Effect of soil substrate on the chemical composition of fruit of some tomato cultivars grown in an unheated plastic tunnel

The effect of cultivar and soil substrate on the chemical composition of tomato fruit was studied in an experiment conducted over the years 2004-2006 in an unheated plastic tunnel. The experimental materials comprised eight tomato cultivars: Atut F-1, Baron F1, Bekas F-1, Carmello F-1, Gracia F-1, Ognik F-1, Slonka F-1, Terra F-1, as well as two types of soil: peat substrate purchas and hotbed soil. Tomato fruit was assayed for the content of: (try matter, L-ascorbic acid, total sugars, simple sugars, organic acids and nitrates. The levels of dry matter and L-ascorbic acid in tomato fruit were found to be significantly dependent on both the cultivar and the cultivar-substrate interaction. Cultivar Atut F-1 had the lowest water content of fruit, while cv. Terra F, was the richest source of L-ascorbic acid. The fruit of tomato cultivars grown in hotbed soil accumulated more dry matter. Hotbed soil, compared to peat substrate, had a more beneficial influence on the concentrations of sugars and nitrates in tomato fruit. The average N-NO3 content of the fruit of the investigated tomato cultivars was below the maximum permissible level, whose exceedance would pose a hazard to human health. The fruit of all tomato cultivars accumulated more nitrates when grown in peat substrate. The lowest nitrate content was recorded in cv. Bekas F-1.