Tetraploid races of Paspalum notatum showed polysomic inheritance and preferential chromosome paring around the apospory-controlling locus.

STEIN, J.; QUARIN, CAMILO LUIS; MARTINEZ, ERIC JAVIER; PESSINO, SILVINA CLAUDIA; JUAN PABLO AMELIO ORTIZ

Theoretical and Applied Genetics

Springer-Verlag

Lugar: Heidelberg; Año: 2004 vol. 109 p. 186 - 191

0040-5752

Abstract The objective of this work was to determine the type of inheritance (disomic/polysomic) in tetraploid (2n=4x=40) Paspalum notatum and investigate the transmission pattern of the chromosome region associated with apospory. An F1 family segregating for the reproductivemode (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 au-totetraploid 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 apo-spory was detected. The possible relationship between a chromosome rearrangement and the inheritance of apo-spory is discussed.