Scion/interstock/rootstock effect on sweet cherry yield, tree size and yield efficiency

Abstract Yield and trunk cross-sectional area of ‘Bing’ and ‘Chinook’ cherries were measured on four tart cherry interstocks, ‘Kansas Sweet’, ‘Northstar’, ‘Montmorency’ and ‘Redrich’, and on four rootstocks, Mahaleb 4, Mahaleb 900, F 12-1 Mazzard and New York Mazzard, over a 20-year period. Additional treatments included both scions on either mahaleb or mazzard rootstocks without interstocks. Fifty-seven percent of total mortality was associated with ‘Redrich’ interstock, with no other single treatment showing disproportionately high mortality. After 20 years, cumulative yield was highest on Mahaleb rootstocks, but there were no significant differences in cumulative yield among interstocks. Trees lacking interstocks had significantly lower cumulative yield than trees with interstocks. Trunk cross-sectional area of ‘Bing’ was smaller than ‘Chinook’, and ‘Northstar’ produced smaller trunks than other interstocks tested. However, trees without interstocks tended to have smaller trunks than those with interstocks, although not significantly smaller than those with ‘Northstar’ interstocks. Trunk cross-sectional area was not affected by rootstock. Yield efficiency of ‘Bing’/‘Northstar’/Mahaleb 4 was the highest of the combinations tested.