GROWTH, YIELD AND FRUIT QUALITY OF EIGHTEEN PLUM CULTIVARS GRAFTED ON TWO ROOTSTOCKS

The experiment was conducted in central Poland from 1996 to 2003. Eight early and ten late ripening plum cultivars were investigated. Trees of cv. ‘Opal’ were used as a control for the early ripening plums, and ‘Stanley’ trees – for the late cultivars. Trees were grafted on two rootstocks: Myrobalan and ‘Wangenheim Prune’ seedlings. Winter hardiness, tree size, productivity and fruit quality were evaluated. The trees of all the investigated cultivars grafted on ‘Wangenheim Prune’ seedlings grew significantly weaker than those on Myrobalan. The ‘Wangenheim Prune’ seedling as a rootstock was more precocious for all the investigated plum trees and improved their productivity. The trees of ‘Krasnaja Desertnaja’, ‘Uśmiech Jesieni’ (‘The Smile of Autumn’) and ‘Vision’ grew most vigorously of all the cultivars. ‘Katinka’ and ‘Elena’ trees were the smallest of all. The trees of cv. ‘Pitestean’ were the most productive in the group of early ripening cultivars, and ‘Hanita’, ‘Amers’, ‘S 1’ and ‘President’ were the best croppers in the late ripening group of cultivars. The fruit of the cultivars: ‘Katinka’, ‘Diana’, ‘Silvia’, ‘Hanita’, ‘Amers’, ‘S 1’ and ‘Vision’ were characterized by the best taste and the highest fruit quality.