Genetic variation and cultivar identification in Cymbidium ensifolium

As a popular flowering species with many cultivars, Cymbidium ensifolium (L.) is commercially important in horticulture. However, so far little has been known about genetic diversity and conservation genetics of this species. Understanding of the genetic variation and relationships in cultivars of C.?ensifolium is a prerequisite for development of future germplasm conservation and cultivar improvement. Here we report assessment of genetic variations in C.?ensifolium cultivars using the DNA fingerprinting technique of inter-simple sequence repeats (ISSR). A total of 239 ISSR loci were identified and used for evaluation of genetic variation with a selection of 19 ISSR primers. Among these ISSR loci, 99.16% were polymorphic with wide genetic variation as shown by Nei??s gene diversity (H?=?0.2431) among 85 tested cultivars. ISSR fingerprinting profiles showed that each cultivar had its characteristic DNA pattern, indicating unequivocal cultivar identification at molecular level. Eighteen cultivar-specific ISSR markers were identified in seven cultivars. The cultivar Sijiwenhan was confirmed as hybrid by four ISSR primers. Several cultivars with same name but different geographical origins were distinguished based on their ISSR profiles. A dendrogram generated with ISSR markers could group 73 of 85 cultivars into four major clusters. Further analysis of ISSR variation revealed that about 69% of total genetic variation in this species is due to genetic divergence inside geographical groups. Our results suggest that both germplasm collection and in?situ conservation are important for future planning of C.?ensifolium species conservation.