Genome size in eight diploid Paspalum L. species.

REUTEMANN, ANNA V.; ECKERS, FABIANA; DAVIÑA, JULIO R.; MARTÍNEZ, ERIC J.; RUA, GABRIEL H.; HOJSGAARD, DIEGO H.; HONFI, ANA I.

Foz de Iguazu

Congreso; 2018 International Congress of Genetics; 2018

Karyotype characteristics combined with DNA absolute content is a useful way to unveil evolutionary trends in plants. The relationship between karyotype and genome size variation has proven an efficient method to understand chromosomal evolution in many plant groups. However, this type of analyses is scarse among Paspalum species. The aim of this work was to analyze the main karyotype features in relation with the genome size of eight diploid species of Paspalum.Chromosome analyses were made by classical staining and DNA contents were estimated by flow cytometry using propidium iodide and Zea mays CE-777 as standard. Two karyotype formulae, 20m (P. indecorum, P. jurgensii, P. lilloi, P. paniculatum, P. umbrosum) and 18m+2sm (P. falcatum, P. paucifolium, P. quarinii) were found. All Paspalum diploid species (2n=2x=20) have unimodal, highly symmetric karyotypes, composed by small metacentric and submetacentric chromosomes, but species differ by TCL and chromosome volume. All genomes are small but vary between species: 0.709pg of DNA per monoploid genome (Cx) in P. umbrosum (TCL=30.9μm), 0.803 pg/Cx in P. indecorum (TCL=29.6μm), 0.804 pg/Cx P. lilloi (TCL=45.4μm), 0.933 pg/Cx in P. paucifolium (TCL=43.2μm), and 1.005 pg/Cx P. falcatum (TCL=37.5μm). The observed differences in Cx values are significant (p