Spatial genetic structure, genetic diversity and pollen dispersal in a harvested population of Astrocaryum aculeatum in the Brazilian Amazon.

Santiago Linorio Ferreyra Ramos,Alexandre Magno Sebbenn,Jeferson Luis Vasconcelos De Macêdo,Paulo Yoshio Kageyama,Matias Kirst,Maria Teresa Gomes Lopes,Gabriel Dequigiovanni,Elizabeth Ann Veasey

doi:10.1186/s12863-016-0371-8

Santiago Linorio Ferreyra Ramos, Alexandre Magno Sebbenn + Show 6 more

Open Access

https://doi.org/10.1186/s12863-016-0371-8

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Abstract

BackgroundAstrocaryum aculeatum is a palm tree species native to the tropical regions of South America, exploited commercially by local farmers for the pulp extracted from its fruits. The objective of this research was to compare the genetic diversity between adult plants and seedlings from open-pollinated seeds, quantify the pollen flow and dispersal, the spatial genetic structure, and the effective size of a population that has been continuously harvested for its fruits. The study was carried out in a natural population of A. aculeatum distributed over approximately 8 ha in the State of Amazonas (Brazil), separated by 400 m from the closest neighboring population. In total, 112 potential pollen donors, 12 mother plants and 120 offspring were mapped and genotyped.ResultsGenetic diversity was high for parents and the offspring. The fixation indexes for adults (F = -0.035) and offspring (F = -0.060) were negative and not significant. A significant spatial genetic structure was detected for the adult plants (up to the distance of 45 m) indicating short-distance seed dispersal. Paternity analysis detected 9.2 % of pollen immigration and the average distance of pollination within the population was 81 m. The average effective pollination neighborhood area between plants was 1.51 ha.ConclusionsOur results indicate that substantial introduction of new alleles has occurred in the population through pollen immigration, contributing to the maintenance of genetic diversity. Conservation efforts aimed at maintaining the gene pool of the current population or establishing new populations should utilize offspring from mother plants selected to be spaced by at least 50 m to prevent collecting seeds from relatives.

Highlights

Astrocaryum aculeatum is a palm tree species native to the tropical regions of South America, exploited commercially by local farmers for the pulp extracted from its fruits
Genetic diversity A set of 12 microsatellite loci was used in this study, of which two (Aac01 and Aac13) were monomorphic in the population and excluded from further analysis
The results show that this harvest practice has not had a negative effect on the genetic diversity of A. aculeatum offspring

Summary

Introduction

Astrocaryum aculeatum is a palm tree species native to the tropical regions of South America, exploited commercially by local farmers for the pulp extracted from its fruits. The palm tree Astrocaryum aculeatum (Arecaceae) is found in the tropical forest of the Brazilian Amazon region It is a monoecious species, morphologically showing an inflorescence that has the two floral structures (male and female) and that presents protogyny. Informative co-dominant microsatellite molecular markers [6] can be applied to measure the impact of current harvesting methods on natural populations of A. aculeatum These markers can be used to measure the degree of genetic variation within and between populations, supplying important answers in population genetics and in ecological and evolutionary approaches [7], as well as estimating genetic diversity, endogamy, spatial population structure, mating system, and gene flow [8]

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