Influence of hand thinning of flowers and fruits on yielding and fruit quality of apples cultivar Szampion

The thinning of flowers and fruit sets did not change the strength of tree growth in a signifi cant way. Szampion cv. trees on rootstock A 2 grew better than on M.7. The trees of Szampion RENO cv. grew significantly worst. The thinning of flowers and fruit sets decreased the yield from a tree and the total yield from 1 ha of the studied biological material. Flower thinning slightly increased the mean commercial yield as compared to the control trees. Thinning of 50% of flowers at the stage of the pink bud and sets after the June fall decreased the number of fruits on the trees of Szampion cv. grafted on M.7. It was only in 2004 that the flower thinning treatment significantly increased the fruit weight. Flower thinning increased the percentage of fruits with a diameter of over 7 cm in the case of Szampion cv. trees grafted on M.7. This treatment considerably (in 2006 significantly) improved fruit colouring. A positive reaction to flower thinning was also observed in Szampion RENO trees. In the case of Szampion cv., which shows a tendency to excessive fruit setting and small fruits, it is better to apply flower thinning eliminating the excess of sets in the period of cell division in growing fruits than do it later, after the June fall. The inflorescence removal treatment requires much more time than thinning of fruit sets.