Evaluation of genetic variability within actual hop (Humulus lupulus L.) cultivars by an enlarged set of molecular markers

Abstract

Traditional hop (Humulus lupulus L.) cultivars have been used in the brewing industry for a long time. Globally, about ten new breeding lines were released to the market in each decade from ~1970 to 1999. Since 2006, the rate of release of new cultivars has increased tenfold. It is, therefore, important to identify their genotype and origin. Molecular genetic methods based on DNA are the most appropriate technology for this purpose. Recently, we developed an efficient marker system for the authenticity control of hop genotypes based on expressed sequence tag-simple sequence repeats (EST-SSR). In the present study, we enlarged the previously established EST-SSR set with 27 new polymorphic markers and evaluated molecular genetic variability within 135 traditional and new world hop cultivars. Two sets of 10 markers effectively differentiated all used cultivars, with the exception of cultivars derived from the same original genotype such as Saaz, Spalt, Tettnang and Nadwislawsky. Results of molecular genetic variability analyses corresponded with the genealogical and geographical origin of the key cultivars.