The Growth and Yields of Eight Plum Cultivars Grafted on Two Rootstocks in Central Poland

The pomological values of eight different plum cultivars (Prunus domestica L.): 'Renklod Haritonowoj', 'Valcean', 'Jubileum', 'Felsina', 'V72333', 'Yellow Afaska', 'President' and 'Record' were evaluated. The field experiment was set up in spring of 2004, in the Experimental Orchard in Dabrowice (central Poland). Trees were grown on two generative rootstocks: Myrobalan and 'Wangenheim Prune' seedlings. Assessments of tree growth, yields, fruit quality and susceptibility to diseases and to frost of the plum cultivars were the aims of investigations. The trees of the cultivars: 'Record' and 'Renklod Haritonowoj' grafted on Myrobalan seedlings grew most vigorously in first years after planting. Growth of the trees of all cultivars grafted on 'Wangenheim Prune' seedling was about 20-50% weaker than on Myrobalan. Healthy status of trees was good. Symptoms of PPV appeared on single trees of the cultivars: 'Jubileum', 'Valcean' and 'Record'. The biggest yields were harvested from the trees of: 'Felsina' and 'President', grafted on 'Wangenheim Prune' seedling, and the smallest from the trees of the 'Valcean' cultivar grafted on Myrobalan seedlings. Crops so far have been small because of the young age of the trees, and they were also affected by spring frosts in 2007. The damages to floral buds by spring frosts were different, depending on the cultivar. The buds of 'Felsina' were not so sensitive to low temperatures. The most severe frost injuries (100% buds) were observed on the trees of the two early cultivars: 'Valcean' and 'Renklod Haritonowoj'.