The genes, located outside of nucleus (i.e., within the cytoplasm) also governes some traits, are referred to as plasmogenes or cytoplasmic genes. Cytoplasmic male sterility (i.e., dominance of female cytoplasmic genes over male is due to plasmogenes located in mitochondrial DNA (mtDNA). Related Theory Male sterility in plants is often cytoplasmically based and maternally inherited. Male sterile plants produce no functional pollen, but do produce viable eggs. Cytoplasmic male sterility is used in agriculture to facilitate the production of hybrid seed. Hybrid seed is produced from a cross between two genetically different lines; such seeds usually result in larger, more vigorous plants.