The evaluation of the virus-free hop quality after five years growing in the Czech Republic
1997
Fric, V. | Krofta, K. | Svoboda, P. | Kopecky, J. (Chmelarsky Institut, Zatec (Czech Republic))
Virus-free hops are grown at considerable area at the present time (1996). It represents 13 % of total hop gardens area (including new plantings from the year 1996). Virus-free hops still hold (i.e. five years after first planting in the year 1991) considerable quality and quantity advantages comparing with traditional hops. They contain substantially more hop resins, the content of alpha bitter acids is higher by nearly 100 % in dependence on the year of harvest. Content of beta bitter acids changes slightly and does not exceed 10 to 15 % as a rule. The analyses of hop oils confirm presence of farnesene as the most important marker of the Saaz semi-early red-bine hops in hop oils. Virus-free hops give higher yield. The difference, comparing to traditional hops, is the most significant in the first crop. After achievement of full effectiveness virus-free hops give higher yield by 20 to 25 %. No reinfection by ApMV has not been detected yet.
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