Polyembryony in many citrus varieties is an impediment in breeding because it makes hard to identify hybrids after crossbreeding. So, it has become imperative for developing efficient methods to distinguish zygotic seedling generated from polyembryonic seed depending on citrus variety. Simple sequence repeat(SSR) marker is one of useful systems for such purpose. However, SSR markers to separate zygotic seedlings derived from the crossbreeding between ‘Marita unshiu’ (Citrus unshiu) ‘Seongjeon’ and ‘Shiranuhi mandarin’ [(C. unshiu x C. sinensis) x C. reticulata] ‘Hallabong’ have not been developed yet. In this study we tried to identify an effective SSR marker to screen zygotic seedling after crossbreeding between ‘Seongjeon’ and ‘Hallabong’. For this investigation, 387 seedlings were generated from 114 seeds produced from crossing those two varieties. A total of 116 SSR markers were tested to identify a special marker for distinguishing origin, zygotic or nucellar seedling. As a result, two markers, SSR012 and SSR093, were found to be more effective than other markers. These two SSR markers might be useful to select zygotic individuals in crossbreeing between ‘Seongjeon’ and ‘Hallabong’.