Abstract: The genetic relationship and diversity of 8 tomato germplasm resources which were resistant or suscepti- ble to tomato yellow leaf curl disease （TYLCD） were analyzed by the optimized AFLP （amplified fragments length polymorphism）. Five primer combinations selected from 64 primer pairs revealed a total number of 149 unambiguous bands,62 of which were polymorphic with a polymorphism frequency of 41.6%. This result showed molecular variations of some enzyme digestion sites among the used tomato germplasm resources. The genetic similarity coefficient of 8 tomato resources ranged from 0.83 to 0.95. Based on the coefficient value of 0.89,these tomato germplasm resources were clustered into 1 multiple-member group and 3 one-member groups by UPGMA （unweighted pair group method with arithmetic mean） analysis ,which provided molecular reference for parent selection in tomato breeding for resistance to TYLCD.

Key words: tomato, AFLP, fingerprinting