Fuente: WIPO "tobacco agriculture" The invention discloses a molecular marker capable of improving breeding of low-nicotine tobacco by utilizing a nic1 site and application of the molecular marker. The application comprises the following steps: synthesizing a major regulation mutant site nic1 by utilizing tobacco nicotine; according to the method, tobacco single plant genome DNA in a segregation population is detected in a hybrid segregation offspring, and the selection efficiency of restoring a chromosome region where the nic1 site is located to a recurrent genetic background is improved through a systematic breeding or backcross breeding means while the nic1 site is reserved, so that the bad agronomic traits of a non-recurrent parent are improved; the genetic background selection efficiency of offspring tobacco plants is improved, and the application of the mutant nic1 site in breeding of low-nicotine tobacco varieties is accelerated. The molecular marker provided by the invention can be used as a molecular marker-assisted application for improving the recovery selection efficiency of the genetic background of the low-nicotine tobacco strain while utilizing the mutant nic1 site in tobacco quality breeding.