PURPOSE:To establish a means for improving the variety of a plant and for detecting plant pathogenic fungi. CONSTITUTION:A DNA participating in the dwarfing and rooting of a plant and comprising a basic sequence represented by the sequence number 1 or its part, a plant in whose chromosome the DNA is recombined, and a method for producing a dwarfed and rooted plant, and a method for detecting the plant DNA with two or more kind of oligonucleotide primers comprising the DNA are obtained.