Abstract
Chromosome pairing in two haploid Sorghum plants was studied. Chiasmatic bivalents and secondary pairing appearing as end to end and side by side configurations of two chromosomes are described. On the basis of frequency of these chromosomal associations observed in diakinesis and metaphase I cells, it is suggested that upto a maximum of 5 chromosomes in the haploid genome of Sorghum carry duplicated segments. The evidence obtained, therefore, justifies the alloploid origin of grain sorghums with perhaps a base mumber of five chromosomes.
A possible method of formation of functional gametes by the haploids of Sorghum investigated is suggested by the occasional segregation of 10-10 chromatids observed at early anaphase I.
