Identification of DNA Markers Linked to thermo-sensitive genic male sterile (tms) in Rice IR68301S (Oryza sativa L.)

Abstract

Hybrid rice can increase yield of rice (Oryza sativa L.) which is the most important food crop in Thailand. Thermo-sensitive genic male sterility (TGMS) facilitates hybrid rice seed production. In this study, genetic analysis was conducted using F2 populations derived from crosses between IR68301S, an indica TGMS rice line and IR 14632 a japonica rice line. The ratio between normal pollen and sterile pollen of F2 plants was 3:1 indicating that TGMS trait was controlled by a single recessive gene. To identify markers linked to the tms gene, Bulked Segregant Analysis (BSA), simple sequence repeat (SSR) markers and insertiondeletion (InDel) markers were used. We found 12 SSR markers and 10 InDel markers closely associated withmale sterile F2 population. The results showed that the tms locus was located on chromosome 2 between SSR marker RM12676 and InDel marker 2gAP003974. The genetic distance from the tms gene to these two flanking markers were 1.10 and 1.37 cM, respectively. The position of tms locus in IR68301S is not the same as that of tms locus in IR75589. These tightly linked markers will provide useful tools for marker assisted selection
of this gene in rice breeding programs. Furthermore, the approximate position of this tms gene will be useful for further studying on molecular mechanism controlling pollen sterility.