A male sterile mutant gene was transfered to a rice line in order to get male sterile isolines usable in population improvement recurrent selection programs. Three germoplasms were used: TOX 1011-4-1 (m.s.) Col l/M312A (ocasional pollinator) and CT 6047-I3-5-34M (recurrent parent). Two backcrosses F1 and F2 generations were evaluated. Individual and family selection were based on phenotypic expression of m.s. on panicles, spikelets and pollen grains after tinctions iodin, acetocarmin and fluorcein. Plant height days to flowering, panicle length, % filled seeds and empty florets were evaluated. Five families and 16 lines were selected exhibiting m.s. stability positive genetic gain was for characters for the recurrent parent. There were significt differences between the m.s,. lines and the recurrent parent for the 6 characters evaluated the uniform expression of the m.s. trait plus good agronomic characteristics show great potentiality to uso these materials in recurrent selection breeding programs.