Inventory methods for finding historically cultivated hop (Humulus lupulus L.) in Sweden

Abstract

The relationship between the conservation of plant genetic resources and their culture history is intimate. Consequently, biodiversity research must also take into account historical and cultural factors. An inventory of plants collected from all over Sweden was made with the aim of establishing a national Swedish gene bank for once cultivated hop. Only female hop, which could be regarded as cultivated hop on the basis of history, were selected. In this study, two different inventory methods were used: one based on plant habitat and the other involving the use of historical documents, primarily large-scale maps from the first half of the seventeenth century, used to locate their cultivars today. The documented history of the hop, combined with its biology, is the basis for the methods used. Hop is the only Swedish crop that according to a 1442 law had to be cultivated. The law lasted for over 400 years. Since the hop is a perennial, dioecious plant and only female individuals are cultivated, over time very few genetic recombination events are expected. Today, it is possible to connect and identify living plants using historical documents. The degree of connection between today's living plants and the historical evidence for hop cultivation differ between the two methods.

Genetic Diversity in Remnant Swedish Hop (Humulus lupulus L.) Yards from the 15th to 18th Century

“…number of hop gardens or number of hop poles. Coordinates for hamlets, villages and also thematic features like farmsteads and hop yards are specified in a Geographic Information System (GIS) and the information was transferred to a present day map and used for localization of remnant hop yards (Karlsson Strese et al, 2010). In total ten sites where hops grew abundantly were chosen for genetic analysis (Table 1, Figure 2).…”