Interploidy hybridization in sympatric zones: the formation of Epidendrum fulgens × E. puniceoluteum hybrids (Epidendroideae, Orchidaceae)

Authors

  • Ana P. Moraes,

    Corresponding author
    1. Laboratório de Biossistemática e Evolução de Plantas, Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas/UNICAMP, Campinas, São Paulo, Brasil
    2. Programa de Pós Graduação em Evolução e Diversidade, Universidade Federal do ABC/UFABC, Santo André, São Paulo, Brasil
    • Correspondence

      Ana P. Moraes, Programa de Pós Graduação em Evolução e Diversidade, Universidade Federal do ABC/UFABC, Avenida dos Estados, 5001. Bairro Bangu, Santo André, São Paulo, CEP 09210-580, Brasil. Tel: +55 11 4996 7960; Fax: +55 11 4996 0090; E-mail: apaulademoraes@gmail.com

    Search for more papers by this author
  • Mariana Chinaglia,

    1. Laboratório de Biossistemática e Evolução de Plantas, Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas/UNICAMP, Campinas, São Paulo, Brasil
    Search for more papers by this author
  • Clarisse Palma-Silva,

    1. Departamento de Ecologia, Instituto de Biologia, Universidade Estadual Paulista/UNESP, Rio Claro, São Paulo, Brasil
    Search for more papers by this author
  • Fábio Pinheiro

    1. Instituto de Botânica, Núcleo de Pesquisas do Orquidário do Estado, São Paulo, Brasil
    Search for more papers by this author

Abstract

Interspecific hybridization is a primary cause of extensive morphological and chromosomal variation and plays an important role in plant species diversification. However, the role of interploidal hybridization in the formation of hybrid swarms is less clear. Epidendrum encompasses wide variation in chromosome number and lacks strong premating barriers, making the genus a good model for clarifying the role of chromosomes in postzygotic barriers in interploidal hybrids. In this sense, hybrids from the interploidal sympatric zone between E. fulgens (2n = 2x = 24) and E. puniceoluteum (2n = 4x = 56) were analyzed using cytogenetic techniques to elucidate the formation and establishment of interploidal hybrids. Hybrids were not a uniform group: two chromosome numbers were observed, with the variation being a consequence of severe hybrid meiotic abnormalities and backcrossing with E. puniceoluteum. The hybrids were triploids (2n = 3x = 38 and 40) and despite the occurrence of enormous meiotic problems associated with triploidy, the hybrids were able to backcross, producing successful hybrid individuals with broad ecological distributions. In spite of the nonpolyploidization of the hybrid, its formation is a long-term evolutionary process rather than a product of a recent disturbance, and considering other sympatric zones in Epidendrum, these events could be recurrent.

Ancillary