Chromosome number, microsporogenesis, microgametogenesis, and pollen viability in the Brazilian native grass Mesosetum chaseae (Poaceae).
The genus Mesosetum is a primarily South  American genus with 42 species. Mesosetum chaseae, regionally known as  'grama-do-cerrado', is abundant in the Pantanal Matogrossense (Brazil); it is a  valuable resource for livestock and for environmental conservation. We collected  specimens from the Nhecolandia sub-region of the Brazilian Pantanal, located in  Corumbá, Mato Grosso do Sul, Brazil. We examined chromosome number, ploidy  level, meiotic behavior, microgametogenesis, and pollen viability of 10  accessions. All the accessions were diploid, derived from x = 8, presenting 2n  = 2x = 16 chromosomes. Chromosomes paired as bivalents showing, predominantly,  two terminal chiasmata. Interstitial chiasmata were rare. Meiosis was quite  normal producing only a few abnormal tetrads in some accessions.  Microgametogenesis, after two mitotic divisions, produced three-celled pollen  grains. Pollen viability was variable among plant and accessions and was not  correlated with meiotic abnormalities.
Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR, Brasil.
L A C
LA
Silva
M S
MS
Pagliarini
S A
SA
Santos
N
N
Silva
V F
VF
Souza
D001938:Brazil; D032461:Chromosomes, Plant / Q000235:genetics*; D060146:Ecotype; D056130:Gametogenesis, Plant / Q000235:genetics*; D049469:Meiotic Prophase I / Q000235:genetics; D006109:Poaceae / Q000166:cytology / Q000235:genetics*; D011058:Pollen / Q000166:cytology / Q000235:genetics*; D014022:Tissue Survival / Q000235:genetics*