To directionally improve blast resistance of the indica rice restorer line R599 and its hybrid,a dominant DNA marker MS-1 was designed based on the promoter sequence of the cloned broad-spectrum and durable blast resistance gene Pi9,and the technology of molecular marker-assisted selection(MAS) was implemented in the successive backcrossing breeding.The results showed that the blast resistance performance and resistance spectrum to 23 M.oryzae isolates were quite different between the Pi9 gene donor 75-1-12...