PROBLEM TO BE SOLVED: To provide a gene marker existing in the genome DNA of a gramineous plant such as barley and connected to a gene locus participating on the length of culm, and to provide a method for utilizing the gene marker. SOLUTION: The detailed chain map of barley was made, and a QTL analysis was carried out. Thus, two gene markers connected to a gene locus participating on the length of culm and boarded on barley 2H chromosome, two gene markers connected to a gene locus participating on the length of culm and boarded on barley 5H chromosome, and two gene markers connected to a gene locus participating on the length of culm and boarded on barley 6H chromosome were found. COPYRIGHT: (C)2005,JPO&NCIPI