Identification of Native Minnesota/Midwestern U.S. Hop (Humulus lupulus L.) Communities as a Resource for Novel Disease Resistance Traits

Identification of Native Minnesota/Midwestern U.S. Hop (Humulus lupulus L.) Communities as a Resource for Novel Disease Resistance Traits

Summary

In 2016 135 wild hop accessions were screened for their response to Pseudoperonospora humuli, causal organism of hop downy mildew and a obligate parasite of hops.  These 135 accessions originated from private collections or USDA-sponsored collection trips and encompassed the native distribution of hop within North America.  Private collections were made from multiple locations within Minnesota, Michigan, Wisconsin, and Vermont.  Additionally, USDA-collected materials originated from Kazahkstan, Manitoba and Sakatchewan, CA, and Arizona, Colorado, Missouri, New Mexico, and North Dakota.

Our preliminary experiments indicated that botanical varieties significantly differ in their tolerance to hop downy mildew, which may be related to exposure to environmental factors that are conducive for the establishment of the disease in a field setting and not directly to their ability to tolerate infection.

Our continued experiments with a larger collection indicated there are significant overlaps in tolerance to hop downy mildew across botanical varieties, indicating that resistance or tolerance may be independent of climatic factors and primarily composed of genetic factors.

Objectives/Performance Targets

We have screened a significant portion of our germplasm collection, which is composed of a mixture of USDA and privately-collected accesssions.  We are currently continuing our evaluations on whole plants and plan to initiate field trials this year at two locations with highly resistant lines to determine agronomic performance of selected accessions.

Accomplishments/Milestones

Results of this work have been disseminated to local groups during presentations (LaCrosse, WI – 2016, St. Paul, MN – 2016, Burlington, VT – 2017) and posters (Tampa, FL – 2016).

Collaborators: