Folia Horticulturae

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Frost resistance of one-year-old shoots on the trees of three pear cultivars

Piotr Iwaniszyniec, Tadeusz Hołubowicz

Department of Pomology
Faculty of Horticulture, Agricultural University
D±browskiego 159, 60-594 Poznań, Poland

In the years 1993-1997, at the Department of Pomology of Poznań Agricultural University, experiments were carried out on the effect of cultivars and rootstocks on the growth, yield, and winter hardiness of three pear cultivars grown in the intensive triple-row-bed system orchard (3000 trees/ha). Results concerning the effect of the three rootstocks, i.e. quince MA, quince MC, quince S1 on growth and yield have been published separately (Iwaniszyniec, Hołubowicz, 1998). The present paper concerns the effect of rootstocks and cultivars on the level of frost resistance of one-year-old pear shoots in four seasons of investigation: 1993/94, 1994/95, 1995/96, and 1996/97. It was found that the one-year-old shoots of the cultivars General Leclerc had a higher level of frost resistance than those from the trees of the cultivars Buerre A. Lucas and Triumph Packhama. A positive effect of the quince S1 rootstock was found in terms of greater winter resistance of one-year-old pear shoot. The means for the four winters of investigation permitted calculation of the temperature conditions of the western part of Poland, critical with regard to resistance for one-year-old pear tree shoots. These temperatures reach: -20°C in November, -24°C - in December, -25°C - in January, and from -23°C to -27°C - in February. The critical temperature in February depended upon the cultivar and the rootstock. In March, when the resistance processes begin to fall, the critical temperature drops to -23°C.

Iwaniszyniec P., Hołubowicz T., 1998. Frost resistance of one-year-old shoots on the three pear cultivars. Folia Horticulturae 10/2: 63-72.