THE ESTIMATION OF FROST DAMAGE OF SOME PEACH AND SWEET CHERRY CULTIVARS AFTER WINTER 2005/2006

Abstract

The winter 2005/2006 was the most severe in Lower Silesia during last 18 years. In January, the temperature fell to -25°C, which could damage peach and sweet cherry trees. A survey was done to estimate frost damages on sweet cherry cultivars: 'Octavia', 'Johanna', 'Bianca', 'Regina' and 'Viola', planted in 1994, and 'Karina', 'Kordia', 'Merton Premier', 'Regina' and 'Summit', planted in 1999. For peach, tenyear-old trees of cultivars: 'Inka', 'Redgold', 'Redhaven', 'Early Redhaven', 'Suncrest' and four-year-old: 'Tenira', 'Early Redhaven', 'Cresthaven' and 'Harnaś' were studied. The extent of frost damage was evaluated on excised shoots following Holubowicz's method. At the beginning of May, the visual inspection of blooming and fruit set was done in order to estimate the extent of frost damage on generative parts of trees. The frost at -25°C caused limited damages only in sweet cherry trees. Generally, younger trees were more susceptible to frost than the older ones. The high rate of frost damages was noted on 'Summit' cv. and the lowest on twelve-year-old 'Regina' trees. The frost at -25°C caused very strong damage of one-year-old shoots on peach trees. The visual observation of peach trees at the beginning of May showed a high ability for regeneration of destroyed shoots. The frost at -25°C damaged all flower buds in peach trees whereas sweet cherry blossomed very abundantly and fruit set amounted to 14-58%.