Study of flow and contemporary pollen dispersal, mating system, spatial distribution of genotypes and inbreeding depression in fragmented population Cariniana estrellensis (Raddi) Kuntze, using microsatellite loci

Author(s)

Thaisa Yuriko Kuboyama Kubota

• Document type: Doctoral Thesis
• Press: Ilha Solteira. 2017-03-29.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Ilha Solteira
• Defense date: 2017-02-03
• Advisor: Alexandre Magno Sebbenn

Abstract

Cariniana estrellensis (Raddi) Kuntze (Lecythidaceae), popularly known as jequitibá-branco, is a tropical tree species typical of advanced successional stages, characteristic of climax forests. Although it ecological importance, the species is threatened with extinction, mainly due to the intense exploitation and degradation of its natural environment. The objective of this study was to investigate the genetic diversity, intrapopulation spatial genetic structure (SGS), the mating system and contemporary gene flow of a population of C. estrellensis, located in a forest fragment (448.2 ha) in the city of Bataguassu (State of Mato Grosso do Sul, Brazil), using microsatellite markers. Were mapped, measured (height and diameter at breast height) and genotyped all 285 adult trees found in the area and collected seeds from 20 matrices trees, 32 seeds per tree for the hierarchical analyses within and among fruits. Using the genotypes of adults and progenies were investigated Mendelian inheritance, genetic linkage and genotypic disequilibrium of nine loci of C. estrellensis, which exhibited Mendelian inheritance, are not linkaged and segregate independently. Although the allelic richness ( R ), observed heterozygosity ( Ho ) and expected ( He ) were similar among adults ( R = 8.3, Ho = 0.648, He = 0.686) and seeds ( R = 7.8, Ho = 0.640, He = 0.682), these indexes were significantly lower in the seeds. The average fixation index ( F ) was not significantly greater than zero, suggesting absence of inbreeding in adults and seeds. The rate of multilocus outcrossing ( m t ) was significantly less than unit (1.0), suggesting selfing. The outcrossing rate between related individuals ( m s t  t ) was significantly greater than zero (0.062) and the paternity correlation was higher within ( p(w) r = 0.835) than that among fruits ( p(a) r = 0,062). The average coefficient of coancestry (  ) was higher and the effective size ( Ne ) lower than expected for progenies of panmitic populations. The estimated number of matrices trees to collect seeds to obtain the effective size of 150 was of 52. The immigration rate of pollen was 9.4%. The effective radius of pollen dispersal ( ep r ) was of 974 m. The analysis of Kernel pollen dispersion modeling indicated the exponential dispersion model as the best explanation for pollen dispersion, with a pollen dispersion average of 610.9 m. Therefore, the population of C. estrellensis is not reproductively isolated due to the dispersion of pollen over long distances and presents great potential for in situ and ex situ genetic conservation purposes. (AU)

• FAPESP's process: 14/02675-8 - Study of flow and contemporary pollen dispersal, mating system, spatial distribution of genotypes and inbreeding depression in fragmented populations Cariniana estrellensis (Raddi) Kuntze, using microsatellite loci
• Grantee: Thaisa Yuriko Kuboyama Kubota
• Support Opportunities: Scholarships in Brazil - Doctorate