Performance of Hop Cultivars Grown with Artificial Lighting under Subtropical Conditions

Abstract

The objective of this study was to determine the duration of the main phenological stages, plant growth development, yield, and cone quality of hop cultivars grown under artificial light (17 h per day) during vegetative development (early season) in a subtropical climate region. The study was conducted in Palotina, Paraná, Brazil (24° S), during the 2021 and 2022 growing seasons. The plants were cultivated in a 5.5 m high trellis system with artificial light supplementation during vegetative development. The hop cultivars Hallertau Mittelfrüher, Mapuche, Northern Brewer, Spalter, and Yakima Gold were used in the treatments. The duration of the phenological stages, vegetative growth (plant height, fresh mass of the plants, number of lateral branches per plant), components of productive yield (number of cones per side branch, number of cones per plant, fresh mass, length, and width of the cone, production of fresh cones per plant, and yield), and chemical components of the cones (alpha- and beta-acid contents, and essential oil concentrations) were recorded. The duration of the phenological stages was visually evaluated, and plant growth was analyzed using non-linear log-logistic regression. The remaining data were subjected to analysis of variance and the means were compared using Tukey’s test. The data were also subjected to multivariate analysis using the principal components test, correlation analysis, and hierarchical grouping. The cultivar Mapuche was considered an early hop in both seasons, and the cultivars Spalter and Yakima Gold were considered early cultivars in the second season. In both seasons, the productive yield components were positively correlated with the precocity of the cultivars, in which Mapuche in the 2021 season and Mapuche, Spalter, and Yakima Gold in the 2022 season had the highest mean of the number of cones per side branch and per plant, production per plant, and productivity. The cultivar Yakima Gold had a positive correlation with the chemical quality of cones, alpha and beta acid contents, and essential oil concentrations, for both seasons.

Does organic hop cultivation in subtropical conditions promote physiological and productive changes?

“…The morphometric and productive characteristics evaluated did not have significant differences between production management, however, it is possible to compare the size of the cones and the height of the plants with other Brazilian research evaluating the Hallertau Mittelfrueh variety, thus creating more reference for research with Brazilian hops. LELES et al (2023) evaluated in the same year that this research was carried out (2021) some characteristics of Hallertau Mittelfrueh, among them, the length of the cones and the results found were similar, they obtained 2.5 cm cones and in this research we obtained 2.83 cm, thus, in both studies, the cones are considered small.…”

“…Despite what is known about the hop growing zone, several crops are currently observed growing in Brazil under subtropical conditions, especially in the southern and southeastern regions (GUIMARÃES, 2021). The city of Botucatu is located in the state of São Paulo in the southeastern region of the country and at latitude 22°50'S, where the photoperiod varies from approximately 10 hours on the shortest day of the year to 13 hours on the longest day of the year, not reaching the ideal photoperiod of 16 hours for crop development, thus promoting early floral induction (PEARSON et al, 2016;KOLENC et al, 2016), we soon noticed that there is a limiting factor for Brazilian production, the length of the day being less than 14 hours maximum, which has already led to many crops failing (LELES et al, 2023).…”