Sexual Plant Reproduction

, Volume 23, Issue 1, pp 45–51 | Cite as

Physical mapping of rDNA genes corroborates allopolyploid origin in apomictic Brachiaria brizantha

  • Stephan Nielen
  • Lucas M. Almeida
  • Vera T. C. Carneiro
  • Ana Claudia G. Araujo
Short Communication


Brachiaria (Trin.) Griseb belongs to the family Poaceae, and within the genus, apomixis or sexuality is present in different accessions of the same species. The majority of Brachiaria species are polyploid and apomictic, making strategies for crop improvement by breeding very intricate. In spite of the high frequency of apomictic polyploids, the relationship of polyploidy and hybridization with apomixis in Brachiaria is still unclear. Further analysis requires detailed knowledge regarding the genomic composition of the polyploids. The present work introduces the use of fluorescent in situ hybridization (FISH) into cytogenetic analysis of Brachiaria. Physical mapping of heterologous rDNA sequences, associated with conventional karyotyping of the B. brizantha diploid sexual (BRA 002747) and the tetraploid apomictic (BRA000591) accessions, provided evidence of the latter being of allopolyploid origin. Based on our results and on previous knowledge on apomixis in B. brizantha, we suggest that the origin of apomixis was probably a consequence of hybridization.


Allopolyploid Apomixis Chromosomes Cytogenetics FISH Hybridization 


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Stephan Nielen
    • 1
  • Lucas M. Almeida
    • 1
  • Vera T. C. Carneiro
    • 1
  • Ana Claudia G. Araujo
    • 1
  1. 1.Embrapa Genetic Resources and BiotechnologyParque Estação Biológica (PqEB)BrasíliaBrazil

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