The presence of synaptic and chromosome disjunction mutants in Cenchrus ciliaris (Poaceae : Paniceae)

Synaptic mutants are present in Cenchrus ciliaris L. This species, due to t he presence of linear bivalents and occasional trivalents and quadrivalents , is an intermediate desynaptic species. In addition, geographical distribu tion and environmental factors, such as high temperatures and low humidity, could also have had an influence on the desynapsis observed. The disjuncti on of chromosomes during anaphase I was mostly abnormal in this desynaptic species. Precocious disjunction of chromosomes into chromatids occurred dur ing anaphase I. Due to the high incidence of this chromosome abnormality, a mutant gene, 'pc', responsible for the disjunction of chromosomes, must be present. The absence of cytokinesis in one specimen indicates a recessive mutant gene, 'va', to be active in this species.