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Print version ISSN 0100-2945On-line version ISSN 1806-9967
Rev. Bras. Frutic. vol.30 no.2 Jaboticabal June 2008
Blueberry is a fruit belonging to Ericaceae family and native to several regions of Europe and The United States. Plants are shrubs or have a spreading growth and show deciduous habit. The presence of bees to pollination is fundamental to commercial production of blueberries, since some cultivars are not self-fertile and need cross-pollination. The fruit is a dark-blue berry, slightly flat, with approximately 1 to 2.5 cm of diameter and 1.5 to 4 g, with a crown like structure formed by the persistent lobe of the calyx. Its appearance is similar to cattley guava but showing a blue color and sizing as a grape-berry. Fruits innerly carry lots of seeds and have sweet-acid to acid flavor. The fruit has achieved great focus because of its high medicinal properties.
Blueberry (mirtilo in Portuguese and arándano in Spanish) is included in the small fruit group together with blackberry, strawberry, raspberry and physalis. It is one of the better studied fresh fruits richer in antioxidants. It has a particularly high amount of polyphenols in both peel and flesh, what adds protection function to the cell wall.
It is a little-known specie in Brazil and was first introduced in 1983 through a plant collection brought to Embrapa Clima Temperado (Pelotas, RS) by the scientist Alverides Machado dos Santos. In 1990, the first commercial initiative was launched in Vacaria (RS).
Although blueberry is a recent specie in Brazil, it is largely grown in some countries in the North Hemisphere, mainly Europe and The United State. In these regions, blueberry has a significative commercial importance and moreover, the fruits have been widely divulgated as a "source of longevity" due their nutritional composition. These factors has boosted the blueberry cultivation to non-traditional regions, such as South America (Chile - 2.500 ha, Argentina - 1.500 ha and Uruguay - 200 ha). Some of these countries have the advantage of being able to produce fruits between the harvest season of Europe and North America.
Blueberry growing area in Brazil is superior to 150 hectares, being the production designated either to exportation or domestic market. Rio Grande do Sul is the number one state in blueberry production with 45 growers cultivating 65 ha and 150 ton.
The berries produced in Brazil is commercialized in packages of 125 grams at a price around R$ 8.00. However, according to Instituto de Economia Agrícola, on June/2007 the 125 grams-punnet was sold for about R$ 15.90 (imported blueberry). There is a minimum price for the fresh market because the cost of commercialization is very high. The frozen fruit, destined to industry, is commercialized for half price of the fresh product.
The largest Brazilian consumer market is São Paulo; and the Entreposto Terminal de São Paulo (ETSP) of the Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP) is where there is the large number of wholesalers of the fruit.
Practically, all production is fresh commercialized and few are attended to processing (juice, ice cream and jelly).
There are several species of blueberry. The main species showing commercial expression are separated into three groups according to genotype, growth habit, fruit type and other characteristics. The cultural practices are differenced to each group from plant production to harvest and fruit destination. 1) "Highbush" (large bushes), tetraploid, native to west coast of North America. Among the groups, it shows high quality of both fruit size and flavor. The main specie of this group is Vaccinium corymbosum L.; 2) "Rabbiteye", hexaploid, native to south of North America. It comprises the specie Vaccinium ashei Reade. Comparing to Highbush, it produces smaller fruits and of lower quality. However, it has higher yield per plant and the fruits have a long-term storage. Also, this group has larger commercial importance in low-chill regions because of the plant tolerance to high temperatures and water stress; and 3) "Lowbush", diploid, spreading growth habit, small fruits, processing market destination. Vaccinium ashei is the more promising specie for most cold regions in South of Brazil.
Blueberries can be propagated by a variety of methods such as seeds, suckers and cuttings. Seed propagation is useful in the development of new varieties, since seed-originated plants are different in many characteristics from mother plant. The use of suckers allows obtaining few large plants in a relatively short time. Grafting and layering can be used under particulars aiming.
Under commercial exploration, blueberry is mainly propagated by semi-hardwood or softwood cuttings. Generally, two leaves remain attached in the cutting and the base is treated with auxin to stimulate root formation. Using hardwood cuttings the results are not satisfactory.
Differently from other species blueberry plants grow best in acid soils (pH 4.0 to 5.2) that are well-drained, moist, and high in organic matter (superior to 5%). Soils where the pH is superior to 5.2 it is necessary to correct with sulphur, otherwise the plant will not well develop.
Chill requirements vary from 100 to 1000 hours below 7.2ºC, depending on specie and cultivar.
Harvesting season runs from November to April. The better adapted cultivars are: Aliceblue, Bluebelle, Bluegen, Briteblue, Clímax, Delite, Powderblue, Woodhard, etc.
The plant spacing recommended is 1.2-1.5 x 3.0 meters. The cost of a blueberry plant is approximately R$ 5.00.
The yield per hectare varies from 6 to 10 tons; and commercialization price per kilogram of fruit can reach R$ 20.00.
The fruit can be consumed fresh or utilized for processing such as frozen, deshidratation, canning, jams, liquor, juices, ice-creams and sweeties in general. The ornamentals characteristics of blueberry contribute for an additional commercial alternative.
Blueberry is not only a delicious fruit. Researchers from Universidade Federal do Rio Grande do Sul (UFRGS) proved that the fruit produced in Brazil has the same characteristics of the blueberry cultivated in the United States and Europe, having the same amount of anthocianins pigments. This is the pigment that beneficially acts in our organism: combating the free-radicals, anti-inflammatory action, improving circulation and reducing the "bad" cholesterol. Another fruit benefit is related to eye health and vision.
Scientifics researches have shown that blueberry prevents diseases related to vision, such as cataract and glaucoma, by improving the capacity of reading and the focus of vision. According to the pharmaceutic José Ângelo Zuanazzi of UFRGS, the anthocianins presents in blueberry have the capacity to reverse or prevent the problem, prolonging the visual capacity.
The fact of improving vision attributed to blueberry comes from the Second World, when Britannic pilots ate blueberries before night flights. They believed they would better see the enemy's target.
Some factors make difficult the blueberry expansion in Brazil. They are: climate and soil conditions, slow plant growth, difficulties in harvest practices, little technical knowledge about the culture and the lack of blueberry plants due to non-successful propagation of some cultivars. On the other hand, the growth perspectives in Brazil are promising as for domestic consumption as exportation. As it is a specie that requires high labour, depends on a transportation logistic, adequate packaging and a cooling system to get market, it is fundamental that the growers are well organized (through growers association) at the moment of commercialization.
In most regions of South of Brazil where blueberry has better possibility of adaptation Vaccinium ashei is the more promising specie.
José Carlos Fachinello
Professor of Fruit Crops of Faculdade de Agronomia Eliseu Maciel
Universidade Federal de Pelotas
Caixa Postal 354
96001.970 Pelotas, RS, Brazil.