Bases to make an adequate choice of variety

24/10/2016

From certain key factors for the cultivation of cranberry, there are cultivars that fit better than others to different regions of the country. Know the factors that will allow you to make the best decision when choosing a variety.

Despite what you may think, the blueberry is a rustic plant. But, although it has adapted well to the country, not all varieties perform equally in different regions of the country.

As the crop grows in the country it has become clear that it is crucial to choose the varieties according to the climatic and geographical characteristics of the place where the crop will be installed.

«Each species and variety has specific agroclimatic requirements, which allows us to deduce what will be its best ecological niche in our country», says Walter Lobos, director of the Department of Agricultural Production of the University of La Frontera.

What are the varieties that respond best in each region? «There are varieties for all climates where there is agricultural activity, so the issue is choosing the cultivars that meet the quality and production requirements that make the crop profitable», says Raúl Olivares, production manager of Driscoll's Chile.

When the commercial development of cranberry began in Chile in the mid-eighties, the idea of the experts was to develop this species from Chillán to the south, for which there were varieties such as blue haven, stanley, bluejay, blueray; Herbert, Patriot, Ivanhoe and others. Over time some were replaced by varieties with better production and quality expectations, such as elliott; bluecrop; blue gold; brigitta and others.

«Many are still present in the spectrum of varieties used in southern Chile», says Walter Lobos, from the University of La Frontera.

One of the main problems of the time was the poor quality of the fruit that was cultivated. For example, patriot or herbert stood out for generating a berry of good size, but with reduced firmness.

«When at first it was exported by plane, that didn't matter. Today, however, when most fruit is transported by boat, it does matter. Thus, these varieties have been left out, because they do not withstand the journey., comments Humberto Serri, academic of the Department of Plant Production of the Faculty of Agronomy of the University of Concepción.

In order to increase production and address more markets, the industry's strategy aimed to expand the plantation area from the Coquimbo Region to the Maule Region. To do so, work began with varieties from breeding centers, whose climates were less restrictive and more benign. In this group o'neil stand out; duke; legacy, star and jewel.

Thus, in the last 15 years have seen advances that have allowed to expand the availability of plant material.

Know to differentiate

In this sense, the best way to avoid making mistakes in choosing the variety is to carry out a complete evaluation, which starts at the farm, identifying the factors that can not be controlled and that determine the development of the cultivar. For example, the pH level of the soil (land), its electrical conductivity and the availability of cold hours (commune-region). The next step will be to distinguish the cultivars that best fit those conditions and those that will perform best in that orchard.

«A variety may be growing in San Fernando and Temuco, and have a different behavior, without being bad or having to be discarded, but in one sector it will have certain advantages more than in the other», says Walter Lobos.

According to the experience of the specialist, no more than 20% of producers receive technical advice of this type.

Characteristics and aptitudes

The ideal conditions to grow blueberries (depending on the variety) are, in general, to have soils whose pH levels vary between 4,5 and 5,5 and have availability of cold hours (with threshold of 7º C), in order to comply with the winter recess (northern higbush cultivars need between 800 and 1.100 hours, while southern highbush require between 400 and 500 hours).

In the Maule and Biobío regions, for example, the soils have a pH that, in general, reaches 7 and, depending on the area, they can have up to 1.000 cold hours. As you move north, the acidity of the soil will increase, while the availability of cold hours will be reduced. Even when there is clarity about the indices that exist in each zone, it is important to know the requirements of each cultivar, because these, in some cases, are lower than the mentioned ranges.

«Considering both factors, varieties with a low requirement for hours of winter cold and a high sum of degree days 'adapt' better to areas in the north or central-north of the country; On the contrary, varieties originating in areas with a cold climate will have the opposite requirement, so they will be better adapted to the central-southern and southern areas of the country., says Walter Lobos.

Raúl Olivares, for example, highlights duke, a variety that has a high cold requirement and which is still in effect these days. «In temperate climates, meanwhile, the standard variety for many years has been o'neal», he adds.

New plant material

According to the study «Update on the Marketing of Fruit Plants, Vines and Vegetable Plants in Chile» of the Office of Agricultural Studies and Policies (Odepa), 2014 commercialized 35 varieties of blueberry plants in the country, of which 15 corresponded to protected cultivars.

Today, cultivars are commercialized in the country for all climates. Those of the evergreen type, with low cold requirement, for example, can be planted from Ovalle to Rancagua, but also from the interior coastal dry land to the Biobío Region. Those of high cold requirement, meanwhile, adapt to the pre-cordilleran zone (east of the 5 Route) from Rancagua to Los Angeles, going through the entire valley to Osorno and even further south.

«All this must be qualified with varieties that are a bit wildcard, such as legacy, with the microclimates of each region, and with the option of using plastic tunnels to have conditions that allow an earlier harvest», says Raúl Olivares, who points out that although some evergreen cultivars are already being tested in the country, there are still no conclusions regarding their performance.

Within the group of southern and northern highbush, there are new cultivars developed through private breeding programs, which have shown different results. However, given that its commercialization often contemplates the payment of a royalty, it is not always possible to know its performance.

Source: Berries Special. The Mercury