Spatial genetic structure, genetic diversity and pollen dispersal in a harvested population of Astrocaryum aculeatum in the Brazilian AmazonReport as inadecuate

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BMC Genetics

, 17:63

Plant population genetics


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.

KeywordsCoancestry coefficient Effective size Gene flow Microsatellites Paternity analysis Population genetics Genetic structure Tucumã of amazonas AbbreviationsσpVariance of gene frequencies due to genetic drift

AAverage number of alleles per locus

aDispersal kernel scale

AepEffective pollination neighboring area

ApNumber of private alleles

bShape parameters

bkSlope of the regression curve in relation to the logarithm of the spatial distance

CgfCryptic gene flow

DKolmogorov-Smirnov test

dxySpatial distance between individuals x and y

FFixation indexes

HeExpected heterozygosity

HoObserved heterozygosity

mpPollen immigration rate

nSample size

NeEffective population size

npNumber of candidate parents

pFrequency for a given neutral allele

P2pThe combined probability of exclusion of the second parent

RCorrelation coefficient among the number of offspring fertilized by pollen of male genitor and the distance between mother plants

sSelfing rate

SGSSpatial genetic structure

SpStatistic which measure the extension of spatial genetic structure in the fist distance class

δPollen dispersal distance

ΘThe group coancestry coefficient

θ1Average coancestry coefficient calculated in the first distance class

θijMean coancestry coefficient

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Author: Santiago Linorio Ferreyra Ramos - Gabriel Dequigiovanni - Alexandre Magno Sebbenn - Maria Teresa Gomes Lopes - Paulo Yos


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