Abstract: The genetic diversity and relationship of 42 cultivars of hybrid Cymbidium introduced from Japan, Korea and USA, and 2 wild species from China (C. aloifolium and C. f loribundum ) were evaluated using AFLP molecularmarkers in this study. Among the 1 597 AFLP bands obtained from nine selective p rimer
pairs, 1 565 (98.0% ) were polymorphic. The average number of DNA bands per p rimer pairwas 177, with
a range of 156 - 193. All the cultivars have their characteristic bands and can be identified based on the AFLP markers. Genetic similarity based on dice coefficients among the cultivars ranged from 0.3399 to 0.8223, with an average of 0.5783. The cultivars could be divided into four group s based on the UPGMA dendrogram, and this division is in consistence with the morphological classification based on the type of flower inflorescence,
flower size or flower color. Cultivars originated from the same country or the same breeding company could be clustered together in the AFLP dendrogram and this rep resents the genetic relationship of the cultivars.

Key words: Ochidaceae, Hybrid Cym bidium, AFLP, Genetic diversity, Genetic relationship