Abstract Pterodon emarginatus Vogel and P. pubescens (Benth.) Benth. are phylogenetically related trees that compose a clade of sister species abundant in the Brazilian Savanna. Despite their morphological differences, some individuals with intermediate morphological characteristics have been reported, indicating the formation of interspecific hybrids. This study proposed to evaluate the genetic structure and controlled pollination of individuals of P. pubescens and P. emarginatus in areas of sympatry with the presence of putative hybrids. For this purpose, we genotyped seven microsatellite loci from 61 individuals collected from four apparent contact zones between P. pubescens and P. emarginatus. Controlled pollination experiments were performed on 4,133 flowers from six trees of P. emarginatus and five of P. pubescens. We observed two genetic clusters (k= 2) that corroborate the divergence between P. pubescens and P. emarginatus. The individual genetic assignment showed evidence of natural hybridization between P. pubescens and P. emarginatus. The genetic assignment did not fully support the visual description of the diagnoses of individual morphological characteristics. Controlled interspecific pollination generated fruit and seed production, possibly indicating the absence of a reproductive barrier at the pollination and ovule fertilization levels between these species. Our results enlarge the understanding of the diversification process of Pterodon species.

RESUMO Hymenaea stigonocarpa (Mart. Ex Hayne), popularmente conhecida como jatobá-do-cerrado, é uma árvore frutífera amplamente distribuída no Cerrado, a qual possui múltiplos usos e é um recurso genético promissor. Objetivou-se caracterizar fisicamente frutos e sementes de H. stigonocarpa, bem como estimar a variabilidade fenotípica em três níveis hierárquicos: populações, matrizes dentro de populações e frutos/sementes dentro de matrizes. Frutos de seis matrizes foram amostrados de cada uma das 25 populações naturais encontradas no Cerrado. A caracterização morfométrica de 742 frutos foi realizada avaliando-se 10 caracteres quantitativos em frutos e sementes. Além disso, foram realizadas análises comparativas entre os valores médios de H. stigonocarpa e a variedade botânica H. stigonocarpa var. brevipetiolata. Variações fenotípicas significativas ocorreram em todos os níveis hierárquicos. Observou-se alta diferenciação fenotípica entre as populações para caracteres quantitativos (massa e tamanho do fruto, massa da polpa e da semente), a qual foi ainda maior quando H. stigonocarpa var. brevipetiolata foi incluída na análise

ABSTRACT Hymenaea stigonocarpa (Mart. Ex Hayne), popularly known as jatobá-do-cerrado, is a fruit tree widely distributed in the Brazilian Savanna, has multiple uses and is a promising genetic resource. This study aimed to physically characterize fruits and seeds of H. stigonocarpa, as well as to estimate the phenotypic variability at three hierarchical levels: populations, mother trees within populations, and fruits/seeds within mother trees. Fruits from six mother trees were sampled from each of the 25 natural populations found in the Brazilian Savanna. The morphometric characterization of 742 fruits was carried out by evaluating 10 quantitative traits in fruits and seeds. In addition, comparative analyses were performed between the average values of H. stigonocarpa and the botanical variety H. stigonocarpa var. brevipetiolata. Significant phenotypic variations were noticed at all hierarchical levels. A high phenotypic differentiation among the populations was observed for quantitative traits (fruit mass and size, pulp mass and seed mass), being higher when H. stigonocarpa var. brevipetiolata was included in the analysis.