THE EVALUATION OF YIELD AND ALPHA-BITTER ACID CONTENT IN SELECTED HOPVARIETIES

Almost 300 various hop varieties from 23 countries were planted in the collection of Hop Research Institute in Zatec. This collection repres ents rich generic source for hop breeding. Selected varieties are exam ined from efficiency of main parametres (yield and cc-bitter acids con tent) and its stability pint of view. These parametres are evaluated i n the group of 20 world hop varieties from seven countries in time per iod of 20 years. Brewers Gold variety has the highest yield and Aurora variety shows the highest or-bitter acids content. Under the influenc e of aging just Neoplanta variety shows decline of yield and in Vojvod ina and Aurora varieties declines ex-bitter acids content. Instability of efficiency is more affected by weather conditions of the vegetatio n season than by age of plants (time factor).