The influence of climatic conditions on accumulation of α-acids was determined during the six years (2001 – 2006) of stationary experiment in hop cultivar Aurora. The research results show that increasing sum of effective temperatures during the technological maturity stay in negative correlation with accumulation of α-acids in hop cones (r = - 0.39*), whereas total rainfalls stays in positive one (r = 0.46*) At the same time sum of hours of sun shining stay in not significant negative correlation with the accumulation of α-acids (r = - 0.38). The results of factorial analysis show significant positive multiple correlation between sum of effective temperatures and total rainfalls with α-acids accumulation (multiple r = 0.6232**) and at the same time show a significant positive multiple correlation between total rainfalls and sunshine hours with α-acids accumulation (multiple r = 0.5492*). However, there was a very strong negative influence of reference crop evapotranspiration during the phenological phase of hop cones formation on yield of hop cones and of α-acids (rs = - 0.75* and – 0.88*, respectively). The total rainfalls during the hop vegetation in interval of [212.1; 391.8] mm and also the sum of effective temperature in interval of [1601.74; 2000] ºC caused the α-acids accumulation in hop cones of cultivar Aurora in interval of [7.41; 12.35] % in dry matter. It is important to point out that the level of provided tillage, plant protection measures and fertilization was the same in all six experimental years, which excluded their effects on accumulation of α-acids. These results could possibly contribute in creating a model of predication of α-acids accumulation and beginning of hop harvest.

α-acids; effective temperatures; total rainfalls; reference crop; evapotranspiration; correlations

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia