Performance of Ten Vigorous and Semi-Vigorous Apple Rootstocks Over Ten Years in British Columbia

Abstract

A trial of ‘Macspur McIntosh’ on four seedling rootstocks (open-pollinated Antonovka, open-pollinated Haralson, Antonovka x Beautiful Arcade, Haralson x Beautiful Arcade) and six clonal rootstocks (B.118, I.48-41, M.2, M.4, M.7 and MO.56-4) was planted in 1986 to identify cold-hardy, yield-efficient apple rootstocks adapted to southern British Columbia. Spread and trunk cross-sectional area (TCA) were greatest for trees on MO.56-4 and smallest for trees on M.7. The height, spread and TCA of trees on the open-pollinated seedling rootstocks did not differ significantly, but TCA for trees on Haralson x Beautiful Arcade and Antonovka x Beautiful Arcade were smaller than on the open-pollinated seedling rootstocks. Trees on M.7 were the most precocious. Cumulative yield was high on MO.56-4, but its cumulative yield efficiency (cumulative yield/final trunk cross-sectional area) was among the lowest. Cumulative yield efficiency and canopy efficiency (cumulative yield/canopy volume over the last five years) were highest on M.7, M.4, and I.48-41. B.118 was similar to M.4 in height, spread, and TCA, but slightly lower in cumulative yield efficiency. All the seedling rootstocks were less precocious than M.7, and lower in cumulative yield efficiency than M.7 or M.4, but not M.2. Fruits from trees on Haralson x Beautiful Arcade and Antonovka x Beautiful Arcade were among the smallest. Rootstock did not affect the incidence of windfalls or the degree of bienniality of the scion. I.48-41, M.7 and open pollinated Haralson produced the most root suckers. Although yield performance was good on M.7, one of tne trees died and another was seriously injured by a winter freeze during the study. Overall, M.4, B.118 and I.48-41 appear to have the greatest potential for cold sites.