Ocena nowo wyhodowanych odmian i klonów jeżyny (Rubus fruticosus L.) z programu hodowlanego Sadowniczego Zakładu Doświadczalnego ISK w Brzeznej

Blackberry (Rubus fruticosus L.) breeding has been carried out at the Experimental Fruit - Growing Station of the Research Institute of Pomology and Floriculture in Brzezna since 1979. Approximately 40 - 50 combinations of crosses are carried out annually; these produce in the region of 3000 - 4000 seedlings in total. The basic aim of the programme is to provide frost resistant cultivars with high - quality fruits, for dessert or processing use. The aim of this experiment was to evaluate the following cultivars: ‘Gazda’, ‘Orkan’, three new thornless cultivars: ‘Gaj’, ‘Polar’, ‘Ruczaj’, and three other blackberry clones: 97472, 97524, 97563. In 2008 the largest yield was obtained from ‘Orkan’ (4.0 kg/plant) , but in 2009 and 2010, much of the yield was lost due to winter frosts. On 6 January 2009 and 20 December 2009, temperatures of about - 20 °C were recorded. In addition, from 23 to 27 January 2010 there were lows of - 22 and - 20 °C, and from 7 to 10 March 2010, the temperature was - 15 °C. The highest yield was obtained from clone 97524 (3.4 kg/plant), but it had a too sour taste. A significantly high yield was obtained from clone 97563 (2.8 kg/plant). Amongst the three new varieties, the highest yield was obtained from ‘Polar’ (1.9 kg/plant), slightly less from ‘Gaj’ (1.6 kg/plant) and then ‘Ruczaj’ (1.4 kg/plant). The lowest yield was produced by clone 97472 (0.8 kg/plant). The highest percentage of marketable fruit during 2008 - 2010 was obtained from the cultivars 'Gazda', 'Ruczaj' as well as the breeding clones 97472 and 97563; the smallest percentage came from 'Gaj' and 97524. ‘Polar’ had the largest fruits (6.8 g) and ‘Gazda’ the smallest (2.2 g). ‘Gaj’ and ‘Ruczaj’ had an average fruit weight of 5.5 g and 4.3 g, respectively. All the varieties and breeding clones, with the exception of ‘Orkan’, were characterised by good resistance of their flower buds to frost damage. The highest number of young shoots was produced by ‘Polar’. ‘Gazda’ had the highest number of root suckers.