The article introduces MutMap, a method for rapid gene isolation in rice using whole-genome resequencing of pooled DNA from a segregating population of plants with useful phenotypes. MutMap involves crossing a mutant to the original wild-type line and then selfing, allowing unequivocal segregation in the second filial generation ($F_2$) progeny of subtle phenotypic differences. This approach is particularly suitable for crop species as it minimizes the number of genetic crosses and $F_2$ progeny required. The authors applied MutMap to seven mutants of a Japanese elite rice cultivar, identifying genomic positions likely to harbor mutations causing pale green leaves and semidwarfism, which are agronomically important traits. The results demonstrate that MutMap can accelerate the genetic improvement of rice and other crop plants. The method is compared with other related methods, such as SHOREmap and NGM, highlighting its advantages in terms of simplicity, efficiency, and practicality for crop breeding. The authors also discuss the potential applications of MutMap in identifying genes for salt tolerance and other agronomically important traits.The article introduces MutMap, a method for rapid gene isolation in rice using whole-genome resequencing of pooled DNA from a segregating population of plants with useful phenotypes. MutMap involves crossing a mutant to the original wild-type line and then selfing, allowing unequivocal segregation in the second filial generation ($F_2$) progeny of subtle phenotypic differences. This approach is particularly suitable for crop species as it minimizes the number of genetic crosses and $F_2$ progeny required. The authors applied MutMap to seven mutants of a Japanese elite rice cultivar, identifying genomic positions likely to harbor mutations causing pale green leaves and semidwarfism, which are agronomically important traits. The results demonstrate that MutMap can accelerate the genetic improvement of rice and other crop plants. The method is compared with other related methods, such as SHOREmap and NGM, highlighting its advantages in terms of simplicity, efficiency, and practicality for crop breeding. The authors also discuss the potential applications of MutMap in identifying genes for salt tolerance and other agronomically important traits.