OFF-SEASON PRODUCTION OF SOUTHERN HIGHBUSH BLUEBERRIES IN THE NORTH OF SPAIN

Asturias in Northern Spain has suitable soil and climatic conditions and is adequate for growing soft fruits. Considering the new European market trends, off-season production of cane and bush fruits seems to be an interesting and profitable way of diversifying the alternatives for the agrarian sector. So, the aim of this work was to evaluate the agronomic behaviour of Southern highbush blueberry cultivars (Vaccinium corymbosum) grown in trenches and under Italian-type tunnels, without heat. Research was started in March 1998 at an experimental farm in VillaviciosaAsturias (5 degrees 26'W, 43 degrees 281N), Northern Spain, with two-year-old Southern highbush blueberry plants. Six cultivars were included in the study: 'Avonblue', 'Flordabluel, 'Misty', 'Reveille', 'Sharpblue' and 'Sunshineblue'. They were planted at 0.75 x 2.0 m. Trenches were filled in with acid peat and pine bark (1:1). The first yield was harvested in 2000, with 'Flordablue', 'Misty' and 'Sharpblue' producing more than 1750 g plant(-1). For the average marketable yield over three years, 'Sharpblue' produced 2061 g plant-1. Ripening of fruit started in the middle of May, berry weight decreased for all the cultivars as the picking period progressed. This trial shows that it is possible to grow Southern highbush blueberry cultivars under plastic and achieve good yields before those obtained in the open field. The cultivar 'Reveille' must be avoided because of both its low productive potential and small fruit size for the fresh market.