Autoploidy in PMCs of a protogynous form of Saccharum spontaneum L.

High degree of protogyny (by 4–6 days with mode value of 5 days) was a regular feature in a dwarf done of Saccharum spontaneum L. collected from Bhagalpur. The diploid chromosomesin the PMCs (pollen mother cells) of the dwarf form were 64, arranged as 32 bivalents at premetaphase I as well as metaphase I. Some syndiploid PMCs with 64 bivalents and two nucleoli were also seen regularly with changing frequency. A syndiploid PMC received an additional set of chromosomes from another diploid donor PMC making the recipient one almost syntriploid. Obviously, the phenomenon of cytomixis lead to the origin of autopolyploid PMCs (autotetraploids and autohexaploids) in protogynous form. The possible relationship between protogyny and autopolyploidy is discussed.