A comparison of Gardenia augusta cultivars using isozymes and RAPD markers

Numerous cultivars of the florist gardenia [Gardenia augusta (L) Merrill. = G jasminoides J. Ellis] exist but there is confusion over naming as a result of different sources that apply different names to their materials. Two studies were conducted with (some) of the same plant materials to determine whether clear distinctions could be made. Comparisons were also made to other Gardenia species available to us. The isozyme study compared polymorphisms in seven enzyme systems in buffered leaf extracts using starch gel electrophoresis. Total genomic DNA was extracted recently matured leaves using the DNeasy Mini Kit (QIAGEN, Inc., Valencia, CA, USA) extraction protocol. Nine random 10-mer RAPD primers (Operon Technologies, Alameda, CA, USA) were selected for analyses. Gels were digitally imaged and analyzed to compile a presence/absence matrix. For the isozyme study, phosphoglucomutase (PGM), phos-phoglucoisomerase (PGI), and uridine diphosphoglucopyro-phosphorylase(UDPP) were the only successful enzyme systems to yield clear interpretations for a total of 5 loci, and dendrograms based on Jaccard's or simple matching coefficients of similarity were very comparable. However, the three enzyme systems were not sufficient to uniquely fingerprint all of the G augusta accessions. The RAPD analysis using the nine 10-mer primers showed well-defined (bootstrap values > 80) groups: the G augusta, with subgroupings and the G brighamii and species. Both isozyme and RAPD analyses separated or matched cultivars of G augusta as well as G brighamii and other Gardenia species. Coupled with leaf and floral measurements and morphological descriptions, it is possible to distinguish among commercial florist gardenias in a decisive manner.