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

BONASORA MARISA; LOPEZ ALICIA; VAIO MAGDALENA; SPERANZA P.R.; HONFI ANA ISABEL; RUA GABRIEL HUGO

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 188 p. 21 - 33

0024-4074

Paspalum stellatum is widely distributed in the American continent and it is known to include basic diploid (2n = 2x = 20) as well as polyploid cytotypes with 2n = 32 and 2n = 52. It is closely related to P. eucomum, P. malmeanum, and P. schesslii. After chromosome counting and geographic mapping of the different cytotypes, the phylogenetic relationships between them were explored, in order to infer the origin and evolution of the polyploid complex Paspalum stellatum and related species. Additionally, several unusual chromosome numbers are here reported for P. stellatum (2n = 30, 46, 48, 56, and 60) from the Brazilian Cerrado. Phylogenetic analysis using cpDNA showed that the cytotypes of P. stellatum split into two clades, one of which included all accessions with 2n = 32 together with P. schesslii. Using ITS for phylogenetic analysis showed that P. schesslii, P. malmeanum, and P. eucomum were grouped together as expected. The origin of the cytotype 2n = 32 of P. stellatum may have involved P. schesslii as one of the putative progenitors with a diploid cytotype of P. stellatum as the other.