Climatological conditions of the southern Santa Catarina state highlands for hop production

ABSTRACT This study aimed to characterize solar brightness, photoperiod, phenology and productivity of Chinook, Columbus, Cascade and Yakima Gold hop cultivars grown in the municipalities of Lages and São Joaquim in Santa Catarina state, southern Brazil. The phenological stages evaluated were: beginning of sprouting, emission of lateral branches, beginning of flowering, formation of cones and beginning of harvest in the 2018/2019 production cycle. Photoperiod and solar brightness were calculated with data obtained from the Environmental Resources and Hydrometeorology Information Center of Santa Catarina State, in Lages and São Joaquim. The observed results demonstrate hops develops at latitude 27º South, there was a difference in behavior in the phenological cycle of the cultivars, characterizing Yakima Gold as early, with 143 days and Columbus with 191 days, late. Since the first agricultural harvest, there is the production of cones. With 5.87 hours per day solar brightness average, in Lages, 3,300 kg of fresh hops were produced per hectare. In São Joaquim, with a 5.53 hour per day solar brightness average, 6,000 kg of fresh hops were produced per hectare.


INTRODUCTION
As one of the five largest beer producers, Brazil stands out in the beer market internationally, producing and selling around 13 billion liters.As a necessary raw material for the preparation of beer, four basic ingredients are needed: water, malt, yeast and hops.This last ingredient is imported in full volume, to serve the national brewing industry.
World hop production is concentrated between latitudes 35º and 45º, south and north, however the largest world hop producers are located in the northern hemisphere, with the United States and Germany being the largest producers of this culture (Fagherazzi & Rufato, 2018).
Hop farming got its place in Brazil more than 60 years ago, with the arrival of European immigrants (Pereira, 2021).However, the cultivation of hops has given way to other economic activities in the country.Less than 10 years ago, hop farming returned to the fields of cultivation, due to the growing number of microbreweries registered in recent years in Brazil (Spósito et al., 2019).
For several plant species, flowering is dependent on the relative length of day and night, so the duration in hours of the day, in relation to the night, is called the photoperiod.
This mechanism quantifies intervals of darkness with intervals of light to which plants are exposed (Baruzzi, 2005).
According to Rybacek (1991), cultivated quality hops generally require 1,800 to 2,000 hours of solar radiation per year.Within this interval, 1,300-1,500 hours must occur in the vegetative period, where hop plant needs more energy to create biomass.Considering vegetative period of hops Mariana Mendes Fagherazzi et al. lasts between 122 and 127 days (Rybacek, 1991), plants need an average of 11.2 hours of sunshine per day in the spring.In field, warmer temperatures and longer photoperiods bring the hop at transition from juvenile to adult phase.Warmer temperature is a condition to hop flower under shorter day length.However, to achieve a plenty of flowering and yield, the plants need more hours of light during early season (Jastrombek et al., 2022).Recently the effect of photoperiod was disentangled of vernalization temperature.Increasing the photoperiod above the critical length for hop flower induction in both vernalized and non-vernalized plant material, hops do not require either low temperature chilling or dormancy to achieve typical flower initiation, formation, and cone yield (Bauerle, 2019).
This study aimed to characterize phenological development and quantify the photoperiod, solar brightness and productivity of four hop cultivars in the southern highlands region of Santa Catarina State, in order to identify new cultivation options for small producers.(Cardoso et al., 2003).The soils in the experimental areas are classified as aluminum humic cambisol (Bertol, 1994) Phenology analysis was performed only for the municipality of Lages.

MATERIAL AND METHODS
Photoperiod was calculated for Lages and São Joaquim, for the period of one year, through the astronomical Earth-Sol relations (Silva, 2006).The mathematical relationship (Equation 1) for the calculation of the photoperiod (N) is given by: Hn considered as the hour angle for sunrise, in hours.
The Hour angle, in turn, depends on a mathematical relationship (Equation 2) that considers the latitude of the location (Ф) and the solar declination (δ): Solar declination is calculated by the following mathematical relationship (Equation 3), considering the number of the day in the year (NDA), or Julian day: Data referring to the number of hours of sunlight, from the cultivation period, were obtained from the Epagri Automatic Meteorological Station, for the locations of São

Joaquim and Lages
Determination of plant phenology was carried out by the same person and on the same plants.The beginning of sprouting, the emission of lateral branches, the beginning of flowering, the formation of cones and the beginning of harvest were evaluated weekly, following the phenological scale proposed by BBCH (Rossbauer, 1995).
Estimated productivity was determined from the production of fresh cones obtained by plant and estimated per hectare.The treatments consisted of cultivars in a fourblock randomized design with six plants per treatment.
The data obtained were evaluated descriptively, according to Silvestre (2007), since through descriptive statistics it is possible to compare the same phenomena under different conditions.

