A 4-HPPD inhibitor-resistant gene is identified as a gene (HIS1 gene) which is estimated as an iron-/ascorbic acid-dependent oxidoreductase gene located on the short arm of chromosome-2 of a rice plant, by carrying out QTL analysis using a 4-HPPD inhibitor-sensitive rice plant and a 4-HPPD inhibitor-resistant rice plant or the like. It is also found that a homologous gene (HSL1 gene) to the HIS1 gene is located on chromosome-6 of a rice plant. It is found that a plant having improved resistivity or sensitivity to a 4-HPPD inhibitor can be produced with high efficiency and the resistivity or sensitivity of a plant to a 4-HPPD inhibitor can be determined with high efficiency using the aforementioned genes.
