Interspecific hybrids between Paspalum plicatulum and P. oteroi: a key tool for forage breeding

NOVO PATRICIA ELDA; JOSÉ FRANCISCO MONTENEGRO VALLS; FLORENCIA GALDEANO; ANA ISABEL HONFI; FRANCISCO ESPINOZA; CAMILO LUIS QUARIN

SCIENTIA AGRICOLA

UNIV SAO PAOLO

Lugar: Piracicaba; Año: 2016 vol. 73 p. 356 - 362

0103-9016

Grama-tio-pedro (Paspalum oteroi Swallen) is a rare stoloniferous grass of the Plicatulagroup of Paspalum, well adapted to continuous grazing in areas subject to seasonal floodingin the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexualreproduction by seed) tetraploid, sporadically cultivated on Pantanal farms, propagated eitherby cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tiopedroappears as a candidate for genetic improvement within the Plicatula group through plantbreeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx.to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The verysimilar meiotic chromosome behavior observed in both parents, with main quadrivalent and bivalentassociations, suggested that P. oteroi is a natural autotetraploid. The hybrids showed lessirregular meiotic behavior with fewer quadrivalents and more bivalents than either parent. Fertilityamong interspecific hybrids varied from complete sterility in some of them to seed productionsin others that were approximately twice as much as for either parent. The great variability of seedset performance may well be a drastic genetic consequence of joining two homologous chromosomesets of P. plicatulum together with two homologous sets of P. oteroi that, in turn, havesome homeology between them. Most hybrids reproduce by sexual means, thus, they could beused as female parents in backcrosses and in crosses with other species of the Plicatula groupfor interspecific gene transferring in breeding programs.