Analysis of Genetic Variability among Phalaenopsis Species and Hybrids Using Amplified Fragment Length Polymorphism

Phalaenopsis is the second most valuable potted plant in the United States. Information on the genetic diversity and relationships among species and hybrids is important for breeding purposes and species conservation. In this study, genetic variability of 16 Phalaenopsis species and hybrids was analyzed using amplified fragment length polymorphism (AFLP) markers. Ten AFLP primer combinations amplified 1353 DNA fragments ranging in size from 100 to 350 bp and 1285 (95%) of them were polymorphic. The genetic similarity among Phalaenopsis species and hybrids ranged from 0.298 to 0.774 based on Dice coefficient. The dendrogram derived by the unweighted pair group method with arithmetic mean analysis clustered the germplasm into two main groups. Bootstrap values for the groups supported 70% of the clustering. A significant linear relationship ( r = 0.724, P < 0.0001) was observed between known pedigrees and AFLP-derived genetic similarity for 136 pairwise comparisons of Phalaenopsis species and hybrids. The results of this study demonstrate the usefulness of AFLP analysis in Phalaenopsis and its potential application in breeding and species conservation.