Yield and Quality Traits of Field Grown Tomato as Affected by Cultivar and Nitrogen Application Rate

This study was conducted in 2014-2015 to determine the effects of nitrogen (N) fertilization on yield, quality traits, and storage ability of two tomato cultivars, namely, ‘Calista’, for processing, and ‘Volna’, for fresh market. N was applied in doses of 0, 50, 100, and 200 kg N·ha-1. Significant interactions were found between the studied years, N fertilization, and cultivars. Both tested cultivars produced high and similar yields in the year with good growing conditions during vegetation period. In the year with unfavorable weather conditions (lower average temperature, more total rainfall, and a smaller sum of GDD), cv. ‘Volna’ produced a significantly lower yield compared to the cv. ‘Calista’. N fertilization had a significant impact on yield, however, the reaction of cultivars varied in each years. In 2014, quadratic positive regression was found between N rates and yield of cv. ‘Calista’ (R2=0.90) and linear relation for cv. ‘Volna’ (R2=0.77). In 2015, however a linear positive regression was found for cv. Volna (R2=0.71) and cv. Calista (R2= 0.44). The chemical and physical parameters of tomato quality varied depending on the year of cultivation. On average for the studied years and cultivar, increasing N fertilization affected the lycopene and soluble polyphenols content, as well as total flavonoids and ascorbic acid content and antiradical activity. N rate did not affect dry matter and soluble solids content, fruit firmness, fruit redness, and acidity. Cultivar ‘Calista’ had significantly higher lycopene content and better fruit firmness than cv. ‘Volna’ for fresh market. Furthermore, the storage ability of tomatoes cv. ‘Calista’ was significantly better than cv. ‘Volna’.