Molecular breeding method for improving drought resistance of rice

The invention discloses a molecular breeding method for improving the drought resistance of rice. The molecular breeding method comprises the following steps: carrying out hybridization by taking a rice three-line maintainer line Zhenshan 97B with poor comprehensive drought resistance as a recurrent parent and a Brazil dry rice resource IRAT109 carrying drought-resistant main effect QTL sites as adonor, so as to obtain F1; continuously backcrossing an obtained F1-generation plant and recurrent parent Zhenshan 97B for three generations, so as to obtain BC3F1; carrying out selfing on the BC3F1so as to obtain BC3F2, hybridizing a single plant with wild abortion type sterile line Zhenshan 97A, carrying out bagging, selfing and seed collection on the single plant, so as to obtain BC3F3, wherein the single plant has good drought resistance, has agronomic traits similar to the recurrent parent and is capable of labeling homozygous genotypes; and carrying out continuous backcrossing for three generations, and carryin