Effects of spring frosts in selected apple and pear orchards in the Lublin region in the years 2000, 2005 and 2007. Part I. Experiment at EF Felin. Part II. Selected production orchards

Data concerning the effect of spring frosts on the survival of flower buds of several apple and pear cultivars, as well as on the damage caused by spring frosts to apple fruit are presented in the present paper. Observations were conducted in experimental and commercial orchards in the Lublin area in the years 2000, 2005 and 2007. The lowest temperature in spring in the consecutive years occurred on the following dates: 2000 - 3rd and 4th May, 2005 - 1st April and 22nd May, and 2007 - 2nd and 4th May. The most serious damages of buds were found in apple trees of Red Boskoop, Rubin and Jonagold cvs. grown in the experimental orchard in Felin (Lublin) (this was an average value for the years 2000 and 2007), whereas the buds of the late flowering cultivars of Golden Delicious Smoothee, Royal Gala and Ligol survived with significantly lesser damages. These observations generally confirmed those made in commercial orchards in 2005 and 2007, in which buds of cv. Elise also showed high resistance to spring frosts. Pear trees of cv. Concorde showed low damage to flower buds in 2007 and produced a reasonably good crop. Fruits of cv. Jonagold and its mutations Wilmuta, Jonica, Decosta and Rubinstar proved to be very sensitive to spring frosts, as well as fruits of cv. Lired. The positive influence of the Polish rootstock P60 on flower bud survival was observed in the year 2000. However, this was not confirmed in 2007, thus further observations are necessary to check these effects