Meiotic behavior in tetraploid populations of Pfaffia tuberosa (Amaranthaceae)

Four populations of Pfaffia tuberosa, the Brazilian ginseng, collected in the central region of the state of Rio Grande do Sul (Brazil) were cytologically analyzed for meiotic behavior. All were tetraploid (2n = 4x = 68) and this condition could be observed through multiple chromosome pairing in pachytene and quadrivalent formation at diakinesis. Irregular chromosome segregation in both divisions led to the formation of a wide diversity of meiotic products. Chromosome stickiness was also frequently found among microsporocytes. Pollen grains of different sizes were observed, while pollen sterility ranged from 49.56 to 64.20% among analyzed populations. This is the first cytological report involving chromosome number determination and meiotic behavior for the species