It is intended to provide a quick breeding method whereby the efficiency of selecting an individual to be used in the crossing in the next generation can be elevated in continuous back crossing for constructing an improved plant variety and to construct an improved rice variety which has lodging resistance while holding the favorable taste of koshihikari within a short period of time. Namely, a method of quickly breeding an improved plant variety having a desired characteristic introduced thereinto which comprises the following steps: (a) crossing a subject plant variety with another plant variety having the desired characteristic; (b) typing the genotype of chromosome of the post-crossing generation in the young plant stage with the use of a single nucleotide polymorphism (SNP) marker; (c) selecting an individual to be used in the crossing in the next generation based on the thus typed genotype; (d) back-crossing the thus selected individual with the subject plant variety as described above; and (e) repeating the procedures of the above (b) to (d) at least thrice.
