Genetic Behavior for Reverse Thermo-Sensitive Genic Male Sterility (RTGMS) through Segregating Generations of some Rice Genotypes in Egypt

FIFTY populations selected from F2 for two crosses i.e. cross I (M.J. 5460 S × Sakha 106) and  cross II (M.J. 5460 S × GZ7768) were planted as F3 generation in 2013 season and twenty  populations were selected from F3 and planted as F4 generation in 2014 season. The selected  populations were studied for reverse thermo-sensitive genic male sterility (rTGMS) trait, some  growth and yield traits were measured. The F4 populations  means were lower than the means of F3  populations  only in the days to heading  trait while, F4 means were higher than F3 means in the other  studied traits. These data indicated the improvement for most studied traits by selection. High  heritability was estimated in broad sense for all growth and yield traits in both crosses as F3 and F 4generations. Heritability in narrow sense ranged between 35.79 % for number of tillers trait  in cross I as F3 generation to 74.95 % for days to heading trait in cross I as F3 generation. The  highest genetic advance from selection as percentage of mean (Δg %) was 63.72 for yield per  plant trait in cross II in F4 generation. Molecular studies indicated that, the RM222 as specific  SSR primer revealed the presence of one specific band with molecular size of (200 bp) with  M.J 5460S line as reverse thermo-sensitive genic male sterile line which indicated that, this  band may be related to reverse thermo-sensitive genic male sterility gene. It could be concluded  that RM222 as specific SSR primer could be used to identify the rtms1 gene in reverse thermo- sensitive genic male sterile lines, which could be used in japonica hybrid rice seed production u nder Egyptian conditions.