An apomictic mutant for sticky chromosomes in the fern Ceratopteris

A meiotic mutant has been derived from a triploid hybrid of the fern genus Ceratopteris. The mutant behavior involves chromosome stickiness that is regularly observed during both meiotic divisions. Chromosome stickiness is also infrequently observed during mitotic division. In addition, the first meiotic division frequently fails and results in the formation of a restitution nucleus. A single second meiotic division follows restitution and results in the production of a dyad of unreduced spores. Viable unreduced spores germinate to produce gametophytes containing the sporophytic number of chromosomes. Spermatozoids produced by the gametophytes are non-functional. However, sporophytes regularly develop apogamously from the gametophytes. Because meiotic reduction and syngamy are absent, the mutants are, reproductively, obligate apomicts.