AFLP Discrimination of Native North American and Cultivated Hop

Hop (Humulus lupulus L.) is cultivated for the female fl owers, or “cones,” which traditionally have been used as a bittering and fl avoring agent in beer. Hop breeding historically relied on relatively simple selection techniques within established breeding lines. Supplementing current breeding material with new genetic sources would enhance a hop breeder’s ability to select for new traits. The objective of this research was to assess the genetic relationship of H. lupulus var. lupuloides and H. lupulus var. pubescens accessions with hop germplasm currently utilized by hop breeding programs. A total of 60 hop accessions representing both cultivated (n = 21) and native (n = 39) Humulus were evaluated using amplifi ed fragment length polymorphism (AFLP) molecular markers. The four primer combinations used generated 296 scorable fragments of which 176 (59.5%) were polymorphic. Principal components analysis and hierarchal cluster analysis showed the native American accessions clustering separately from the cultivated germplasm. Within each of the two main groups, two smaller subgroups were evident with H. lupulus var. lupuloides and H. lupulus var. pubescens segregated into unique clusters. This research provides the fi rst molecular genetic evidence of H. lupulus var. pubescens and H. lupulus var. lupuloides being two separate botanical varieties. Results from this research suggest incorporating the native American hop accessions studied in this experiment would enhance the genetic diversity within hop breeding programs. M.S. Townsend, Dep. of Crop and Soil Science, Oregon State Univ., Corvallis, OR 97331; J.A. Henning, National Forage Seed Production Research Center, USDA-ARS, Corvallis, OR 97331. Received 28 Mar. 2008. *Corresponding author ([email protected]). Abbreviations: AFLP, amplifi ed fragment length polymorphism. Published in Crop Sci. 49:600–607 (2009). doi: 10.2135/cropsci2008.03.0182 © Crop Science Society of America 677 S. Segoe Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.