Tagging of novel thermosensitive genic male sterility gene in rice (Oryza sativa L.)

The discovery of thermosensitive genic male sterility (TGMS) system has wide potential for creating new path to hybrid seed production technology in rice. It is imperative to study the mechanism of rice TGMS, a core component of two line hybrid development. In this study, TNAU 60S with male sterility was crossed with IET 21009, male fertile line and F-2 population was developed. Six hundred and forty SSR makers covering twelve chromosomes of rice were screened between two bulk populations obtained from F-2 representing fertile and sterile plants. Out of 640 markers, 181 markers were polymorphic between parents, out of which five markers viz. RM171, RM12665, RM6374, RM6942 and RM5015 located on chromosome 2 showed polymorphism between bulks. In order to identify the precise location of thermosensitive genic male sterile (tms) gene, 86 markers were screened further and reduced to eleven. The tms gene was fine mapped on short arm of chromosome 2 at 24.3 cM between flanking markers RM12713 and RM12722. The identified tms locus can facilitate the screening of lines possessing tms gene. The markers linked to/flanking tms gene can be harnessed through marker assisted selection to accelerate two line hybrid rice breeding program.