Apomixis in Brachiaria decumbens stapf.: Gametophytic development and reproductive calendar

Brachiaria decumbens is a forage grass widely cultivated in tropical areas. This apomictic species reproduces mainly by facultative apospory. A comparison of male and female gamete development between the diploid sexual ecotype and the tetraploid apomictic B. decumbens was made. Aspects of sporophytic and gametophytic development such as developmental stage, several morphological variations, and callose deposition during meiosis are compiled in a real-time reproductive calendar which can be used to select plants as well as reproductive stages. Based on this calendar, part of the differences observed may be related to tetraploidy. Apomictic embryo sacs are formed earlier than the sexual ones, and callose deposition during meiosis follows a different pattern in sexual and apomictic plants. Effects of apomixis are expressed during both male and female development.