The evaluation of yield and alpha bitter acid content in selected hop varieties

Almost 300 various hop varieties from 23 countries were planted in the collection of Hop Research Institute in Zatec. This collection represents rich generic source for hop breeding. Selected varieties are examined from efficiency of main parametres (yield and cc-bitter acids content) and its stability pint of view. These parametres are evaluated in the group of 20 world hop varieties from seven countries in time period of 20 years. Brewers Gold variety has the highest yield and Aurora variety shows the highest or-bitter acids content. Under the influence of aging just Neoplanta variety shows decline of yield and in Vojvodina and Aurora varieties declines ex-bitter acids content. Instability of efficiency is more affected by weather conditions of the vegetation season than by age of plants (time factor).