Chemical fruit composition of highbush blueberry cultivars grown on different substrates

The aim of this study was to evaluate the influence of the planting substrates on the basic chemical fruit composition of six blueberry cultivars: 'Brigita Blue, 'Bluetta', 'Bluecrop', 'Sunrise', 'Blueray', and 'Safir'. Research has been conducted at the experimental field of the Research Institute for Fruit Growing Pitesti, in the period of 2010-2012. On average, 'Safir' fruits had the highest content of L-ascorbic acid on three planting substrates tested in all years of study. The average values of dry matter, total acidity and ash showed no significant differences between the planting substrates and cultivars. The mean values of reducing sugars, tannin substances and potassium contents on the b3 planting substrate (50% acid peat + 25% sawdust + 20% native soil + 40 g powder sulphur) were significantly higher for 12.23% compared to the average values obtained on b2 planting substrate (70% sawdust + 25% native soil) and for 12.42% higher than the values obtained using b1 planting substrate (50% peat + 25% manure + 25% native soil + 60 g powder sulphur).