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Dr John A. Henning, Research Geneticist, U.S. Department of Agriculture-ARS Forage Seed and Cereal Research Unit, Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon
This project is one of vital interest for Brewers, hop producers and hop marketing companies. The development of new hop varieties possessing superior qualities ensures continued productivity for growers and a ready source of excellent hop and hop extracts in the future. The specific objectives of this project are: 1) Develop new hop germplasm that is resistant to powdery mildew and/or downy mildew, two disease that impact quality and yield in U.S. hop-producing regions and 2) Identify molecular markers to aid the selection of new germplasm that possess fungal disease resistance genes. Fungal pathogens are the source of greatest loss in hop production, typically requiring extensive spraying regimens that are costly and environmentally undesirable. Most currently produced varieties are susceptible or moderately susceptible to one or of both of these pathogens. Simply developing hop varieties possessing resistance to these diseases is not enough, however. New varieties must also have high yields and exhibit excellent brewing qualities with no off-flavors. The proven success of this research program is well known. Up to 60% of all USA hops currently produced were developed by the USDA-ARS program. Each year new experimental lines are evaluated for brewing quality, disease resistance and productivity. Members of the Hop Research Council (HRC) have direct input in the process of determining which experimental lines are advanced for further evaluation. The HRC meetings provide a forum for which brewers provide feedback to the breeding program regarding the specific needs of their brewery. No other forum exists for this purpose.
In addition to the development of new hop varieties, the USDA-ARS Genetics and Breeding program constantly seeks new and more efficient means to develop superior hop varieties. Much of this research focuses upon the identification of molecular markers that will accelerate the selection process. Typically, it can take up to six years for a new experimental line to be evaluated on a commercial scale sufficient to warrant pilot brewing tests. The use of molecular markers in selection has potential to eliminate 1 to 3 years of field evaluation. Furthermore, the use of molecular markers should increase accuracy in estimating the true potential of a variety—particularly in response to severe disease pressure which may not be present in the early stages of evaluation. The use of molecular markers to aid selection has proven valuable in other crops such as tomato and it is only a matter of time before molecular-assisted selection is implemented in hop breeding.
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