Onion ( Allium cepa L.) is one of the most important vegetables cultivated for its widespread consumption of food and medicine. Onion is a highly cross-pollinated crop that lead to non-uniformity morphology, genetics, low quality and performance of seeds. The production of hybrid seeds of vegetables is a major necessity in agriculture. Hybrid seed production in onion involves the use of male sterility. In the hybrid seed production project, prepare and reproduce three-line is essential that A lines with the genotype S (msms) as maternal parent and B with genotype N(msms) as a maintainer parent for A line and C as a paternal parent with active and fertile pollen that maintainer lines is needed to multiplication of male sterile line. Onion is a biennial there for, identification of the maintainer line using traditional and Key words Allium cepa , Cytoplasmic male sterility, Maintainer line, Cytoplasmic markers, Nuclear markers
