PERFORMANCE OF EIGHT SEMI-DWARF APPLE ROOTSTOCKS AT THREE APPLE GROWING REGIONS IN EASTERN CANADA

This study was conducted to evaluate the performance of the apple cultivars ‘Idared’, ‘McIntosh’ (spur type clone, ‘Hartenhoff’) and ‘Fuji’ on hardy semi-dwarf rootstocks (B.490, Y.P., KSC.07, and KSC.18) in comparison to English rootstocks (AR.86-1-25, M.26, MM.106, and MM.111). The trial was conducted over a period of 5 to 10 years in three provinces of Eastern Canada (Quebec, New Brunswick and Nova Scotia). Vegetative (trunk-cross sectional area, TCA) and reproductive traits (yield, fruit size, and yield efficiency) were monitored yearly. The ranking of rootstocks from largest to smallest were KSC.07, Y.P., B.490, KSC.18, MM.106, MM.111, AR.86-1-25 and M.26, and the cultivars ‘Idared’ and ‘McIntosh’ grew larger than ‘Fuji.’ Highest yielding trees were on KSC.07 and Y.P., but only Y.P. was able to maintain good fruit size for all three cultivars over the duration of the trial. Although the objective of this trial was to find a hardy, semi-dwarf rootstock of moderate to low vigour, all hardy rootstocks were found to be larger than any of the English rootstocks.