THE ISOLATION AND IDENTIFICATION OF POLYPLOID STRAINS OF USTILAGO VIOLACEA

Abstract

A method for the synthesis of polyploid strains of Ustilago violacea and the criteria for their identification are described. Cell length increases directly in proportion to the ploidy and thus the volume of the cell increases very rapidly at higher ploidies. The volume of the nucleus also increases but remains at a constant 3-4% of the cell volume. Stability and growth rate decrease with increasing ploidy. The a2 mating-type allele acts as a simple dominant allele in log phase cells, but there is no dominance in stationary phase cells.