Freezing injuries to flower buds and their influence on yield of apricot (Prunus armeniaca L.) and peach (Prunus persica L.)

Each spring, for 3 consecutive years, 2009-2011, the degree of freezing injury to overwintering flower buds of selected cultivars and clones of apricot and peach was evaluated at the Dabrowice Research Institute of the Horticulture E$xperimental Orchard (District of Skierniewice, Poland). Apricot flower buds were damaged less severely than those of peach during the winter of 2009/2010 when the lowest temperatures (maximum drop in temperature) coincided with the full dormancy stage of the trees. Conversely, peach flower buds were less damaged than buds of apricot when the maximum drop in temperature occurred after the late winter thaw in both 2008/2009 and 2010/2011. Under Polish climatic conditions, peach proved to be more reliable than apricot in consistency to produce fruit. Results have shown that the most hardy apricot and peach cultivars can develop very strong winter hardiness allowing the trees to survive temperatures as low as-28°C, as long as there are no severe temperature fluctuations during late winter.