A Polyhaploid Plant of Amaranthus Dubius

A. dubius is the only natural polyploid reported so far in the genus Amaranthus and meiosis in its polyhaploid would throw light on the nature of its polyploidy. There are on an average about 2–24^II+27.52¹ accompanied by total sterility. The lack of pairing in the polyhaploid is in total contrast to the formation of bivalents in the interspecific hybrids in the Sect. Amaranthus to which this species belongss Whether the predominant asynapsis seen in the polyhaploid reflects the situation of the original hybrid that gave rise to A. dubius, or has arisen subsequent to the origin by progressive differentiation and divergence of the 2 genomes or by fixation of mutations for multivalent suppression enabling strict preferential pairing is not known.