Studies were carried out in the years 2006–2008 in Przybroda near Poznań. Objects of studies consisted of 8-year old peach trees ‘Harbinger’ cultivar grown on three rootstocks: Manchurian Peach, Sand Cherry and Rakoniewicka Seedling. Tree crowns had a vase form and they were strongly damaged by frost during the winter 2005/2006. In spring 2006, intensive tree pruning was carried out. The objective of the studies was the estimation of the effect of a radical pruning of frostbitten trees on their regeneration and yielding, as well as to estimate the role of rootstocks in this process. Studies have shown that the tree pruning evoked a very strong compensation growth, the reaction of trees was the stronger, the more intensive was the tree pruning. As a result of the pruning, after 3 years, the lowered tree height (on the average by 40–50 cm) was maintained in relation to the control trees. After pruning, in the tree crown, longer productive long-shoots with diameters > 0.5 cm, developed as compared with the control. However, the radical pruning of trees caused in the third year after pruning a decrease in tree yielding from 30 to 40%, in comparison with the not pruned trees.
The aim of the study conducted during 2007-2009 was to estimate the growth and cropping of four peach tree cultivars growing on three vegetative rootstocks (Ra- konievicka, Hui-Hun-Tao, and Minnesota seedlings). The growth of the trees in the orchard was evaluated on the basis of trunk cross-sectional area and canopy volume. In the years 2008-2009, the fruit yield and 100 fruits from each tree were weighed separately. The weakest growth of trees was observed on Minnesota seedling root- stock as well as 'Harnaś', and 'Royalvee' peach tree cultivars. A better total yield was obtained from peach trees growing on Rakonievicka and Minnesota seedling root- stocks. 'Harbinger' cultivar gave a weaker yield in comparison with other cultivars. Fruits on Minnesota seedling rootstock had a smaller mass. The highest yield efficiency was from trees growing on Minnesota seedling, except for the 'Harbinger' cultivar, which had the lowest yield efficiency.
The usefulness of four rootstocks for peach trees was evaluated in the experiment, conducted during 2006-2007. One-year old maiden peach trees of the cultivars: 'Harbinger', 'Royalvee', 'Redhaven' and 'Reliance' were produced in nursery on four rootstocks: Rakoniewicka seedling, 'Siberian C', 'Hui-hun-tao' and Minnesota seedling. The highest percentage of maiden peach trees was obtained on 'Siberian C' and Minnesota seedling rootstocks. The maiden peach trees obtained on Minnesota seedling rootstocks had the weakest growth vigour while these on 'Siberian C' rootstock were characterised by an average growth. The growth of maiden trees of 'Harbinger' cultivar was the strongest whereas the growth of maiden trees of ' Redhaven' cultivar was the weakest, independently of the rootstock used. The percentage of maiden peach trees compatible with Polish Norm depended on the growth vigour of the rootstock and the best result was obtained on Rakoniewicka seedling.