The relationships of hop cultivars and wild variants of Humulus lupulus

Abstract

European, Japanese, and North American hop cultivars were compared with each other and with wild plants by means of numerical taxonomic analyses of vegetative morphological characters. The cultivars originating from the three geographical areas tended to be distinguishable. European cultivars proved to be very similar to indigenous wild European Humulus lupulus and almost certainly are derived from the wild plants. Japanese cultivars seem to be imported European stocks which have been introgressed by indigenous wild Japanese H. lupulus. Similarly American cultivars appear to be of hybrid origin, apparently between European cultivars and one of the three major indigenous varieties of wild North American plants. All domesticates examined were notably dissimilar to the midwestern United States H. lupulus var. pubescens, suggesting that this taxon is a potential source of new breeding germ plasm.