Abstract: In this paper, the molecular marker system-SRAP (sequence-related amplified polymorphism) was firstly applied on 58 Petunia hybrids' genetic relationship research, the results obtained was as follows: 20 primer pairs selected from 88 primer pairs amplified 389 polymorphic bands with an average of 19.5 polymorphic bands per primer pair, and the number of bands amplified by each primer pair was ranged from 13 to 40. Moreover, Jaccard's similarity coefficient ranged from 0.55 to 0.87. 58 varieties could be divided into 4 groups when the genetic distance was 0.67. The first group mainly included warm colour serieses, and yellow flower variety was in the second group, while cold colour varieties were clustered in the third and forth group. In addition, the white colour varieties were clustered in a wide range. Study on genetic relationship of Petunia is benefit for variety protection, seed purity testing and genetic breeding.

Key words: petunia hybrida, SRAP, genetic relationship