The origin of unreduced microspores due to aberrant cytokinesis in the meiocytes of potato and its genetic significance

Summary In 7 aneuhaploids of Solanum tuberosum and one clone of S. phureja the mechanism of unreduced microspore production has been studied. It has been observed that the unreduced microspores are produced not only by nuclear restitution at meiosis but also by aberrant cytokinesis in the meiocyte. The size and the number of nucleoli that are present in young microspores at the sporad stage give a fairly reliable indication of the ploidy level and the type of nuclear restitution that has occurred. These two aspects are helpful to deduce the meiotic events that have probably led to the formation of unreduced microspores in some cases. It has been found that triads and dyads are formed regardless of the type of nuclear division or restitution, indicating that cytokinesis is independent of karyokinesis to some extent. Cytological basis of unreduced microspore formation in diploid forms of potato appears to be more complex than it was supposed earlier.