Performance of Two Apple Cultivars Grafted on 10 New Polish-Bred Rootstocks During 6-Year-Experiment

Abstract

Growth and fruiting of ‘Gloster’ and ‘Melrouge’ apple trees grafted on 10 Polish-bred rootstocks (P series) were studied during a 6-year-experiment (1991-1996). The most vigorous were trees on semidwarfing rootstocks P 1, P 14 and on M.26. The trees of both cultivars on P 16 and P 59 dwarfing rootstocks were similar in size and smaller than those grafted on standard M 9. Size of the trees on P 22 was between those on P 59 and M.9.

Trees of both cultivar on dwarfing rootstocks started to bear fruit in the second year and semi-dwarfing trees (on M.26, P 1, P 14 and P 60) started fruiting in the third year after planting. A cumulative yield over 6 years was the highest for trees of both cultivars on P 14. Of the dwarf trees, the highest cumulative yield was from those on P 2 and M.9. Yield efficiency, expressed as a yield per square cm of TCA, was the highest for both cultivars on P 16, P 2, P 22 and P 59 rootstocks and for ‘Melrouge’ also for the trees on P 14. Of the tested semi-dwarfing rootstocks the most valuable are P 14 and P 60. In the dwarfing group trees on P 2, P 16 and P 59 performed well. Pomological value of P 16 rootstock is similar to M.9 and it should be planted in a milder climate. Also promising is the very dwarfing rootstock P 59 but it requires future studies on winter hardiness.