Tetraploid races of Paspalum notatum show polysomic inheritance and preferential chromosome pairing around the apospory-controlling locus

Theor Appl Genet. 2004 Jun;109(1):186-91. doi: 10.1007/s00122-004-1614-z. Epub 2004 Feb 25.

Abstract

The objective of this work was to determine the type of inheritance (disomic/polysomic) in tetraploid (2 n=4 x=40) Paspalum notatum and investigate the transmission pattern of the chromosome region associated with apospory. An F(1) family segregating for the reproductive mode (aposporous vs non-aposporous) was generated by crossing a tetraploid sexual plant as female parent with an apomictic individual as pollen donor. Pollen mother cells from both parental plants were examined to ascertain chromosome-pairing behavior at meiosis. The high rate of quadrivalent chromosome associations indicated an autotetraploid origin of the species, although bivalent pairing and occasional univalents were detected. The observation of a lagging bivalent, a bridge of chromatin, or two aligned laggards in the aposporous parent suggested a chromosome inversion in this strain. Segregation ratios of AFLP markers and the proportion of linkages in repulsion versus coupling phase denoted tetrasomic inheritance, but markers displaying disomic ratios were also observed. Preferential chromosome pairing (disomic inheritance) in the chromosome segment related to apospory was detected. The possible relationship between a chromosome rearrangement and the inheritance of apospory is discussed.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Chromosome Mapping
  • Chromosome Pairing / genetics*
  • Chromosome Segregation / genetics*
  • Crosses, Genetic
  • Genetic Markers
  • Inheritance Patterns / genetics*
  • Meiosis / genetics
  • Paspalum / genetics*
  • Ploidies*
  • Pollen / genetics*
  • Random Amplified Polymorphic DNA Technique
  • Reproduction / genetics

Substances

  • Genetic Markers