The aim of the experiment was to assess the effect of applied fertilizers: Hydrocote + Kristalon, Osmocote + Peters and Polyon + Hortimix on the length of the production period and the quality of two heterosis cultivars of Cyclamen persicum from Halios group during two years of the study late date cultivation. The experiment was conducted in the following cycles: 04.08.2003–12.01.2004 and 29.07.2004–30.12.2004. Plant growth was evaluated on the basis of the following characters: total height, plant diameter, the number of leaves, the weight of the aboveground part and tuber diameter. The following characters were assessed in the evaluation of flowering: earliness of the cultivar, flower development rate and the number of flowers and buds. The experiment was completed when most plants reached commercial value, i.e. after developing five flowers per plant. It was found that slow-release fertilizers did not have a significant effect on the growth and flowering of Cyclamen persicum from Halios group, only the application of fertilizer Osmocote resulted in an increase of plant diameter and weight. A bigger effect was found for the year of cultivation: bigger insolation during cultivation boosts growth. Earliness of flowering was not affected by the year of cultivation, cultivars formed similar numbers of flowers, whereas the rate of flower development depended on both factors and in the year with bigger insolation it was higher and resulted in the formation of a bigger number of flowers.

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