Origins of polyploidy in Paspalum stellatum and related species (Poaceae, Panicoideae, Paspaleae) inferred from phylogenetic and cytogenetic analyses

BONASORA, MARISA; LÓPEZ, ALICIA; VAIO, MAGDALENA; SPERANZA, PABLO; HONFI, ANA; RUA, GABRIEL

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018

0024-4074

Paspalum stellatum is widely distributed in the American continent and it is known to include diploid cytotypes(2n = 2x = 20) and polyploid cytotypes (2n = 32 and 52). It is closely related to P. eucomum, P. malmeanum and P. schesslii.After chromosome counting and geographical mapping of the different cytotypes, phylogenetic relationships betweenthem were explored in order to infer the origin and evolution of the polyploid complex P. stellatum and relatedspecies. Additionally, several unusual chromosome numbers are here reported for P. stellatum (2n = 30, 46, 48, 56 and60) from the Brazilian cerrado. Phylogenetic analysis using plastid DNA showed that the cytotypes of P. stellatumsplit into two clades, one of which included all accessions with 2n = 32 and P. schesslii. Using ITS for phylogeneticanalysis showed that P. schesslii, P. malmeanum and P. eucomum were grouped together as expected. The origin ofthe cytotype 2n = 32 of P. stellatum may have involved P. schesslii as one of the putative progenitors with a diploidcytotype of P. stellatum as the other.