RESULTS AND DISCUSSION
Figure 1 shows weeks and months of the main phenological stages of the cultivars evaluated, during the 2018/2019 harvest according to the methodology proposed by BBCH (Rossbauer, 1995).Results demonstrate different periods of Climatological conditions of the southern Santa Catarina state highlands for hop production development among the cultivars evaluated, corroborating with studies carried out in Italy, in the Mediterranean that point out that there is a significant difference between cultivars in relation to their phenology (Rossini et al., 2016).
Sprouting phase started in first week of September for Gold presented the shortest period of formation of the lateral branches, the most recent was from the fourth week of November until the second week of December (Figure 1).
Main branch started growing in the third week of November in Chinook and lasted for six weeks, until the fourth week of December together with Columbus.Cascade also showed a period of growth of the main branch of five weeks like Columbus, but this was later, from the second week of December and extended until the second week of January.Yakima Gold had the shortest period, only in the third week of December (Figure 1).
Cascade and Yakima Gold shown a short reproductive period, between the emergence of the inflorescences and the harvest, when compared with the other cultivars.It was 37 days for Cascade, 38 days for Yakima Gold and approximately 60 days for Chinook and Columbus cultivars (Figure 1).
Yakima Gold is more precocious (143 cycle days), followed by Cascade (180 days), Chinook (189 days) and Columbus (191 days) (Figure 1).The lower cycle of cultivar Yakima Gold can be explained by its lower requirement in degrees days to enter the reproductive period, which can be confirmed by the results of 885.66 hours of accumulated sunlight throughout the period of vegetative and reproductive cycles (Table 1).Photoperiod is not related to the total time of exposure to the Sun, but to the period in which it will be possible to have situations of sunlight (Silva, 2006).In this way, the number of hours of sunlight will be less than or equal to the photoperiod, which will be the maximum possible value for heat stroke.
Due to the proximity between cities, the minimum and maximum values of the photoperiod throughout the year are similar (Figure 2).Considering the two locations studied, and their respective cultivation areas with four hop cultivars (Lages) and three hop cultivars (São Joaquim), and based on information of hours of sunlight (hours and tenths) provided by the Automatic Meteorological Station of Epagri, for the entire growing period, we have the following information (Table 1).

Reference information about hop cultivars in north
hemisphere, on the amount of sunlight vary from 1,800 to 2,000 hours per year (Rybacek, 1991), from 1,330 to 1,500 in the growing season, so it has to be that, con- August, for the northern hemisphere.In the study conditions, daily brightness average values varied between 5.81 to 6.19 hours per day (Table 03).There are no data in Brazilian literature that relate the number of sunlight hours and productivity of cones and/or stadiums of hops development.
Fresh cones estimated yields of studied cultivars ranged from 157.13 kg/ha to 3,365.54 kg/ha in Lages, and from 4,983.21 kg/ha to 6,192.44 kg/ha in São Joaquim.
Considering cultivars, Columbus was the most productive in both evaluated regions, but there was similarity in estimated productivity between Chinook and Cascade in Lages.However, Yakima Gold showed the lowest estimated yield (Table 3).
Therefore, for choosing a cultivar it is necessary to know initially the maximum production potential in each region, to analyze at least the climatic conditions of the region and possible conditions of cloudiness, which results in different sum of sunlight hours from the photoperiod, and then verify the relationship between productivity and effective hours of sunlight.
Chinook and Columbus, in the second week for Cascade and in the fourth week of September for Yakima Gold, that takes longer to start sprouting, 15 days after the first early cultivar, Columbus.Analyzing phenology of different grape varieties inSerra Gaúcha region, northern Rio Grande do Sul State,Mandelli (2003) explains the classification based on the growing season is important for wine growers, as it allows the use of early growing varieties in places with low risk of the occurrence of late frosts, and varieties of late sprouting in places prone to this phenomenon.If this same reasoning were used for hops cultivation, due to the fact that grapes are also grown in the studied regions and there is still no theoretical reference for the basis of discussions for hops varieties in Brazil, it could be indicating Yakima Gold as cultivar best option, of late sprouting, to try to avoid frost damage in the southern highlands of Santa Catarina.Leaf development started in third and fourth weeks of September for Chinook and Cascade lasting three weeks.Columbus started leaf development in the fourth week of September and extended until the first week of October.However, Yakima Gold cultivar showed late leaf development if compared to other cultivars, from the second week of October, until the third week of November.Formation of lateral branches started in the second week of October in Chinook and Columbus, extending until the second and third week of November.Cascade had the formation of the lateral branches from the third week of October to the first week of December.However, Yakima
sidering the duration of 122 to 127 days, 11.2 hours of sunshine per day in such a period.This is not observed in the present research, since the entire production cycle presented between 800 to approximately 1,200Pavlovic et al., (2012) studied four meteorological parameters on the influence of alpha-acid in the cultivar Aurora during 16 harvests in Slovenia.Solar brightness total average for those years was 1,139.2hours.Under the study conditions, Yakima Gold cultivar completed the production cycle with less than 1000 hours of sunlight (Table02) and for São Joaquim the studied cultivars completed the cycle with more hours of sunlight when compared to the study conditions in Slovenia.Smith (1974) studying four cultivars in four agricultural harvests in different European countries found that the average hours of sunlight varied from 4.4 hours and 8.8 hours in the period considered critical, July to

Table 1 :
Characterization of accumulated daily sunlight amount for hop cultivars of the 2018/2019 production cycle, for Lages and São Joaquim.Source: the authors, 2020 Climatological conditions of the southern Santa Catarina state highlands for hop production Photoperiod values for the two cities analyzed vary from 10.2 to 13.8 hours, minimum and maximum, respectively throughout the year.Therefore, a maximum variation of 3.6 hours between the shortest day (winter solstice) and the longest day (summer solstice) for the southern hemisphere.However, it is worth mentioning that these values are actually possible values of solar brightness during certain times of the year.What is really important to know is the amount, in effective hours of sunlight, available in a given region.

Table 2 :
Number of hours of medium, maximum and minimum solar brightness (BS) for the 2018/2019 harvest, in São Joaquim and Lages-SC.Lages, SC, 2020.Source: the authors, 2020

Table 3 :
Cone productivity (mass) and average solar brightness in the 2018/2019 growing period.Source: the authors, 2020