CONICET | Buscador de Institutos y Recursos Humanos

We investigated changes in floral developmental patterns and sex determination in the PCK (phosphoenolpyruvatecarboxykinase) clade using a comparative approach and SEM. We identified variation in patterns offloral development that may be correlated with sex determination. Nine different patterns of floret developmentwere identified, based on sex of the lower floret, sequence of stamen development, and rate of glume and lemmadifferentiation. Although staminate florets are always formed by the abortion of the gynoecium, the timing ofabortion differs among species. Similarly, the formation of sterile lower florets showed different pathways thatmay operate at the level of floral meristem or organ identity. Finally, we discuss several reasons why patternsdescribed for maize and closely related species may not be easily extrapolated to other grasses.