The fertilities of indigenous and cultivated mulberry species(varieties) which were polli nated with Morus nigra L. brought from Turkey were investigated. The percentage of ripening sorosis was very high in indigenous species, Morus tiliaefolia Makino and cultivated variety, Keomseolppong and it was around 50% in both Daeryukppong and Cheongilppong However, the flowers of Morus bombycis Koidz. (BOM5-8) and Yongcheonppong fell after pollination. Looking at the sizes of seeds, they are also various. Generally, it was extremely small in Morus tiliaefolia, but it was medium in Keomseolppong, Cheongilppong and Daeryukppong. The fertilization percentage was generally low with 32-42% in the varieties, but it was comparatively high in Keomseolppong and Morus tiliaefolia. The seed germination percentages of Daeryukppong and Morus tiliaefolia are 88.0% and 23.6%, respectively, but it was below 2% in Cheongilppong and Keomseolppong. The cross success percentages are 14.2% and 8.0% in Daeryukppong and Morus tiliaefolia, respectively, but it was below 0.3% in Cheongilppong and Keomseolppong.