RFLP markers isolated from barley, wheat and rice were applied to construct a fine structure map of brachytic1, a semi-dwarf gene located on chromosome 1(7H) short arm in barley. The map covered 15.2 cM with the average distance 0.8 cM between markers. A barley cDNA clone, MWG2074B co-segregated with brh1 gene in the test population. Another major band of this clone MWG2074A was 0.8 cM away from brh1 toward centromere. CDO545 and BCD129 were two flanking markers mapped on both sides of brh1, toward distal and pistal, respectively. CDO545 fitted the systenic region of rice genome, chromosome 6 short arm perfectly. However, two major bands of MWG2074 could not be mapped to the target position of rice genome.