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



Genetic 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.



Our 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.
Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil. slfr03@hotmail.com.
Santiago Linorio Ferreyra
SL
Ramos
Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil.
Gabriel
G
Dequigiovanni
Instituto Florestal de São Paulo, Seção de Melhoramento e Conservação Genética Florestal, C.P. 1322, CEP 01059-970, São Paulo, SP, Brazil.
Alexandre Magno
AM
Sebbenn
Faculdade de Ciências Agrárias, Universidade Federal do Amazonas (UFAM), CEP 60077-000, Manaus, AM, Brazil.
Maria Teresa Gomes
MT
Lopes
ESALQ/USP, Departamento de Ciências Florestais, Av. Pádua Dias, 11, C.P. 9, CEP 13418-900, Piracicaba, SP, Brazil.
Paulo Yoshio
PY
Kageyama
Embrapa Amazônia Ocidental, C.P. 319, CEP 69048-660, Manaus, AM, Brazil.
Jeferson Luis Vasconcelos
JL
de Macêdo
University of Florida, School of Forest Resources & Conservation, PO Box 110410, Gainesville, FL, 32611-0410, USA.
Matias
M
Kirst
Escola Superior de Agricultura "Luiz de Queiroz"/Universidade de São Paulo (ESALQ/USP), Departamento de Genética, C.P. 9, CEP 13418-900, Av. Pádua Dias, 11, Piracicaba, SP, Brazil. eaveasey@usp.br.
Elizabeth Ann
EA
Veasey
D028023:Arecaceae / Q000235:genetics*; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D011058:Pollen / Q000235:genetics*; D054817:Pollination / Q000235:genetics*; D058614:Seed Dispersal
Coancestry coefficient; Effective size; Gene flow; Genetic structure; Microsatellites; Paternity analysis; Population genetics; Tucumã of amazonas