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' (R-2 = 0.90) and linear relation for cv. 'Volna' (R-2 = 0.77). In 2015, however a linear positive regression was found for cv. Volna (R-2 = 0.71) and cv. Calista (R-2 = 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'.

Summary The investigations were conducted at the Research Institute of Horticulture in Skierniewice in 2012−2014. The aim of the research was to evaluate the effect of pre-harvest protection with products: Amistar 250 SC (reference product), Silvit and Huwa-San TR 50 on control of soft root rot and quality and storage potential of celeriac roots. Celeriac plants were protected during the growing season and the last spraying was performed 7 days before harvest. After 7 months of storage characteristic symptoms of soft rot were observed and then evaluation of percentage of infected roots and percentage of marketable and unmarketable roots and decrease of weight were conducted. In the both seasons of investigations the product Silvit showed the best efficacy against soft rot during long storage in comparison to the reference product. There was the highest percentage of marketable roots too. In contrast the influence of Huwa- San TR 50 on soft rot gave inconsistent results. In the first year of investigation its effectiveness was higher than in the control, but next year its effectiveness was significantly lower.