Evaluation of Hop Cultivars for Commercial Production in North Carolina

Many farmers in North Carolina have started growing hops (Humulus lupulus) or expressed interest in doing so to supply wet and dry hops to the burgeoning craft brew industry in the Southeast. In the US, the available hop cultivars and growing information have been generated almost entirely from the relatively dry regions in the Pacific Northwest. Since hops are perennial, photoperiod sensitive plants and susceptible to several foliar fungal diseases, identifying cultivars that perform well in southern environments with higher humidity is considered essential for success in growing hops in the Southeastern US. In 2011, ten hop cultivars, Cascade, Centennial, Chinook, Galena, Magnum, Mt. Hood, Newport, Nugget, Willamette, and Columbus (Zeus) were grown on a 6 m trellis in a replicated field trial in the southern mountains of North Carolina (Mills River). Over three years, significant variations in plant growth, cone yield, and downy mildew infection were found among these cultivars. Growth and cone yields in the second year of production (2012) were abnormally low because of severe downy mildew infection. Using plant height as an indicator of plant vigor and adaptability, when not under severe disease pressure, Columbus was the most vigorous in growth (>6 m). Magnum and Willamette were weak all three years, never growing more than 3 m. The remaining cultivars were generally intermediate in height. Cascade and Columbus were the top yield performers in 2011 and 2013. Cone yields averaged over those two years were statistically the same for Cascade, Columbus, and Nugget. Galena yielded the same as Nugget but less than Cascade and Columbus. Excluding the disease impacted year, there was a significant yield increase from 2011 to 2013 for the top five cultivars (Columbus, Cascade, Nugget, Galena, and Chinook); more than doubling for Chinook, and increasing 170% and 184% for Galena and Nugget, respectively. Yields of the remaining cultivars (Centennial, Magnum, Mt. Hood, Newport, and Willamette) were significantly lower than the other five varieties for the two growing seasons. In 2012, when exposed to severe downy mildew, Cascade, Chinook, and Nugget were the best performers, followed by Centennial and Willamette. Galena produced the tallest plants that year, even though it had the most disease symptoms. Plant height of Columbus, however, was significantly reduced due to the downy mildew infection. These results will help growers in the Southeast choose hop cultivars with the best chances of success.