelic diversity patterns observed indicated the occurrence of the genetic bottleneck in all populations, according to the stepwise mutation model (SMM). The infinite allele model (IAM) revealed an imbalance between mutation and genetic drift only in the PAD population. Genetic conservation strategies for H. speciosa should cover each genetic group that was differentially structured. We recommend in situ conservation and the creation of germplasm banks, especially with the PAD population which demonstrated the lower genetic diversity and decreased effective population size according to the two mutational models.

SPATIAL PATTERN AND ALLOMETRY OF A KEY TREE FOR THE AGROINDUSTRY SECTOR: Hancornia speciosa Gomes

“…They concluded there were allometric differences due to phylogenetic evaluations, which are not influenced by the environment. Ganga et al (2010) found for H. speciosa trees an average of 4.58 m for height, ranging from 1.5 m to 10 m. The observed variation may be related to the existing phenotypic variation among trees, also observed for the CBH and DBH, and genetic diversity (FAJARDO et al, 2018). The relation between DBH and total height is a key factor to help trees to maintain their balance and is related to the ability of the trunk to remain standing.…”

“…All trees were inventoried in natural remnants of seasonal semideciduous Atlantic Forest in Rio Grande do Norte State, Brazil. The H. speciosa populations are historically threatened by the marked reduction of the natural habitats due to the deforestation and development of monoculture agricultural activities, causing a decrease in the effective population size (FAJARDO et al, 2018). The geographical coordinates of each plant were recorded by the Global Positioning System (GPS) in two populations in an area called Macaíba.…”

“…Most fruits are collected from natural habitats. Thus, it is crucial to obtain information to support management and conservation programs (FAJARDO et al, 2018).…”

Genetic diversity and structure of Hancornia speciosa Gomes populations characterized by microsatellites markers

“…The conservation of genetic resource should be carried out using the knowledge of the diversity and genetic structure of its populations. Genetic diversity can also be used to select more divergent individuals according to the research study objective (Nunes et al 2021) and is also the basis for genetic improvement (Fajardo et al 2018). However, some species have particularities concerning the physiologic aspect, reproductive system, etc., which also is very important and demand specific strategies to conserve their genetic resources.…”

Overcoming Hancornia speciosa seed recalcitrance: harvest season and storage time

“…The species has high commercial interest due to its fruits (Nunes et al 2022b) used for the production of pulp and ice cream, produced during two annual harvest seasons. H. speciosa is a species threatened by habitat loss (Fajardo et al 2018;Álvares-Carvalho et al 2022;Silva et al 2022) and is considered a priority for research in Brazil (Coradin et al 2018). Moreover, its recalcitrant seeds have shown an increase in longevity under storage in an osmoprotective solution (Nunes et al 2022a).…”