ASSESSMENT OF GROWTH AND CROPPING OF PLUM TREES GRAFTED ON ‘WANGENHEIM PRUNE ‘ ROOTSTOCK AND ORIGINATED FROM IN VITRO

ABSTRACT. Growth and cropping of plum trees both originated from in vitro (TC trees) and grafted on ‘Wangenheim Prune ’ rootstock, of seven cultivars – ‘Seneca’, ‘Čačanska Najbolia’, ‘Čačanska Rodna’, ‘Stanley’, ‘Bluefre’, ‘Valor’, ‘Oneida’, were compared. The orchard was established in the spring of 1995. Trees started fruiting in the third year after planting. The following parameters were compared: yield, trunk cross-sectional area (TCSA) and index of productivity. In the first and second year of cropping the highest yield was obtained from trees grafted on ‘Wangenheim Prune ’ rootstock, while in the third and fourth year it was provided by TC trees. Total yield of four-year cropping did not statistically differ between the TC trees and those grafted on the rootstock, but the growth of the first was greater. The productivity index (kg·cm-2) was higher for trees grafted on ‘Wangenheim Prune ’ rootstock. Key words: grafted trees, tree growth, crop, tissue culture trees 124 INTRODUCTION. One of the aims of fruit production research is obtaining a higher yield per unit area by increasing the number of trees per hectare. Tree growth can be controlled by the rootstoc