ENGLISH VERSION

Studies conducted in the years 1998–2005 comprised two independent experiments. Experiment I concerned an estimation of the yielding, chemical composition and anatomical features of fruit of 10 tomato cultivars determining their usefulness for freezing. Experiment II evaluated the effect of a reduced number of harvests on the size of the commercial yield and the quality features of fruit meant for freezing.

The best yielding cultivars in the experiments were Benito F 1 (79.8 t • ha -1), Red Hunter (77.8 t • ha -1), Konsul (74.2 t • ha -1) and Kmicic (73.3 t • ha -1). The fruit of cultivars Kmicic, Incas F 1, Benito F 1, Konsul and Red Hunter were characterized by a significantly higher content of dry weight as compared to the standard variety Lima . Significantly the highest content of total sugars was found in the fruit of cultivars Kmicic and Red Hunter.

As far as the usefulness for freezing is concerned, the best fruit were found to be those of Red Hunter, Granit, Benito F 1, Elko F 1 and Incas F 1.

The studies showed a significantly positive correlation between the mean fruit weight and the number of seed cases in the fruit. The thickness of the pericarps was significantly negatively correlated with the number of fruit cases and the proportion of the cases in the fruit volume, and positively correlated with the coefficient of the shape, hardness and firmness. A highly significant relation was found between the number of the seed cases and their total volume in the fruit.

It was shown that a reduction of the number of harvests in the cultivars recommended for freezing did not cause any significant decrease of the yield size. A significantly lower commercial yield of the fruit was obtained as a result of a single harvest.

The decrease of the number of harvests had a significant effect on the quality of tomato fruit. The fruit from double and single harvests were characterized by a significantly lowered firmness as compared to the fruit from a multiple harvest; however, even those were twice better as for the firmness than the fruit of the generally used cultivar Etna F 1. As a result of a reduced number of harvests the fruit of better colouring and with twice as much lycopene were obtained.

The studies found out a relation between the ripeness stage of the fruit and their colouring and the content of lycopene. With the process of colouring of the fruit from the phase of “breakers” to “intensively red”, their colour coefficient increased (the relation a */b * from 0.66 to 1.21) and so did the content of lycopene (from 0.52 to 12.57 mg • 100 g -1).

On the basis of the yielding dynamics of the evaluated tomato cultivars, it seems that the optimum date of the first harvest in the Lublin district is, depending on the weather conditions, the turn of August and September or the first week of September; of the second harvest – the turn of the second and third 10-days’ periods of September.

A single harvest gave a significantly smaller yield of fruit, which were characterized by lowered, but still satisfactory, hardness, much better colouring and a higher content of lycopene as compared to the harvest repeated twice or more times. The optimum date for a single harvest in the Lublin district is in the middle of September.