Average numbers of fruits (female), stamens (male), and filled seeds were assessed from 30 individuals of 12 dog rose (Rosa canina L.) populations in Turkey. Fertility variation and gene diversity (effective number) were estimated based on the assessments. Average numbers of fruits and stamens were 158 (98-233) and 3350 (1827-5126), respectively, in the entire populations. Average number of filled seeds was 13 per fruit. The number of filled seeds per individual was 2412, varying from 1170 to 4074.