title: Chromosome numbers and meiotic analysis in the pre-breeding of Brachiaria decumbens (Poaceae).
abstract: A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.
authors.affiliation: Department of Cell Biology and Genetics, State University of Maringá, 87020-900 Maringá, PR, Brazil. mspagliarini@uem.br
authors.forename: Gléia Cristina Laverde
authors.initials: GC
authors.lastname: Ricci
authors.forename: Alice Maria
authors.initials: AM
authors.lastname: De Souza-Kaneshima
authors.forename: Mariana Ferrari
authors.initials: MF
authors.lastname: Felismino
authors.forename: Andrea Beatriz
authors.initials: AB
authors.lastname: Mendes-Bonato
authors.forename: Maria Suely
authors.initials: MS
authors.lastname: Pagliarini
authors.forename: Cacilda Borges
authors.initials: CB
authors.lastname: Do Valle
mesh_terms: D060832:Apomixis; D035201:Brachiaria / Q000166:cytology / Q000235:genetics*; D020090:Chromosome Segregation; D032461:Chromosomes, Plant / Q000235:genetics*; D048749:Cytokinesis; D006824:Hybridization, Genetic; D008540:Meiosis; D011003:Ploidies