Influence of weather conditions, irrigation and plant age on yield and alpha-acids content of Czech hop (Humulus lupulus L.) cultivars
This study quantifies the effects of weather conditions, irrigation, and plant age on yield and alpha-acids content of Czech hop cultivars Saaz, Sládek, Premiant and Agnus in a 25-year long period, i.e., from 1993 to 2018. The yields of Czech hop cultivars were increasing for the first three years of plant age until they stabilized and then started to decline slightly for 15 to 20 years until they reached the optimal time for replanting. The highest alpha-acids content in hop cones was achieved in the first year of cultivation, followed by a logarithmic decline in the upcoming years. Rainfall was the most significant factor that positively influenced the yield of Saaz hops with correlations of r = 0.59 and 0.61 (P < 0.01) for total seasonal rainfall (April–August), 0.65 (P < 0.001) and 0.60 (P < 0.01) for daily rainfall above 3 mm, 0.37 (P < 0.05) and 0.58 (P < 0.01) for rainfall in May and 0.50 (P < 0.01) and 0.32 (P < 0.05) in July in the Saaz region and the Stekník farm, respectively. The yield of cultivars Sládek, Premiant and Agnus was not statistically influenced by the amount of precipitation, but there was a positive effect of irrigation level on yield increase with correlations 0.58 (P < 0.01), 0.55 and 0.49 (P < 0.05), respectively. High air temperatures during summer were the most significant factor that negatively influenced the alpha-acids content with the correlations ranging from –0.56 to –0.83. However, cv. Agnus showed a stable weather-independent alpha-acids content.
Analytica EBC (1998): Method 7.4. Nürenberg, Hans Carl Getränke Fachverlag.
Črepinšek Z., Čeh B. (2016): Yield of hop variety Celeia related to weather conditions until the end of July. Hop Bulletin, 23: 14–26. (In Slovenian)
Črepinšek Z., Čeh B. (2018): Dependence of hop yield cv. Aurora and Savinjski Golding on weather conditions until the end of July. Hop Bulletin, 25: 5–17. (In Slovenian)
Fandiño M., Olmedo J.L., Martínez E.M., Valladares J., Paredes P., Rey B.J., Mota M., Cancela J.J., Pereira L.S. (2015): Assessing and modelling water use and the partition of evapotranspiration of irrigated hop (Humulus lupulus), and relations of transpiration with hops yield and alpha-acids. Industrial Crops and Products, 77: 204–217. https://doi.org/10.1016/j.indcrop.2015.08.042
Hniličková H., Novák V. (2000): Changes in energy content in vege-
tative and generative hop organs (Humulus lupulus L.) during vegetation. Scientia Agriculturae Bohemica, 31: 241–248.
Keukeleire J.D., Janssens I., Heyerick A., Ghekiere G., Cambie J., Roldan-Ruiz I., Bockstaele E.V., Keukeleire D.D. (2007): Relevance of organic farming and effect of climatological conditions on the formation of α-acids, β-acids, desmethylxanthohumol, and xanthohumol in hop (Humulus lupulus L.). Journal of Agricultural and Food Chemistry, 55: 61–66. https://doi.org/10.1021/jf061647r
Kopecký J., Ježek J. (2007): Influence of weather conditions and irrigation on yield and quality of hops. In: Proceedings of the Scientific Commission of the Imternational Hop Growers´ Convention, Tettnang, 116.
Kopecký J., Ciniburk V., Kořen J., Krofta K., Vostřel J., Klapal I., Brynda M., Nesvadba V., Kozlovský P., Kudrna T., Ježek J. (2008a): Establishment of Hop-Yards by Hybrids Varieties. Methodology for Praxis 1/08. Žatec, Hop Research Institute Co. Ltd., 32. (In Czech)
Kopecký J., Ježek J., Klíma B., Slavík L. (2008b): Principles for Utilization of Progressive Systems in Hop Irrigation under the Condition of Hop Regions in the Czech Republic. Methodology for Praxis 3/08. Žatec, Hop Research Institute Co. Ltd., 80. (In Czech)
Kučera J., Krofta K. (2009): Mathematical model for prediction of yield and alpha acid contents from meteorological data for Saaz aroma variety. ISHS Acta Horticulturae, 848: 131–139. https://doi.org/10.17660/ActaHortic.2009.848.14
Možný M., Tolasz R., Nekovar J., Sparks T., Trnka M., Žalud Z. (2009): The impact of climate change on the yield and quality of Saaz hops in the Czech Republic. Agricultural and Forest Meteorology, 149: 913–919. https://doi.org/10.1016/j.agrformet.2009.02.006
Nakawuka P., Peters T.R., Kenny S., Walsh D. (2017): Effect of deficit irrigation on yield quantity and quality, water productivity and economic returns of four cultivars of hops in the Yakima Valley, Washington State. Industrial Crops and Products, 98: 82–92. https://doi.org/10.1016/j.indcrop.2017.01.037
Patzak J., Henychová A. (2018): Evaluation of genetic variability within actual hop (Humulus lupulus L.) cultivars by enlarged set of molecular markers. Czech Journal of Genetics and Plant Breeding, 54: 86–91. https://doi.org/10.17221/175/2016-CJGPB
Patzak J., Nesvadba V., Henychová A., Krofta K. (2010): Assessment of the genetic diversity of wild hops (Humulus lupulus L.) in Europe using chemical and molecular analyses. Biochemical Systematics and Ecology, 38: 136–145. https://doi.org/10.1016/j.bse.2009.12.023
Pavlovič V., Pavlovič M., Čerenak A., Košir I.J., Čeh B., Rozman C., Turk J., Pazek K., Krofta K., Gregorič G. (2012): Environment and weather influence on quality and market value of hops. Plant, Soil and Environment, 58: 155–160. https://doi.org/10.17221/499/2011-PSE
Pokorný J. (2011): Influence of locality and year on hop production and quality. [Ph.D. thesis] Prague, Czech University of Life Sciences in Prague, 179. (In Czech)
Srečec S., Kvaternjak I., Kaučič D., Marič V. (2004): Dynamics of hop growth and accumulation of α-acids in normal and extreme climatic conditions. Agriculturae Conspectus Scientificus, 69: 59–62.
Srečec S., Kvaternjak I., Kaučič D., Špoljar A., Erhatič R. (2008): Influence of climatic conditions on accumulation of α-acids in hop clones. Agriculturae Conspectus Scientificus, 73: 161–166.
Svoboda P., Hniličková H., Hnilička F. (2008): Changes in yield and quality of hop depending on the irrigation. Cereal Research Communication, 36: 891–894.