Isolation and identification of a gene associated with the number of primary panicle branches in a plant, and use of the gene. A gene encoding a protein having the amino acid sequence set forth in SEQ ID NO:2 is isolated as a gene associated with the number of primary panicle branches in a plant. By using the gene, it is possible to readily create a plant which has a large number of primary panicle branches and a large number of grains.
