The 2012 ASHS Annual Conference

Japanese barberry (Berberis thunbergii DC.) is a popular ornamental shrub appreciated for its hardiness and ornamental attributes. Currently over 60 cultivars of barberry are sold across the United States and Canada. These cultivars are identified using their botanical descriptions such as leaf color and plant habit. Since plants are sold when young, differentiating between cultivars with closely similar traits can be difficult and mislabeling can occur. In addition, the nursery industry has long suspected the widespread presence of subclones, or variants, in some cultivars such as ‘Crimson Pygmy’. DNA fingerprinting is a reliable technique that can be used for barberry cultivar identification. At the University of Connecticut, AFLP profiles of 52 cultivars have been developed using seven primer combinations.  These profiles were used to confirm the identity and check for correct labeling of barberry cultivars in the market. We screened 274 plants representing 20 different cultivars to determine the extent of mislabeling or presence of subclones. These plants were obtained from different nurseries and retail outlets across the United States. A total of 263 plants were accurately identified and confirmed as correctly labeled while 11 plants were determined to be mislabeled.  Almost half of the ‘Crimson Pygmy’ plants tested exhibited some genetic variations from the reference cultivar and other same named plants.  However, these plants contained cultivar specific markers and were still designated as ‘true-to-name’. The profiles of four ‘Crimson Pygmy’ plants were substantially different from the reference profile and these plants could not be considered ‘true-to-name’. The intra-cultivar genetic variations observed in ‘Crimson Pygmy’ could be due to random genetic mutations that can occur in clonally propagated plants especially those that have been propagated repeatedly over a long period of time. Overall, these AFLP profiles could be utilized to develop a ‘true-to-name’ barberry certification program for the industry.