Patent ID: 8889948

Claim:
A method of creating a new rice cultivar, comprising: (1-0) a step of constructing a chromosome fragment-substituted rice line by substituting parts of a chromosome of an original rice cultivar with fragments derived from a foreign rice cultivar; (1-1) a step of defining markers, comprising: (1-1-a) a step of defining a DNA marker M2 at an end on an upstream side of a target region of a chromosome of the original rice cultivar, or upstream thereof; (1-1-b) a step of defining a DNA marker M1 upstream of the DNA marker M2 on the chromosome of the original rice cultivar; (1-1-c) a step of defining a DNA marker M4 at an end on a downstream side of the target region on the chromosome of the original rice cultivar, or downstream thereof; (1-1-d) a step of defining a DNA marker M5 downstream of the DNA marker M4 on the chromosome of the original rice cultivar; and (1-1-e) a step of defining a DNA marker M3 in the target region on the chromosome of the original rice cultivar, so that a distance between M1 and M2 is in a range of 1.6 to 344.3 kbp, a distance between M2 and M4 is in a range of 37 to 1509 kbp, and a distance between M4 to M5 is in a range of 6.8 to 1279 kbp; (1-2) a step of mating the chromosome fragment-substituted rice line and the original rice cultivar to obtain a progeny individual in which the DNA marker M3 is a hetero-chromosome region of an allele derived from the original rice cultivar and an allele derived from the foreign rice cultivar; (1-3) a step of self-mating the progeny individual obtained in the step (1-2) to obtain a progeny individual; (1-3′) an optional step of backcrossing the progeny individual obtained in the step (1-3) to the original rice cultivar to obtain a progeny; (1-4) a step of selecting a progeny individual from the progeny of the step (1-3) or from the progeny of the step (1-3′), wherein in the selected progeny individual, the DNA marker M1 is a homo-chromosome region of an allele derived from the original rice cultivar, and the DNA marker M2 and the DNA marker M3 are each a hetero-chromosome region of an allele derived from the original rice cultivar and an allele derived from the foreign rice cultivar; (1-5) a step of self-mating the progeny individual selected in the step (1-4) to obtain a progeny individual; (1-5′) an optional step of self-mating the progeny obtained in the step (1-5); and (1-6) a step of selecting a progeny individual from the progeny obtained in the step (1-5) or the progeny obtained in the step (1-5′), wherein in the selected progeny individual, the DNA marker M1 and the DNA marker M5 are each a homo-chromosome region of an allele derived from the original rice cultivar, and the DNA marker M2, the DNA marker M3, and the DNA marker M4 are each a homo-chromosome region of an allele derived from the foreign rice cultivar, wherein the steps (1-0) to (1-6) are performed for one or more target regions in the chromosome of the original rice cultivar.