Yield and Quality Performance of Italian and American Strawberry Genotypes in Brazil

The strawberry cultivars show variation in agronomic performance when grown in different regions of the world, due to the genotype × environment interaction. The aim of the study was to evaluate the yield performance and quality of Italian and American strawberry cultivars. We evaluated the phyllochron, which measures the time required for the emission of successive leaves in a plant, the number and commercial and non-commercial fruit yield, titratable acidity and total soluble solids (obtained from evaluations of the Brix degree of the fruit). The experimental design was a randomized complete block with 11 treatments, which were composed of the Italian strawberry cultivars (CREA-FRF PIR 29, CREA-FRF PA3, CREA-FRF CE 51, CREA-FRF CE 56, CREA-FRF Jônica and CREA-FRF Pircinque) and American (Albion, Camarosa, San Andreas, Camino Real and Aromas), with four replications per treatment, eight plants per plot, giving a total 32 plants per cultivar. Analysis of variance showed differences for phyllochron, marketable fruits yield and total soluble solids content. The American cultivar Albion showed higher phyllochron, the cultivar CREA-FRF Pircinque the lowest phyllochron. The highest yields of marketable fruits were found in American cultivars Camino Real and CREA-FRF Pircinque. The higher solids soluble was observed in Italian cultivars. Thus, we highlight the Italian strawberry cultivars, because they reflect good yield when compared to the American cultivars.


Introduction
The main strawberry (Fragaria × ananassa) producers worldwide are China, United States, Spain and Japan, which together produced 4949479.00tons of the fruit (FAOSTAT, 2017).The Brazil produced in 2014 about 3527 tons of strawberry (FAOSTAT, 2017), distributed in the states of Minas Gerais, Rio Grande do Sul, Paraná, Santa Catarina, São Paulo, Espírito Santo, Distrito Federal, Bahia and Ceará.The strawberry crop (Fragaria × ananassa) had great development in the last decade due to its high return and possibilities of transformation in the cultivation process (Rigon, 2015).Usually, the crop yield varies according to several variables, such as cultivar, production system, management culture and local cultivation which are able to influence the profitability of production.For this, the cultivars have been evaluated for acclimatization to different regions, which wouldl contribute to the lower production costs (Dávalos-González et al., 2014).
production and the size of the strawberry fruits are influenced by genotype characteristics, planting season, as well as its interaction with meteorological conditions (Rahman et al., 2014;Zheng et al., 2009), which stimulate the ideal conditions for plant growth, contributing to increased or reduced crop yield.However, there is still little research on sensory and nutritional analysis of cultivars in growing regions.
The cultivation environment, the production system, temperature and solar radiation may modify the plant phenology, requiring its knowledge in order to determine planting season and requirement of meteorological variables for a better development and expression of agronomic traits of different cultivars (Rosa et al., 2013;Costa et al., 2014;Tazzo et al., 2015).Thus, it comes to using the phyllochron to measure the time required for issuing successive leaves on a plant (Hermes et al., 2001), taking into account the effect of temperature on the plant development (Streck et al., 2005).
Thus, the aim of this study was to evaluate the performance and yield components of Italian and American strawberry cultivars including phyllochron and fruit quality.

