PRELIMINARY EVALUATION OF THE GROWTH AND YIELD OF FOUR JAPANESE PLUM CULTIVARS (Prunus salicina Lindl.) GRAFTED ON WANGENHEIM PRUNE SEEDLINGS

Japanese plum trees of the cultivars ‘Kometa’, ‘Najdiena’, ‘Skoropłodnaja ’ and ‘Shiro ’ grafted on Wangenheim Prune seedlings, were planted in the spring of 2006 at the Fruit Experimental Station in Samotwór near Wrocław, Poland. As the control, trees of the ‘Amers ’ cultivar, which belong to European plums, were used. All trees were planted at a spacing of 4.0 x 2.0 m (1250 trees per hectare). The experiment was established in a randomized block design, in four replications, with 5 trees per plot. In 2006-2009, records of vegetative growth, abundance of blooming, yield, and fruit weight were taken. The first significant yield was achieved in the third year after planting. In 2008-2009 trees of ‘Shiro ’ had an abundant yield (48.5 kg∙tree-1). ‘Shiro ’ produced a sig-nificantly higher yield compared to other cultivars. There were no significant differ-ences between ‘Amers ’ (27.3 kg∙tree-1) and the Japanese plum cultivars ‘Kometa’ (29.2 kg∙tree-1) and ‘Skoropłodnaja ’ (21.5 kg∙tree-1). Japanese plum fruits were sig-nificantly smaller compared to the European ones. The cultivar ‘Amers ’ had the heaviest fruit (53 g). The Japanese plum trees had smaller fruits, and among the them, the cultivar ‘Shiro ’ had the largest fruit (44 g). The observations showed that ‘Shiro’ produced higher yields, gave large fruits, and had intensive blooming, but the growth of the trees was very strong