The rDNA-IGS of 11 Ustilaginoidea virens isolates from different geographical regions in China were amplified by PCR and sequenced. The results showed that the rDNA-IGS fragments consisted of one cen-tral variable region and two lateral conservative regions. The two conservative sequences among the11 isolates shared the sequence similarity of 99.44%. The variable region consisted of 2,4,or 6 of 77 bp-length-repeats in the isolates and the sequences of the repeat units were high conservative. Primers UIGS III and UIGS IV were designed for amplification of the variable region in the rDNA-IGS.