Material and Methods
The work was conducted under low tunnels (height 0.6 meters, with distance between arches of 2 meters, covered with plastic of 100 microns) in the experimental field of the Federal University of Santa Maria, Frederico Westphalen campus, Frederico Westphalen, Rio Grande do Sul, Brazil, located geographically at 27 o 23′728″ S and 53 o 25′749″ E 493 meters of altitude.
The soil of the experimental area is classified as Red Latosol dystrophic typic with clay texture, deep and well drained (Embrapa, 2006).The climate is Cfa by the Köppen climate classification, being subtropical humid, characteristics of rainy subtropical with an average annual precipitation high and well distributed throughout the year, with mean for anual.Land preparation was carried out with a disc plow and harrowed using a disk harrow.Fertilizer rates were applied according to the previous soil analysis and calculated according to the culture requirements (Santos & Medeiros, 2003).Cattle manure was incorporated into the soil (5.5 kg m -2 ) and before planting, we used a dose of 55 g m -2 chemical fertilizer (10-20-10).
The Italian seedlings were planted on the 6 th of May 2015.And the American cultivars were transplanted on June 3 rd to Camino Real, June 2 nd to Camarosa, June 8 th to Albion, and the San Andreas and Aromas cultivars were transplanted on June 22 nd of this year.The planting dates followed the delivery schedule of the seedlings by nursery owners and importers organs, since most of seedlings used in Brazil for the implementation of crops, are from nurseries located in Chile and Argentina.The irrigation and fertigation were made through drip tape, following with cultural practices in accordance with the requirements of the culture.
The experimental design was a randomized complete block with 11 treatments, which were composed of the Italian strawberry cultivars (CREA-FRF PIR 29, CREA-FRF PA3, CREA-FRF CE 51, CREA-FRF CE 56, CREA-FRF Jônica and CREA-FRF Pircinque) and American (Albion, Camarosa, San Andreas, Camino Real and Aromas), with four replications per treatment, eight plants per plot, giving a total 32 plants per cultivar.The Italian cultivars used in this study came from an agreement between Brazil and Italy, from the Convention for experimentation and dissemination of genetic material from Italian strawberry in Brazil.The agreement was signed in 2012 between the Agroveterinárias Sciences Center at the University of the State of Santa Catarina -UDESC and 'Consiglio per la Ricerca in Agricoltura and L'analisi dell'Economia Agraria' -Unità di Ricerca per la Fruticultura (CREA-FRF) from Italy.
The average air temperature was carried out using a data logger where the minimum and maximum air temperatures data inside the low tunnels was captured.The following formula was used to calculate the mean air tempertaure, where T represent the temperature: (1) Based on the average air temperature, the daily thermal time (DTt) was calculated according to the following aquation (Arnold, 1960): The base temperature (Tb) is defined as the daily thermal time units above a lower base temperature, below which the plant does not grow or its development is so slow that it can be ignored (Rosa et al., 2011), for the strawberry evaluation a 7 °C as a base temperature (Mendonça et al., 2012).
Then, we calculated the accumulated thermal time (ATt), which is the sum of DTt:

During the fruits (NC titratable a
For phyllo the leaves the count w estimate th thermal tim The fruits non-comm than 6.0 g.

Qualitative the harves of total ac of total sol
The data w Pearson co

Results
The follow the experim the experi oscillated   (Rahman et al., 2014).In Vrbovec, Croatia, the Albion cultivar showed higher TSS content in relation to the Monterey, Capri and Murano cultivars in hydroponic crop (Samec et al., 2016).Cao et al. (2015) reported that genetic factors and environmental conditions influence the flavor and fruit quality (as measured by soluble solids and titratable acidity).The soluble sugars are products derived directly from the photosynthesis and the differences in sugar content reflects indirectly higher photosynthetic efficiency (Yu et al., 2015), and may list phyllochron plant with TSS, the lower the phyllochron the greater the number of leaves, reflected in higher photosynthetic and productive efficiency.For example, in the present work, CREA-FRF Pircinque cultivar showed lower phyllochron, higher leaf emission rate, and probably higher photosynthetic rate, that resulted in greater productive efficiency and higher total soluble solids content (Table 1).Note.NCF: number of comercial fruits; CFY: comercial fruits yield; NNCF: number of non-comercial fruits; NCFY: non-comercial fruits yield.TA: titrable acidity; TSS: total soluble solids; TSS/TA: ratio of total soluble solids and titratable acidity.ns = non-meaningful; * = meaningful to 5% of error probability.
The Pearson correlation analysis indicated strong and positive meaningful correlation of Phyllochron with the AT variable, strong negative correlation with TSS, strong negative correlation with ratio TSS/TA, in addition to NCF, indicating that the higher the phyllochron (less the number of leaves), the greater the total acidity of the plant and the smaller the amount of sugars, due to reduced photosynthetic capacity of the plant.The same was observed for the NCF, which was lower the higher the phyllochron, reflecting the lower assimilates translocation capacity for the fruit yield.
Meaningful and positive correlation was also observed between NCF and NNCF and TSS/AT, inferring that larger commercial fruit values also increase the amount of NNCF and decreased TA fruits.The CFY variable showed a meaningful positive correlation with the NNCF and NCFY variables, because as it increases the production of commercial fruits it also increases the number and the production of non-comercial fruits.In the same way, TA and TSS variables showed negative and positive correlation respectively with the variables TSS/TA, that is, fruit with higher titratable acidity (TA) had lower TSS/TA, and fruits with higher TSS presented positive relationship with TSS/TA (Table 1).
Thus, must be search alternatives that increase the leaf area and leaf emission rate in order to produce fruit with lower total acidity and higher soluble solids content, because these are a direct product of photosynthesis, and differences in sugar content also reflects indirectly on the higher photosynthetic efficiency (Yu et al., 2015).
The Italian cultivars, especially the cultivar CREA-FRF Pircinque, realised higher yields when compared to the American cultivars.It is concluded that the evaluated cultivars differ for the yield and fruit quality variables.

Table 1 .
Correlation coefficients between phyllochron variables, yield and quality of fruit grown strawberry cultivars under low tunnels in northern region of Rio Grande do Sul, Brazil