| Abstract
| - The concentrations of α-acids, β-acids, desmethylxanthohumol, and xanthohumol were monitored inthe hop varieties Admiral (A), Wye Challenger (WC), and First Gold (FG) during the harvest seasonsof 2003 through 2005. Hops grown under an organic regimen were compared to plants grownconventionally in hop fields in close vicinity. The concentrations of the key compounds dependedvery much on climatological conditions showing, in general, highest levels in poorest weather conditions(2004). Of the three varieties studied, FG was the only one showing a clear trend for higherconcentrations of secondary metabolites under organic growing conditions than under conventionalfarming conditions. Cultivation of A and WC seems to be very sensitive to climatic conditions andenvironmental stresses caused by pests and diseases, thereby leading to various results. WC provedto be a rich source of bioactive chalcones, particularly desmethylxanthohumol. Keywords: Organic hop (Humulus lupulus L.); secondary metabolites; α-acids; β-acids; desmethylxanthohumol; xanthohumol
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